Schematic Design of an Accelerated Bridge Construction ProjectMichael P. Culmo, P.E.

Vice President of Transportation and Structures

CME Associates, Inc., East Hartford, CT

Reference Manual

• Use the Connections Details Manual– Type study concept– Select details from various

states

Case Scenario

• 4 lane bridge over an expressway

• Existing bridge has deteriorated beyond repair

• Heavy traffic on both roadways

• There is a short but undesirable detour

Public Involvement

• Public hearing heldPublic hearing held

• Businesses do not want a long Businesses do not want a long construction process with stage construction process with stage constructionconstruction

• Businesses are not keen about a detourBusinesses are not keen about a detour

• They will accept a short term closure with They will accept a short term closure with the detourthe detour– As opposed to a long term staged projectAs opposed to a long term staged project

Design Approach Options

• Build a temporary bridge to speed up construction of the new bridge– $$$$– Not that fast

• Use multi-stage construction– Very long construction– Will require long term lane closures

• Establish the detour and accelerate the bridge construction to less than 30 days

Existing Bridge

Deck Joints

Low Clearance

Existing bridge issues

Proposed Bridge Type

• After a formal type study, the owner opted with the following structure criteria– Use NEXT Beams to accelerate construction

• Design as simple span for Dead Load and continuous spans for Live Load

– Increase clearance by raising approach grades (3’)– Use integral abutments (no deck joints)– Composite concrete deck– Membrane waterproofing and Bituminous wearing

surface– Use Precast Rail System

• (Vermont/NH system)

Substructures

• Push abutments back to top of slopePush abutments back to top of slope– Minimize wingwall requirementsMinimize wingwall requirements– Use integral abutments with flying wingsUse integral abutments with flying wings– Eliminate spray attack on abutmentsEliminate spray attack on abutments

• Place abutments in a different footprint than the Place abutments in a different footprint than the existingexisting– facilitates constructionfacilitates construction

• Use open frame pier bent on spread footingsUse open frame pier bent on spread footings

Proposed Bridge

Move abutment away from

roadway

No Deck joints Increase vertical clearance

Bridge Section

Beam Design

• Preliminary Beam Sizing– Use PCI NEXT

Beam Standards

Beam Design

• LLDF

Beam Design

• AASHTO LL Distribution Factor – Type K

Moment

Shear

Beam Design

• AASHTO LLDF

Type H

Moment

Shear

Beam Design

Structure Type H K

LLDF

Moment

0.96 0.752

LLDF

Shear

1.17 0.938

How to select details

FHWA manual “Connection details for prefabricated bridge elements and systems”

1. Review Chapter 1• Investigate connection types, materials,

tolerances

2. Search applicable sections of other chapters for details

Section 1.4 Typical Connection Types

• After reviewing chapter 1, the owner chose the following connection types– Grouted reinforcing splice couplers

• Quick, proven system• Can develop full bar strength• Simplifies the design process (similar to CIP)

– Grouted Voids• Easy for simple connections

– Concrete Closure pours between precast elements• Use for a limited number of connections (slower)

Grouted Reinforcing Splice Connectors

• Emulates a reinforcing steel lap splice

• Multiple companies – non-proprietary

• Used in precast parking garages and stadiums and bridges

Grouted Reinforcing Splice Connectors

• Emulates a reinforcing steel lap splice

• Multiple companies – non-proprietary

• Used in precast parking garages and stadiums and bridges

• Time Lapse Video on YoutubeTM – Search “Georgia Pier

Construction”• Installation Video on YoutubeTM

Search “Georgia Pier Construction”Installation video

Footing to Sub-grade Connection

Footing Details

Footing to Column Connection

Footing to Column Connection

Column to Cap Connection

Column to Cap Connection

Completed Pier

Footing to subgrade

connection

Column to footing

connection

Column to cap

connection

Abutment Details

• Integral Abutment to precast piles– Section 3.2.3.1 Precast Integral Abutment to

Piles

• Detail developed by Maine DOT– Used on three different bridges

Abutment to Pile Connection

Abutment to Pile Connection

Abutment To Wingwall Connection

Abutment To Wingwall Connection

Approach Slab Connection

Completed Abutment

Pile to cap connection

Approach slab connection

Flying Wingwall

connection

Abutment cap connection

Deck Design with Next Beam

• Design as a conventional cast in place deck– Use max stem spacing for design (5.0 feet)– Design overhang from outside stem (2.53 feet)

Parapet Connection

Parapet Connection

Superstructure to Integral Abutment Connection

Use a similar detail at the pier

Completed Bridge

Precast Integral Abutment

Composite Deck Membrane

waterproofing with bit.

Wearing surface

Precast Pier

Precast Parapet

Final Bridge

Estimated Construction Schedule

Costs

• Typical New Bridge (Cost=$200/sf) = $1,920,000

• Premium for ABC (assume 20%) = $384,000

• Temporary Bridge (Cost=$60/sf) = ($576,000)

Net Savings = $192,000

Note: These prices will vary by region

• Ways to reduce bid prices with ABC• Standardization• Programmatic (not one of a kind)• Reduced project site costs (trailers, etc.)• Reduced Maintenance of Traffic Costs• Inflation

• Other Non- Bid Savings with ABC• Fewer Police Details• Reduced Resident Engineering time

• User Costs• Plus: $$ Can be significant• Minus: $$ Not in the budget

Other Cost Savings

Quality

• Florida has had very good success with precast piers in very harsh environments

• Precast concrete beams require no maintenance

• Integral abutments eliminate deck joints

Old Adage

By elimination of temporary bridges or costly By elimination of temporary bridges or costly stage construction schemes, stage construction schemes,

you you CANCAN have all three have all three

Rapid Rapid ConstructionConstruction

High QualityHigh Quality

Low CostLow Cost

You can only You can only have any twohave any two

Conclusions• It is possible to build a complete bridge in 30

days (or less)• The FHWA manual provides a starting point for

a complete bridge prefabrication project• You do not need to sacrifice quality to get rapid

construction• You can save money on an accelerated bridge

project by:– Reducing construction time– Eliminate temporary bridges or staging

Questions

culmo@cmeengineering.com