CHAPTER 22

SUBSTRUCTURES

CHAPTER 22

SUBSTRUCTURES

CHAPTER 22

SUBSTRUCTURES

Old Chapters– 66: Foundations– 67: Bents, Piers and Abutments– 68: Retaining Walls (not published)

New Chapters– 22-1: Foundations– 22-2: Abutments, Bents, Piers and

Bearings– 22-3: Earth Retaining Systems

CHAPTER 22

SUBSTRUCTURES

Revisions and Updates– Chapter 22-1: Foundations

Limit States and Resistance Factors Maximum Axial Nominal Geotechnical Pile

Resistances Rn max for HP and shell piles Additional structural considerations for scour Seismic design

– Chapter 22-2: Abutments, Bents, Piers and Bearings

Limit States and Resistance Factors Load Combination and Load Factors New Section on Semi Integral End Bents

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SUBSTRUCTURES

– Chapter 22-3: Earth Retaining Systems Limit States and Resistance Factors Fill Walls

– Cast-in-place Reinforced Concrete Cantilever– Retaining Walls with or without Ground Reinf– Prefabricated Modular Gravity Wall– Reinforced Soil Slopes

Cut Walls– Soldier Pile Wall– Drilled Shaft Wall– Anchored Wall– Soil Nailed Wall– Micropile Wall

CHAPTER 22

SUBSTRUCTURES

Integral andSemi Integral

End Bents

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SUBSTRUCTURES

Benefits of Integral and Semi-Integral End Bents

Eliminate expansion jointsReduce future maintenance costsReduce construction costsEffective way to accommodate seismic forces (dampening effect)

CHAPTER 22

SUBSTRUCTURES

Uses of Integral and Semi-Integral End Bents

Chapter 22 describes integral end bent limitations.Use integral end bents whenever possible.Use semi-integral end bents when integral end bents are not possible.

Skew angle > 30 and/orBridge Length > 500 ft or Expansion Length > 250 ftTwisting or racking of the bridge should be analyzedRehabilitating existing bridge with battered pile

Use expansion end bents as a last resort.

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SUBSTRUCTURES

Details of Integral End Bents

Beams attached directly to piles

CHAPTER 22

SUBSTRUCTURES

Details of Integral End Bents

CHAPTER 22

SUBSTRUCTURES

Details of Integral End Bents

Beams attached to concrete cap

CHAPTER 22

SUBSTRUCTURES

Details of Integral End Bents

CHAPTER 22

SUBSTRUCTURES

Details of Semi-Integral End Bents

Method 1Use keyway with expanded polystyrene and anchor plateUse polychloroprene joint membrane behind end bent

CHAPTER 22

SUBSTRUCTURES

Details of Semi-Integral End Bents

CHAPTER 22

SUBSTRUCTURES

Details of Semi-Integral End Bents

Method 2Use elastomeric bearing pad and expanded polystyreneUse polychloroprene joint membrane behind end bent

CHAPTER 22

SUBSTRUCTURES

Details of Semi-Integral End Bents

CHAPTER 22

SUBSTRUCTURES

Interior Pier Requirements

Designed for vertical load.Designed for transverse lateral load (stream, earth, wind; usually minor).All longitudinal lateral loads distributed to end bent embankments.Piers can be either:

fixed (frame bents, hammerhead, on pile caps) with movable bearingsextended pile bentswall pier on a single row of piles (extended pile bent with large cap)

save money on foundations and cofferdamsfriction of approach slab help resist longitudinal forces

CHAPTER 22

SUBSTRUCTURES

Interior Pier Requirements

CHAPTER 22

SUBSTRUCTURES

Beyond the Maximum

BFS designing an integral bridge on the US 31 Kokomo Bypass that is 810 ft and zero skew.Edward Wasserman, Tennessee DOT designed a 1175 ft curved, jointless bridge on State Road 50 over Happy Hollow Creek.

Forces at end bents were less due to curvature

CHAPTER 22

SUBSTRUCTURES

References

Massachusetts Department of Public Works “Integral Bridge Seminar”presented by Steve Weintraut and Martin Burke, Jr.

“The Emergence of Semi-Integral Bridges”by Martin Burke, Jr.

“The Structure Movement Systems Approach to Effective Bridge Design”by Martin Burke, Jr.

“Design of Integral Concrete Bridges”by Martin Burke, Jr.

“Jointless and Smoother Bridges”by Professor Robert Frosch

CHAPTER 22

SUBSTRUCTURES

BEARINGS

Minimize Bearing Pad Sizes– Minimize different types and sizes

INDOT Specs require extra bearing pad for each size and type.

Cost savings can be realized by using the same bearing pad– Shim Thickness

Shims in elastomeric bearings should be 12 gage (0.1046”) Old standard of 3/32” (0.09375”) should not be specified