Difference between revisions of "Category:712 Structural Steel Construction"

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|[http://library.modot.mo.gov/RDT/reports/Ri97003/RDT99004.pdf Report 1999]
 
|[http://library.modot.mo.gov/RDT/reports/Ri97003/RDT99004.pdf Report 1999]
 
|-
 
|-
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|'''See also:''' [http://www.modot.gov/services/OR/byDate.htm Innovation Library]
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|'''See also:''' [https://www.modot.org/research-publications Research Publications]
 
|}
 
|}
 
{|style="padding: 0.3em; margin-left:15px; border:1px solid #a9a9a9; text-align:center; font-size: 95%; background:#f5f5f5" width="160px" align="right"  
 
{|style="padding: 0.3em; margin-left:15px; border:1px solid #a9a9a9; text-align:center; font-size: 95%; background:#f5f5f5" width="160px" align="right"  
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|'''Approved Products'''
 
|'''Approved Products'''
 
|-
 
|-
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|[http://modot.mo.gov/business/materials/pdf/vol_1/FS0712T1.pdf Qualified Protective Coatings for Machined Finished Surfaces]
+
|[https://www.modot.org/media/465 Qualified Protective Coatings for Machined Finished Surfaces]
 
|}
 
|}
  
  
 
==712.1 Construction Inspection for Sec 712==
 
==712.1 Construction Inspection for Sec 712==
−
The important feature of structural steel inspection include such items as:
+
The important feature of structural steel inspection includes such items as:
 
:(a) inspection of handling, unloading, storing, and erecting of the various members to make sure they are not subjected to excessive stress
 
:(a) inspection of handling, unloading, storing, and erecting of the various members to make sure they are not subjected to excessive stress
 
:(b) erection with proper camber, adequately supported
 
:(b) erection with proper camber, adequately supported
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Successful structural steel erection work will directly relate to skill of the workmen and thoroughness of the inspector. Welders must be qualified by passing required tests. Even though no tests are required for the bolting crew, the inspector has authority to insist that an experienced crew be used.
 
Successful structural steel erection work will directly relate to skill of the workmen and thoroughness of the inspector. Welders must be qualified by passing required tests. Even though no tests are required for the bolting crew, the inspector has authority to insist that an experienced crew be used.
  
−
Fabrication Inspection Reports for structural steel and other metal products such as hand rail and similar fabrication are made by the Bridge Division shop inspector. Copies of this report are mailed to the resident engineer. The inspector should examine the report and study the remarks section. When steel arrives, check it against the list of corrections required of the fabricator, as noted on the report. The shop inspector often depends on field inspection to assure that shop corrections were made prior to shipment. Should material arrive with corrections not made, the inspector should immediately inform the contractor that material will not be accepted until corrections are completed.
+
Fabrication Inspection Shipment Releases (FISRs) for structural steel and other metal products on structures such as decorative fences and similar steel fabrications are issued by the Bridge Division Fabrication Section inspector. These FISRs are issued by email to the fabricator and the Resident Engineer. The fabricator shall send these FISRs to the contractor. Refer to [[:Category:1080 Structural Steel Fabrication|EPG 1080 Structural Steel Fabrication]] for more information regarding fabrication inspection shipment releases.
−
 
 
−
A sample of the fabrication inspection report, Form B-708R2, is shown:
 
−
 
 
−
[[Image:712 Fabrication Inspection Report.gif|center|thumb|600px]]
 
−
 
 
−
Steel shipments should also be accompanied by a Fabrication Inspection Shipment Release form issued by the Bridge Division.
 
  
 
===712.1.1 Expansion Joints===
 
===712.1.1 Expansion Joints===
Line 89: Line 83:
  
 
===712.1.4 Welding===
 
===712.1.4 Welding===
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Project personnel are frequently asked to conduct tests for field qualification of welders. The [[Media:712 Welder Qualification Test Details.pdf|Welder Qualification Test Details]] provide instructions to inspectors as to how specimens should be prepared for various test positions:
+
====712.1.4.1 Field Welding====
 
{|style="padding: 0.3em; margin-right:20px; border:2px solid #a9a9a9; text-align:center; font-size: 95%; background:#f5f5f5" width="260px" align="right"  
 
{|style="padding: 0.3em; margin-right:20px; border:2px solid #a9a9a9; text-align:center; font-size: 95%; background:#f5f5f5" width="260px" align="right"  
 
|-
 
|-
 
|[[media:712.1.4 welding safety tips.pdf|<center>'''Welding Safety Tips'''</center>]]
 
|[[media:712.1.4 welding safety tips.pdf|<center>'''Welding Safety Tips'''</center>]]
 
|}
 
|}
−
Current specifications allow welders to be qualified by an established facility with an accredited AWS certified welder program as defined in AWS Standard QC 4-89.
 
  
−
Test specimens are to be submitted to the Construction and Materials Division laboratory. [[media:712 Form B-711.gif|Form B-711]] must be submitted by the testing inspector. At the option and expense of the contractor the test specimens may be submitted to an approved testing laboratory for radiographic testing. The radiograph film will then be submitted to the engineer for approval.
+
=====712.1.4.1.1 Field Welder Cards=====
 +
Specifications require that field welders shall be certified by an established facility with an accredited American Welding Society (AWS) certification program defined in the current AWS Standard QC4. Welders shall be certified per the current QC7 Standard for AWS Certified Welders. The code of acceptance shall be in accordance with [https://www.modot.org/missouri-standard-specifications-highway-construction Sec 1080.3.3.4 Applicable Codes]. Welders who have successfully completed the certification program will be issued an AWS Welder Card. AWS also has an agreement with the Ironworkers Union that allows them to be accredited test facilities for Ironworkers Union members that meet the same requirements of QC4 and QC7. A copy of the AWS Welder card and the Ironworkers Union card are shown:
 +
[[image:712.1.4.1.1.jpg|center|875px]]
 +
 
 +
The AWS website has a link that provides guidance on interpreting the information that is shown on the back of the cards furnished by both AWS and the Ironworkers Union.  A [https://www.aws.org/certification/onlinecertificationverification link to the AWS website that provides both locations of accredited test facilities (ATF) and interpretation of the welder card information] is available.
  
−
After the welder has completed the test and before samples are submitted for testing, samples should be subjected to visual inspection by the resident engineer, or by a competent inspector other than the one who supervised the test. If samples are obviously faulty, qualification should be denied at the District Level, and the samples should not be submitted to the laboratory.
+
AWS certification shall be considered in effect indefinitely provided that the welder remains active in the process that they are qualified for without an interruption greater than six months and there is no specific reason to question the welder’s ability to produce quality welds.  Certification maintenance is the responsibility of the welder and shall be presented to the engineer upon request.  The welder shall present a copy of their AWS or Ironworkers Union card to the engineer prior to welding.  Welders that have tested within six months of welding on a project may have a temporary certification letter provided by the test facility that may be used while the card is being produced. Certification maintenance shall be in accordance with AWS QC7 and the supplement QC7G.  Questions regarding the validity of temporary cards may be directed to the Construction and Materials Division.
  
−
If weld specimens are found to be satisfactory, a card is issued to the applicant listing the positions and types of material for which qualification is granted. The card is signed by the
+
If the engineer has reason to question the ability of the welder, a retest should be requested. Retests shall be conducted by an AWS accredited test facility.
−
Bridge Engineer. This card expires on a specified date but may be renewed by the holder by applying to the Bridge Division with supporting evidence that there has been no interruption greater than three months in the applicants welding in the position for which qualified, and further establishing that the applicant has worked on a project under Missouri Department of Transportation inspection during the preceding twelve months.
 
  
−
Should the applicant fail the test, a retest is granted only if extenuating circumstances exist. Any circumstance surrounding the test which in the opinion of the inspector could have a
+
=====712.1.4.1.2 Field Welding Minimum Certifications=====
−
direct adverse influence on the results should be noted on [[media:712 Form B-711.gif|Form B-711]] which accompanies test specimens to the laboratory. The Bridge Division will consider these circumstances in determining whether a retest will be permitted.
 
  
−
A welder who fails his first test and is not granted a retest must wait six months before trying again to qualify. A retest will be administered then only if proof is furnished of further training or practice. Any welder granted a retest must then submit four specimens representing two test welds for each type that failed.
+
For inspection purposes some of the specific types of work and the minimum required position certification are as shown in the following table:
 +
<center>
 +
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
 +
|+
 +
! width="350" style="background:#BEBEBE" |Type of Work!! style="background:#BEBEBE" |Required Position Certification
 +
|-
 +
|Steel Pile Splices (HP & Shell Piles) ||2G
 +
|-
 +
|Steel Pile Points (HP & Shell Piles)|| 2G
 +
|-
 +
|Stay-in-Place Form Support Angles ||None
 +
|-
 +
|Girder/Beam Flanges to Bearing Plates|| 2G
 +
|-
 +
|Stiffeners ||3G
 +
|-
 +
|Anything else not listed ||3G unless otherwise specified by the Engineer.
 +
|}
 +
</center>
 +
A welder qualified for one position also qualifies for performing other welds as shown in the following table:
 +
<center>
 +
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
 +
|+
 +
! width="350" style="background:#BEBEBE" |Certified Position!! style="background:#BEBEBE" |Qualified to Perform
 +
|-
 +
|1G|| 1F, 2F, 1G
 +
|-
 +
|2G|| 1F, 2F, 1G, 2G
 +
|-
 +
|3G|| 1F, 2F, 3F, 1G, 2G, 3G
 +
|-
 +
|4G|| 1F, 2F, 4F, 1G, 4G
 +
|-
 +
|3G & 4G|| All Groove and Fillet Positions
 +
|-
 +
|1F|| 1F
 +
|-
 +
|2F|| 1F, 2F
 +
|-
 +
|3F|| 1F, 2F, 3F
 +
|-
 +
|4F|| 1F, 2F, 4F
 +
|-
 +
|3F & 4F|| All Fillet Positions
 +
|-
 +
|align="left" colspan="2"|KEY: 1=flat, 2=horizontal, 3=vertical, 4=overhead, G=groove, F=fillet
 +
|}
 +
</center>
 +
Examples of the weld positions for groove welds and fillet welds are as follows:
 +
 +
[[image:712.1.4.1.2.jpg|center|900px]]
 +
 
 +
In most cases, a welder may elect to take one of two test plate thicknesses.  A limited thickness test will be taken on a 3/8 in. test plate.  This will qualify a welder for groove welds of a maximum plate thickness of 3/4 in. and fillet welds on plates of unlimited thickness.  An unlimited thickness test will be taken on a 1 in. thick plate and qualifies the welder for unlimited plate thickness for both groove welds and fillet welds.  The welder’s card that is to be presented at the job site will show both the test plate thickness as well as the plate thickness limitations.
 +
 
 +
=====712.1.4.1.3 Shear Connector Welding=====
 +
 
 +
Current practices by the contractor may utilize the installation of shear connectors by field personnel. Most shear connector welding is completed by an automated welding process. AWS does not have a qualification procedure established in QC7. Instead, welders shall be qualified in accordance with 2002 AWS Bridge Welding Code D1.5 Clause 7.7 by MoDOT field personnel. Shear connector welders shall be qualified by conducting a preproduction test. This test involves the welder welding two shear connectors to a test plate or to the production plate. The test specimens shall be visually inspected to ensure a full 360° weld. After the welds have cooled, the shear connectors shall then be bent to an angle of approximately 30° from the original axis by either striking with a hammer or placing a pipe over the shear connector and then bending. If the shear connector does not exhibit a complete weld or a failure occurs in the weld of either shear connector, the welder shall adjust the automatic welding machine and retest on a separate weld test plate. The welder may not retest on the actual production plate.
 +
 
 +
Before shear connector production welding in the field begins with a particular welder set-up, a specific shear connector size or type, and at the beginning of production for a particular shift or day, a preproduction test shall be conducted.  The preproduction test shall be conducted on the first two shear connectors welded to the production plate or may be conducted on a separate test plate of the same thickness (+/- 25%).  The acceptance method is the same as given earlier for the welder test.
  
−
The inspector should carefully examine all test specimens and be sure they are cut to exact size. He should list the electrodes by their AWS-ASTM classification number and not by trade name. The inspector should check the box from which the electrode is taken to determine the
+
Once shear connector production welding has commenced, any welds that do not exhibit the full 360° weld may be repaired using a 5/16 in. fillet weld for shear connector diameters up to one inch and 3/8 in. for diameters greater than one inch. The repair weld shall extend 3/8 in. beyond the end of the area to be repaired.
−
classification number.
 
  
−
Each project office is expected to submit [[media:712 Welder Qualification Report.gif|Welder Qualification Reports]] on welders actively engaged on projects under their supervision at completion of the welders employment on the work. Any additional information which might affect the decision and grant renewal of the card should be shown under the remarks. Unsatisfactory workmanship will be considered cause for cancellation of the welder’s qualification card and a requirement that the welder requalify by test.
+
Additional verification of shear connector welds in the field will be performed by sounding a random 25% of the shear connectors on the girder/beam with a sledge hammer. The field inspector will also sound 25 percent of the shear connectors used on expansion device(s) whether shop or field installed.  A sharp ping sound is heard on a good weld. A thud sound will occur if the weld is possibly not sufficient and a bent test needs to be performed on this shear connector.  A random 5% of all shear connectors will be bent to an approximately 30° from the original axes to verify the integrity and welding of the shear connector. If a failed weld is discovered, all adjacent connectors shall be tested. Particular emphasis on testing shall be at the start-up of the welding operation. Once an acceptable welding process is established, any weld failures should be rare. For a large bridge with many shear connectors, the 5% testing rate may be decreased at the engineer’s discretion. Any failed welds shall be ground off, base metal pull outs repaired by approved weld procedures, weld surface ground flush and a replacement shear stud installed.
  
−
The dates covering the entire period of welding should be shown. If welding was intermittent or represented only a small part of the time period, this should be noted in the remarks column, along with an estimate of the percentage of the time period when welding was actually done.
+
On a re-deck project, some shear connectors may be bent from the deck removal or from the original construction testing. These shear connectors do not have to be replaced or straightened. Shear connectors on new or re-deck projects may also need to be field bent to accommodate expansion joints, rebar conflicts or other construction needs. If a shear connector is severely bent where concrete coverage is compromised, the shear connector shall be removed and replaced.
  
−
If project personnel consider the welder’s performance to be marginal to the degree that they feel retesting for qualification is desirable, they should indicate the reasons for the recommendation under remarks. Typical would be "high percentage of welds failed X-Ray inspection", or "excessive undercutting", or reference to other specific defects which occur with excessive frequency.
+
[[image:712.1.4.1.3.jpg|center|600px]]
  
−
The completed [[media:712 Welder Qualification Report.gif|Welder Qualification Reports]] should be sent to the State Bridge Engineer for each welder on the project fifteen days prior to the expiration date on the welders qualification card, or at the expiration of his work on the project, whichever is earlier. Where renewal occurs during the active work, it will be necessary to submit a second report covering the period from renewal date to completion of work. Such reports should be identified under remarks "supplemental - subsequent to renewal on "Date"."
+
=====712.1.4.1.4 Acceptable Field Welding Processes=====
 +
All field welding using flux cored arc welding (FCAW) shall require welding procedures be submitted to the Bridge Division  ([mailto:Fabrication@modot.mo.gov Fabrication@modot.mo.gov]) for acceptance prior to any welding on any bridge.  All field welding using shielded metal arc welding (SMAW or commonly known as stick welding) shall require welding procedures be submitted to Bridge Division ([mailto:Fabrication@modot.mo.gov Fabrication@modot.mo.gov]) for acceptance prior to any welding on major bridges (total length ≥ 1000 feet), bridges with structural steel with  f<sub>y</sub> ≥ 70,000 psi (f<sub>s</sub> ≥ 38,000 psi), truss bridges, bridges with 2 girder systems and bridges containing fracture critical members (FCM). All other locations with SMAW, the contractor shall have field welding procedures on file prior to welding and available at the engineer’s request.
  
−
The welder’s request for renewal is to be made directly to the State Bridge Engineer. Action on the request will be based on the record developed from the welder’s qualification report on file.
+
MoDOT permits only two specific welding processes for field welding on steel bridges. These processes are SMAW and FCAW. The preferred method for field welding is SMAW. SMAW on structural steel (f<sub>y</sub> < 69,000 psi, f<sub>s</sub> < 37,000 psi) that will be coated are to be welded with E7018, low hydrogen electrodes. SMAW on uncoated (weathering) structural steel (f<sub>y</sub> < 69,000 psi, f<sub>s</sub> < 37,000 psi) are to be welded with E8018, low hydrogen weathering steel electrodes. Welding on structural steel with f<sub>y</sub> ≥ 70,000 psi (f<sub>s</sub> ≥ 38,000 psi) and fracture critical members (FCM) are to be determined by weld procedures which shall be submitted to the Bridge Division ([mailto:Fabrication@modot.mo.gov Fabrication@modot.mo.gov]). FCAW always require welding procedures be submitted to Bridge Division since the welding code requires procedure qualification record (PQR) for the welding procedures. FCAW on structural steel is preferred to be completed with a self-shielded process where no shielding gas is used. This will be noted on the welder’s card as FCAW-S. Gas shielding for FCAW is discouraged due to the additional requirements to provide protection of the weld area from gas dispersion caused by the wind but FCAW can be used provided the weld area is shielded properly from wind.  
  
−
Shear connectors are generally installed in the field by welding. The inspector is responsible
+
Welding of aluminum products in the field may be completed using gas metal arc welding (GMAW or commonly known as MIG welding) or with SMAW with special aluminum electrodes.  Like FCAW welding using gas shielding, the weld area must be protected to prevent shielding gas dispersion when welding with GMAW.  GMAW is the preferred method of welding aluminum by AWS. However, SMAW may be used provided that special care is taken during welding to control the welding parameters and that all welding slag is removed.
−
for qualifying the contractor’s procedure and operators as specified in [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.3.4.1].
 
  
−
For non-stress welding such as pile caps, angles and channel bracing, and similar welding, and for welding pile splices, it is intended that welders who are not pre-qualified be required to
+
====712.1.4.2 Shop Welding====
−
demonstrate their competence as a welder. The operator should be required to make a weld on the
+
Fabrication shops shall qualify welders in accordance with the governing welding code for the specific process as required in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=14 Sec 1080.3.3.4].  It is the responsibility of the fabrication shop’s quality control personnel to ensure that the welder’s test documentation and period of effectiveness are documented and maintained.
−
job in the position in which plan welds are to be made. This weld should be examined for contour, under-cutting, smoothness, and slag pockets, then be broken from the root side in a vice by use of a sledge hammer, and the weld examined for root penetration. [[media:712 Form B-711.gif|Form B-711]] can be filled out for project records with one copy sent to the district office and one to the Bridge Division.
 
  
−
Detailed instructions concerning welding and weld qualification tests are to be found in
+
===712.1.5 High Strength Bolts (Sec 712.7)===
−
the welders inspection manual published by AWS. Copies have been furnished to each district.
 
  
−
The period of effectiveness for field welder cards is three years. During the period of effectiveness, the field welder will be required to weld on a minimum of one MoDOT project during each year of the time period. For example, a field welder receives a card effective from January 2004 to January 2007, as a minimum, the welder must weld on one project in 2004, one project in 2005 and one project in 2006 in order to renew their card. The Resident Engineer, or designee, should still complete the "MoDOT Welder Qualification Report" each time a welder welds on a project and should provide a copy to the welder and the Bridge Division.
+
Bolts, nuts, and washers must meet applicable requirements of AASHTO as noted in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=14 Sec 1080.2]. ASTM F3125 Grade A325 bolts shall be used on bridge connections unless other types of bolts are specified in the contract. To facilitate easy identification of high strength bolts, the following figure shows some of the typical bolt markings required by the ASTM specification.
  
−
===712.1.5 High Strength Bolts And Washers (Sec 712.7)===
+
<center>
−
[[image:712.1.5.jpg|right|275px]]
+
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
 +
|+
 +
!  style="background:#BEBEBE" |Bolt/Nut!! style="background:#BEBEBE" colspan="2" |Type 1 (Plain or Galvanized)!! style="background:#BEBEBE" colspan="2"|Type 3 (Weathering)
 +
|-
 +
|'''ASTM F3125 Grade A325''' ||colspan="2" style="background:#FFFFFF"|[[image:712.1.5 A325.jpg|70px]]<br/>Three radial lines 120°<br/>Apart are optional||colspan="2" style="background:#FFFFFF"| [[image:712.1.5 A325 line.jpg|70px]]
 +
|-
 +
|'''ASTM F3125 Grade A490''' ||colspan="2" style="background:#FFFFFF"|[[image:712.1.5 A490.jpg|70px]] ||colspan="2" style="background:#FFFFFF"|[[image:712.1.5 A490 line.jpg|70px]]
 +
|-
 +
|rowspan="6" valign="center"|'''ASTM A563 Nuts''' ||'''Type 1<br/>Plain '''|| '''Type 1<br/>Galvanized'''||colspan="2"| '''Type 3<br/>Plain'''
 +
|-
 +
|style="background:#FFFFFF"|[[image:712.1.5 XYZ.jpg|70px]]<br/>Arcs Indicate<br/>Grade C<br/>(Grade A325 bolt) ||style="background:#FFFFFF"|  ||style="background:#FFFFFF"|  ||style="background:#FFFFFF"|
 +
|-
 +
|style="background:#FFFFFF"|[[image:712.1.5 XYZ3.jpg|70px]]<br/>Arcs with “3”<br/>Indicate<br/>Grade C3<br/>(Grade A325 bolt) ||style="background:#FFFFFF"| ||style="background:#FFFFFF"|[[image:712.1.5 XYZ.jpg|70px]]<br/>Arcs with “3”<br/>Indicate<br/>Grade C3<br/>(Grade A325 bolt) ||style="background:#FFFFFF"|
 +
|-
 +
|style="background:#FFFFFF"|[[image:712.1.5 XYZD.jpg|70px]]<br/>Grade D<br/>(Grade A325 bolt) ||style="background:#FFFFFF"|  ||style="background:#FFFFFF"|  ||style="background:#FFFFFF"|
 +
|-
 +
|style="background:#FFFFFF"|[[image:712.1.5 XYZDH.jpg|70px]]<br/>Grade DH<br/>(Grade A325 bolt and<br/>Grade A490 bolt)||style="background:#FFFFFF"|[[image:712.1.5 XYZDH.jpg|70px]]<br/>Grade DH<br/>(Grade A325<br/>bolt)  ||style="background:#FFFFFF"|[[image:712.1.5 XYZDH3.jpg|70px]]<br/>Grade DH3<br/>(Grade A325<br/>bolt) ||style="background:#FFFFFF"|[[image:712.1.5 XYZDH3.jpg|70px]]<br/>Grade DH3<br/>(Grade A490<br/>bolt)
 +
|-
 +
|style="background:#FFFFFF"|[[image:712.1.5 XYZDH3.jpg|70px]]<br/>Grade DH3<br/>(Grade A325bolt and<br/>Grade A490 bolt)||style="background:#FFFFFF"|  ||style="background:#FFFFFF"|  ||style="background:#FFFFFF"|
 +
|}
 +
</center>
 +
::(Reprinted and modified from AISC Steel Construction Manual, 15th Ed., Table 2.1 and Figure C-2.1).
 +
::Note: XYZ represents the manufacturer’s identification mark.
  
−
Bolts, nuts, and washers must meet applicable requirements of ASTM as noted in [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.7.3] illustrates typical dimensions and markings for high strength bolts and nuts. ASTM permits elimination of the three radial lines on the head of heavy hexagon structural bolts if the required A325 mark is present. Markings on the nut may be either raised or depressed, bolt heads must also carry a mark to identify the manufacturer.
+
A permissible alternate type of nut may be furnished. Such nuts would be marked with the symbol 2 or 2H and the manufacturer's symbol.  
  
−
A permissible alternate type of nut may be furnished. Such nuts would be marked with the symbol 2 or 2H and the manufacturer's symbol.
+
Bolts tightened by the calibrated wrench or turn-of-nut method should be checked following the procedures outlined in the Standard Specifications.  
  
−
Bolts tightened by the calibrated wrench or turn-of-nut method should be checked following the procedures outlined in the Standard Specifications.
+
The sides of bolt heads and nuts tightened with an impact wrench will appear slightly peened. This will indicate that the wrench has been applied to the fastener.  
  
−
The sides of bolt heads and nuts tightened with an impact wrench will appear slightly peened. This will indicate that the wrench has been applied to the fastener.
+
====712.1.5.1 Bolted Parts ====
  
−
====712.1.5.1 Bolted Parts (Sec 712.7.1)====
+
[http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 712.7.1] covers cleaning of parts to be bolted. Bolts, nuts, and washers will normally be received with a light residual coating of lubricant. This coating is not considered detrimental to friction type connections and need not be removed. If bolts are received with a heavy coating of preservative, it must be removed. A light residual coating of lubricant may be applied or allowed to remain in the bolt threads, but not to such an extent as to run down between the washer and bolted parts and into the interfaces between parts being assembled.  
−
[http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.7.1] covers cleaning of parts to be bolted. Bolts, nuts, and washers will normally be received with a light residual coating of lubricant. This coating is not considered detrimental to friction type connections and need not be removed. If bolts are received with a heavy coating of preservative, it must be removed. A light residual coating of lubricant may be applied or allowed to remain in the bolt threads, but not to such an extent as to run down between the washer and bolted parts and into the interfaces between parts being assembled.
 
  
 
====712.1.5.2 Bolt Tension====
 
====712.1.5.2 Bolt Tension====
−
A washer is required under nut or bolt head, whichever is turned in tightening, to prevent galling between nut or bolt head and the surface against which the head or nut would turn in tightening, and to minimize irregularities in the torque-tension ratio where bolts are tightened by calibrated wrench method. It is also required under finished nuts and the heads of regular semifinished hexagon bolts against the possibility of some reduction in bearing area due to field reaming.
 
  
−
Standard Specifications require that bolt torque and impact wrenches be calibrated by means of a device capable of measuring actual tension produced by a given wrench effort applied to a representative sample. Current specifications require power wrenches to be set to induce a bolt tension 5 percent to 10 percent in excess of specified values but the Special Provisions for the project should be checked for a possible revision to this requirement.
+
A washer is required under nut or bolt head, whichever is turned in tightening, to prevent galling between nut or bolt head and the surface against which the head or nut would turn in tightening, and to minimize irregularities in the torque-tension ratio where bolts are tightened by calibrated wrench method. Washers are also required under finished nuts and the heads of regular semi-finished hexagon bolts against the possibility of some reduction in bearing area due to field reaming. When oversized holes are used as permitted by the contract, a washer shall be placed under both the bolt head and the nut.
 +
 
 +
Standard Specifications require that bolt torque and impact wrenches be calibrated by means of a device capable of measuring actual tension produced by a given wrench effort applied to a representative sample. Current specifications require power wrenches to be set to induce a bolt tension 5 percent to 10 percent in excess of specified values but the Special Provisions for the project should be checked for a possible revision to this requirement.
 +
 
 +
The contractor is required to furnish a device capable of indicating actual bolt tension for the calibration of wrenches or load indicating device. A certification indicating recent calibration of the device should accompany it. It is recommended that the certification of calibration be within the past year but if the device is being used with satisfactory results, the period may be extended. More frequent calibration may be necessary if the device receives heavy use over an extended period.
 +
 
 +
The contractor will generally use either the calibrated wrench method or the turn-of-nut method for tightening bolts as outlined in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 712.7]. The sides of bolt heads or nuts tightened with an impact wrench will appear slightly peened.  This will usually indicate that the wrench has been applied to the fastener.  If the wrench damages the galvanized coating, the contractor shall repair the coating by an acceptable method.
 +
 
 +
====712.1.5.3 Rotational-Capacity Testing and Installation of ASTM F3125 Grade A325 Type 3 Bolts====
 +
 
 +
Type 3 (weathering steel) bolts behave quite differently than the galvanized bolts used in most MoDOT structures and require additional care to test and install properly. 
 +
 
 +
The contractor '''must''' keep bolts stored in sealed kegs out of the elements until ready for use.  Storage in a warehouse, shed, shipping container or other weatherproof building is best.  The lubricant used on Type 3 bolts dissipates quickly, allowing rust to begin.  Kegs should not be opened until absolutely necessary and promptly resealed whenever work stops.
 +
 
 +
If bolts fail the rotational-capacity test, insufficient lubrication is the most likely cause. Relubrication of Grade A325 bolts is allowed. Several different waxes and lubricants are suggested by FHWA, including Castrol 140 Stick Wax (which has been successfully field tested by MoDOT), Castrol Safety-Film 639, MacDermid Torque’N Tension Control Fluid, beeswax, etc.
 +
 
 +
Galling of the washer may occur, especially with longer bolts. This can be reduced by lubricating the contact area of the bolt face at the washer with an approved lubricant. If this face is lubricated for testing, it must also be lubricated during bolt installation.
 +
 
 +
Failure of the bolts due to galling of the washer can also be prevented by turning the nut in one continuous motion during testing.  For larger diameter bolts, this can be a problem.  Torque multipliers amplify this effect.  If many larger diameter bolts will be tested, ask the contractor to purchase an electric gear reduction wrench with reaction arm.  The Skidmore will need to have a reaction kit installed.  This wrench will produce better results and save time spent performing tests (and, therefore, lower costs).
  
−
The contractor is required to furnish a device capable of indicating actual bolt tension for the calibration of wrenches or load indicating device. A certification indicating recent calibration of the device should accompany it. It is recommended that the certification of calibration be within the past year but if the device is being used with satisfactory results, the period may be extended. More frequent calibration may be necessary if the device receives heavy use over an extended period.
+
For long bolts, (L>8d), use proper spacer bushings on the back of the Skidmore to avoid excessive use of spacers between the washer and front plate of the Skidmore. Stacking spacers can cause bending of long bolts, which will cause inaccurate results, false failures and potential damage to the Skidmore. Consult the Skidmore user manual for maximum allowable spacer lengths.
  
−
The contractor has the option of using the calibrated wrench method or the turn-of-nut method for tightening bolts. The turn of the nut is from a snug tight position, which is somewhat tighter than the finger-tight position. This necessitates that the joint must be first drawn tightly together by use of temporary erection bolts.
+
====712.1.5.4 Bolt Testing and Verification====
  
−
===712.1.6 Painting===
+
Bridges are designed so that many of the steel-to-steel connections that are made in the field are slip-critical connections.  Slip-critical means that once the bolt is tightened, the bolt and the pieces of steel (or plies) will not move. It relies on the bolt to clamp down on the steel and create so much force between the steel plates that they will not move at all.  Should they slip and move it would be a critical issue for the bridge.
−
Painting of structural steel items, other than inaccessible areas, is usually, but not always, the final item of work performed on bridges. A notable exception is when the contract requires application of a shop coat of paint. Since the paint film is the sole protection of the steel from oxidation and corrosion due to exposure to the elements, it is extremely important that cleaning of steel and application of paint be properly done.
 
  
−
====712.1.6.1 Paint Systems====
+
When it comes to bolt design, the bolt is being tensioned in order to establish the clamping force needed. The tightening of the nut on the bolt is what produces the needed tension.  Bridge Designers will design each of these joints based on established minimums for each bolt size. So, for example, a Bridge Designer will assume that an ASTM F3125 Grade A325 7/8” diameter bolt will be able to supply 39,000 pounds of clamping force.  This means that the contractor in the field must ensure that they are tightening each bolt to this tension.
−
All structural steel shall be painted by one of the systems set out in Section 1081 of the Standard Specifications. The required system or a choice of systems will be specified in the contract.
 
  
−
Magnetic type gauges are used to measure the dry film thickness. Instructions for measuring film thickness are included with the gauges.
+
In order to verify that the bolts are installed correctly in the field, it is essential that contractors and inspectors understand the requirements of bolted connections, and the specifications that govern them.  For this work, [https://www.modot.org/missouri-standard-specifications-highway-construction Sec 712 Structural Steel Connection and Sec 1080 Structural Steel Fabrication] will primarily be consulted.
  
−
====712.1.6.2 Surface Preparation====
+
The general steps are:
−
Surfaces to be painted shall be blast cleaned with abrasives producing the nominal height of profile required by the specifications or special provisions. The blast cleaned surface shall be
+
::[[#712.1.5.4.1 Step 1, Determine Bolt Type|Step 1, Determine Bolt Type]]
−
completely free of all oil, grease, dirt, rust, millscale, and other foreign matter except that light shadows, streaks, or slight discolorations caused by rust stain or mill scale oxides, or slight, tight residues may remain. [http://modot.mo.gov/business/standards_and_specs/Sec1081.pdf Sec 1081.3.2.1] lists pictorial surface preparation standards for comparison purposes.
+
::[[#712.1.5.4.2 Step 2, Inspection Type Selection|Step 2, Inspection Type Selection]]
 +
::[[#712.1.5.4.3 Step 3, Rotational Capacity|Step 3, Rotational Capacity Test]]
 +
::[[#712.1.5.4.4 Step 4, Installation|Step 4, Installation]]
 +
::[[#712.1.5.4.5 Step 5, Bolt Verification|Step 5, Bolt Verification]]
  
−
The residue left after blast cleaning operations should be removed with clean brushes, blown off with compressed air or cleaned by vacuum. The blast cleaned surfaces should be given a prime coat of paint within 24 hours after cleaning or before rust forms on the surface. All rusted, damaged, or unpainted areas, including nuts and bolts, to be primed in the field shall be cleaned to the same degree as specified for the applicable paint system.
+
=====712.1.5.4.1 Step 1, Determine Bolt Type=====
  
−
Abrasive blasting or other removal methods create dust and debris that must be contained to prevent environmental contamination. A containment system should prevent lead from being released onto the jobsite, provide ventilation, and allow convenient work access. A containment
+
The first step is to review the contractor’s submittals to see what kind of bolts they will be using.  You can also look at the bolts in the field to check for the bolt type.  Table 712.1.5.4.1 shows what is on the hex head of the bolt, and how the markings can show what type of bolt it is.
−
system may consist of tarps, wind screens or solid panel arrangements, and incorporate funnels or vacuum systems to collect abrasive, dust, and debris.
+
<center>
 +
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
 +
|+ '''Table 712.1.5.4.1'''
 +
!  style="background:#BEBEBE" |Bolt/Nut!! style="background:#BEBEBE" colspan="2" |Type 1 (Plain or Galvanized)!! style="background:#BEBEBE" colspan="2"|Type 3 (Weathering)
 +
|-
 +
|'''ASTM F3125 Grade A325''' ||colspan="2" style="background:#FFFFFF"|[[image:712.1.5 A325.jpg|70px]]<br/>Three radial lines 120°<br/>Apart are optional||colspan="2" style="background:#FFFFFF"| [[image:712.1.5 A325 line.jpg|70px]]
 +
|-
 +
|'''ASTM F3125 Grade A490''' ||colspan="2" style="background:#FFFFFF"|[[image:712.1.5 A490.jpg|70px]] ||colspan="2" style="background:#FFFFFF"|[[image:712.1.5 A490 line.jpg|70px]]
 +
|}
 +
</center>
  
−
Containment systems designed to prevent environmental releases increase the potential for worker exposure, which is regulated under Occupational Safety and Health Administration Construction Industry Standards. Respirators are furnished our inspectors for use in a containment structure. Protective clothing (disposable coveralls) should also be furnished to our inspectors. Inspectors should also have blood lead levels checked periodically.
+
Below is a section from ASTM F3125 that governs the testing requirements for these types of high-strength bolts.  The text shown is a portion of the test method that deals with lot control.  It is an expectation of the standard that not only are all high-strength bolts produced meeting the material properties specified, but the manufacturer also must produce these bolts with a specific tracking procedure that reduces groups of bolts into lots. The lots are a set of bolts that are represented by material tests to prove they meet requirements. Each of these sets of bolts are tracked with paperwork and lot identification numbers.  Not only are the bolts produced this way, but also all the nuts and washers have specific lots assigned.  When a bolt, nut, and washer are put together and sold together, they are referred to as an assembly. Once one piece of the assembly changes, the properties of the bolt could potentially have been changed.
  
−
====712.1.6.3 Shop Coating====
+
[[image:712.1.5.4.1 A325.jpg|center|800px]]
−
Inspection of shop painting is usually done by personnel from the Construction and Materials Division. The contractor is responsible for field touch-up of shop applied paint, including damaged areas and areas masked in the shop. The touch-up field coat should be made with the same type paint used for the shop coat.
 
  
−
====712.1.6.4 Field Coating====
+
Figure 712.1.5.4.1.1 and 712.1.5.4.1.2 below are of bolt heads to show different types and Figure 712.1.5.4.1.3 shows a copy of common shipping form that provides testing verification of the bolts.
−
Field paint, except for touchup painting and painting inaccessible surfaces should not be
 
−
applied until concrete operations are complete and the forms removed. Surfaces not in contact but which will be inaccessible after erection shall receive two coats of specified primer.
 
  
−
The problem of determining what is considered to be an inaccessible surface requires considerable judgment and experience. To assist inspection personnel in this determination, the following list of typical locations, even though incomplete, is provided:
+
{| style="margin: 1em auto 1em auto"
 +
|-
 +
|[[image:712.1.5.4.1.1.jpg|center|250px|thumb|'''<center>Figure 712.1.5.4.1.1, A325/A490 will be stamped on the head of the bolt</center>''']]||[[image:712.1.5.4.1.2.jpg|center|270px|thumb|'''<center>Figure 712.1.5.4.1.2, A325TC/A490TC Tension Control Bolt<br/>These bolts will follow requirements of A325 or A490 listed on bolt.  They will list Standard Number and then TC.</center>''']]
 +
|-
 +
|colspan="2"|[[image:712.1.5.4.1.3.jpg|center|750px]]'''<center>Figure 712.1.5.4.1.3, Copy of Shipping Paperwork</center>'''
 +
|}
  
−
'''(a) Beam and girder spans'''
+
=====712.1.5.4.2 Step 2, Inspection Type Selection=====
−
:l. Bottom of bearing plates where in contact with fabric pads.
+
The second step is to determine the inspection type. The information below shows how to proceed once it is determined what type of bolt is being used in the field. The bolt type and verification method available will dictate the options and the requirements needed to follow for inspection in the field.  
−
:2. End of I-beams and girders.
 
−
:3. Backfaces of end diaphragms at end bents or intermediate bents where final clearance will be less than l2 in.
 
−
:4. Top surfaces of all diaphragms if final clearance is less than 6 in.
 
−
:5. Portions of expansion device where not in contact or embedded in concrete.
 
−
:6. Tops of overhang brackets (if any) if final clearance is less than 6 in.
 
−
:7. Faces of overhang (if any) next to abutment if final clearances will be less than l2 in.
 
−
'''(b) Truss Spans'''
 
−
:l. Bottom of bearing plates where in contact with pads.
 
−
:2. Underside of cover plates and caps.
 
−
:3. Inside of cabins and the backface of members if clearance is less than l2 in.
 
−
:4. Backside of end floor beams at abutments if final clearance will be less than l2 in.
 
−
:5. All steel members in contact with or adjacent to curb and slab (post, diagonals, etc.)
 
−
:6. Tops of overhang brackets (if any) with final clearance of less than 6 in.
 
−
:7. Tops of floor beams or stringers not in contact with concrete, if final clearance will be less than 6 in.
 
−
:8. Steel rail posts where bolted against the slab or curb.
 
  
−
====712.1.6.5 Application====
+
Prior to going into the field, determine the bolt type and the inspection method that will be used. This will allow you to know the equipment needed and discuss test procedures with the contractor. For some test methods, the contractor will provide the calibrated equipment to check the bolts.
−
[http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.10] and [http://modot.mo.gov/business/standards_and_specs/Sec1081.pdf Sec 1081] specifies various methods of application for paint. The inspector should enforce all requirements of the Standard Specifications to prevent unauthorized thinning of paint. The Job Special Provisions should be checked for paint and paint applications for new bridges and repaint of existing bridges.
 
  
−
The contractor is required to arrange the work schedule to provide ample time for each coat of paint to dry before the next coat is applied. In no case should a coat of paint be applied until the previous coat has been approved by the inspector.
+
======712.1.5.4.2.1 Bolt Type======
 +
The first step is to find out what type of bolt you are using in the field. The bolt type will dictate how much information is needed for the Rotational Capacity Testing.
  
−
====712.1.6.6 Inspection====
+
======712.1.5.4.2.2 A325/A490 Hex Head Bolt======
−
The alert paint inspector should ensure that the surface of the steel is properly cleaned and that each surface to be painted is clean and dry at the time of paint application. The following checklist is provided for guidance.
+
The use of A325/A490 bolts will come with standard nuts, bolts, and washers. These will be tightened in the field using air tools and torque wrenches.
−
:l. Steel is properly cleaned and dust removed.
 
−
:2. First coat application is within 24 hours of cleaning or before rust forms on the surface.
 
−
:3. Paint has been inspected and approved.
 
−
:4. Temperature is not below 40&deg; F for Systems C, D and E.
 
−
:5. Air is not misty and surface to be painted is dry and frost free.
 
−
:6. Paint is applied in accordance with the specifications.
 
−
:7. Paint is not thinned except as approved by the Standard Specifications.
 
−
:8. Preceding coat of paint is thoroughly dry before application of next coat.
 
−
:9. Paint is applied only on sections which have been approved by the inspector.
 
  
−
'''Field Coating.''' This note is to give some guidance on how to clean shop applied zinc paint that has been exposed to exhaust fumes and the elements. This would primarily occur on an overpass that has been in place for some time and exposed to exhaust fumes. Typically a painting contractor will use a power washer to remove dirt and debris before the intermediate and final paint coatings. Vehicle emissions can only be removed by using a detergent when power washing. A cleaning solution must be used in the power washing process or there could be significant failures to the coatings that are applied over the zinc paint. Once the detergent has been used it is important to then clean water rinse the steel to make sure all of the detergent has been removed. The detergent, if not properly rinsed off, will be harmful for subsequent coatings also.
+
Rotational Capacity Testing is based on Table 712.1.5.4.3.1, Long Bolts, or 712.1.5.4.3.2, Short Bolts. Bolt checks will need to address questions shown in the table used.
  
−
This should not be an additional pay item and would be covered under [http://modot.mo.gov/business/standards_and_specs/Sec1081.pdf Sec 1081.3.2.1]. There is no practical test for the vehicle emission residue. A light colored cloth to wipe on the steel to look for an oily residue is recommended.
+
Bolt inspection acceptance by calibrated wrench will be made using Sec 712.7.5 and Sec 712.7.12(c).
  
−
====712.1.6.7 Touching Up Damaged Primer====
+
Bolt inspection acceptance by turn-of-nut method will be made using Sec 712.7.6 and Sec 712.7.12(c).
−
If the inorganic zinc primer is damaged or small imperfections in the primer are discovered, the following repair procedure is acceptable. Inorganic zinc only adheres well to raw steel. Therefore an epoxy mastic paint can be used for repairs. The epoxy mastic paint should be from the same supplier as the inorganic zinc to assure compatibility. The epoxy mastic paint will be a different color. Therefore it should only be used where intermediate and final coats will be
 
−
applied, where it will be encapsulated in concrete, or in an area where aesthetics is not a concern. The epoxy mastic paint should be applied according to the manufacturer's recommendation.
 
  
−
'''Lead Paint Disposal.''' Recently there have been proposals by bridge painting contractors to use a compound (such as BLASTOX) to encapsulate lead based paint on bridges / steel structures. When this product is sprayed onto girders containing lead based paint, it encapsulates the lead which in effect yields a lower value on analytical tests or Toxic Characteristic Leaching Procedure (TCLP) tests. The encapsulate does not remove the lead from the lead based paint, rather it masks the lead content when tested.
+
======712.1.5.4.2.3 A325TC/A490TC Tension Control Bolt======
 +
The use of A325TC/A490TC bolts will come with nuts, bolts and washers. These will be tightened in the field using a specialized tool designed to tighten the nut and the spline of the bolt.
  
−
If the TCLP test results are above 5.0 Parts Per Million (PPM) lead, then the removed material is subject to hazardous waste handling requirements and transportation by a licensed hazardous waste transporter and hazardous waste manifest. In some situations, material containing greater than 5.0 PPM lead may be allowed to be shipped to a lead smelter as an ingredient to make more lead. In this case only a bill of lading is required for shipment of the material.
+
Rotational Capacity Testing is based on Table 712.1.5.4.3.3. Bolt checks will need to address questions shown in the table.
  
−
If the TCLP result is less than 5.0 PPM, it is legal for landfills to accept this material for disposal (as long as it does not contain other hazardous waste materials). However, landfilling this material is not in the best interest of MoDOT because the encapsulates do not remove the lead. Landfilling this material could subject MoDOT to long term liability and expensive environmental cleanups. On the other hand, when lead paint material is taken to a lead smelter,
+
Bolt inspection acceptance by load indicating bolt method will be made using Sec  712.7.7 and Sec 712.7.12(c).
−
MoDOT is reassured that the material is being reclaimed for reuse which significantly reduces
 
−
MoDOT's long term liability.
 
  
−
The contractor wants to be paid for all of the material disposal as if it all had to go to a special waste site. This type of proposal should not be accepted. The lead is still there and the encapsulate could break down over time exposing MoDOT to long term liability. MoDOT reimburses the contractor for disposal of the lead so the contractor is not out of any money.
+
=====712.1.5.4.3 Step 3, Rotational Capacity=====
  
−
==712.2 Materials Inspection for Sec 712==
+
The third step is to verify that the bolts on the jobsite are going to perform as intended by the design team.  Each of these bolts must achieve a specific tension that will be confirmed using the Rotational Capacity Testing. This test is described in Sec 712.7 and Sec 1080.2.5.4.
−
===712.2.1 Scope===
 
−
This guidance establishes procedures for inspecting and reporting those items specified in [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712] which are not always inspected by Bridge Division personnel or are not specifically covered in the Materials details of the Specifications, and inspection of shop coating of structural steel.
 
  
−
===712.2.2 Apparatus===
+
The goal of the Rotational Capacity test is to verify that the bolts will perform as intended. The main component that is being tested is that the bolts can be brought to the correct tension. This must be accomplished without applying too much torque to the bolts and  field installed bolts will be turned to the correct rotation meeting or exceeding the design tension for the fastener. For the bolts to work correctly, it is critical for the threads to be clean and there must be plenty of lubricant on the bolts and nuts. There is a chance that the protective coatings and lubricants will be washed away anytime the bolts, nuts, and washers are allowed to sit out in the elements. In addition, there is a chance that rust could develop from water being on the bolts, and carelessness could lead to physical damage of the bolts. Any of these issues could cause the bolts and the nuts to not interact as designed. It may take more torque to achieve the needed tension in the bolts or the installed fasteners cannot be checked accordingly with a torque wrench.  
−
(a) Magnetic gauge, reading range of 0-40 mils (0-1000 mm) with calibration tool.
 
−
(b) Calibration Standard Set (1.5-8 mils (38-200 mm)).
 
−
(c) Pictorial Surface Preparation Standards for painting steel surfaces.
 
−
(d) Surface profile gauge, Keane-Tator Comparator, with appropriate reference disc for sand, grit, or shot blast.
 
−
(e) Sling psychrometer and relative humidity tables.
 
−
(f) Ferrous Surface Temperature Thermometer.
 
−
(g) Flashlight and mirror.
 
−
(h) Rule with suitable graduations to accurately measure the material to be inspected.
 
  
−
===712.2.3 Procedure===
+
The bolt manufacturer may provide documentation to show that a Rotational Capacity Test (RoCap) has been performed. The inspector and contractor will still have to perform Rotational Capacity Tests in the field even if this paperwork is provided. According to Sec 712.7.10, “rotational capacity test shall be performed on 3 bolts of each rotational-capacity lot prior to the start of bolt installation.” All bolt assemblies provided shall be a part of a rotational capacity lot, which means that all bolt assembly lots used on MoDOT jobs shall be tested on the jobsite prior to incorporation.  The first time a new lot of bolts is opened, plan on performing the test. Also, the Rotation Capacity Test should be run any time questions or issues arise when torqueing a bolt to achieve design tension, or bolt hardware conditions change.
−
Normally all materials in [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712] except paint and shear connectors will be inspected by Bridge Division personnel.  Bolts, nuts and washers accepted by PAL may be delivered directly from the manufacturer to the project without prior inspection. When requested by the Bridge Division or construction office, the Construction and Materials Division will inspect these and other miscellaneous items. The Bridge Division is responsible for the inspection of shop coating of structural steel at fabricating plants.
 
  
−
====712.2.3.1  Project Inspection and Sampling for PAL====
+
The RoCap test should only be run once per lot, unless one of the following conditions occur:
−
Inspecting of PAL material will be as stated in this section and [[106.12 Pre-Acceptance Lists (PAL)|Pre-Acceptance Lists (PAL)]].
 
  
−
===712.2.4 Miscellaneous Materials===
+
:1. Bolts arrive on the jobsite for the first time
−
====712.2.4.1 High Strength Bolts====
+
::: All bolt assembly lots must be tested once they are on the jobsite. If conditions do not change, then the one test should suffice.
−
All bolts, nuts, and washers should be from a PAL supplier in accordance with [[106.12 Pre-Acceptance Lists (PAL)|Pre-Acceptance Lists (PAL)]]. If a supplier proposes to furnish structural steel connectors and is not on PAL, a request is to be made to the Construction and Material Division for acceptance into the PAL program. Once satisfactory submittals have been received, the supplier will be placed on the PAL. Bolts, nuts, and washers, for use other than bridge construction and in quantities less than 50, may be accepted from a PAL supplier without a PAL identification number.
+
:2. Bolt, washer, or nut lots have been interchanged
 +
::: It is important when the Rotational Capacity test is run that lot numbers for all the individual pieces (bolts, nuts, and washers) remain the same.  Once any of these lots change, the Rotational Capacity test must be run again.
 +
:3. Bolt lubrication appears to have been compromised
 +
::: Once a Rotation Capacity test has been run, another one will not have to be run, unless the bolt condition changes.  One aspect that is a factor is bolt lubrication.  If the bolt is left in the wind and rain, the lubrication likely will be compromised. Once it is noticed that a bolt lubrication has changed, the Rotation Capacity test must be run again.
 +
:4. Bolts appear rusty or damaged
 +
::: Rust is the far extreme of a lack of lubrication. Not only has the lubrication gone away, but the protective coating is gone, and the bolt has been allowed to rust.  They will need to be cleaned, re-lubricated and tested again for Rotation Capacity.
 +
[[image:712.1.5.4.3 skidmore.jpg|right|175px]]
 +
There is not a way to test tension once the bolt has been tightened.  The Rotational Capacity Test is a way to verify not only that the bolts are in good condition, but also that they have not been impacted by field conditions.  The test will require two components.  One component is to visually inspect the bolts and record the results on the form provided in eProjects.  The second component is to run tests on the three bolts in the field using a Skidmore-Wilhelm Bolt tension measuring device and a torque wrench.  Both the Skidmore and torque wrench must have a calibration performed on it within the previous year from the manufacturer or a test lab.  There must be a sticker on it, as well as all supporting documentation to show it has been calibrated.
  
−
'''712.2.4.1.1 Manufacturer's Certification.''' Bolts and nuts specified to meet the requirements of ASTM A307 shall be accompanied by a manufacturer's certification statement that the bolts and nuts were manufactured to comply with requirements of ASTM A307 and, if required, galvanized to comply with requirements of AASHTO M232 (ASTM A153) or were mechanically galvanized and meet the coating thickness, adherence, and quality requirements of AASHTO M232 (ASTM A153) Class C. Certification shall be retained by the shipper. A copy should be obtained when sampling at the shipper and submitted with the samples to the lab.
+
[https://epg.modot.org/forms/CM/RoCap_Test_Form_Long_Bolts.pdf RoCap Test Form Long Bolts] are shown in Table 712.1.5.4.3.1 and Table 712.1.5.4.3.3, [https://epg.modot.org/forms/CM/RoCap_Test_Form_Short_Bolts.pdf RoCap Test Form Short Bolts] are shown in Table 712.1.5.4.3.2.  These forms will assist in obtaining all the required information for the testing methods allowed by MoDOT.  
  
−
All bolts, nuts and washers are to be identifiable as to type and manufacturer.  Bolts, nuts, and washers manufactured to meet ASTM A307 will normally be identified on the packaging since no special markings are required on the item.  Dimensions are to be as shown on the plans or as specified.
+
Table 712.1.5.4.3.1 and Table 712.1.5.4.3.2 is to be used when the Calibrated Wrench (Sec 712.7.5) or Turn-Of-Nut (Sec 712.7.6) Methods are used.  By running  the calculations in the spec book to verify the bolts, the values needed for the equipment in the field will also be determined. The entire test will need to be completed to verify that the bolt is good for use in the field.  
 +
   
 +
:Calibrated Wrench – The values from Table 712.1.5.4.3.1 and Table 712.1.5.4.3.2 that will be needed are the recorded Torque Values.
 +
:Turn-Of-Nut – When using the Turn-Of-Nut Method, the Rotation Capacity Test provides a check that the turn requirements of Sec 712.7.6 will generate the minimum tension required. Verify that the amount the nut has turned going to the minimum bolt tension is less than the specified nut rotation in Sec 712.7.6 Nut Rotation from Snug Tight Condition table.  
  
−
Weight (mass) of zinc coating, when specified, is to be determined by magnetic gauge in the same manner as described for bolts and nuts in [[:Category:1040 Guardrail, End Terminals, One-Strand Access Restraint Cable and Three-Strand Guard Cable Material|EPG 1040 Guardrail, End Terminals, One-Strand Access Restraint Cable and Three-Strand Guard Cable Material]].
+
The RoCap test for Calibrated Wrench and Turn-Of-Nut Methods is split based on long and short bolts.  Long bolts are those bolts that can fit into the Skidmore-Wilhelm Bolt Tension Measuring Device or the Skidmore-Wilhelm short bolt setup.  Short bolts are those that are too short to fit into the short bolt setup tension measuring device.
  
−
Samples for Laboratory testing are only required when requested by the State Construction and Materials Engineer, or when field inspection indicates questionable compliance. When samples are taken, they are to be taken at the frequency and of the size shown below. When galvanized bolts, nuts and washers are submitted to the Laboratory, a minimum of 3 samples of each are required for Laboratory testing.
+
Table 712.1.5.4.3.1 provides info about how to run the test, and the information to be recorded.
  
−
{| border="1" class="wikitable" style="margin: 1em auto 1em auto"
+
<center>
−
|width="230"|3 for lots of 0 to 800 pcs.||rowspan="4" width="500" align="center"|Each sample is to consist of one bolt, nut and washer - Submit for Dimensions, Weight (Mass) of Coating, Mechanical Properties.
+
{| class="wikitable"
 +
|-
 +
!  colspan="12"| Rotation Capacity Testing Steps for Calibrated Wrench Method (Sec 712.7.5) and
 +
Turn-Of_Nut Method (Sec 712.7.6)
 +
|-
 +
!  colspan="12"| Table 712.1.5.4.3.1
 +
Job Site Rotational Capacity Test (RoCap Test) – A325 & A490 Long Bolts
 +
|-
 +
! rowspan="2"|<div style="transform:rotate(-90deg);">Test No.!!colspan="8"|Part 1!!colspan="3"|Part 2
 
|-
 
|-
−
|6 for lots of 801 to 8,000 pcs.
+
!style="background:white"width="150"|Sec 712.7.3  Minimum Bolt Tension (P)!! style="background:white" width="50" |<div style="transform:rotate(-90deg);">Less Than!! style="background:white" width="100"|Bolt Tension Gauge Reading (P)!! style="background:white" width="130"|Sec 1080.2.5.4.6 Maximum Allowable Torque (T) !! style="background:white"width="50"|<div style="transform:rotate(-90deg);">Greater Than!! style="background:white" width="100"|Torque Gauge Reading!!style="background:white"width="100"|Actual Nut Rotation (turn)!!style="background:white"width="130"|Sec 721.7.6 Nut Rotation (turn) Less than actual(Y/N)!!style="background:white"width="130"|Sec 1080.2.5.4 Required Rotation (turn)  Tension Gauge Reading!!style="background:white"height="150"width="100"|<div style="transform:rotate(-90deg);">Equal or Greater Than!!style="background:white" width="130"|Sec 1080.2.5.4.5  Required Turn Test Tension
 
|-
 
|-
−
|9 for lots of 8,001 to 22,000 pcs.
+
|align="center"|1 ||  ||align="center"|<||  || || align="center"|> || || || || || align="center"|>=||
 
|-
 
|-
−
|15 for lots of 22,001+ pcs.
+
|align="center"|2 ||  ||align="center"|<||  || || align="center"|> || || || || ||align="center"|>=||
 +
|-
 +
|align="center"|3 ||  ||align="center"|<||  || || align="center"|> || || || || || align="center"|>=||
 +
|-
 +
|align="center"|R1 ||  ||align="center"|<||  || || align="center"|>|| || || || || align="center"|>=||
 +
|-
 +
|align="center"|R2 ||  ||align="center"|<||  || || align="center"|>|| || || || || align="center"|>=||
 +
|-
 +
|align="center"|R3 ||  ||align="center"|<||  ||  || align="center"|>|| || || || || align="center"|>=||
 +
|-
 +
!  style="background:white" colspan="12"|Torque Formula (T=0.25P x Dia./12), T in ft-lbs, P in lbs, Bolt Dia. in inches
 
|}
 
|}
 +
</center>
  
−
If ASTM A325 bolts are to be used in lieu of ASTM A307 bolts or for other uses, the inspection and sampling procedures as set forth in [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.4.1.2] shall still be followed. Notify Construction and Materials if the substitution is made on PAL material.
+
'''Long Bolt Test'''
 +
:1. Measure the ratio of diameter/length of the bolt.
 +
:2. Place the bolt into the Skidmore and set it to snug tight (10% of installation tension in Sec 712.7.3 Bolt Tension Table).  This is to be done with a spud wrench. The contractor should add washers until three to five threads are in the grip, if less than 3 threads, the test will fail.  Mark reference rotation marks on the fastener assembly element turned and on face plate of Skidmore. (Mark starting point on bolt end, nut and calibrator face with straight line.)  Note that some short bolts may require the shortbolt setup for the Skidmore.
 +
:3. Turn the fastener with the wrench to be used for the daily testing in the field to the installation minimum tension in Sec 712.7.3 Bolt Tension Table. Stop and record the torque at that moment from the torque wrench and record the tension on the Skidmore. Verify the recorded torque does not exceed the maximum allowable torque (refer to Sec 1080.2.5.4.6 formula).  Verify that the amount the nut has turned going to the minimum bolt tension is less than the specified nut rotation in Sec 712.7.6 Nut Rotation from Snug Tight Condition table.
 +
[[image:712.1.5.4.3_Bolt-test_2022.png|right|280px]]
 +
:4. Further turn the bolt according to Sec 1080.2.5.4.4. This rotation is measured from the initial match mark made in step 2. . Record the tension achieved and then compare the tension at this point to the Turn Test Tension in Sec 1080.2.5.4.5 Required Bolt Tensions Table. The tension must be equal or greater than Turn Test Tension.
 +
:5. Remove the bolt and inspect for damage and record it on our form. Turn the nut by hand on the bolt threads to the position it was in during the test. Not being able to turn the nut by hand is thread failure.
 +
:6. Repeat the process 2 additional times for each type of bolt assembly (Total of 3 tests per assembly lot).
 +
:7. Once the 3 tension and torque values have been obtained from Step 3, use the higher of the 3 numbers.
  
−
'''712.2.4.1.2''' High strength bolts, nuts, and washers specified to meet the requirements of ASTM A325.  Field inspection shall include examination of the certifications or mill test reports; checking identification markings; and testing for dimensions.  The certifications or mill test reports, conforming to [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.2.4], shall be retained in the district office.  Samples for Laboratory testing shall be taken and submitted in accordance with the provisions set forth herein.
+
Table 712.1.5.4.3.2 provides info about how to run the short bolt test for those bolts that are too short to fit into the Skidmore-Wilhelm short bolt setup tension measuring device and the information to be recorded.
  
−
All lots containing 501 or more high strength bolts shall be sampled and submitted to the Laboratory for testing. If no lots offered contains 501 or more bolts, sample 10 percent of the lots offered, or one lot, whichever is greater. A lot is defined as all bolts of the same size and length, with the same manufacturer's lot identification, offered for inspection at one time. Samples shall be taken as follows:
+
<center>
−
 
+
{| class="wikitable"
−
{| border="1" class="wikitable" style="margin: 1em auto 1em auto"
+
|-
−
|+
+
!  colspan="7"| Rotation Capacity Testing Steps for Calibrated Wrench Method (Sec 712.7.5) and
−
! style="background:#BEBEBE"| Number of Bolts in the lot !!style="background:#BEBEBE"| Number of Bolts Taken for a sample*
+
Turn-Of_Nut Method (Sec 712.7.6)
 +
|-
 +
!  colspan="7"| Table 712.1.5.4.3.2
 +
Job Site Rotational Capacity Test (RoCap Test) – A325 & A490 Short Bolts
 +
|-
 +
!style="background:white"|Test No.!!style="background:white" width="130"|Sec 1080.2.5.4.5 Turn Test Tension (P)!! style="background:white" width="100" |20% of Max. Turn Test Torque (T)!! style="background:white" width="100"|Maximum Calculated Turn Test Torque!!style="background:white" width="80"|Greater Than!!style="background:white" width="100"|Torque Gauge Reading at End of First Rotation!! style="background:white" width="150"|Visual Inspection of nut and bolt after Second Rotation (Acceptable/Not Acceptable)
 +
|-
 +
|align="center"|1 || || || || align="center"|>||  ||
 +
|-
 +
|align="center"|2 || || || || align="center"|>|| ||
 +
|-
 +
|align="center"|3 || || || || align="center"|>|| ||
 +
|-
 +
|align="center"|R1 || || || || align="center"|>|| ||
 
|-
 
|-
−
|150 and less ||3
+
|align="center"|R2 || || || ||align="center"|>|| ||
 
|-
 
|-
−
|151 through 800 ||3
+
|align="center"|R3|| || || || align="center"|>|| ||
 
|-
 
|-
−
|801 through 8,000 ||6
+
|align="left" style="background:white" colspan="7"|20% Torque Formula (T = 0.20T), T in ft-lbs.
 
|-
 
|-
−
|8,001 through 22,000 ||9
+
|align="left" style="background:white" colspan="7"|Torque Formula (T=0.25P x Dia./12), T in ft-lbs., P in lbs., Bolt Dia. in inches
 
|-
 
|-
−
|22,001 plus ||15
+
|align="right" style="background:white" colspan="2"|First Rotation
 +
|align="left" style="background:white" colspan="5"|[L<= 4D, 1/3 turn (120°)], [4D< L<8D, 1/2 turn (180°)]
 
|-
 
|-
−
|colspan="2" |*A minimum of 3 samples will be required for galvanized materials.
+
|align="right" style="background:white" colspan="2"|Second Rotation
 +
|align="left" style="background:white" colspan="5"|A325 [L<= 4D, 1/3 turn (120°)], [4D< L<8D, 1/2 turn (180°)]
 +
A490 [L<= 4D, 1/4 turn (90°)], [4D< L<8D, 1/3 turn (120°)]
 
|}
 
|}
 +
</center>
 +
 +
'''Short Bolt Test'''
 +
:1. Measure the ratio of diameter/length of the bolt and refer to Sec 712.7.6 on the installation rotation.
 +
:2. Place the bolt into the steel plate. The contractor should add washers until three to five threads are in the grip, if less than 3 threads the test will fail. Set it to snug tight (Not exceed 20% of maximum torque at first rotation). Maximum torque at first rotation is equal to Turn Test Tension, Sec 1080.2.5.4.5 and applying that tension to the torque formula in Sec 1080.2.5.4.6. This is to be done with a measuring torque wrench.
 +
[[image:712.1.5.4.3_Bolt-test_2022.png|right|280px]]
 +
:3. Mark reference rotation marks on the fastener assembly element turned and on face of steel plate. (Mark starting point on bolt end, nut and steel plate face with straight line.)
 +
:4. Turn the fastener with the torque wrench to be used for the daily testing in the field to the rotation shown in Sec 712.7.6 Nut Rotation from Snug Tight Condition Table. Once the first target rotation has been reached, stop and record the torque at that moment from the torque wrench. Verify the recorded torque does not exceed the maximum torque.  Maximum torque at first rotation is turn test tension, Sec 1080.2.5.4.5 with torque formula Sec 1080.2.5.4.6, as shown in step 2.
 +
:5. Further turn the bolt further according to Sec 1080.2.5.4.4. This rotation is measured from the initial match mark made in step 3.  Assemblies that strip or fracture prior to this rotation fail the test.
 +
:6. Remove the bolt and inspect for damage and record it on our form. Turn the nut by hand on the bolt threads to the position it was in during the test. Not being able to turn the nut by hand is thread failure.
 +
:7. Repeat the process 2 additional times for each type of bolt assembly (Total of 3 tests per assembly lot).
 +
:8. Once the 3 torque values have been obtained from Step 3, use the higher of the 3 torque numbers.
 +
 +
 +
'''Rotation Capacity Testing Steps For Load Indicating Bolt Method (Sec 712.7.7)'''
 +
 +
The Load Indicating Bolt Method is less common.  The bolt is designed to automatically verify that the bolts are not overtightened.  The Rotational Capacity test in the field is to verify that the threads are not binding due to rust and dirt.  This binding will give a false reading and cause the bolt spline to shear off prior to the design tension being achieved.  Also due to the consistency of the bolt, there will not be a need to tighten the bolt to 1.15 times the Minimum Target Tension.  The spline of the bolts will snap off within 5-10% of the designed tension of the fastener and exceed the Minimum Target Tension when properly lubricated.
  
−
All lots containing 501 or more high strength nuts shall be sampled and submitted to the Laboratory for testing. If no lot offered contains 501 or more nuts, sample 10 percent of the lots offered or one lot, whichever is greater. A lot is defined as all nuts of the same grade, size, style, thread series and class, and surface finish, with the same manufacturer's lot identification, offered for inspection at one time. Samples shall be taken as follows:
+
Table 712.1.5.4.3.3 provides info about how to run the test, and the information to be recorded.
 +
<center>
  
−
{| border="1" class="wikitable" style="margin: 1em auto 1em auto"
+
{| class="wikitable"
−
|+
+
|-
−
! style="background:#BEBEBE"| Number of Nuts in the lot !!style="background:#BEBEBE"| Number of Nuts Taken for a sample*
+
!  colspan="5"|Table 712.1.5.4.3.3
 +
Rotation Capacity Testing Steps for Load Indicating Bolt Method (Section 712.7.7)
 +
|-
 +
!  colspan="5"|Job Site Rotational Capacity Test A325/A490 Bolts
 +
|-
 +
!style="background:white" width="80"|Test No.!!style="background:white" width="150"|Sec 712.7.3  1.05xMinimum Bolt Tension (P)!! style="background:white" width="80" |Less Than!! style="background:white" width="150"|Bolt Tension Gauge Reading (P)!!style="background:white" width="150"|Inspection Torque Calculated Value
 +
|-
 +
|align="center"|1 || ||align="center"|< || || 
 +
|-
 +
|align="center"|2 || ||align="center"|< || ||
 
|-
 
|-
−
|800 and under ||1
+
|align="center"|3 || ||align="center"|< || ||
 
|-
 
|-
−
|801 through 8,000 ||2
+
|align="center"|R1 || || align="center"|< || ||
 
|-
 
|-
−
|8,001 through 22,000 ||3
+
|align="center"|R2 || ||align="center"|<|| ||
 
|-
 
|-
−
|22,000 and over ||5
+
|align="center"|R3|| ||align="center"|< || ||
 
|-
 
|-
−
|colspan="2" |*A minimum of 3 samples will be required for galvanized materials.
+
|align="left" style="background:white" colspan="5"|(Inspection Torque formula = 0.95 x 0.25 x Gauged Tension Reading x Bolt Dia. / 12; Bolt Dia. in inches)
 
|}
 
|}
 +
</center>
  
−
All lots containing 501 or more high strength washers shall be sampled and submitted to the Laboratory for testing. If no lot offered contains 501 or more washers, sample 10 percent of the lots offered, or one lot, whichever is greater. A lot is defined as all washers of the same type, grade, size and surface finish, with the same manufacturer's lot identification, offered for inspection at one time. Samples shall be taken as follows:
+
:1. Measure the ratio of diameter/length of the bolt.
 +
:2. Place the bolt into the Skidmore and set it to snug tight (10% of installation tension). This is to be done with a spud wrench. The contractor should add washers until only three threads are showing.
 +
:3. Place the specialty tool used on the end of the bolt and tighten until the spline of the bolt snaps off.
 +
:4. Record the tension value on the Skidmore once the bolt has snapped.
 +
:5. Verify that the recorded value is greater than 1.05 times the Minimum Target Tension from Sec 712.7.3.
 +
:6. Remove the bolt and inspect for damage.
 +
:7. Repeat the process 2 additional times for each type of bolt assembly (Total of 3 tests per assembly lot).
  
−
{| border="1" class="wikitable" style="margin: 1em auto 1em auto"
+
 
 +
It is most important to verify plies were in contact when bolts were snugged and that a fastener was not subsequently loosened when accompanying splice bolts were tightened and compacted the splice faying surfaces into contact after other fasteners had been already tightened.
 +
 
 +
=====712.1.5.4.4 Step 4, Installation=====
 +
 
 +
The next step is to ensure the proper process is used in the assembly of structural steel.  It is important that the contractor is placing temporary bolts, drift pins and permanent bolts in the correct pattern.  Read Sec 712.5 for additional requirements when fitting-up the structural steel.
 +
 
 +
The order in which bolts are tightened is important.  If not done correctly, the plates will not be sandwiched tightly, and gaps will be introduced.  Due to these being slip-critical connections, the joints need to experience 100% contact between all the plies.  The contractor will need to start tightening the joints in the center of the plate, and then work radially out from the center to the extents of the joint. 
 +
 
 +
Once the bolts are tightened by the contractor using one of the three approved methods, MoDOT will be responsible to check a portion of the bolts. We will review 10% of the bolts, or two per lot, whichever is greater. If bolt issues are discovered, more bolts may need to be reviewed. The following steps are generally what is seen in the field. There may be differences per contractor, but MoDOT's roles and requirements should be the same across the state.
 +
 
 +
:'''Contractor/QC:''' The contractor will be installing the bolts through various methods.  It can be expected to see Turn-Of-Nut Method or Calibrated Wrench (Torque Wrench).  You could also see the contractor using Stall Out guns that are designed to stop spinning the bolts once a certain torque is reached.  Sometimes air impact guns are used and have the air pressure adjusted to stop gun at torque desired using a Skidmore to verify they are exceeding the design tension of the fastener(s).  This tool would be considered the Calibrated Wrench.  This is an acceptable method, provided they do not change any conditions.  They should run the Rotation Capacity Test with the equipment to be used.  Once they change any part of the setup (add or remove an air hose, add an additional gun or item ran off of air hose supply, change air pressure, etc.), they will need to rerun the Rotation Capacity Test.  If the contractor is using the Turn-Of-Nut Method, then they are not required to use a torque wrench on the nuts as well. 
 +
 
 +
:'''MoDOT/QA:''' Inspectors will have different checks based upon the type of verification used by the contractor.  If the contractor is using Calibrated Wrench (Torque Wrench or Stall Out Gun) to check every bolt, MoDOT will use a torque wrench and will follow the Calibrated Wrench Method. 
 +
 +
:If the contractor is using Turn-Of-Nut, MoDOT will follow two steps.  We will visually watch the contractor install and snug tighten the fastener assembly, ensuring the plies are in contact after doing so and ensure that they are marking the nut, bolt, and plies correctly.  Then watch as they turn the nut (or bolt) to make sure it is generating the correct number of turns.  A visual check of all the bolts turned so far can be quickly done to make sure they are marked, and that the marks are turned the correct amount.  As a double check, the inspector will also take a torque wrench to check bolt torque on 10% of the bolts. If bolt issues are discovered, more bolts may need to be checked. Even if the contractor did not use a torque wrench to check the bolts, MoDOT inspectors will still use a torque wrench and record findings.
 +
 
 +
EPG 712.1.5.4.5 Step 5 details the three verification procedures.
 +
 
 +
=====712.1.5.4.5 Step 5, Bolt Verification=====
 +
 
 +
======712.1.5.4.5.1 Calibrated Wrench Method, Sec 712.7.5======
 +
 
 +
The first option listed in the specification book is the Calibrated Wrench Method.  This method will use a calibrated wrench to check that the torque delivered to the bolt is the minimum torque needed to induce the needed minimum tension, as shown in Sec 712.7.3.  In order to do this, information must be available from the Rotational Capacity Test completed for each lot. 
 +
 
 +
Sec 712.7.5 states that when the calibrated wrench is used, it needs to be set 5-10% over the torque gauge value from Column 4 of the Rotational Capacity Test. Take the maximum Torque Gauge Reading from the Rotational Capacity Test and multiply by 1.05. This new value will be the one set onto the calibrated wrench. 
 +
 
 +
'''Day-to-Day Verification'''
 +
 
 +
Each day the inspector will need to verify the installed bolts are correctly tensioned. Most of the time, MoDOT inspectors will use the contractor's equipment for the verification. The important thing is that the contractor is verifying the calibrated wrench daily. This will mean that the contractor will need to have the Skidmore on site each day to verify that the wrench is generating the correct tension at the torque it is reading.  MoDOT inspectors will pick 10% of the bolts to also check bolt torque. The torque value they are checking is the maximum torque gauge reading generated from Step 3 of the Rotation Capacity Test.
 +
 
 +
======712.1.5.4.5.2 Turn-Of-Nut Method, Sec 712.7.6======
 +
The second option listed in the specification book is the Turn-Of-Nut Method.  This method uses the fact that the nuts must be turned to the rotation specified in Sec 712.7.6 to induce the needed minimum tension, as shown in Sec 712.7.3.  In order to do this, verification will be needed from the Rotational Capacity Test completed for each lot. 
 +
 
 +
When the Rotational Capacity Test is run, in Step 3 is to verify the bolt rotation is less than that specified in Sec 712.7.6. Once this is verified, all the bolts can be tightened to the rotation needed and that will confirm that the needed tension has been achieved. This is provided that all the plies are in contact when snug tightened.
 +
 
 +
'''Example'''
 +
 
 +
On a project you are installing 7/8” diameter bolts that are 4” long.  The RoCap test was performed on the bolt assemblies.  When the bolts were tensioned during RoCap, they were tensioned to 39,050 lb.  From the formula in Sec 1080.2.5.4.6, the maximum torque is to be 712 lb-ft.  The bolt was torqued to 701 lb-ft, so it passes the RoCap test.  During the test, the inspector also noted that the bolt nut turned 2 flats (or 1/3 of a turn).  Sec 712.7.6 Nut Rotation from Snug Tight Condition table says that this bolt is to be turned 1/2 turn for Turn-Of-Nut in the field.  Since the bolt achieved the minimum tension in 1/3 turn, we know that the turning it to 1/2 turn will achieve a higher tension value.  If the RoCap test shows a higher turn value needed than the Sec 712.7.6 table, then further discussions should be had with the contractor about next steps before any bolts are installed in the field. 
 +
 
 +
'''Day-to-Day Verification'''
 +
 
 +
For the day-to-day verifications, MoDOT inspectors will visually verify that the Turn-Of-Nut Method is completed correctly.  They will review marks made by the contractor and make sure that there is a general comfort level with how the contractor is doing the work.  In addition to this, MoDOT inspectors will pick 10% of the bolts to also check bolt torque.  The torque value they are checking is the maximum torque gauge reading generated from Step 3 of the Rotation Capacity Test.
 +
[[image:712.1.5.4.5.2.jpg|right|225px]]
 +
The photograph to the right shows what the markings will look like when the Turn-Of-Nut Method is used.  In order to perform the test, three marks are made: one on the nut, one on the bolt, and one on the steel plate underneath.  To begin with, mark the nut at a corner, and follow that line all the way through to the steel.  Notice the left side bolts are all starting in the same position.  The right-side bolts have been rotated 1/3 of a turn, or two flats of the hex head.  Notice how the bolt and the steel still line up, and only the nut has moved.  Marking the bolt and steel ensures that the bolt does not move during tightening.  The nut will show how much it has moved.  Marking the hex head accordingly is a semi-permanent record that the test was run.  This also provides the inspector with the necessary information to quickly verify tightness, but a random check of 10% of bolts with a torque wrench by the QA inspector shall still occur.  The inspector will not have to tighten the bolts themselves but can witness the ironworker who is tightening some of the bolts to ensure they are following the proper procedure of the Turn-Of-Nut Method.
 +
 
 +
 
 +
======712.1.5.4.5.3 Load Indicating Bolt Method, Sec 712.7.7======
 +
 
 +
The third option listed in the specification book is the Load Indicating Bolt Method.  This method uses the fact that the bolts have been specially designed to shear off once a specific torque has been reached in the bolt.  This torque has been correlated to the needed minimum tension as shown in Sec 712.7.3.  In order to do this, the verification must be available from the Rotational Capacity Test completed for each lot. 
 +
[[image:712.1.5.4.5.3.jpg|right|175px]]
 +
When the Rotational Capacity Test is run, there is one piece of information needed.  The Tension Gauge Reading when the spline shears off.  Since the spline shears off, and the drill cannot provide any more compactive effort, there is generally not a concern about overtightening the bolt provided that the bolt hardware is clean and well lubricated.  Once the bolt shears off, the tension achieved is the final tension.  The Rotation Capacity Test will verify that the final tension is at or above the minimum bolt tension required in Sec 712.7.3.
 +
 
 +
'''Day-to-Day Verification'''
 +
 
 +
Since the machine will shear the bolt off at the specified tension, the biggest piece to verify is done during the Rotational Capacity Test. Once that is done, the inspector just needs to ensure that the contractor is following the correct tightening procedure shown in Sec 712.7.7. Ensure that all plies are in contract when snug tight and that bolt hardware is clean and well lubricated. The QA Inspector should also perform checks of at least 10% of the fastener assemblies with a torque wrench to verify the fastener is tight using the Inspection Torque value (0.95 x 0.25 x highest gauged tension from RoCap Test x bolt diameter in inches / 12). If bolt issues are discovered, more bolts may need to be checked.
 +
 
 +
===712.1.6 High Strength Anchor Bolts===
 +
 
 +
When high strength anchor bolts are specified, ASTM F1554 Grade 55 anchor bolts shall be used unless higher grade anchor bolts are required by design. Grade 105 bolts shall not be used in applications where welding is required. Grade 36 anchor bolts are commonly referred to as “low-carbon” and may be used if specified on the plans.  Grade 55 anchor bolts may be substituted for applications where Grade 36 is specified. To facilitate easy identification of anchor bolt, the following figure shows some of the typical bolt markings required by the ASTM specification. The end of the anchor bolt intended to project from the concrete shall be steel die stamped with the grade identification and color coded as follows.
 +
 
 +
<center>
 +
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
 
|+  
 
|+  
−
! style="background:#BEBEBE"| Number of Washers in the lot !!style="background:#BEBEBE"| Number of Washers Taken for a sample*
+
! style="background:#BEBEBE" width="125"|Grade!! style="background:#BEBEBE" width="125"|Color Code!! style="background:#BEBEBE" width="150"|Identification
 
|-
 
|-
−
|800 and under ||1
+
|36 ||style="background:#FFFFFF"| [[image:712.1.5 azul.jpg|50px]] ||style="background:#FFFFFF"|AB36<br/>XYZ
 
|-
 
|-
−
|801 through 8,000 ||2
+
|55 ||style="background:#FFFFFF"|  [[image:712.1.5 amarillo.jpg|50px]] ||style="background:#FFFFFF"|AB55<br/>XYZ
 
|-
 
|-
−
|8,001 through 22,000 ||3
+
|105|| style="background:#FFFFFF"| [[image:712.1.5 rojo.jpg|50px]]  ||style="background:#FFFFFF"|AB105<br/>XYZ
−
|-
 
−
|22,000 and over ||5
 
−
|-
 
−
|colspan="2" |*A minimum of 3 samples will be required for galvanized materials.
 
 
|}
 
|}
  
−
====712.2.4.2 Slab Drains====
+
Note: XYZ represents the manufacturer’s identification mark.
−
Slab drains are to be accepted on the basis of field inspection of dimensions, weight (mass) of zinc coating, and a satisfactory fabricators certification.  The dimensions, weight (mass) of zinc coating, and material specification requirements are shown on the bridge plans.
+
</center>
 +
 
 +
===712.1.7 Non-destructive Testing===
 +
 
 +
In certain instances, non-destructive testing (NDT) may be required to be conducted on steel components of a bridge.  The contractor will be responsible for providing and certified NDT technician to conduct the testing.  This technician will usually be an employee of a third party inspection agency.  Certification for NDT technicians will be in accordance with the requirements of The American Society for Nondestructive Testing (ASNT) Recommended Practice SNT-TC-1A.  MoDOT does not maintain an approved list of NDT technicians.  The Bridge Division does review certifications for testing agencies and keep a list of personnel of these agencies with their respective certifications.
  
−
Field determination of weight (mass) of coating is to be made on each lot of material furnished. The magnetic gauge is to be operated and calibrated in accordance with ASTM E376. At least three members of each size and type offered for inspection are to be selected for testing. A single-spot test is to be comprised of at least five readings of the magnetic gauge taken in a small area and those five readings averaged to obtain a single-spot test result. Three such areas should be tested on each of the members being tested. Test each member in the same manner. Average all single-spot test results from all members to obtain an average coating weight (mass) to be reported. The minimum single-spot test result would be the minimum average obtained on any one member. Material may be accepted or rejected for galvanized coating on the basis of magnetic gauge. If a test result fails to comply with the specifications, that lot should be resampled at double the original sampling rate. If any of the resampled members fail to comply with the specification, that lot is to be rejected. The contractor or supplier is to be given the option of sampling for Laboratory testing, if the magnetic gauge test results are within minus 15 percent of the specified coating weight (mass).
+
For projects that require NDT in the field, the inspector will collect the information from the contractor as to who will be providing the NDT services. The contractor shall submit the certifications to the Resident Engineer to be forwarded to the Bridge Division at [mailto:Fabrication@modot.mo.gov Fabrication@modot.mo.gov]. These certifications shall include the following documentation for each individual performing NDT: their certifications, current eye exam, and the NDT company written practice, including the Level III individual certification used for the written practice.
 +
 +
At the Resident Engineer’s option, they may choose to keep a list of personnel who have performed NDT work for a quick reference for future projects. However, the Resident Engineer and the inspector will always request to see the current eye exam results prior the technician providing the NDT on these future projects.
  
−
A fabricators certification shall be submitted to the engineer in triplicate stating that "The steel used in the fabrication of the slab drains was manufactured to conform to ASTM A709" or "A500, A501" as the case may be.
+
==712.2 Materials Inspection for Sec 712==
 +
===712.2.1 Scope===
  
−
====712.2.4.3 Ties and Clips====
+
This guidance establishes procedures for inspecting and reporting those items specified in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 712] that are not always inspected by Bridge Division personnel or are not specifically covered in the Materials details of the Specifications.  
−
Clips and ties made of wire, plastic, or other materials inert in concrete may be used. The clip or tie will be considered acceptable if the reinforcing steel is securely held in the correct position preventing displacement until incorporated into the finished product.
 
  
−
====712.2.4.4 Miscellaneous Structural Steel====
+
===712.2.2 Procedure===
−
Other structural steel items not requiring shop drawings also require inspection.  Inspection includes a fabricator's certification identifying the source and grade of steel, as well as verification of dimensions and inspection of any coating applied.  The report is to include the grade of steel, coating applied, and results of inspection.
 
  
−
===712.2.5 Shop Coating===
+
Normally all materials in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 712] will be inspected by Bridge Division personnel. Bolts, nuts and washers accepted by PAL may be delivered directly from the manufacturer to the project without prior inspection. When requested by the Bridge Division or construction office, the Construction and Materials Division will inspect fencing and other miscellaneous items. The Bridge Division is responsible for the inspection of shop coating of structural steel at fabricating plants.  
−
====712.2.5.1 General====
 
−
Structural steel members and their components vary from project to project. The inspector should thoroughly familiarize himself with the plans, specifications, and special provisions pertaining to the particular project. The contractor is required to submit shop drawings for approval to the State Bridge Engineer, showing in detail his proposed procedure for fabricating and choice of paint system for shop painting if alternates are allowed. The District in which the fabrication plant is located will receive one copy of the approved shop drawing. If painting is done in another District, it will be the responsibility of that District to request drawings or special provisions from the other District. The inspector shall become thoroughly familiar with the approved shop drawings and pay particular attention to high strength field bolted contact surfaces, inaccessible areas, areas to be field welded, and other miscellaneous requirements. Changes or deviations from the approved plans, shop drawings or specifications are not permitted without written approval of the State Bridge Engineer. The Bridge Division will inspect and approve the fabrication of all members prior to shop coating. Fabrication approval may be documented and signed by the bridge inspector on [[#Form B-179|Form B-179]]. The districts will be notified by the plants when fabrication is completed and the steel is ready for shopcoat inspection.
 
  
−
====712.2.5.2 Surface Preparation====
+
====712.2.2.1  Project Inspection and Sampling for PAL====
−
The blast cleaned metal substrate shall be inspected prior to shop coat painting.  This inspection requires experience, judgment, and care.  The inspector should attempt to be as consistent as possible from day to day in his determinations of profile height and evaluation of the condition of blast cleaned surfaces as specified in [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.12.2]. Any grease or oil shall be removed with solvent before blasting. After blasting, steel imperfections such as slivering shall be scraped off. Also care should be taken to be sure all blasting material is blown out of corners, etc.
+
Inspecting of PAL material will be as stated in this section and [[106.12 Pre-Acceptance Lists (PAL)|Pre-Acceptance Lists (PAL)]].
  
−
The nominal profile height in mils (mm) is determined by a Keane-Tator surface profile comparator with reference to the appropriate disc for the type of abrasive used in the blast cleaning. The type of referenced disc must correspond with the type abrasive being used by the fabricator in blast cleaning. For example, if a mechanical Wheelabrator containing "shot" as the abrasive was utilized in cleaning the metal, the inspector shall use a "shot" reference disc on the comparator when estimating profile height of the metal substrate. A sufficient number of estimations, taken at random over the member, shall be made to assure specification compliance for profile height. Areas of surface irregularities, due to steel mill rolling, pitting by rust, etc., should not be considered part of the profile height readings. However, the degree of cleaning of these surface irregularities shall comply with the requirements of [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.12.2, Surface Preparation].
+
===712.2.3 Miscellaneous Materials===
 +
====712.2.3.1 High Strength Bolts====
 +
All bolts, nuts, and washers should be from a PAL supplier in accordance with [[106.12 Pre-Acceptance Lists (PAL)|Pre-Acceptance Lists (PAL)]]. If a supplier proposes to furnish structural steel connectors and is not on PAL, a request is to be made to the Construction and Material Division for acceptance into the PAL program. Once satisfactory submittals have been received, the supplier will be placed on the PAL. Bolts, nuts, and washers, for use other than bridge construction and in quantities less than 50, may be accepted from a PAL supplier without a PAL identification number.
  
−
Contact surface areas of high strength and machine bolted connections shall receive detail inspection as to profile height and also dry film paint thickness. On these surfaces, [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.12.8] requires a dry film inorganic zinc paint thickness of not less than 1.5 (38 mm) and not more than 2.5 mils (64 mm). Dry film paint thickness shall be corrected by substrate readings as described in [[106.3.2.45 TM-45, Determination of Dry Film Coating Thickness Using Magnetic Gauges|MoDOT Test Method T45]].
+
'''712.2.3.1.1 Manufacturer's Certification.''' Bolts and nuts specified to meet the requirements of ASTM A307 shall be accompanied by a manufacturer's certification statement that the bolts and nuts were manufactured to comply with requirements of ASTM A307 and, if required, galvanized to comply with requirements of AASHTO M232 (ASTM A153), Class C or were mechanically galvanized and meet the coating thickness, adherence, and quality requirements of ASTM B695, Class 55. Certification shall be retained by the shipper. A copy should be obtained when sampling at the shipper and submitted with the samples to the lab.  
  
−
A required machine surface finish of 125 micro-inches (3 mm) or less, as described in [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.3.3.14], shall not be blast cleaned or painted. A protective coating as described in [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.2.7] shall be applied to these machine surfaces for protection until delivered to the project site. A list is maintained of [http://modot.mo.gov/business/materials/pdf/vol_1/FS0712T1.pdf|Qualified Protective Coatings for Machine Finished Surfaces]. All machine surfaces greater than 125 micro-inches (3 µm) may be blast cleaned and painted.
+
All bolts, nuts and washers are to be identifiable as to type and manufacturer. Bolts, nuts, and washers manufactured to meet ASTM A307 will normally be identified on the packaging since no special markings are required on the item. Dimensions are to be as shown on the plans or as specified.
  
−
====712.2.5.3 Paint====
+
Weight (mass) of zinc coating, when specified, is to be determined by magnetic gauge in the same manner as described for bolts and nuts in [[:Category:1040 Guardrail, End Terminals, One-Strand Access Restraint Cable and Three-Strand Guard Cable Material|EPG 1040 Guardrail, End Terminals, One-Strand Access Restraint Cable and Three-Strand Guard Cable Material]].
−
The inspector shall ensure that only inspected and approved paint or paint components of the specified system are used. Paint shall comply with [http://modot.mo.gov/business/standards_and_specs/Sec1045.pdf Sec 1045]. Each batch or lot of each component of inorganic zinc paint for System C painting may have to be sampled at the fabricating plant and approved by the Laboratory prior to use if it has not been previously sampled. SiteManager data can be queried to determine whether a batch has been sampled. If sampling of paint is necessary, it shall be in accordance with procedures described in [[:Category:1045 Paint for Structural Steel|Paint for Structural Steel]]. A sample record, completed in SiteManager, shall be used as an identification record for the sample, and shall show necessary identifying information for each batch or lot.
 
  
−
====712.2.5.4 Paint Application====
+
Samples for Laboratory testing are only required when requested by the State Construction and Materials Engineer, or when field inspection indicates questionable compliance. Samples shall be taken according to [[#712.2.3.2.1.1 ASTM A307 Bolts|EPG 712.2.3.2.1.1 ASTM A307 Bolts]].
−
Prior to application of shop coat paint, the inspector shall ensure that the weather conditions, equipment, and procedures comply with [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.12.4 and 712.12.7] respectively. Dew point shall be determined in accordance with [[106.3.2.38 TM-38, Determination of Dew Point for Structural Steel Painting|MoDOT Test Method T38]]. System C, inorganic zinc, in a spray application, will often show mud cracking if applied too heavily.  Because of its very short drying time, it will form a powdery build up that will not flow properly and will not produce uniform coverage if the spray nozzle is not held perpendicular to the surface.  Too thin of a film may result in salting, producing a porous coating and subsequent progressive rusting.  System C does not have the ability to flow into contact joint areas so particular attention should be given at these points to ensure uniform application of the paint.  Paint shall be applied within 24 hours after blast cleaning. When more than one coat of paint is required, [http://modot.mo.gov/business/standards_and_specs/Sec0712.pdf Sec 712.12.3.1 and 712.12.7.4] shall govern.
 
  
−
'''Contamination.''' When newly painted surfaces are contaminated with sand, grit, dirt, etc., the area affected shall be cleaned of all paint and contaminates and repainted.
+
'''712.2.3.1.2''' High strength bolts, nuts, and washers specified shall meet the requirements of ASTM F3125 Grade A325. Field inspection shall include examination of the certifications or mill test reports; checking identification markings; and testing for dimensions. The certifications or mill test reports, conforming to EPG 712.2.3.1.1 Manufacturer's Certification, shall be retained in the district office. Samples for Laboratory testing shall be taken and submitted in accordance with EPG 712.2.3.2.1.2 ASTM F3125 Grade A325 Bolts.
  
−
Dry film paint thickness shall be measured in accordance with [[106.3.2.45 TM-45, Determination of Dry Film Coating Thickness Using Magnetic Gauges|MoDOT Test Method T45]].
+
====712.2.3.2 PAL Manufacturer Facilities Sampling====
  
−
===712.2.6 Records===
+
Prior to visiting a PAL supplier or manufacturer facility, the Cognos report “PAL Shipments Within Date Range” should be run for the facility to determine what material has been given MoDOT PAL numbers. For each PAL material, the sample shall consist of six pieces rather than determined from lot quantities as given in the following sections. An individual sample shall consist of bolts, nuts, or washers as these are treated as different materials in the PAL system.  
−
The inspector shall maintain a complete file of all data pertaining to shop coat painting of structural steel. Complete and accurate records of each day of blast cleaning and painting operations shall be kept in a field book. All pertinent data which in any way affects painting procedures such as weather conditions, equipment, type of abrasives, etc. shall be recorded in the field book. Data and all significant information shall be promptly entered in the field book.
 
  
−
===712.2.7 Sample Record===
+
=====712.2.3.2.1 Sample sizes=====
−
The sample record shall be completed in SiteManager, as described in [[:Category:101 Standard Forms#Sample Record General Information| Sample Record General Information]] [[image:bulldozer.jpg|20px]], and shall indicate acceptance, qualified acceptance or rejection. Appropriate remarks, as described in [[106.20 Reporting|EPG 106.20 Reporting]], are to be included in the remarks to clarify conditions of acceptance or rejection.
 
  
−
====712.2.7.1 Miscellaneous Materials====
+
======712.2.3.2.1.1 ASTM A307 Bolts======
−
SiteManager is to be used to submit samples to the Laboratory and as an inspection report. If all tests are performed and acceptance or rejection is made in the field, the inspector may authorize the sample. Otherwise, the inspector's supervisor shall authorize the sample. Completion of sample records for materials purchased under a Department purchase order is to be as described in [[:Category:1101 Materials Purchased by a Department Purchase Order|EPG 1101 Materials Purchased by a Department Purchase Order]].
+
Samples for Laboratory testing are only required when requested by the State Construction and Materials Engineer, or when field inspection indicates questionable compliance. When samples are taken, they are to be taken as shown in the following table. When galvanized bolts, nuts and washers are submitted to the Laboratory, a minimum of 3 samples of each are required for Laboratory testing.  
  
−
====712.2.7.2 Shop Coat Painting====
+
<center>
−
SiteManager is to be used to report shop coat painting of fabricated structural steel bridge members. The fabricator will furnish to the inspector a copy of completed Form [[#Form B-179|Form B-179]], "Fabrication Inspection Shipment Release", Bridge, if the structural steel was inspected by the Bridge Division. Form B-179 will have been signed by the bridge inspector and shall also be signed by the shop coat inspector signifying approval and release for shipment of the itemized members after shop coating. A copy of this completed and signed form should be retained in the District files. There will not be a From B-179, “Fabrication Inspection Shipment Release”, Bridge Division, for supplementary items accepted on Brand Name Registration and Guarantee or Certification and mill tests. Shop coat inspection conducted by Materials personnel shall include the fabricator's job number, Laboratory number under which paint was tested, and the system of paint used. Each item is to be identified, showing quantity and shop mark. A record shall be made in SiteManager indicating that the material has been properly inspected and which contract it applies to.
+
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
 +
|+
 +
|-
 +
|width="300"|3 for lots of 0 to 800 pcs. ||rowspan="4"|Each sample is to consist of one bolt, nut and washer. Submit for dimensions, weight (mass) of coating, mechanical properties.  
 +
|-
 +
|6 for lots of 801 to 8,000 pcs.
 +
|-
 +
|9 for lots of 8,001 to 22,000 pcs.
 +
|-
 +
|15 for lots of 22,001+ pcs.
 +
|}
 +
</center>
  
−
<div id="Form B-179"></div>
+
======712.2.3.2.1.2 ASTM F3125 Grade A325 Bolts======
−
[[Image:712 Form B-179.gif|center|thumb|600px]]
+
Samples for Laboratory testing shall be taken and submitted as follows: All lots containing 501 or more, high strength bolts shall be sampled and submitted to the Laboratory for testing. If no lot offered contains 501 or more bolts, sample 10 percent of the lots offered, or one lot, whichever is greater. A lot is defined as all bolts of the same size and length, with the same manufacturer's lot identification, offered for inspection at one time. Samples shall be taken as follows:
 +
 
 +
<center>
 +
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
 +
|+
 +
! width="300" style="background:#BEBEBE" |Number of Bolts in the Lot!! style="background:#BEBEBE" |Number of Bolts Taken for a Sample'''*'''
 +
|-
 +
|150 and less ||3
 +
|-
 +
|151 through 800 ||3
 +
|-
 +
|801 through 8,000 ||6
 +
|-
 +
|8,001 through 22,000 ||9
 +
|-
 +
|22,001 plus ||15
 +
|-
 +
|align="left" colspan="2"|'''*''' A minimum of 3 samples will be required for galvanized materials.
 +
|}
 +
</center>
 +
All lots containing 501 or more, high strength nuts shall be sampled and submitted to the Laboratory for testing. If no lot offered contains 501 or more nuts, sample 10 percent of the lots offered or one lot, whichever is greater. A lot is defined as all nuts of the same grade, size, style, thread series and class, and surface finish, with the same manufacturer's lot identification, offered for inspection at one time. Samples shall be taken as follows:
 +
 
 +
<center>
 +
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
 +
|+
 +
! width="300" style="background:#BEBEBE" |Number of Nuts in the Lot!! style="background:#BEBEBE" |Number of Nuts Taken for a Sample'''*'''
 +
|-
 +
|800 and under ||1
 +
|-
 +
|801 through 8,000 ||2
 +
|-
 +
|8,001 through 22,000 ||3
 +
|-
 +
|22,000 and over ||5
 +
|-
 +
|align="left" colspan="2"|'''*''' A minimum of 3 samples will be required for galvanized materials.  
 +
|}
 +
</center>
 +
All lots containing 501 or more, high strength washers shall be sampled and submitted to the Laboratory for testing. If no lot offered contains 501 or more washers, sample 10 percent of the lots offered, or one lot, whichever is greater. A lot is defined as all washers of the same type, grade, size and surface finish, with the same manufacturer's lot identification, offered for inspection at one time. Samples shall be taken as follows:
 +
 
 +
<center>
 +
{| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
 +
|+
 +
! width="300" style="background:#BEBEBE" |Number of Washers in the Lot!!style="background:#BEBEBE" | Number of Washers Taken for a Sample'''* '''
 +
|-
 +
|800 and under || 1
 +
|-
 +
|801 through 8,000 || 2
 +
|-
 +
|8,001 through 22,000 || 3
 +
|-
 +
|22,000 and over || 5
 +
|-
 +
|align="left" colspan="2"|'''*''' A minimum of 3 samples will be required for galvanized materials.
 +
|}
 +
</center>
 +
 
 +
=====712.2.3.2.2 Bolts for Highway Lighting, Traffic Signals or Highway Signing=====
 +
 
 +
Bolts, nuts, and washers for highway lighting, traffic signals, or highway signing shall meet the requirements given in EPG 712.2.3.1.2 High Strength Bolts. Samples for Central Laboratory testing are only required when requested by the State Construction and Materials Engineer or when field inspection indicates questionable compliance.
 +
 
 +
====712.2.3.3 Slab Drains====
 +
Slab drains are to be accepted on the basis of field inspection of dimensions, weight (mass) of zinc coating, and a satisfactory fabricators certification.  The dimensions, weight (mass) of zinc coating, and material specification requirements are shown on the bridge plans.
 +
 
 +
Field determination of weight (mass) of coating is to be made on each lot of material furnished. The magnetic gauge is to be operated and calibrated in accordance with ASTM E376. At least three members of each size and type offered for inspection are to be selected for testing. A single-spot test is to be comprised of at least five readings of the magnetic gauge taken in a small area and those five readings averaged to obtain a single-spot test result. Three such areas should be tested on each of the members being tested. Test each member in the same manner. Average all single-spot test results from all members to obtain an average coating weight (mass) to be reported. The minimum single-spot test result would be the minimum average obtained on any one member. Material may be accepted or rejected for galvanized coating on the basis of magnetic gauge. If a test result fails to comply with the specifications, that lot should be resampled at double the original sampling rate. If any of the resampled members fail to comply with the specification, that lot is to be rejected. The contractor or supplier is to be given the option of sampling for Laboratory testing, if the magnetic gauge test results are within minus 15 percent of the specified coating weight (mass).
 +
 
 +
A fabricators certification shall be submitted to the engineer in triplicate stating that "The steel used in the fabrication of the slab drains was manufactured to conform to ASTM A709" or "A500, A501" as the case may be.
 +
 
 +
====712.2.3.4 Miscellaneous Structural Steel====
 +
Other structural steel items not requiring shop drawings also require inspection.  Inspection includes a fabricator's certification identifying the source and grade of steel, as well as verification of dimensions and inspection of any coating applied.  The report is to include the grade of steel, coating applied, and results of inspection.
  
 
==712.3 Lab Testing==
 
==712.3 Lab Testing==
Line 393: Line 680:
 
===712.3.2 Procedure===
 
===712.3.2 Procedure===
 
====712.3.2.1 Chemical Tests - Bolts, Nuts, and Washers====
 
====712.3.2.1 Chemical Tests - Bolts, Nuts, and Washers====
−
Weight (mass) of coating shall be determined in accordance with AASHTO M232. Chemical analysis of the base metal shall be determined, when requested, according to [[Category:1020 Corrugated Metallic-Coated Steel Culvert Pipe, Pipe-Arches and End Sections#1020.8 Laboratory Testing Guidelines for Sec 1020|Laboratory Testing Guidelines for Sec 1020. Original test data and calculations shall be recorded in Laboratory workbooks.
+
Weight (mass) of coating shall be determined in accordance with AASHTO M232. Chemical analysis of the base metal shall be determined, when requested, according to [[:Category:1020 Corrugated Metallic-Coated Steel Culvert Pipe, Pipe-Arches and End Sections#1020.8 Laboratory Testing Guidelines for Sec 1020|Laboratory Testing Guidelines for Sec 1020]]. Original test data and calculations shall be recorded in Laboratory workbooks.
  
 
====712.3.2.2 Physical Tests - Bolts and Nuts====
 
====712.3.2.2 Physical Tests - Bolts and Nuts====
−
Original test results and calculations shall be reported through SiteManager.
+
Original test results and calculations shall be reported through AASHTOWare Project.  
  
 
'''Low carbon steel bolts and nuts''' shall be tested according to ASTM A307. Tests are to be as follows:
 
'''Low carbon steel bolts and nuts''' shall be tested according to ASTM A307. Tests are to be as follows:
Line 404: Line 691:
 
Due to the shape and length of some bolts and the shape of some nuts, it may not be possible or required to determine the tensile strength of the bolts or the proof load of the nuts.
 
Due to the shape and length of some bolts and the shape of some nuts, it may not be possible or required to determine the tensile strength of the bolts or the proof load of the nuts.
  
−
'''High strength bolts, nuts, and washers''' shall be tested according to AASHTO M164. Tests are to be as follows:
+
'''High strength bolts, nuts, and washers''' shall be tested according to ASTM F3125 Grade A325. Tests are to be as follows:
 
:(a) Bolts shall be tested for dimensions, markings, hardness, proof load, and tensile strength.
 
:(a) Bolts shall be tested for dimensions, markings, hardness, proof load, and tensile strength.
 
:(b) Nuts shall be tested for dimensions, markings, hardness, and proof load.
 
:(b) Nuts shall be tested for dimensions, markings, hardness, and proof load.
Line 410: Line 697:
  
 
Due to the shape and length of some bolts and the size of some nuts, it may not be possible or required to determine the proof load and tensile strength of the bolts or the proof load of the nuts.
 
Due to the shape and length of some bolts and the size of some nuts, it may not be possible or required to determine the proof load and tensile strength of the bolts or the proof load of the nuts.
−
 
−
====712.3.2.3 Structural Steel Welding====
 
−
Tests are to be performed in accordance with AWS D2.0-69 and the 1970 supplement. This method specifies that tensile requirements for the reduced section tensile specimens and the all-weld-metal tensile specimens shall be determined in accordance with AASHTO T244.
 
−
 
−
'''Welding Procedure Qualification.''' Tests conducted for procedure qualification are as follows:
 
−
:(a) Groove welds for all welding procedures except electroslag and electrogas welding.
 
−
::(1) Limited thickness. Tests required for 3/8 in. (9.5 mm) welded test plate are:
 
−
:::Two root bend;
 
−
:::Two face bend and;
 
−
:::Two reduced section tensile tests.
 
−
 
−
::(2) Unlimited thickness. Tests required for welded test plate over 3/8 in.[9.5 mm] thick are:
 
−
:::Four side bend and;
 
−
:::Two reduced section tensile tests.
 
−
 
−
:(b) Groove weld tests required for procedure qualifications for electroslag and electrogas welding are:
 
−
::Four side bend;
 
−
::Two reduced section tensile and;
 
−
::One all-weld-metal tensile test.
 
−
 
−
:(c) Fillet weld procedure qualification requires five macroetch test specimens. The test specimens are evaluated for:
 
−
::Fusion;
 
−
::Fillet size and;
 
−
::Profile.
 
−
 
−
Test results and calculations shall be recorded through SiteManager.
 
−
 
−
'''Welder Qualification.''' Tests conducted for welder qualification are as follows:
 
−
:(a) Groove weld.
 
−
::(1) Limited thickness. Tests required for 3/8 in. (9.5 mm) welded test plate are:
 
−
:::One face bend and;
 
−
:::One root bend test
 
−
 
−
::(2) Unlimited thickness. Tests required for welded test plate over 3/8 in. [9.5 mm] thick are:
 
−
:::Two side bend tests.
 
−
 
−
:(b) Fillet weld.
 
−
::(1) Two root bend tests.
 
−
 
−
Test results shall be recorded through SiteManager.
 
−
 
−
'''Welder Operator Qualification.''' Test results shall be recorded through SiteManager. Tests required for welder operator qualification are:
 
−
:(a) Two side bend tests.
 
  
 
===712.3.3 Sample Record===
 
===712.3.3 Sample Record===
−
The sample record shall be completed in SiteManager, as described in [[:Category:101 Standard Forms#Sample Record General Information| Sample Record General Information]] [[image:bulldozer.jpg|20px]], and shall indicate acceptance, qualified acceptance, or rejection. Appropriate remarks, as described in [[106.20 Reporting|EPG 106.20 Reporting]], are to be included in the report to clarify conditions of acceptance or rejection.
+
The sample record shall be completed in AASHTOWARE Project (AWP), as described in [[:Category:101 Standard Forms#Sample Record, General|AWP MA Sample Record, General]], and shall indicate acceptance, qualified acceptance, or rejection. Appropriate remarks, as described in [[106.20 Reporting|EPG 106.20 Reporting]], are to be included in the report to clarify conditions of acceptance or rejection.
−
 
 
−
Test results for bolts, nuts and washers shall be reported through SiteManager.
 
  
−
Procedure qualification test results for structural steel welding shall be reported through SiteManager. Welder qualification and welder operator qualification test results shall be reported through SiteManager.
+
Test results for bolts, nuts and washers shall be reported through AWP.
  
 
[[image:712.3.3.jpg|center|1050px]]
 
[[image:712.3.3.jpg|center|1050px]]

Latest revision as of 07:45, 6 September 2024

Steel Girder Bridge, Testing, Load Rating
Report 1999
See also: Research Publications
Approved Products
Qualified Protective Coatings for Machined Finished Surfaces


Contents

712.1 Construction Inspection for Sec 712

The important feature of structural steel inspection includes such items as:

(a) inspection of handling, unloading, storing, and erecting of the various members to make sure they are not subjected to excessive stress
(b) erection with proper camber, adequately supported
450px
(c) use of the required number of pins and erection bolts to hold all members rigidly in place
(d) welding or bolting in such a manner that the designed stress and desired appearance is maintained. Any high strength bolts used as temporary erection bolts must be replaced with new permanent bolts.

Successful structural steel erection work will directly relate to skill of the workmen and thoroughness of the inspector. Welders must be qualified by passing required tests. Even though no tests are required for the bolting crew, the inspector has authority to insist that an experienced crew be used.

Fabrication Inspection Shipment Releases (FISRs) for structural steel and other metal products on structures such as decorative fences and similar steel fabrications are issued by the Bridge Division Fabrication Section inspector. These FISRs are issued by email to the fabricator and the Resident Engineer. The fabricator shall send these FISRs to the contractor. Refer to EPG 1080 Structural Steel Fabrication for more information regarding fabrication inspection shipment releases.

712.1.1 Expansion Joints

Expansion joints include all devices by which expansion due to temperature is dissipated within the joint instead of being transmitted to adjacent elements. Expansion joints will normally be provided for bridge superstructure steel, bridge decks and handrails. For this instruction, joints in floors and handrails will also be considered.

Prior to Setting Expansion Joints:

Check vertical and horizontal dimensions.
Check condition of joint upon delivery and provision for storage until installation.
Check filler material for closed joints.
Compute temperature correction.

During Construction:

Set joints according to temperature correction.
Align finger type joints exactly to ensure free movement without lateral contact.
If compressible fill material is specified, joints to be filled must be clean and all paint or rust adhering to the structural steel must be removed to obtain necessary adhesion for a waterproof joint. Provide bottom support to prevent it from falling out of the joint, if loosened.
Where the plans call for sealing of joints with hotpoured rubber-asphalt type compound, special care and equipment are required to obtain a satisfactory job. Heating of joint material must be done in a special double boiler kettle. Temperature of the material should be maintained at or very near that specified by the manufacturer. The joint must be dry and cleaned with air just ahead of the actual pouring operation. The joint should also be poured high to allow for settlement and contraction of joint material as it cools.
If sleeve type joints are specified, as in handrails, set the inside element symmetrically with outside so that no localized friction will prevent free action of the sleeve.
No material shall be allowed to enter the joint to prevent its free movement.

After Construction:

After normal dead load has been taken by all elements of the structure, check freedom of movement.
Check final position of joint against computed position for the current temperature.
Remove any foreign material which may have entered the joint during construction.

712.1.2 Expansion And Contraction Computations

Expansion joints at ends of continuous units should be set carefully for elevation and opening, as well as checking the meshing of fingers in finger joints. Joint openings are given on bridge plans for a specified temperature, usually 60° F. Should the joint be set at a temperature other than specified, the opening must be adjusted. The coefficient of expansion of steel is 0.0000065 per degree F. Suppose for instance, that a joint opening is given as 1-1/8 in. at 60° F and the sum of the distances each side of the joint to the adjacent fixed shoes in the bridge is 165 ft. Assume temperature of the structural steel to be 95° F when this joint is set. The correction is found by multiplying the difference in degrees coefficient of expansion of steel; that is:

(95° - 65°) x 165 ft. x 0.0000065 per degree
= 35 x 165 x 0.0000065
= 7/16 in.

Since the temperature when setting the joint was greater than 60° F, at which the joint was computed, the correction of 7/16 in. should be deducted if the joint is to give 1-1/8 in. opening at 60°. The opening at which the joint should be set at 95° would be 1-1/8 in. less 7/16 in. or 11/16 in. Likewise if the temperature at which the joint is set should be lower than that given on the plans, the correction should be added to the joint opening to give the required opening at plan temperature. Both sides of each joint should be set in place and checked for alignment and fit before any permanent connections are made to either side to ensure: (1) smooth riding surface, (2) proper depth of concrete slab, and (3) a joint which will operate correctly with expansion and contraction movements of the bridge.

For bearing devices, specified temperatures will be used as the basic temperature on which to base an allowance for expansion or contraction. Rockers and rollers should be vertical and masonry plates in a neutral position for full dead load at this specified temperature. The masonry plates shall be placed in this position for all degrees of temperature but the rockers shall be tipped in the proper direction and the rollers placed in the required position to compensate for the amount of expansion or contraction of steel at the time they are placed.

712.1.3 Bearings

Bearings are devices for transferring superstructure loads to bridge seats. They include masonry bearing plates, elastomeric pads, shoes, rockers, rollers, and combinations of them some of which may be teflon coated. Anchors are the means of preventing movement of bearing devices on bridge seats and include anchor bolts, bars, or structural shapes. Earthquake retainers are provided on some bridges to prevent the bearing devices from moving off the bearing area.

Prior to setting of Bearings or Anchorage:

Check vertical and horizontal dimensions.
Check condition of bearing upon delivery and provisions for storage until installation.
Inspect bridge seats to ensure that they are finished to receive bearings.
If anchorages have been cast in place during construction of bridge seat, check for accuracy.
Compute temperature correction.

During Construction:

Anchor bolt wells which are formed will be detailed on the bridge plans typically. Holes for anchor bolts may be drilled as a contractor option and will be noted on the plans typically. Either wells or holes must be kept free of water in freezing weather.
Position of anchor bolts with respect to expansion bearing details shall correspond with the position indicated for the temperature at time of erection.
Formed wells or drilled or formed holes will be backfilled after anchors are set with non-shrink grout completely filling the space in the hole.
Correct any irregularities in bearing plate areas of bridge seat.
Set bearing plates in exact position with full uniform bearing on contact surface.
Unless otherwise specified, contact surfaces shall be painted in accordance with the specifications. Compressed rubber and fabric pads shall be placed under the bearing plates as shown on the plans.
Rocker or roller, if used, shall be set in the position dictated by temperatures at time of setting.
Where expansion bearings include sliding plates of different coefficients of friction, care must be taken not to reverse the position of the two plates with respect to each other and to the bridge seat.

712.1.4 Welding

712.1.4.1 Field Welding

Welding Safety Tips
712.1.4.1.1 Field Welder Cards

Specifications require that field welders shall be certified by an established facility with an accredited American Welding Society (AWS) certification program defined in the current AWS Standard QC4. Welders shall be certified per the current QC7 Standard for AWS Certified Welders. The code of acceptance shall be in accordance with Sec 1080.3.3.4 Applicable Codes. Welders who have successfully completed the certification program will be issued an AWS Welder Card. AWS also has an agreement with the Ironworkers Union that allows them to be accredited test facilities for Ironworkers Union members that meet the same requirements of QC4 and QC7. A copy of the AWS Welder card and the Ironworkers Union card are shown:

712.1.4.1.1.jpg

The AWS website has a link that provides guidance on interpreting the information that is shown on the back of the cards furnished by both AWS and the Ironworkers Union. A link to the AWS website that provides both locations of accredited test facilities (ATF) and interpretation of the welder card information is available.

AWS certification shall be considered in effect indefinitely provided that the welder remains active in the process that they are qualified for without an interruption greater than six months and there is no specific reason to question the welder’s ability to produce quality welds. Certification maintenance is the responsibility of the welder and shall be presented to the engineer upon request. The welder shall present a copy of their AWS or Ironworkers Union card to the engineer prior to welding. Welders that have tested within six months of welding on a project may have a temporary certification letter provided by the test facility that may be used while the card is being produced. Certification maintenance shall be in accordance with AWS QC7 and the supplement QC7G. Questions regarding the validity of temporary cards may be directed to the Construction and Materials Division.

If the engineer has reason to question the ability of the welder, a retest should be requested. Retests shall be conducted by an AWS accredited test facility.

712.1.4.1.2 Field Welding Minimum Certifications

For inspection purposes some of the specific types of work and the minimum required position certification are as shown in the following table:

Type of Work Required Position Certification
Steel Pile Splices (HP & Shell Piles) 2G
Steel Pile Points (HP & Shell Piles) 2G
Stay-in-Place Form Support Angles None
Girder/Beam Flanges to Bearing Plates 2G
Stiffeners 3G
Anything else not listed 3G unless otherwise specified by the Engineer.

A welder qualified for one position also qualifies for performing other welds as shown in the following table:

Certified Position Qualified to Perform
1G 1F, 2F, 1G
2G 1F, 2F, 1G, 2G
3G 1F, 2F, 3F, 1G, 2G, 3G
4G 1F, 2F, 4F, 1G, 4G
3G & 4G All Groove and Fillet Positions
1F 1F
2F 1F, 2F
3F 1F, 2F, 3F
4F 1F, 2F, 4F
3F & 4F All Fillet Positions
KEY: 1=flat, 2=horizontal, 3=vertical, 4=overhead, G=groove, F=fillet

Examples of the weld positions for groove welds and fillet welds are as follows:

712.1.4.1.2.jpg

In most cases, a welder may elect to take one of two test plate thicknesses. A limited thickness test will be taken on a 3/8 in. test plate. This will qualify a welder for groove welds of a maximum plate thickness of 3/4 in. and fillet welds on plates of unlimited thickness. An unlimited thickness test will be taken on a 1 in. thick plate and qualifies the welder for unlimited plate thickness for both groove welds and fillet welds. The welder’s card that is to be presented at the job site will show both the test plate thickness as well as the plate thickness limitations.

712.1.4.1.3 Shear Connector Welding

Current practices by the contractor may utilize the installation of shear connectors by field personnel. Most shear connector welding is completed by an automated welding process. AWS does not have a qualification procedure established in QC7. Instead, welders shall be qualified in accordance with 2002 AWS Bridge Welding Code D1.5 Clause 7.7 by MoDOT field personnel. Shear connector welders shall be qualified by conducting a preproduction test. This test involves the welder welding two shear connectors to a test plate or to the production plate. The test specimens shall be visually inspected to ensure a full 360° weld. After the welds have cooled, the shear connectors shall then be bent to an angle of approximately 30° from the original axis by either striking with a hammer or placing a pipe over the shear connector and then bending. If the shear connector does not exhibit a complete weld or a failure occurs in the weld of either shear connector, the welder shall adjust the automatic welding machine and retest on a separate weld test plate. The welder may not retest on the actual production plate.

Before shear connector production welding in the field begins with a particular welder set-up, a specific shear connector size or type, and at the beginning of production for a particular shift or day, a preproduction test shall be conducted. The preproduction test shall be conducted on the first two shear connectors welded to the production plate or may be conducted on a separate test plate of the same thickness (+/- 25%). The acceptance method is the same as given earlier for the welder test.

Once shear connector production welding has commenced, any welds that do not exhibit the full 360° weld may be repaired using a 5/16 in. fillet weld for shear connector diameters up to one inch and 3/8 in. for diameters greater than one inch. The repair weld shall extend 3/8 in. beyond the end of the area to be repaired.

Additional verification of shear connector welds in the field will be performed by sounding a random 25% of the shear connectors on the girder/beam with a sledge hammer. The field inspector will also sound 25 percent of the shear connectors used on expansion device(s) whether shop or field installed. A sharp ping sound is heard on a good weld. A thud sound will occur if the weld is possibly not sufficient and a bent test needs to be performed on this shear connector. A random 5% of all shear connectors will be bent to an approximately 30° from the original axes to verify the integrity and welding of the shear connector. If a failed weld is discovered, all adjacent connectors shall be tested. Particular emphasis on testing shall be at the start-up of the welding operation. Once an acceptable welding process is established, any weld failures should be rare. For a large bridge with many shear connectors, the 5% testing rate may be decreased at the engineer’s discretion. Any failed welds shall be ground off, base metal pull outs repaired by approved weld procedures, weld surface ground flush and a replacement shear stud installed.

On a re-deck project, some shear connectors may be bent from the deck removal or from the original construction testing. These shear connectors do not have to be replaced or straightened. Shear connectors on new or re-deck projects may also need to be field bent to accommodate expansion joints, rebar conflicts or other construction needs. If a shear connector is severely bent where concrete coverage is compromised, the shear connector shall be removed and replaced.

712.1.4.1.3.jpg
712.1.4.1.4 Acceptable Field Welding Processes

All field welding using flux cored arc welding (FCAW) shall require welding procedures be submitted to the Bridge Division (Fabrication@modot.mo.gov) for acceptance prior to any welding on any bridge. All field welding using shielded metal arc welding (SMAW or commonly known as stick welding) shall require welding procedures be submitted to Bridge Division (Fabrication@modot.mo.gov) for acceptance prior to any welding on major bridges (total length ≥ 1000 feet), bridges with structural steel with fy ≥ 70,000 psi (fs ≥ 38,000 psi), truss bridges, bridges with 2 girder systems and bridges containing fracture critical members (FCM). All other locations with SMAW, the contractor shall have field welding procedures on file prior to welding and available at the engineer’s request.

MoDOT permits only two specific welding processes for field welding on steel bridges. These processes are SMAW and FCAW. The preferred method for field welding is SMAW. SMAW on structural steel (fy < 69,000 psi, fs < 37,000 psi) that will be coated are to be welded with E7018, low hydrogen electrodes. SMAW on uncoated (weathering) structural steel (fy < 69,000 psi, fs < 37,000 psi) are to be welded with E8018, low hydrogen weathering steel electrodes. Welding on structural steel with fy ≥ 70,000 psi (fs ≥ 38,000 psi) and fracture critical members (FCM) are to be determined by weld procedures which shall be submitted to the Bridge Division (Fabrication@modot.mo.gov). FCAW always require welding procedures be submitted to Bridge Division since the welding code requires procedure qualification record (PQR) for the welding procedures. FCAW on structural steel is preferred to be completed with a self-shielded process where no shielding gas is used. This will be noted on the welder’s card as FCAW-S. Gas shielding for FCAW is discouraged due to the additional requirements to provide protection of the weld area from gas dispersion caused by the wind but FCAW can be used provided the weld area is shielded properly from wind.

Welding of aluminum products in the field may be completed using gas metal arc welding (GMAW or commonly known as MIG welding) or with SMAW with special aluminum electrodes. Like FCAW welding using gas shielding, the weld area must be protected to prevent shielding gas dispersion when welding with GMAW. GMAW is the preferred method of welding aluminum by AWS. However, SMAW may be used provided that special care is taken during welding to control the welding parameters and that all welding slag is removed.

712.1.4.2 Shop Welding

Fabrication shops shall qualify welders in accordance with the governing welding code for the specific process as required in Sec 1080.3.3.4. It is the responsibility of the fabrication shop’s quality control personnel to ensure that the welder’s test documentation and period of effectiveness are documented and maintained.

712.1.5 High Strength Bolts (Sec 712.7)

Bolts, nuts, and washers must meet applicable requirements of AASHTO as noted in Sec 1080.2. ASTM F3125 Grade A325 bolts shall be used on bridge connections unless other types of bolts are specified in the contract. To facilitate easy identification of high strength bolts, the following figure shows some of the typical bolt markings required by the ASTM specification.

Bolt/Nut Type 1 (Plain or Galvanized) Type 3 (Weathering)
ASTM F3125 Grade A325 712.1.5 A325.jpg
Three radial lines 120°
Apart are optional		 712.1.5 A325 line.jpg
ASTM F3125 Grade A490 712.1.5 A490.jpg 712.1.5 A490 line.jpg
ASTM A563 Nuts Type 1
Plain 		Type 1
Galvanized		 Type 3
Plain
712.1.5 XYZ.jpg
Arcs Indicate
Grade C
(Grade A325 bolt)
712.1.5 XYZ3.jpg
Arcs with “3”
Indicate
Grade C3
(Grade A325 bolt)		 712.1.5 XYZ.jpg
Arcs with “3”
Indicate
Grade C3
(Grade A325 bolt)
712.1.5 XYZD.jpg
Grade D
(Grade A325 bolt)
712.1.5 XYZDH.jpg
Grade DH
(Grade A325 bolt and
Grade A490 bolt)		 712.1.5 XYZDH.jpg
Grade DH
(Grade A325
bolt)		 712.1.5 XYZDH3.jpg
Grade DH3
(Grade A325
bolt)		 712.1.5 XYZDH3.jpg
Grade DH3
(Grade A490
bolt)
712.1.5 XYZDH3.jpg
Grade DH3
(Grade A325bolt and
Grade A490 bolt)
(Reprinted and modified from AISC Steel Construction Manual, 15th Ed., Table 2.1 and Figure C-2.1).
Note: XYZ represents the manufacturer’s identification mark.

A permissible alternate type of nut may be furnished. Such nuts would be marked with the symbol 2 or 2H and the manufacturer's symbol.

Bolts tightened by the calibrated wrench or turn-of-nut method should be checked following the procedures outlined in the Standard Specifications.

The sides of bolt heads and nuts tightened with an impact wrench will appear slightly peened. This will indicate that the wrench has been applied to the fastener.

712.1.5.1 Bolted Parts

Sec 712.7.1 covers cleaning of parts to be bolted. Bolts, nuts, and washers will normally be received with a light residual coating of lubricant. This coating is not considered detrimental to friction type connections and need not be removed. If bolts are received with a heavy coating of preservative, it must be removed. A light residual coating of lubricant may be applied or allowed to remain in the bolt threads, but not to such an extent as to run down between the washer and bolted parts and into the interfaces between parts being assembled.

712.1.5.2 Bolt Tension

A washer is required under nut or bolt head, whichever is turned in tightening, to prevent galling between nut or bolt head and the surface against which the head or nut would turn in tightening, and to minimize irregularities in the torque-tension ratio where bolts are tightened by calibrated wrench method. Washers are also required under finished nuts and the heads of regular semi-finished hexagon bolts against the possibility of some reduction in bearing area due to field reaming. When oversized holes are used as permitted by the contract, a washer shall be placed under both the bolt head and the nut.

Standard Specifications require that bolt torque and impact wrenches be calibrated by means of a device capable of measuring actual tension produced by a given wrench effort applied to a representative sample. Current specifications require power wrenches to be set to induce a bolt tension 5 percent to 10 percent in excess of specified values but the Special Provisions for the project should be checked for a possible revision to this requirement.

The contractor is required to furnish a device capable of indicating actual bolt tension for the calibration of wrenches or load indicating device. A certification indicating recent calibration of the device should accompany it. It is recommended that the certification of calibration be within the past year but if the device is being used with satisfactory results, the period may be extended. More frequent calibration may be necessary if the device receives heavy use over an extended period.

The contractor will generally use either the calibrated wrench method or the turn-of-nut method for tightening bolts as outlined in Sec 712.7. The sides of bolt heads or nuts tightened with an impact wrench will appear slightly peened. This will usually indicate that the wrench has been applied to the fastener. If the wrench damages the galvanized coating, the contractor shall repair the coating by an acceptable method.

712.1.5.3 Rotational-Capacity Testing and Installation of ASTM F3125 Grade A325 Type 3 Bolts

Type 3 (weathering steel) bolts behave quite differently than the galvanized bolts used in most MoDOT structures and require additional care to test and install properly.

The contractor must keep bolts stored in sealed kegs out of the elements until ready for use. Storage in a warehouse, shed, shipping container or other weatherproof building is best. The lubricant used on Type 3 bolts dissipates quickly, allowing rust to begin. Kegs should not be opened until absolutely necessary and promptly resealed whenever work stops.

If bolts fail the rotational-capacity test, insufficient lubrication is the most likely cause. Relubrication of Grade A325 bolts is allowed. Several different waxes and lubricants are suggested by FHWA, including Castrol 140 Stick Wax (which has been successfully field tested by MoDOT), Castrol Safety-Film 639, MacDermid Torque’N Tension Control Fluid, beeswax, etc.

Galling of the washer may occur, especially with longer bolts. This can be reduced by lubricating the contact area of the bolt face at the washer with an approved lubricant. If this face is lubricated for testing, it must also be lubricated during bolt installation.

Failure of the bolts due to galling of the washer can also be prevented by turning the nut in one continuous motion during testing. For larger diameter bolts, this can be a problem. Torque multipliers amplify this effect. If many larger diameter bolts will be tested, ask the contractor to purchase an electric gear reduction wrench with reaction arm. The Skidmore will need to have a reaction kit installed. This wrench will produce better results and save time spent performing tests (and, therefore, lower costs).

For long bolts, (L>8d), use proper spacer bushings on the back of the Skidmore to avoid excessive use of spacers between the washer and front plate of the Skidmore. Stacking spacers can cause bending of long bolts, which will cause inaccurate results, false failures and potential damage to the Skidmore. Consult the Skidmore user manual for maximum allowable spacer lengths.

712.1.5.4 Bolt Testing and Verification

Bridges are designed so that many of the steel-to-steel connections that are made in the field are slip-critical connections. Slip-critical means that once the bolt is tightened, the bolt and the pieces of steel (or plies) will not move. It relies on the bolt to clamp down on the steel and create so much force between the steel plates that they will not move at all. Should they slip and move it would be a critical issue for the bridge.

When it comes to bolt design, the bolt is being tensioned in order to establish the clamping force needed. The tightening of the nut on the bolt is what produces the needed tension. Bridge Designers will design each of these joints based on established minimums for each bolt size. So, for example, a Bridge Designer will assume that an ASTM F3125 Grade A325 7/8” diameter bolt will be able to supply 39,000 pounds of clamping force. This means that the contractor in the field must ensure that they are tightening each bolt to this tension.

In order to verify that the bolts are installed correctly in the field, it is essential that contractors and inspectors understand the requirements of bolted connections, and the specifications that govern them. For this work, Sec 712 Structural Steel Connection and Sec 1080 Structural Steel Fabrication will primarily be consulted.

The general steps are:

Step 1, Determine Bolt Type
Step 2, Inspection Type Selection
Step 3, Rotational Capacity Test
Step 4, Installation
Step 5, Bolt Verification
712.1.5.4.1 Step 1, Determine Bolt Type

The first step is to review the contractor’s submittals to see what kind of bolts they will be using. You can also look at the bolts in the field to check for the bolt type. Table 712.1.5.4.1 shows what is on the hex head of the bolt, and how the markings can show what type of bolt it is.

Table 712.1.5.4.1
Bolt/Nut Type 1 (Plain or Galvanized) Type 3 (Weathering)
ASTM F3125 Grade A325 712.1.5 A325.jpg
Three radial lines 120°
Apart are optional		 712.1.5 A325 line.jpg
ASTM F3125 Grade A490 712.1.5 A490.jpg 712.1.5 A490 line.jpg

Below is a section from ASTM F3125 that governs the testing requirements for these types of high-strength bolts. The text shown is a portion of the test method that deals with lot control. It is an expectation of the standard that not only are all high-strength bolts produced meeting the material properties specified, but the manufacturer also must produce these bolts with a specific tracking procedure that reduces groups of bolts into lots. The lots are a set of bolts that are represented by material tests to prove they meet requirements. Each of these sets of bolts are tracked with paperwork and lot identification numbers. Not only are the bolts produced this way, but also all the nuts and washers have specific lots assigned. When a bolt, nut, and washer are put together and sold together, they are referred to as an assembly. Once one piece of the assembly changes, the properties of the bolt could potentially have been changed.

712.1.5.4.1 A325.jpg

Figure 712.1.5.4.1.1 and 712.1.5.4.1.2 below are of bolt heads to show different types and Figure 712.1.5.4.1.3 shows a copy of common shipping form that provides testing verification of the bolts.

Figure 712.1.5.4.1.1, A325/A490 will be stamped on the head of the bolt
Figure 712.1.5.4.1.2, A325TC/A490TC Tension Control Bolt
These bolts will follow requirements of A325 or A490 listed on bolt. They will list Standard Number and then TC.
712.1.5.4.1.3.jpg
Figure 712.1.5.4.1.3, Copy of Shipping Paperwork
712.1.5.4.2 Step 2, Inspection Type Selection

The second step is to determine the inspection type. The information below shows how to proceed once it is determined what type of bolt is being used in the field. The bolt type and verification method available will dictate the options and the requirements needed to follow for inspection in the field.

Prior to going into the field, determine the bolt type and the inspection method that will be used. This will allow you to know the equipment needed and discuss test procedures with the contractor. For some test methods, the contractor will provide the calibrated equipment to check the bolts.

712.1.5.4.2.1 Bolt Type

The first step is to find out what type of bolt you are using in the field. The bolt type will dictate how much information is needed for the Rotational Capacity Testing.

712.1.5.4.2.2 A325/A490 Hex Head Bolt

The use of A325/A490 bolts will come with standard nuts, bolts, and washers. These will be tightened in the field using air tools and torque wrenches.

Rotational Capacity Testing is based on Table 712.1.5.4.3.1, Long Bolts, or 712.1.5.4.3.2, Short Bolts. Bolt checks will need to address questions shown in the table used.

Bolt inspection acceptance by calibrated wrench will be made using Sec 712.7.5 and Sec 712.7.12(c).

Bolt inspection acceptance by turn-of-nut method will be made using Sec 712.7.6 and Sec 712.7.12(c).

712.1.5.4.2.3 A325TC/A490TC Tension Control Bolt

The use of A325TC/A490TC bolts will come with nuts, bolts and washers. These will be tightened in the field using a specialized tool designed to tighten the nut and the spline of the bolt.

Rotational Capacity Testing is based on Table 712.1.5.4.3.3. Bolt checks will need to address questions shown in the table.

Bolt inspection acceptance by load indicating bolt method will be made using Sec 712.7.7 and Sec 712.7.12(c).

712.1.5.4.3 Step 3, Rotational Capacity

The third step is to verify that the bolts on the jobsite are going to perform as intended by the design team. Each of these bolts must achieve a specific tension that will be confirmed using the Rotational Capacity Testing. This test is described in Sec 712.7 and Sec 1080.2.5.4.

The goal of the Rotational Capacity test is to verify that the bolts will perform as intended. The main component that is being tested is that the bolts can be brought to the correct tension. This must be accomplished without applying too much torque to the bolts and field installed bolts will be turned to the correct rotation meeting or exceeding the design tension for the fastener. For the bolts to work correctly, it is critical for the threads to be clean and there must be plenty of lubricant on the bolts and nuts. There is a chance that the protective coatings and lubricants will be washed away anytime the bolts, nuts, and washers are allowed to sit out in the elements. In addition, there is a chance that rust could develop from water being on the bolts, and carelessness could lead to physical damage of the bolts. Any of these issues could cause the bolts and the nuts to not interact as designed. It may take more torque to achieve the needed tension in the bolts or the installed fasteners cannot be checked accordingly with a torque wrench.

The bolt manufacturer may provide documentation to show that a Rotational Capacity Test (RoCap) has been performed. The inspector and contractor will still have to perform Rotational Capacity Tests in the field even if this paperwork is provided. According to Sec 712.7.10, “rotational capacity test shall be performed on 3 bolts of each rotational-capacity lot prior to the start of bolt installation.” All bolt assemblies provided shall be a part of a rotational capacity lot, which means that all bolt assembly lots used on MoDOT jobs shall be tested on the jobsite prior to incorporation. The first time a new lot of bolts is opened, plan on performing the test. Also, the Rotation Capacity Test should be run any time questions or issues arise when torqueing a bolt to achieve design tension, or bolt hardware conditions change.

The RoCap test should only be run once per lot, unless one of the following conditions occur:

1. Bolts arrive on the jobsite for the first time
All bolt assembly lots must be tested once they are on the jobsite. If conditions do not change, then the one test should suffice.
2. Bolt, washer, or nut lots have been interchanged
It is important when the Rotational Capacity test is run that lot numbers for all the individual pieces (bolts, nuts, and washers) remain the same. Once any of these lots change, the Rotational Capacity test must be run again.
3. Bolt lubrication appears to have been compromised
Once a Rotation Capacity test has been run, another one will not have to be run, unless the bolt condition changes. One aspect that is a factor is bolt lubrication. If the bolt is left in the wind and rain, the lubrication likely will be compromised. Once it is noticed that a bolt lubrication has changed, the Rotation Capacity test must be run again.
4. Bolts appear rusty or damaged
Rust is the far extreme of a lack of lubrication. Not only has the lubrication gone away, but the protective coating is gone, and the bolt has been allowed to rust. They will need to be cleaned, re-lubricated and tested again for Rotation Capacity.
712.1.5.4.3 skidmore.jpg

There is not a way to test tension once the bolt has been tightened. The Rotational Capacity Test is a way to verify not only that the bolts are in good condition, but also that they have not been impacted by field conditions. The test will require two components. One component is to visually inspect the bolts and record the results on the form provided in eProjects. The second component is to run tests on the three bolts in the field using a Skidmore-Wilhelm Bolt tension measuring device and a torque wrench. Both the Skidmore and torque wrench must have a calibration performed on it within the previous year from the manufacturer or a test lab. There must be a sticker on it, as well as all supporting documentation to show it has been calibrated.

RoCap Test Form Long Bolts are shown in Table 712.1.5.4.3.1 and Table 712.1.5.4.3.3, RoCap Test Form Short Bolts are shown in Table 712.1.5.4.3.2. These forms will assist in obtaining all the required information for the testing methods allowed by MoDOT.

Table 712.1.5.4.3.1 and Table 712.1.5.4.3.2 is to be used when the Calibrated Wrench (Sec 712.7.5) or Turn-Of-Nut (Sec 712.7.6) Methods are used. By running the calculations in the spec book to verify the bolts, the values needed for the equipment in the field will also be determined. The entire test will need to be completed to verify that the bolt is good for use in the field.

Calibrated Wrench – The values from Table 712.1.5.4.3.1 and Table 712.1.5.4.3.2 that will be needed are the recorded Torque Values.
Turn-Of-Nut – When using the Turn-Of-Nut Method, the Rotation Capacity Test provides a check that the turn requirements of Sec 712.7.6 will generate the minimum tension required. Verify that the amount the nut has turned going to the minimum bolt tension is less than the specified nut rotation in Sec 712.7.6 Nut Rotation from Snug Tight Condition table.

The RoCap test for Calibrated Wrench and Turn-Of-Nut Methods is split based on long and short bolts. Long bolts are those bolts that can fit into the Skidmore-Wilhelm Bolt Tension Measuring Device or the Skidmore-Wilhelm short bolt setup. Short bolts are those that are too short to fit into the short bolt setup tension measuring device.

Table 712.1.5.4.3.1 provides info about how to run the test, and the information to be recorded.

Rotation Capacity Testing Steps for Calibrated Wrench Method (Sec 712.7.5) and

Turn-Of_Nut Method (Sec 712.7.6)

Table 712.1.5.4.3.1

Job Site Rotational Capacity Test (RoCap Test) – A325 & A490 Long Bolts

Test No.
 Part 1 Part 2
Sec 712.7.3 Minimum Bolt Tension (P)
Less Than
 Bolt Tension Gauge Reading (P) Sec 1080.2.5.4.6 Maximum Allowable Torque (T)
Greater Than
 Torque Gauge Reading Actual Nut Rotation (turn) Sec 721.7.6 Nut Rotation (turn) Less than actual(Y/N) Sec 1080.2.5.4 Required Rotation (turn) Tension Gauge Reading
Equal or Greater Than
 Sec 1080.2.5.4.5 Required Turn Test Tension
1 < > >=
2 < > >=
3 < > >=
R1 < > >=
R2 < > >=
R3 < > >=
Torque Formula (T=0.25P x Dia./12), T in ft-lbs, P in lbs, Bolt Dia. in inches

Long Bolt Test

1. Measure the ratio of diameter/length of the bolt.
2. Place the bolt into the Skidmore and set it to snug tight (10% of installation tension in Sec 712.7.3 Bolt Tension Table). This is to be done with a spud wrench. The contractor should add washers until three to five threads are in the grip, if less than 3 threads, the test will fail. Mark reference rotation marks on the fastener assembly element turned and on face plate of Skidmore. (Mark starting point on bolt end, nut and calibrator face with straight line.) Note that some short bolts may require the shortbolt setup for the Skidmore.
3. Turn the fastener with the wrench to be used for the daily testing in the field to the installation minimum tension in Sec 712.7.3 Bolt Tension Table. Stop and record the torque at that moment from the torque wrench and record the tension on the Skidmore. Verify the recorded torque does not exceed the maximum allowable torque (refer to Sec 1080.2.5.4.6 formula). Verify that the amount the nut has turned going to the minimum bolt tension is less than the specified nut rotation in Sec 712.7.6 Nut Rotation from Snug Tight Condition table.
712.1.5.4.3 Bolt-test 2022.png
4. Further turn the bolt according to Sec 1080.2.5.4.4. This rotation is measured from the initial match mark made in step 2. . Record the tension achieved and then compare the tension at this point to the Turn Test Tension in Sec 1080.2.5.4.5 Required Bolt Tensions Table. The tension must be equal or greater than Turn Test Tension.
5. Remove the bolt and inspect for damage and record it on our form. Turn the nut by hand on the bolt threads to the position it was in during the test. Not being able to turn the nut by hand is thread failure.
6. Repeat the process 2 additional times for each type of bolt assembly (Total of 3 tests per assembly lot).
7. Once the 3 tension and torque values have been obtained from Step 3, use the higher of the 3 numbers.

Table 712.1.5.4.3.2 provides info about how to run the short bolt test for those bolts that are too short to fit into the Skidmore-Wilhelm short bolt setup tension measuring device and the information to be recorded.

Rotation Capacity Testing Steps for Calibrated Wrench Method (Sec 712.7.5) and

Turn-Of_Nut Method (Sec 712.7.6)

Table 712.1.5.4.3.2

Job Site Rotational Capacity Test (RoCap Test) – A325 & A490 Short Bolts

Test No. Sec 1080.2.5.4.5 Turn Test Tension (P) 20% of Max. Turn Test Torque (T) Maximum Calculated Turn Test Torque Greater Than Torque Gauge Reading at End of First Rotation Visual Inspection of nut and bolt after Second Rotation (Acceptable/Not Acceptable)
1 >
2 >
3 >
R1 >
R2 >
R3 >
20% Torque Formula (T = 0.20T), T in ft-lbs.
Torque Formula (T=0.25P x Dia./12), T in ft-lbs., P in lbs., Bolt Dia. in inches
First Rotation [L<= 4D, 1/3 turn (120°)], [4D< L<8D, 1/2 turn (180°)]
Second Rotation A325 [L<= 4D, 1/3 turn (120°)], [4D< L<8D, 1/2 turn (180°)]

A490 [L<= 4D, 1/4 turn (90°)], [4D< L<8D, 1/3 turn (120°)]

Short Bolt Test

1. Measure the ratio of diameter/length of the bolt and refer to Sec 712.7.6 on the installation rotation.
2. Place the bolt into the steel plate. The contractor should add washers until three to five threads are in the grip, if less than 3 threads the test will fail. Set it to snug tight (Not exceed 20% of maximum torque at first rotation). Maximum torque at first rotation is equal to Turn Test Tension, Sec 1080.2.5.4.5 and applying that tension to the torque formula in Sec 1080.2.5.4.6. This is to be done with a measuring torque wrench.
712.1.5.4.3 Bolt-test 2022.png
3. Mark reference rotation marks on the fastener assembly element turned and on face of steel plate. (Mark starting point on bolt end, nut and steel plate face with straight line.)
4. Turn the fastener with the torque wrench to be used for the daily testing in the field to the rotation shown in Sec 712.7.6 Nut Rotation from Snug Tight Condition Table. Once the first target rotation has been reached, stop and record the torque at that moment from the torque wrench. Verify the recorded torque does not exceed the maximum torque. Maximum torque at first rotation is turn test tension, Sec 1080.2.5.4.5 with torque formula Sec 1080.2.5.4.6, as shown in step 2.
5. Further turn the bolt further according to Sec 1080.2.5.4.4. This rotation is measured from the initial match mark made in step 3. Assemblies that strip or fracture prior to this rotation fail the test.
6. Remove the bolt and inspect for damage and record it on our form. Turn the nut by hand on the bolt threads to the position it was in during the test. Not being able to turn the nut by hand is thread failure.
7. Repeat the process 2 additional times for each type of bolt assembly (Total of 3 tests per assembly lot).
8. Once the 3 torque values have been obtained from Step 3, use the higher of the 3 torque numbers.


Rotation Capacity Testing Steps For Load Indicating Bolt Method (Sec 712.7.7)

The Load Indicating Bolt Method is less common. The bolt is designed to automatically verify that the bolts are not overtightened. The Rotational Capacity test in the field is to verify that the threads are not binding due to rust and dirt. This binding will give a false reading and cause the bolt spline to shear off prior to the design tension being achieved. Also due to the consistency of the bolt, there will not be a need to tighten the bolt to 1.15 times the Minimum Target Tension. The spline of the bolts will snap off within 5-10% of the designed tension of the fastener and exceed the Minimum Target Tension when properly lubricated.

Table 712.1.5.4.3.3 provides info about how to run the test, and the information to be recorded.

Table 712.1.5.4.3.3

Rotation Capacity Testing Steps for Load Indicating Bolt Method (Section 712.7.7)

Job Site Rotational Capacity Test A325/A490 Bolts
Test No. Sec 712.7.3 1.05xMinimum Bolt Tension (P) Less Than Bolt Tension Gauge Reading (P) Inspection Torque Calculated Value
1 <
2 <
3 <
R1 <
R2 <
R3 <
(Inspection Torque formula = 0.95 x 0.25 x Gauged Tension Reading x Bolt Dia. / 12; Bolt Dia. in inches)
1. Measure the ratio of diameter/length of the bolt.
2. Place the bolt into the Skidmore and set it to snug tight (10% of installation tension). This is to be done with a spud wrench. The contractor should add washers until only three threads are showing.
3. Place the specialty tool used on the end of the bolt and tighten until the spline of the bolt snaps off.
4. Record the tension value on the Skidmore once the bolt has snapped.
5. Verify that the recorded value is greater than 1.05 times the Minimum Target Tension from Sec 712.7.3.
6. Remove the bolt and inspect for damage.
7. Repeat the process 2 additional times for each type of bolt assembly (Total of 3 tests per assembly lot).


It is most important to verify plies were in contact when bolts were snugged and that a fastener was not subsequently loosened when accompanying splice bolts were tightened and compacted the splice faying surfaces into contact after other fasteners had been already tightened.

712.1.5.4.4 Step 4, Installation

The next step is to ensure the proper process is used in the assembly of structural steel. It is important that the contractor is placing temporary bolts, drift pins and permanent bolts in the correct pattern. Read Sec 712.5 for additional requirements when fitting-up the structural steel.

The order in which bolts are tightened is important. If not done correctly, the plates will not be sandwiched tightly, and gaps will be introduced. Due to these being slip-critical connections, the joints need to experience 100% contact between all the plies. The contractor will need to start tightening the joints in the center of the plate, and then work radially out from the center to the extents of the joint.

Once the bolts are tightened by the contractor using one of the three approved methods, MoDOT will be responsible to check a portion of the bolts. We will review 10% of the bolts, or two per lot, whichever is greater. If bolt issues are discovered, more bolts may need to be reviewed. The following steps are generally what is seen in the field. There may be differences per contractor, but MoDOT's roles and requirements should be the same across the state.

Contractor/QC: The contractor will be installing the bolts through various methods. It can be expected to see Turn-Of-Nut Method or Calibrated Wrench (Torque Wrench). You could also see the contractor using Stall Out guns that are designed to stop spinning the bolts once a certain torque is reached. Sometimes air impact guns are used and have the air pressure adjusted to stop gun at torque desired using a Skidmore to verify they are exceeding the design tension of the fastener(s). This tool would be considered the Calibrated Wrench. This is an acceptable method, provided they do not change any conditions. They should run the Rotation Capacity Test with the equipment to be used. Once they change any part of the setup (add or remove an air hose, add an additional gun or item ran off of air hose supply, change air pressure, etc.), they will need to rerun the Rotation Capacity Test. If the contractor is using the Turn-Of-Nut Method, then they are not required to use a torque wrench on the nuts as well.
MoDOT/QA: Inspectors will have different checks based upon the type of verification used by the contractor. If the contractor is using Calibrated Wrench (Torque Wrench or Stall Out Gun) to check every bolt, MoDOT will use a torque wrench and will follow the Calibrated Wrench Method.
If the contractor is using Turn-Of-Nut, MoDOT will follow two steps. We will visually watch the contractor install and snug tighten the fastener assembly, ensuring the plies are in contact after doing so and ensure that they are marking the nut, bolt, and plies correctly. Then watch as they turn the nut (or bolt) to make sure it is generating the correct number of turns. A visual check of all the bolts turned so far can be quickly done to make sure they are marked, and that the marks are turned the correct amount. As a double check, the inspector will also take a torque wrench to check bolt torque on 10% of the bolts. If bolt issues are discovered, more bolts may need to be checked. Even if the contractor did not use a torque wrench to check the bolts, MoDOT inspectors will still use a torque wrench and record findings.

EPG 712.1.5.4.5 Step 5 details the three verification procedures.

712.1.5.4.5 Step 5, Bolt Verification
712.1.5.4.5.1 Calibrated Wrench Method, Sec 712.7.5

The first option listed in the specification book is the Calibrated Wrench Method. This method will use a calibrated wrench to check that the torque delivered to the bolt is the minimum torque needed to induce the needed minimum tension, as shown in Sec 712.7.3. In order to do this, information must be available from the Rotational Capacity Test completed for each lot.

Sec 712.7.5 states that when the calibrated wrench is used, it needs to be set 5-10% over the torque gauge value from Column 4 of the Rotational Capacity Test. Take the maximum Torque Gauge Reading from the Rotational Capacity Test and multiply by 1.05. This new value will be the one set onto the calibrated wrench.

Day-to-Day Verification

Each day the inspector will need to verify the installed bolts are correctly tensioned. Most of the time, MoDOT inspectors will use the contractor's equipment for the verification. The important thing is that the contractor is verifying the calibrated wrench daily. This will mean that the contractor will need to have the Skidmore on site each day to verify that the wrench is generating the correct tension at the torque it is reading. MoDOT inspectors will pick 10% of the bolts to also check bolt torque. The torque value they are checking is the maximum torque gauge reading generated from Step 3 of the Rotation Capacity Test.

712.1.5.4.5.2 Turn-Of-Nut Method, Sec 712.7.6

The second option listed in the specification book is the Turn-Of-Nut Method. This method uses the fact that the nuts must be turned to the rotation specified in Sec 712.7.6 to induce the needed minimum tension, as shown in Sec 712.7.3. In order to do this, verification will be needed from the Rotational Capacity Test completed for each lot.

When the Rotational Capacity Test is run, in Step 3 is to verify the bolt rotation is less than that specified in Sec 712.7.6. Once this is verified, all the bolts can be tightened to the rotation needed and that will confirm that the needed tension has been achieved. This is provided that all the plies are in contact when snug tightened.

Example

On a project you are installing 7/8” diameter bolts that are 4” long. The RoCap test was performed on the bolt assemblies. When the bolts were tensioned during RoCap, they were tensioned to 39,050 lb. From the formula in Sec 1080.2.5.4.6, the maximum torque is to be 712 lb-ft. The bolt was torqued to 701 lb-ft, so it passes the RoCap test. During the test, the inspector also noted that the bolt nut turned 2 flats (or 1/3 of a turn). Sec 712.7.6 Nut Rotation from Snug Tight Condition table says that this bolt is to be turned 1/2 turn for Turn-Of-Nut in the field. Since the bolt achieved the minimum tension in 1/3 turn, we know that the turning it to 1/2 turn will achieve a higher tension value. If the RoCap test shows a higher turn value needed than the Sec 712.7.6 table, then further discussions should be had with the contractor about next steps before any bolts are installed in the field.

Day-to-Day Verification

For the day-to-day verifications, MoDOT inspectors will visually verify that the Turn-Of-Nut Method is completed correctly. They will review marks made by the contractor and make sure that there is a general comfort level with how the contractor is doing the work. In addition to this, MoDOT inspectors will pick 10% of the bolts to also check bolt torque. The torque value they are checking is the maximum torque gauge reading generated from Step 3 of the Rotation Capacity Test.

712.1.5.4.5.2.jpg

The photograph to the right shows what the markings will look like when the Turn-Of-Nut Method is used. In order to perform the test, three marks are made: one on the nut, one on the bolt, and one on the steel plate underneath. To begin with, mark the nut at a corner, and follow that line all the way through to the steel. Notice the left side bolts are all starting in the same position. The right-side bolts have been rotated 1/3 of a turn, or two flats of the hex head. Notice how the bolt and the steel still line up, and only the nut has moved. Marking the bolt and steel ensures that the bolt does not move during tightening. The nut will show how much it has moved. Marking the hex head accordingly is a semi-permanent record that the test was run. This also provides the inspector with the necessary information to quickly verify tightness, but a random check of 10% of bolts with a torque wrench by the QA inspector shall still occur. The inspector will not have to tighten the bolts themselves but can witness the ironworker who is tightening some of the bolts to ensure they are following the proper procedure of the Turn-Of-Nut Method.  

712.1.5.4.5.3 Load Indicating Bolt Method, Sec 712.7.7

The third option listed in the specification book is the Load Indicating Bolt Method. This method uses the fact that the bolts have been specially designed to shear off once a specific torque has been reached in the bolt. This torque has been correlated to the needed minimum tension as shown in Sec 712.7.3. In order to do this, the verification must be available from the Rotational Capacity Test completed for each lot.

712.1.5.4.5.3.jpg

When the Rotational Capacity Test is run, there is one piece of information needed. The Tension Gauge Reading when the spline shears off. Since the spline shears off, and the drill cannot provide any more compactive effort, there is generally not a concern about overtightening the bolt provided that the bolt hardware is clean and well lubricated. Once the bolt shears off, the tension achieved is the final tension. The Rotation Capacity Test will verify that the final tension is at or above the minimum bolt tension required in Sec 712.7.3.

Day-to-Day Verification

Since the machine will shear the bolt off at the specified tension, the biggest piece to verify is done during the Rotational Capacity Test. Once that is done, the inspector just needs to ensure that the contractor is following the correct tightening procedure shown in Sec 712.7.7. Ensure that all plies are in contract when snug tight and that bolt hardware is clean and well lubricated. The QA Inspector should also perform checks of at least 10% of the fastener assemblies with a torque wrench to verify the fastener is tight using the Inspection Torque value (0.95 x 0.25 x highest gauged tension from RoCap Test x bolt diameter in inches / 12). If bolt issues are discovered, more bolts may need to be checked.

712.1.6 High Strength Anchor Bolts

When high strength anchor bolts are specified, ASTM F1554 Grade 55 anchor bolts shall be used unless higher grade anchor bolts are required by design. Grade 105 bolts shall not be used in applications where welding is required. Grade 36 anchor bolts are commonly referred to as “low-carbon” and may be used if specified on the plans. Grade 55 anchor bolts may be substituted for applications where Grade 36 is specified. To facilitate easy identification of anchor bolt, the following figure shows some of the typical bolt markings required by the ASTM specification. The end of the anchor bolt intended to project from the concrete shall be steel die stamped with the grade identification and color coded as follows.

Grade Color Code Identification
36 712.1.5 azul.jpg AB36
XYZ
55 712.1.5 amarillo.jpg AB55
XYZ
105 712.1.5 rojo.jpg AB105
XYZ

Note: XYZ represents the manufacturer’s identification mark.

712.1.7 Non-destructive Testing

In certain instances, non-destructive testing (NDT) may be required to be conducted on steel components of a bridge. The contractor will be responsible for providing and certified NDT technician to conduct the testing. This technician will usually be an employee of a third party inspection agency. Certification for NDT technicians will be in accordance with the requirements of The American Society for Nondestructive Testing (ASNT) Recommended Practice SNT-TC-1A. MoDOT does not maintain an approved list of NDT technicians. The Bridge Division does review certifications for testing agencies and keep a list of personnel of these agencies with their respective certifications.

For projects that require NDT in the field, the inspector will collect the information from the contractor as to who will be providing the NDT services. The contractor shall submit the certifications to the Resident Engineer to be forwarded to the Bridge Division at Fabrication@modot.mo.gov. These certifications shall include the following documentation for each individual performing NDT: their certifications, current eye exam, and the NDT company written practice, including the Level III individual certification used for the written practice.

At the Resident Engineer’s option, they may choose to keep a list of personnel who have performed NDT work for a quick reference for future projects. However, the Resident Engineer and the inspector will always request to see the current eye exam results prior the technician providing the NDT on these future projects.

712.2 Materials Inspection for Sec 712

712.2.1 Scope

This guidance establishes procedures for inspecting and reporting those items specified in Sec 712 that are not always inspected by Bridge Division personnel or are not specifically covered in the Materials details of the Specifications.

712.2.2 Procedure

Normally all materials in Sec 712 will be inspected by Bridge Division personnel. Bolts, nuts and washers accepted by PAL may be delivered directly from the manufacturer to the project without prior inspection. When requested by the Bridge Division or construction office, the Construction and Materials Division will inspect fencing and other miscellaneous items. The Bridge Division is responsible for the inspection of shop coating of structural steel at fabricating plants.

712.2.2.1 Project Inspection and Sampling for PAL

Inspecting of PAL material will be as stated in this section and Pre-Acceptance Lists (PAL).

712.2.3 Miscellaneous Materials

712.2.3.1 High Strength Bolts

All bolts, nuts, and washers should be from a PAL supplier in accordance with Pre-Acceptance Lists (PAL). If a supplier proposes to furnish structural steel connectors and is not on PAL, a request is to be made to the Construction and Material Division for acceptance into the PAL program. Once satisfactory submittals have been received, the supplier will be placed on the PAL. Bolts, nuts, and washers, for use other than bridge construction and in quantities less than 50, may be accepted from a PAL supplier without a PAL identification number.

712.2.3.1.1 Manufacturer's Certification. Bolts and nuts specified to meet the requirements of ASTM A307 shall be accompanied by a manufacturer's certification statement that the bolts and nuts were manufactured to comply with requirements of ASTM A307 and, if required, galvanized to comply with requirements of AASHTO M232 (ASTM A153), Class C or were mechanically galvanized and meet the coating thickness, adherence, and quality requirements of ASTM B695, Class 55. Certification shall be retained by the shipper. A copy should be obtained when sampling at the shipper and submitted with the samples to the lab.

All bolts, nuts and washers are to be identifiable as to type and manufacturer. Bolts, nuts, and washers manufactured to meet ASTM A307 will normally be identified on the packaging since no special markings are required on the item. Dimensions are to be as shown on the plans or as specified.

Weight (mass) of zinc coating, when specified, is to be determined by magnetic gauge in the same manner as described for bolts and nuts in EPG 1040 Guardrail, End Terminals, One-Strand Access Restraint Cable and Three-Strand Guard Cable Material.

Samples for Laboratory testing are only required when requested by the State Construction and Materials Engineer, or when field inspection indicates questionable compliance. Samples shall be taken according to EPG 712.2.3.2.1.1 ASTM A307 Bolts.

712.2.3.1.2 High strength bolts, nuts, and washers specified shall meet the requirements of ASTM F3125 Grade A325. Field inspection shall include examination of the certifications or mill test reports; checking identification markings; and testing for dimensions. The certifications or mill test reports, conforming to EPG 712.2.3.1.1 Manufacturer's Certification, shall be retained in the district office. Samples for Laboratory testing shall be taken and submitted in accordance with EPG 712.2.3.2.1.2 ASTM F3125 Grade A325 Bolts.

712.2.3.2 PAL Manufacturer Facilities Sampling

Prior to visiting a PAL supplier or manufacturer facility, the Cognos report “PAL Shipments Within Date Range” should be run for the facility to determine what material has been given MoDOT PAL numbers. For each PAL material, the sample shall consist of six pieces rather than determined from lot quantities as given in the following sections. An individual sample shall consist of bolts, nuts, or washers as these are treated as different materials in the PAL system.

712.2.3.2.1 Sample sizes
712.2.3.2.1.1 ASTM A307 Bolts

Samples for Laboratory testing are only required when requested by the State Construction and Materials Engineer, or when field inspection indicates questionable compliance. When samples are taken, they are to be taken as shown in the following table. When galvanized bolts, nuts and washers are submitted to the Laboratory, a minimum of 3 samples of each are required for Laboratory testing.

3 for lots of 0 to 800 pcs. Each sample is to consist of one bolt, nut and washer. Submit for dimensions, weight (mass) of coating, mechanical properties.
6 for lots of 801 to 8,000 pcs.
9 for lots of 8,001 to 22,000 pcs.
15 for lots of 22,001+ pcs.
712.2.3.2.1.2 ASTM F3125 Grade A325 Bolts

Samples for Laboratory testing shall be taken and submitted as follows: All lots containing 501 or more, high strength bolts shall be sampled and submitted to the Laboratory for testing. If no lot offered contains 501 or more bolts, sample 10 percent of the lots offered, or one lot, whichever is greater. A lot is defined as all bolts of the same size and length, with the same manufacturer's lot identification, offered for inspection at one time. Samples shall be taken as follows:

Number of Bolts in the Lot Number of Bolts Taken for a Sample*
150 and less 3
151 through 800 3
801 through 8,000 6
8,001 through 22,000 9
22,001 plus 15
* A minimum of 3 samples will be required for galvanized materials.

All lots containing 501 or more, high strength nuts shall be sampled and submitted to the Laboratory for testing. If no lot offered contains 501 or more nuts, sample 10 percent of the lots offered or one lot, whichever is greater. A lot is defined as all nuts of the same grade, size, style, thread series and class, and surface finish, with the same manufacturer's lot identification, offered for inspection at one time. Samples shall be taken as follows:

Number of Nuts in the Lot Number of Nuts Taken for a Sample*
800 and under 1
801 through 8,000 2
8,001 through 22,000 3
22,000 and over 5
* A minimum of 3 samples will be required for galvanized materials.

All lots containing 501 or more, high strength washers shall be sampled and submitted to the Laboratory for testing. If no lot offered contains 501 or more washers, sample 10 percent of the lots offered, or one lot, whichever is greater. A lot is defined as all washers of the same type, grade, size and surface finish, with the same manufacturer's lot identification, offered for inspection at one time. Samples shall be taken as follows:

Number of Washers in the Lot Number of Washers Taken for a Sample*
800 and under 1
801 through 8,000 2
8,001 through 22,000 3
22,000 and over 5
* A minimum of 3 samples will be required for galvanized materials.
712.2.3.2.2 Bolts for Highway Lighting, Traffic Signals or Highway Signing

Bolts, nuts, and washers for highway lighting, traffic signals, or highway signing shall meet the requirements given in EPG 712.2.3.1.2 High Strength Bolts. Samples for Central Laboratory testing are only required when requested by the State Construction and Materials Engineer or when field inspection indicates questionable compliance.

712.2.3.3 Slab Drains

Slab drains are to be accepted on the basis of field inspection of dimensions, weight (mass) of zinc coating, and a satisfactory fabricators certification. The dimensions, weight (mass) of zinc coating, and material specification requirements are shown on the bridge plans.

Field determination of weight (mass) of coating is to be made on each lot of material furnished. The magnetic gauge is to be operated and calibrated in accordance with ASTM E376. At least three members of each size and type offered for inspection are to be selected for testing. A single-spot test is to be comprised of at least five readings of the magnetic gauge taken in a small area and those five readings averaged to obtain a single-spot test result. Three such areas should be tested on each of the members being tested. Test each member in the same manner. Average all single-spot test results from all members to obtain an average coating weight (mass) to be reported. The minimum single-spot test result would be the minimum average obtained on any one member. Material may be accepted or rejected for galvanized coating on the basis of magnetic gauge. If a test result fails to comply with the specifications, that lot should be resampled at double the original sampling rate. If any of the resampled members fail to comply with the specification, that lot is to be rejected. The contractor or supplier is to be given the option of sampling for Laboratory testing, if the magnetic gauge test results are within minus 15 percent of the specified coating weight (mass).

A fabricators certification shall be submitted to the engineer in triplicate stating that "The steel used in the fabrication of the slab drains was manufactured to conform to ASTM A709" or "A500, A501" as the case may be.

712.2.3.4 Miscellaneous Structural Steel

Other structural steel items not requiring shop drawings also require inspection. Inspection includes a fabricator's certification identifying the source and grade of steel, as well as verification of dimensions and inspection of any coating applied. The report is to include the grade of steel, coating applied, and results of inspection.

712.3 Lab Testing

712.3.1 Scope

This establishes procedures for Laboratory testing and reporting samples of structural steel, bolts, nuts, and washers and for welding qualifications.

712.3.2 Procedure

712.3.2.1 Chemical Tests - Bolts, Nuts, and Washers

Weight (mass) of coating shall be determined in accordance with AASHTO M232. Chemical analysis of the base metal shall be determined, when requested, according to Laboratory Testing Guidelines for Sec 1020. Original test data and calculations shall be recorded in Laboratory workbooks.

712.3.2.2 Physical Tests - Bolts and Nuts

Original test results and calculations shall be reported through AASHTOWare Project.

Low carbon steel bolts and nuts shall be tested according to ASTM A307. Tests are to be as follows:

(a) Bolts shall be tested for dimensions, hardness, and tensile strength.
(b) Nuts shall be tested for dimensions, hardness, and proof load.

Due to the shape and length of some bolts and the shape of some nuts, it may not be possible or required to determine the tensile strength of the bolts or the proof load of the nuts.

High strength bolts, nuts, and washers shall be tested according to ASTM F3125 Grade A325. Tests are to be as follows:

(a) Bolts shall be tested for dimensions, markings, hardness, proof load, and tensile strength.
(b) Nuts shall be tested for dimensions, markings, hardness, and proof load.
(c) Washers shall be tested for hardness.

Due to the shape and length of some bolts and the size of some nuts, it may not be possible or required to determine the proof load and tensile strength of the bolts or the proof load of the nuts.

712.3.3 Sample Record

The sample record shall be completed in AASHTOWARE Project (AWP), as described in AWP MA Sample Record, General, and shall indicate acceptance, qualified acceptance, or rejection. Appropriate remarks, as described in EPG 106.20 Reporting, are to be included in the report to clarify conditions of acceptance or rejection.

Test results for bolts, nuts and washers shall be reported through AWP.

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