Category:701 Drilled Shafts - Revision history

Smithk: Per CM, new guidance for the proper steps to be made to remediate a defect in a drilled shaft

2022-01-28T20:51:25Z

Per CM, new guidance for the proper steps to be made to remediate a defect in a drilled shaft

← Older revision		Revision as of 15:51, 28 January 2022
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	Most problems with drilled shafts occur during the concrete pour. The concrete placement requirements in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 701] should be reviewed carefully.		Most problems with drilled shafts occur during the concrete pour. The concrete placement requirements in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 701] should be reviewed carefully.

			An anomaly may be detected on a Cross Hole Sonic log test. If, on further investigation, there is a confirmed defect what are some of the steps needed to remediate the defect?
			:1. The contractor is responsible for submitting a remediation plan for the repair.
			:2. The plan should include as a minimum the following:
			::a) The area of deficient material must be clearly defined using coring or other means.
			::b) The clean-out process is typically accomplished by flushing the weak material. The access holes needed, water pressure used, and disposal of the soils should be addressed.
			::c) Confirmation of the deficient material removal must be made. This can be accomplished by camera inspection, CSL, or by other means acceptable to the engineer.
			::d) The grouting plan should include: grouting type, grout mix design including w/c ratio, complete pressure grouting timeline. The grouting timeline should include placement times, pressure, volume, refusal criteria.
			:3. A final confirmation of the effectiveness of the grouting should be made. This is typically accomplished by coring. The number of cores required, and depth shall be submitted to the engineer for approval prior to coring. If all the CSL tubes are still usable, a final CSL can be made for acceptance. The engineer of record for the design should be consulted for final acceptance.

	'''Question: Per [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 701.4.17.2.1 Installation of Pipes], “The pipes shall be filled with water and plugged or capped before shaft concrete is poured.” Why is this necessary?'''		'''Question: Per [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 701.4.17.2.1 Installation of Pipes], “The pipes shall be filled with water and plugged or capped before shaft concrete is poured.” Why is this necessary?'''

	The water in the tube helps to regulate the temperature of the CSL tube. Without the water, the tube will heat up from the hydrating concrete and cause de-bonding. This de-bonding from the concrete will cause erroneous CSL readings and show up as an anomaly. Typically, de-bonding is more prevalent in the upper 6 ft. of the tube. The water also serves a second purpose: it helps the energy transmission from the wall of the tube to the probes and vice versa.		The water in the tube helps to regulate the temperature of the CSL tube. Without the water, the tube will heat up from the hydrating concrete and cause de-bonding. This de-bonding from the concrete will cause erroneous CSL readings and show up as an anomaly. Typically, de-bonding is more prevalent in the upper 6 ft. of the tube. The water also serves a second purpose: it helps the energy transmission from the wall of the tube to the probes and vice versa.

Smithk: Updated website link (for increased security)

2021-10-22T17:57:57Z

Updated website link (for increased security)

← Older revision		Revision as of 12:57, 22 October 2021
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	columns cast in drilled holes. See [[751.37 Drilled Shafts\|EPG 751.37 Drilled Shafts]] for design guidance and additional information.		columns cast in drilled holes. See [[751.37 Drilled Shafts\|EPG 751.37 Drilled Shafts]] for design guidance and additional information.

	This type of foundation is identified in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally considered a deep foundation. Drilled shafts are to be constructed with or without a casing. When casing is used it can be either a temporary or permanent steel casing. Requirements for plan reporting of steel casing are given in [~~http~~://epg.modot.org/index.php?title=751.37_Drilled_Shafts#751.37.1.3_Casing EPG 751.37.1.3 Casing].		This type of foundation is identified in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally considered a deep foundation. Drilled shafts are to be constructed with or without a casing. When casing is used it can be either a temporary or permanent steel casing. Requirements for plan reporting of steel casing are given in [https://epg.modot.org/index.php?title=751.37_Drilled_Shafts#751.37.1.3_Casing EPG 751.37.1.3 Casing].

	The shaft portion of a drilled shaft is usually founded on rock (limestone, dolomite or other suitable material with q<sub>u</sub> ≥ 100 ksf) or weak rock (shale or other suitable material with 5 ksf ≤ q<sub>u</sub> ≤ 100 ksf) with a smaller diameter rock socket drilled into same. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.		The shaft portion of a drilled shaft is usually founded on rock (limestone, dolomite or other suitable material with q<sub>u</sub> ≥ 100 ksf) or weak rock (shale or other suitable material with 5 ksf ≤ q<sub>u</sub> ≤ 100 ksf) with a smaller diameter rock socket drilled into same. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.

Smithk: updated links

2016-06-13T19:46:08Z

updated links

← Older revision		Revision as of 14:46, 13 June 2016
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	columns cast in drilled holes. See [[751.37 Drilled Shafts\|EPG 751.37 Drilled Shafts]] for design guidance and additional information.		columns cast in drilled holes. See [[751.37 Drilled Shafts\|EPG 751.37 Drilled Shafts]] for design guidance and additional information.

	This type of foundation is identified in [http://modot.~~mo.gov~~/business/standards_and_specs/~~Sec0701~~.pdf Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally considered a deep foundation. Drilled shafts are to be constructed with or without a casing. When casing is used it can be either a temporary or permanent steel casing. Requirements for plan reporting of steel casing are given in [http://epg.modot.org/index.php?title=751.37_Drilled_Shafts#751.37.1.3_Casing EPG 751.37.1.3 Casing].		This type of foundation is identified in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally considered a deep foundation. Drilled shafts are to be constructed with or without a casing. When casing is used it can be either a temporary or permanent steel casing. Requirements for plan reporting of steel casing are given in [http://epg.modot.org/index.php?title=751.37_Drilled_Shafts#751.37.1.3_Casing EPG 751.37.1.3 Casing].

	The shaft portion of a drilled shaft is usually founded on rock (limestone, dolomite or other suitable material with q<sub>u</sub> ≥ 100 ksf) or weak rock (shale or other suitable material with 5 ksf ≤ q<sub>u</sub> ≤ 100 ksf) with a smaller diameter rock socket drilled into same. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.		The shaft portion of a drilled shaft is usually founded on rock (limestone, dolomite or other suitable material with q<sub>u</sub> ≥ 100 ksf) or weak rock (shale or other suitable material with 5 ksf ≤ q<sub>u</sub> ≤ 100 ksf) with a smaller diameter rock socket drilled into same. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.
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	The integrity of the rock socket shall be verified by a foundation inspection hole. This is usually performed after the shaft is drilled. Setting up over a drilled hole can be difficult. The contractor can perform the inspection hole in advance if they submit a procedure that assures the correct location is cored. If the integrity of the cores are questionable the Bridge Division should be contacted to see if the rock socket length should be extended.		The integrity of the rock socket shall be verified by a foundation inspection hole. This is usually performed after the shaft is drilled. Setting up over a drilled hole can be difficult. The contractor can perform the inspection hole in advance if they submit a procedure that assures the correct location is cored. If the integrity of the cores are questionable the Bridge Division should be contacted to see if the rock socket length should be extended.

	Most problems with drilled shafts occur during the concrete pour. The concrete placement requirements in [http://modot.~~mo.gov~~/business/standards_and_specs/~~Sec0701~~.pdf Sec 701] should be reviewed carefully.		Most problems with drilled shafts occur during the concrete pour. The concrete placement requirements in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 701] should be reviewed carefully.

	'''Question: Per [http://modot.~~mo.gov~~/business/standards_and_specs/~~Sec0701~~.pdf Sec 701.4.17.2.1 Installation of Pipes], “The pipes shall be filled with water and plugged or capped before shaft concrete is poured.” Why is this necessary?'''		'''Question: Per [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=11 Sec 701.4.17.2.1 Installation of Pipes], “The pipes shall be filled with water and plugged or capped before shaft concrete is poured.” Why is this necessary?'''

	The water in the tube helps to regulate the temperature of the CSL tube. Without the water, the tube will heat up from the hydrating concrete and cause de-bonding. This de-bonding from the concrete will cause erroneous CSL readings and show up as an anomaly. Typically, de-bonding is more prevalent in the upper 6 ft. of the tube. The water also serves a second purpose: it helps the energy transmission from the wall of the tube to the probes and vice versa.		The water in the tube helps to regulate the temperature of the CSL tube. Without the water, the tube will heat up from the hydrating concrete and cause de-bonding. This de-bonding from the concrete will cause erroneous CSL readings and show up as an anomaly. Typically, de-bonding is more prevalent in the upper 6 ft. of the tube. The water also serves a second purpose: it helps the energy transmission from the wall of the tube to the probes and vice versa.

Smithk: Per CM, clarification why CSL pipes must be filled with water and plugged or capped

2014-08-29T14:50:44Z

Per CM, clarification why CSL pipes must be filled with water and plugged or capped

← Older revision		Revision as of 09:50, 29 August 2014
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	Most problems with drilled shafts occur during the concrete pour. The concrete placement requirements in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] should be reviewed carefully.		Most problems with drilled shafts occur during the concrete pour. The concrete placement requirements in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] should be reviewed carefully.

			'''Question: Per [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701.4.17.2.1 Installation of Pipes], “The pipes shall be filled with water and plugged or capped before shaft concrete is poured.” Why is this necessary?'''

			The water in the tube helps to regulate the temperature of the CSL tube. Without the water, the tube will heat up from the hydrating concrete and cause de-bonding. This de-bonding from the concrete will cause erroneous CSL readings and show up as an anomaly. Typically, de-bonding is more prevalent in the upper 6 ft. of the tube. The water also serves a second purpose: it helps the energy transmission from the wall of the tube to the probes and vice versa.

Smithk: Per Bridge, clarified useage of limestone and other rock. Compressive strengths were identified.

2013-12-02T20:35:06Z

Per Bridge, clarified useage of limestone and other rock. Compressive strengths were identified.

← Older revision		Revision as of 15:35, 2 December 2013
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	This type of foundation is identified in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally considered a deep foundation. Drilled shafts are to be constructed with or without a casing. When casing is used it can be either a temporary or permanent steel casing. Requirements for plan reporting of steel casing are given in [http://epg.modot.org/index.php?title=751.37_Drilled_Shafts#751.37.1.3_Casing EPG 751.37.1.3 Casing].		This type of foundation is identified in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally considered a deep foundation. Drilled shafts are to be constructed with or without a casing. When casing is used it can be either a temporary or permanent steel casing. Requirements for plan reporting of steel casing are given in [http://epg.modot.org/index.php?title=751.37_Drilled_Shafts#751.37.1.3_Casing EPG 751.37.1.3 Casing].

	The shaft portion of a drilled shaft is usually founded on limestone ~~and occasionally hard~~ shale, with a smaller diameter socket into ~~limestone or shale~~. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.		The shaft portion of a drilled shaft is usually founded on rock (limestone, dolomite or other suitable material with q<sub>u</sub> ≥ 100 ksf) or weak rock (shale or other suitable material with 5 ksf ≤ q<sub>u</sub> ≤ 100 ksf) with a smaller diameter rock socket drilled into same. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.

	The integrity of the rock socket shall be verified by a foundation inspection hole. This is usually performed after the shaft is drilled. Setting up over a drilled hole can be difficult. The contractor can perform the inspection hole in advance if they submit a procedure that assures the correct location is cored. If the integrity of the cores are questionable the Bridge Division should be contacted to see if the rock socket length should be extended.		The integrity of the rock socket shall be verified by a foundation inspection hole. This is usually performed after the shaft is drilled. Setting up over a drilled hole can be difficult. The contractor can perform the inspection hole in advance if they submit a procedure that assures the correct location is cored. If the integrity of the cores are questionable the Bridge Division should be contacted to see if the rock socket length should be extended.

	Most problems with drilled shafts occur during the concrete pour. The concrete placement requirements in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] should be reviewed carefully.		Most problems with drilled shafts occur during the concrete pour. The concrete placement requirements in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] should be reviewed carefully.

Smithk: Per Bridge, guidance on steel casing updated to be in compliance with Sec 701. Previously, MoDOT always required 1/2" thick casing.

2012-03-30T13:27:45Z

Per Bridge, guidance on steel casing updated to be in compliance with Sec 701. Previously, MoDOT always required 1/2" thick casing.

← Older revision		Revision as of 08:27, 30 March 2012
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	Substructure foundations may be designed to transmit loads to foundation strata by concrete		Substructure foundations may be designed to transmit loads to foundation strata by concrete
	columns cast in drilled holes. See [[751.37 Drilled Shafts\|~~design guidance for drilled shafts~~]] for additional information.		columns cast in drilled holes. See [[751.37 Drilled Shafts\|EPG 751.37 Drilled Shafts]] for design guidance and additional information.

	This type of foundation is identified in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally considered a deep foundation. Drilled shafts are to be constructed with or without a casing. When casing is used it can be either a temporary or permanent steel casing.		This type of foundation is identified in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally considered a deep foundation. Drilled shafts are to be constructed with or without a casing. When casing is used it can be either a temporary or permanent steel casing. Requirements for plan reporting of steel casing are given in [http://epg.modot.org/index.php?title=751.37_Drilled_Shafts#751.37.1.3_Casing EPG 751.37.1.3 Casing].

	The shaft portion of a drilled shaft is usually founded on limestone and occasionally hard shale, with a smaller diameter socket into limestone or shale. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.		The shaft portion of a drilled shaft is usually founded on limestone and occasionally hard shale, with a smaller diameter socket into limestone or shale. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.

EPG-Admin: These revisions remove outdated information.

2009-05-14T17:46:08Z

These revisions remove outdated information.

← Older revision		Revision as of 12:46, 14 May 2009
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	Substructure foundations may be designed to transmit loads to foundation strata by concrete		Substructure foundations may be designed to transmit loads to foundation strata by concrete
	columns cast in drilled holes. See ~~guidance for~~ [[751.37 Drilled Shafts\|design of drilled shafts]] for additional information.		columns cast in drilled holes. See [[751.37 Drilled Shafts\|design guidance for drilled shafts]] for additional information.

	This type of foundation is identified in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally ~~small in diameter compared to its depth. The design load may be assumed to be carried in end bearing only. There may be some design that includes side friction but this is not typical~~. Drilled shafts are to be constructed with either a temporary or permanent steel casing.		This type of foundation is identified in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally considered a deep foundation. Drilled shafts are to be constructed with or without a casing. When casing is used it can be either a temporary or permanent steel casing.

	The shaft portion of a drilled shaft is usually founded on limestone and occasionally hard shale, with a smaller diameter socket into or limestone or shale~~. The generally assumed maximum~~		The shaft portion of a drilled shaft is usually founded on limestone and occasionally hard shale, with a smaller diameter socket into limestone or shale. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.
	~~(ultimate) bearing values for the founding material are 10 tons per square foot for firm hard~~
	~~shale and 50 tons per square foot for firm limestone~~. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.

	The integrity of the rock socket shall be verified by a foundation inspection hole. This is usually performed after the ~~drilled~~ shaft is drilled. Setting up over a drilled hole can be difficult. The contractor can perform the inspection hole in advance if they submit a procedure that assures the correct location is cored. If the integrity of the cores are questionable the Bridge Division ~~Liaison~~ should be contacted to see if the rock socket length should be extended.		The integrity of the rock socket shall be verified by a foundation inspection hole. This is usually performed after the shaft is drilled. Setting up over a drilled hole can be difficult. The contractor can perform the inspection hole in advance if they submit a procedure that assures the correct location is cored. If the integrity of the cores are questionable the Bridge Division should be contacted to see if the rock socket length should be extended.

	Most problems with drilled shafts occur during the concrete pour. ~~Great care~~ should be ~~made to assure the tremie is not breached and a proper head of concrete is maintained at all times~~.		Most problems with drilled shafts occur during the concrete pour. The concrete placement requirements in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] should be reviewed carefully.

EPG-Admin at 19:28, 1 October 2007

2007-10-01T19:28:34Z

← Older revision		Revision as of 14:28, 1 October 2007
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	Substructure foundations may be designed to transmit loads to foundation strata by concrete		Substructure foundations may be designed to transmit loads to foundation strata by concrete
	columns cast in drilled holes.		columns cast in drilled holes. See guidance for [[751.37 Drilled Shafts\|design of drilled shafts]] for additional information.

	This type of foundation is identified in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally small in diameter compared to its depth. The design load may be assumed to be carried in end bearing only. There may be some design that includes side friction but this is not typical. Drilled shafts are to be constructed with either a temporary or permanent steel casing.		This type of foundation is identified in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally small in diameter compared to its depth. The design load may be assumed to be carried in end bearing only. There may be some design that includes side friction but this is not typical. Drilled shafts are to be constructed with either a temporary or permanent steel casing.

EPG-Admin at 19:41, 27 August 2007

2007-08-27T19:41:34Z

New page

Substructure foundations may be designed to transmit loads to foundation strata by concrete
columns cast in drilled holes.

This type of foundation is identified in [http://modot.mo.gov/business/standards_and_specs/Sec0701.pdf Sec 701] of the Standard Specifications as Drilled Shafts. A drilled shaft is generally small in diameter compared to its depth. The design load may be assumed to be carried in end bearing only. There may be some design that includes side friction but this is not typical. Drilled shafts are to be constructed with either a temporary or permanent steel casing.

The shaft portion of a drilled shaft is usually founded on limestone and occasionally hard shale, with a smaller diameter socket into or limestone or shale. The generally assumed maximum
(ultimate) bearing values for the founding material are 10 tons per square foot for firm hard
shale and 50 tons per square foot for firm limestone. The inspector should carefully study all general specifications and special provisions pertaining to drilled shafts and become familiar with the designer's intent.

The integrity of the rock socket shall be verified by a foundation inspection hole. This is usually performed after the drilled shaft is drilled. Setting up over a drilled hole can be difficult. The contractor can perform the inspection hole in advance if they submit a procedure that assures the correct location is cored. If the integrity of the cores are questionable the Bridge Division Liaison should be contacted to see if the rock socket length should be extended.

Most problems with drilled shafts occur during the concrete pour. Great care should be made to assure the tremie is not breached and a proper head of concrete is maintained at all times.