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4/15/2021
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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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