751.39 Pile Footings - Revision history

Hoskir: updated old math code

2026-01-15T19:35:51Z

updated old math code

← Older revision		Revision as of 14:35, 15 January 2026
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	[[image:Distribution_Reinforcement_10-26-23.png]]		[[image:Distribution_Reinforcement_10-26-23.png]]

	Reinforcement shall be distributed uniformly across the entire width of footing in the long direction. In the short direction, the portion of the total reinforcement given by LRFD Equation 5.12.8.5-1 shall be distributed uniformly over a band width equal to the length of the short side of the footing, '''<math>\~~boldsymbol~~ \beta</math>'''.		Reinforcement shall be distributed uniformly across the entire width of footing in the long direction. In the short direction, the portion of the total reinforcement given by LRFD Equation 5.12.8.5-1 shall be distributed uniformly over a band width equal to the length of the short side of the footing, '''<math>\mathbf \beta</math>'''.

	<math>\~~boldsymbol~~{A _s{}_-{}_B{}_W = A _s{}_-{}_S{}_D \left(\frac{2}{\beta+1}\right) \beta =}</math> the ratio of footing length (long side) to width (short side) = '''L/B'''		<math>\mathbf{A _s{}_-{}_B{}_W = A _s{}_-{}_S{}_D \left(\frac{2}{\beta+1}\right) \beta =}</math> the ratio of footing length (long side) to width (short side) = '''L/B'''

	:: <math>\~~boldsymbol~~{A _s{}_-{}_B{}_W =}</math> '''area of steel in the band width (in.<sup>2</sup>)'''		:: <math>\mathbf{A _s{}_-{}_B{}_W =}</math> '''area of steel in the band width (in.<sup>2</sup>)'''

	:: <math>\~~boldsymbol~~{A _s{}_-{}_S{}_D =}</math> '''total area of steel in short direction (in.<sup>2</sup>)'''		:: <math>\mathbf{A _s{}_-{}_S{}_D =}</math> '''total area of steel in short direction (in.<sup>2</sup>)'''

	The remainder of the reinforcement required in the short direction shall be distributed uniformly outside the center band width of footing.		The remainder of the reinforcement required in the short direction shall be distributed uniformly outside the center band width of footing.

Hoskir: /* 751.39.5 Reinforcement */ updated per RR4140

2025-12-19T14:58:37Z

751.39.5 Reinforcement: updated per RR4140

Hoskir: /* 751.39.3 Pile Design */ updated per RR4140

2025-12-19T14:23:54Z

751.39.3 Pile Design: updated per RR4140

← Older revision		Revision as of 09:23, 19 December 2025
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	'''General'''		'''General'''

	Design the number, size and spacing of piles based on the guidance provided in [[751.36_Driven_Piles#751.36.5.1_Design_Procedure_Outline\|EPG 751.36 .5.1 Design Procedure Outline]], [[751.36_Driven_Piles#751.36.5.8_Additional_Provisions_for_Pile_Cap_Footings\|EPG 751.36.5.8 Additional Provisions for Pile Footings]] and the guidance provided herein.		Design the number, size and spacing of piles based on the guidance provided in [[751.36_Driven_Piles#751.36.5.1_Design_Procedure_Outline\|EPG 751.36 .5.1 Design Procedure Outline]], [[751.36_Driven_Piles#751.36.5.8_Additional_Provisions_for_Pile_Cap_Footings\|EPG 751.36.5.8 Additional Provisions for Pile Footings]] and the guidance provided herein. Battered piles shall be avoided in SDC B, C and D regions and where settlement can lead to drag forces on the piles. Vertical piles are preferred in all applications.

	For friction piles situated in soft cohesive soils or in cohesionless soils underlain by a soft cohesive layer, the pile group shall be checked for block failure in accordance with LRFD 10.7.3.9. Soft cohesive soils are defined as soils with average undrained shear strength less than 1 ksf. For additional guidance refer to <i>FHWA GEC 012: Design and Construction of Driven Pile Foundations - Volume 1, Section 7.2.2.3</i>.		For friction piles situated in soft cohesive soils or in cohesionless soils underlain by a soft cohesive layer, the pile group shall be checked for block failure in accordance with LRFD 10.7.3.9. Soft cohesive soils are defined as soils with average undrained shear strength less than 1 ksf. For additional guidance refer to <i>FHWA GEC 012: Design and Construction of Driven Pile Foundations - Volume 1, Section 7.2.2.3</i>.

Hoskir: /* 751.39.1 Dimensions */ updated per RR4140

2025-12-19T14:21:55Z

751.39.1 Dimensions: updated per RR4140

← Older revision		Revision as of 09:21, 19 December 2025
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	{\|		{\|
	\|-		\|-
	\| style="width: 350px;" \| [[image:~~Dim_Side_Elevation_10-26~~-23.png\|center]] \|\| style="width: 350px;" \| [[image:~~Dim_Front_Elevation_10-26~~-23.png\|center]]		\| style="width: 350px;" \| [[image:751.39.1-01_2025.png\|300px\|center]] \|\| style="width: 350px;" \| [[image:751.39.1-02_2025.png\|250px\|center]]
	\|-		\|-
	\| <center>'''Side Elevation'''</center> \|\| <center>'''Front Elevation'''</center>		\| <center>'''Side Elevation'''</center> \|\| <center>'''Front Elevation'''</center>

Hoskir: /* 751.39.1 Dimensions */ updated per RR4033

2025-04-18T18:20:04Z

751.39.1 Dimensions: updated per RR4033

← Older revision		Revision as of 13:20, 18 April 2025
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	\|-		\|-
	\| (5)		\| (5)
	\| style="text-align:left;" \| 12" for seismic design category A and 18" for SDC B, C, & D. If SDC A ~~SD1~~ ≥ 0.1, provide seismic details similar to SDC B for applicable routes per [https://epg.modot.org/forms/general_files/BR/Bridge_Seismic_Design_Flowchart.pdf Bridge Seismic Design Flowchart].		\| style="text-align:left;" \| 12" for seismic design category A and 18" for SDC B, C, & D. If SDC A S<sub>D1</sub> ≥ 0.1, provide seismic details similar to SDC B for applicable routes per [https://epg.modot.org/forms/general_files/BR/Bridge_Seismic_Design_Flowchart.pdf Bridge Seismic Design Flowchart].
	\|-		\|-
	\| (6)		\| (6)

Hoskir: /* 751.39.5 Reinforcement */ updated per RR4033

2025-04-14T16:34:11Z

751.39.5 Reinforcement: updated per RR4033

← Older revision		Revision as of 11:34, 14 April 2025
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	The term “unreinforced footing” is used for footings where only #6 hairpin bars are required.		The term “unreinforced footing” is used for footings where only #6 hairpin bars are required.

	Do not use unreinforced footing if SDC A, S<sub>D1</sub> ≥ 0.1.		Do not use unreinforced footing if SDC A, S<sub>D1</sub> ≥ 0.1 for applicable routes per [https://epg.modot.org/forms/general_files/BR/Bridge_Seismic_Design_Flowchart.pdf Bridge Seismic Design Flowchart].

	Unreinforced footings shall only be used when the shear line for all piles is within the column projected, or where additional flexural steel is not required by design (not typical).		Unreinforced footings shall only be used when the shear line for all piles is within the column projected, or where additional flexural steel is not required by design (not typical).
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	\| <center>'''Elevation</br>(4 Pile Footing)'''</center> \|\| <center>'''Plan</br>(4 Pile Footing)'''</center>		\| <center>'''Elevation</br>(4 Pile Footing)'''</center> \|\| <center>'''Plan</br>(4 Pile Footing)'''</center>
	\|}		\|}
	<nowiki>*</nowiki> See EPG 751.5.9.2.8.2.		<nowiki>*</nowiki> See [[751.5_Structural_Detailing_Guidelines#751.5.9.2.8.2_Development_and_Lap_Splices_of_Deformed_Bars_in_Tension\|EPG 751.5.9.2.8.2]].

	Notes: Use Class B lap splice of deformed bars in tension.		Notes: Use Class B lap splice of deformed bars in tension.
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	'''Reinforced Footing - Seismic Design Category (SDC) A'''		'''Reinforced Footing - Seismic Design Category (SDC) A'''

	If SDC A, S<sub>D1</sub> ≥ 0.1, provide seismic details similar to SDC B.		If SDC A, S<sub>D1</sub> ≥ 0.1, provide seismic details similar to SDC B for applicable routes per [https://epg.modot.org/forms/general_files/BR/Bridge_Seismic_Design_Flowchart.pdf Bridge Seismic Design Flowchart].

	{\|		{\|
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	\| colspan="2" \| <center>'''Plan'''</center>		\| colspan="2" \| <center>'''Plan'''</center>
	\|}		\|}
	<nowiki>*</nowiki> See EPG 751.5.9.2.8.2		<nowiki>*</nowiki> See See [[751.5_Structural_Detailing_Guidelines#751.5.9.2.8.2_Development_and_Lap_Splices_of_Deformed_Bars_in_Tension\|EPG 751.5.9.2.8.2]].

	Notes: Use Class B lap splice of deformed bars in tension.		Notes: Use Class B lap splice of deformed bars in tension.
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	\| [[image:Plan_Top_BCD_10-26-23.png\|395px\|center]] \|\| [[image:Plan_Bottom_BCD_10-26-23.png\|center]]		\| [[image:Plan_Top_BCD_10-26-23.png\|395px\|center]] \|\| [[image:Plan_Bottom_BCD_10-26-23.png\|center]]
	\|-		\|-
	\| <center>'''Plan Showing Top Reinforcement'''</center> \|\| <center>'''Plan Showing Bottom ~~Reinforcment~~'''</center>		\| <center>'''Plan Showing Top Reinforcement'''</center> \|\| <center>'''Plan Showing Bottom Reinforcement'''</center>
	\|}		\|}
	For anchorage of piles for seismic details for SDC B, C and D, see [[751.36_Driven_Piles#751.36.4_Anchorage_of_Piles_for_Seismic_Details\|EPG 751.36.4 Anchorage of Piles for Seismic Details]].		For anchorage of piles for seismic details for SDC B, C and D, see [[751.36_Driven_Piles#751.36.4_Anchorage_of_Piles_for_Seismic_Details\|EPG 751.36.4 Anchorage of Piles for Seismic Details]].
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	<nowiki> **</nowiki>Place the top reinforcement uniformly outside the column reinforcement. Use same area of steel in the top of the footing as is required for the bottom.		<nowiki> **</nowiki>Place the top reinforcement uniformly outside the column reinforcement. Use same area of steel in the top of the footing as is required for the bottom.

	~~Notes: When complete seismic analysis is required per bridge seismic design flowchart, Joint~~ shear reinforcement ~~shall be provided in accordance with AASHTO Guide Specifications~~ for ~~LRFD Seismic Bridge Design~~ (~~SGS~~) 6.4.~~5.Unreinforced footings shall not be used in seismic performance categories B, C & D~~.		For pile footing joint shear reinforcement requirement for SDC C and D, see [[751.9_Bridge_Seismic_Design#751.9.1.2.4.2_Footing_(Spread_Footing_and_Pile_Cap_Footing)_Joint_Shear_Reinforcement\|EPG 751.9.1.2.4.2 Footing (Spread Footing and Pile Cap Footing) Joint Shear Reinforcement]].

	=751.39.6 Seal Course=		=751.39.6 Seal Course=

Hoskir: /* 751.39.1 Dimensions */ updated per RR4033

2025-04-14T16:31:20Z

751.39.1 Dimensions: updated per RR4033

← Older revision		Revision as of 11:31, 14 April 2025
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	\|-		\|-
	\|		\|
	\| Note: For column diameters 4'-0" and greater use a 4'-0" min. footing</br>thickness. If SDC A ~~SD1~~ ≥ 0.1, provide seismic details similar to SDC B.		\| Note: For column diameters 4'-0" and greater use a 4'-0" min. footing</br>thickness. If SDC A S<sub>D1</sub> ≥ 0.1, provide seismic details similar to SDC B for applicable routes per [https://epg.modot.org/forms/general_files/BR/Bridge_Seismic_Design_Flowchart.pdf Bridge Seismic Design Flowchart].

	\|-		\|-
	\| (5)		\| (5)
	\| style="text-align:left;" \| 12" for seismic design category A and 18" for SDC B, C, & D. If SDC A SD1 ≥ 0.1, provide seismic details similar to SDC B.		\| style="text-align:left;" \| 12" for seismic design category A and 18" for SDC B, C, & D. If SDC A SD1 ≥ 0.1, provide seismic details similar to SDC B for applicable routes per [https://epg.modot.org/forms/general_files/BR/Bridge_Seismic_Design_Flowchart.pdf Bridge Seismic Design Flowchart].
	\|-		\|-
	\| (6)		\| (6)
	\| style="text-align:left;" \| Use 18" for steel HP piles and 14" and 16” CIP piles. The distance from the side of any pile to the nearest edge of the pile ~~cap~~ shall not be less than 9 inches.		\| style="text-align:left;" \| Use 18" for steel HP piles and 14" and 16” CIP piles. The distance from the side of any pile to the nearest edge of the pile footing shall not be less than 9 inches.
	\|}		\|}

Hoskir: /* 751.39.6.2 Pile Pull-out Force */ updated per RR3913

2024-11-21T18:49:18Z

751.39.6.2 Pile Pull-out Force: updated per RR3913

← Older revision		Revision as of 13:49, 21 November 2024
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	: (1) Factored resistance for skin friction = Geotechnical resistance factor for skin friction x Nominal skin friction resistance		: (1) Factored resistance for skin friction = Geotechnical resistance factor for skin friction x Nominal skin friction resistance

	:: Calculate nominal skin friction resistance of pile (without tip resistance).		:: Calculate nominal skin friction resistance of pile (without tip resistance).

	:: Geotechnical resistance factor for skin friction, φ<sub>up</sub>. from LRFD Table 10.5.5.2.3-1		:: Geotechnical resistance factor for skin friction, φ<sub>up</sub>. from LRFD Table 10.5.5.2.3-1

	:: Use φ<sub>up</sub> = 0.2 from LRFD table 10.5.5.2.3.-1 for single pile unless higher resistance factor can be justified based on soil type and test method.		:: Use φ<sub>up</sub> = 0.2 from LRFD table 10.5.5.2.3.-1 for single pile unless higher resistance factor can be justified based on soil type and test method.

	: (2) Factored resistance for pile tension = Structural resistance factor for pile tension x Yield strength of steel x Steel area of pile.		: (2) Factored resistance for pile tension = Structural resistance factor for pile tension x Yield strength of steel x Steel area of pile.

	:: Note: Since CIP pile is not filled at this stage, use steel pipe pile area without concrete to determine the factored resistance for pile tension. ASTM ~~252~~ allows “the wall thickness at any point shall not be more than 12.5% under the specified nominal wall thickness. For steel pipe pile area computation consider 87.5% of wall thickness.		:: Note: Since CIP pile is not filled at this stage, use steel pipe pile area without concrete to determine the factored resistance for pile tension. ASTM A252 allows “the wall thickness at any point shall not be more than 12.5% under the specified nominal wall thickness. For steel pipe pile area computation consider 87.5% of wall thickness.

	:: Structural resistance factor for pile tension, φ<sub>y</sub> = 0.25		:: Structural resistance factor for pile tension, φ<sub>y</sub> = 0.25

Hoskir: /* 751.39.4 Concrete Footing Design */ fixed errors from RR3796

2023-11-02T20:12:23Z

751.39.4 Concrete Footing Design: fixed errors from RR3796

← Older revision		Revision as of 15:12, 2 November 2023
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	Critical Section at <math>\frac {d_v}{2}</math> distance from face of column.		Critical Section at <math>\frac {d_v}{2}</math> distance from face of column.

	<math>V_r = \Phi V_n</math>		<math>V_r = \Phi V_n</math>

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	Notes: 1) f’c for footing is typically 3.0 ksi and matches f’c of column. Column and footing f’c may be increased to 4.0 ksi with approval from SPM or SLE.		Notes: 1) f’c for footing is typically 3.0 ksi and matches f’c of column. Column and footing f’c may be increased to 4.0 ksi with approval from SPM or SLE.

	::2) For simplicity, when calculating V_U, the maximum pile reaction may be assumed to act on all piles located outside the critical section.		::2) For simplicity, when calculating <math>V_U</math>, the maximum pile reaction may be assumed to act on all piles located outside the critical section.

	{\|		{\|

Hoskir: updated per RR3796

2023-11-01T14:22:54Z

updated per RR3796

Show changes

← Older revision		Revision as of 09:58, 19 December 2025
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	{\|		{\|
	\|-		\|-
	\| style="width: 275px;" \| [[image:~~Elevation_4_Pile_Footing_A_10-26~~-23.png\|center]] \|\| style="width: 275px;" \| [[image:Plan_4_Pile_Footing_A_10-26-23.png\|center]]		\| style="width: 275px;" \| [[image:751.39.5-01_2025.png\|250px\|center]] \|\| style="width: 275px;" \| [[image:Plan_4_Pile_Footing_A_10-26-23.png\|center]]
	\|-		\|-
	\| <center>'''Elevation</br>(4 Pile Footing)'''</center> \|\| <center>'''Plan</br>(4 Pile Footing)'''</center>		\| <center>'''Elevation</br>(4 Pile Footing)'''</center> \|\| <center>'''Plan</br>(4 Pile Footing)'''</center>
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	{\|		{\|
	\|-		\|-
	\| style="width: 350px;" \| [[image:Front_Elevation_A_10-26-23.png\|center]] \|\| style="width: 350px;" \| [[image:~~Side_Elevation_A_10-26~~-23.png\|center]]		\| style="width: 350px;" \| [[image:Front_Elevation_A_10-26-23.png\|center]] \|\| style="width: 350px;" \| [[image:751.39.5-03_2025.png\|325px\|center]]
	\|-		\|-
	\| <center>'''Front Elevation'''</center> \|\| <center>'''Side Elevation'''</center>		\| <center>'''Front Elevation'''</center> \|\| <center>'''Side Elevation'''</center>
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	\| colspan="2" \| <center>'''Plan'''</center>		\| colspan="2" \| <center>'''Plan'''</center>
	\|}		\|}
	<nowiki>*</nowiki> ~~See~~ See [[751.5_Structural_Detailing_Guidelines#751.5.9.2.8.2_Development_and_Lap_Splices_of_Deformed_Bars_in_Tension\|EPG 751.5.9.2.8.2]].		<nowiki>*</nowiki> See [[751.5_Structural_Detailing_Guidelines#751.5.9.2.8.2_Development_and_Lap_Splices_of_Deformed_Bars_in_Tension\|EPG 751.5.9.2.8.2]].

	Notes: Use Class B lap splice of deformed bars in tension.		Notes: Use Class B lap splice of deformed bars in tension.
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	<nowiki> **</nowiki>Place the top reinforcement uniformly outside the column reinforcement. Use same area of steel in the top of the footing as is required for the bottom.		<nowiki> **</nowiki>Place the top reinforcement uniformly outside the column reinforcement. Use same area of steel in the top of the footing as is required for the bottom.

	For pile footing joint shear reinforcement requirement for SDC C and D, see [[751.9_Bridge_Seismic_Design#751.9.1.2.4.2_Footing_(~~Spread_Footing_and_Pile_Cap_Footing~~)_Joint_Shear_Reinforcement\|EPG 751.9.1.2.4.2 Footing (Spread Footing and Pile ~~Cap~~ Footing) Joint Shear Reinforcement]].		For pile footing joint shear reinforcement requirement for SDC C and D, see [[751.9_Bridge_Seismic_Design#751.9.1.2.4.2_Footing_(Spread_Footing_and_Pile_Footing)_Joint_Shear_Reinforcement\|EPG 751.9.1.2.4.2 Footing (Spread Footing and Pile Footing) Joint Shear Reinforcement]].

	=751.39.6 Seal Course=		=751.39.6 Seal Course=