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2021 Annual Virginia Concrete Conference

Michael Culmo, PE

Chief Bridge Engineer

CHA Consulting, Inc.

March 5, 2021

ABC State of Practice for Design &

Construction Provisions

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State of Practice for ABC

Widespread use of ABC• Virtually every state has used ABC

• Many have ABC programs

Design and Construction Specifications• We now have a national design and construction specification

• 2018 AASHTO Guide Specifications for ABC

• AASHTO Technical Committee T-4 is the home for ABC at AASHTO

Industry has stepped up• PCI National and Regional Committees

• PCI Northeast Bridge Technical Committee

• Has published many ABC guidelines

• Several key documents have recently been updated

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Available Publications

Free Publications• PCI: State of the Art Report on Full-Depth Bridge Decks Panels

• PCI Northeast: Full Depth Deck Panel Guidelines

• PCI Northeast: Guidelines for Resolution of Non-Conformances in

Precast Concrete Bridge Elements

• PCI Northeast: Suggested Guide Details for Precast Substructures

• PCI Northeast: Northeast Extreme Tee (NEXT) Beam Guide Details

• PCI Northeast: Guidelines for Camber and Profile Management in

Adjacent Beams

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Available Publications

FHWA Publications

• Accelerated Bridge Construction -

Experience in Design, Fabrication and

Erection of Prefabricated Bridge Elements

and Systems

• Engineering Design, Fabrication and

Erection of Prefabricated Bridge Elements

and Systems

• Contracting and Construction of ABC

Projects with Prefabricated Bridge Elements

and System

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Other References

NCHRP Project 12-98

• Guidelines for PBES Tolerances

• Guidelines for Dynamic Effects for Bridge Systems

• Including SPMTs and Lateral Sliding

• Want to know more?• FIU ABC webinar archives recordings

• NCHRP Project 12-98 website

• They are free!

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Guide Spec Contents

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Specification Overview

• Guide Specification Contents

6. Construction Introduction

7. Temporary Works

8. Fabrication and Assembly Planning

9. Layout and Tolerances

10. Concrete Structures

11. Steel Structures

12. Geosynthetic Reinforced Soil / Integrated

Bridge System

1. Design Introduction

2. General Design Provisions

3. Design of Prefabricated Elements

4. Detailing Requirements

5. Durability of ABC Technologies

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Design Specification Overview

Section 1: Introduction

Section 2: General Design Provisions

• Shipping and Handling Provisions

• Load Combinations for SPMT and Lateral Slide

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Design Specification Overview

Section 3: Design of Prefabricated Elements

• Majority of specs are based on emulation

• Significant seismic provisions

• Major Provisions that are not covered in the LRFD BDS

• Lapped hooked and headed bars

• UHPC connections

• Type 2 Mechanical Connectors

• Pocket Connections

• Socket connections

• Link slabs

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Design Specification Overview

Section 4: Detailing Requirements

• Tolerances and layout of precast elements

• Reference to NCHRP Project 12-98 guidelines

Section 5: Durability of ABC Technologies

• Detailing recommendations for durability

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Highlights of the Guide Specifications

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GS Section 1: Designer & Contractor Responsibilities

• Recommended responsibilities are defined for both the

designer and the contractor for:

• Prefabricated bridge elements

• Systems

• SPMTs

• Lateral Slide

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GS Section 2: Loads and Load Combinations

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GS Section 2: Loads and Load Combinations

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GS Section 2: Loads and Load Combinations

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Section 3: Design of PBEs

Largest Section in the Guide Specification• 85 pages

Includes Seismic provisions• Not covered today

• This workshop• Non-seismic details

• Many provisions applicable to seismic regions as well

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Section 3: Design of PBEs

Most common design approach: Emulative design

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Section 3: Connection Design

Most common connections covered:• CIP closure joints using lapped bar reinforcement

• Straight bars

• Headed bars

• Hooked bars

• UHPC with straight bars

• Mechanical Connectors• Bars inserted in grouted PT ducts• Pocket connections:

• Receive reinforcing from other element

• CMP Pipe Voids

• Socket connections: • Portion of one element inserted into a void in another

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Pockets and Sockets

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Pile Cap Pocket Connection

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Section 3: Grouted Couplers

Common design approach• Emulative design

• The same as non-prefabricated element

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Cantilever Abutment Idea (PCI NE)

Upper portion concept• Keep reinforcing above bridge seat

the same

• Detail a cap element with all the

complexities of the bridge seat• One complex element

• Lower elements are simple and less expensive

• The cap element will tie the lower elements

together

• Moment demand on cap connection is minimal,

which makes design easy and inexpensive

• Connect the two using a pocket connection

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Cantilever Abutments

Maine DOT Bridge

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CIP Footing with Precast Column

Pile Supported Footings

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Roughened Column End cast into Footing• Based on FHWA Highways for LIFE Research in Washington

Innovative Socket Connection

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Socket Connection Example

Internal Main Column BarsNote: Spirals not shown

Exposed aggregate column base

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Socket Connection Example

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Socket Connection Example

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Socket Connection Example

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Socket Connection Example

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Longitudinal panels:

FDDP Concepts (PCINE)

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Longitudinal panels:

FDDP Concepts (PCINE)

Commonwealth Ave. Bridge – Boston, MA

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Link Slab Connections

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NEXT Beams

Precast Double Tee for Bridges

Developed by the PCI NE Bridge Tech Committee

Details at: www.pcine.org

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NEXT F plus 8” CIP Deck

- No forming between flanges

- Easily accommodates vertical

- Curves w/CIP topping

- Easily handles camber variations

NEXT D no CIP Deck

- No CIP topping/deck

- Best section for ABC

- Special concrete for flange conn

- Harder to match adjacent members -skews

NEXT E plus 4” CIP Deck

- Uses less topping & reinforcement

- Flange connection made with CIP

- Easily accommodates vertical curve

- Easily accommodates camber variations

NEXT Beam Options

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NEXT Beams

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Lateral Slide Recommended Details

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Simplified Lateral Slide Details

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Simplified Lateral Slide Details

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Simplified Lateral Slide Details

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Simplified Lateral Slide Details

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GRS-IBS

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Bolted to beam ends• Simple version of a complex detail

• Lap backwall behind abutment

• Can be wrapped around side walls

Semi-integral precast backwall

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Key Construction Specifications

• Fabrication and assembly planning

• Quality Control for Precast Concrete

• Repairs to Elements

• Materials specifications

• High early strength concrete

• UHPC

• Non-shrink grout

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ConclusionsABC is here to stay

The AASHTO LRFD Guide Specs for ABC cover all

aspects of typical ABC Design and Construction• Loads and Load Factors

• Element Design

• Connection Design

• SPMT and Lateral Slide Systems

• Construction Specifications

You have all the tools required to design and specify

an ABC project• Let’s go build something - Fast

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Questions?

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