Cost Effective Use of
Accelerated Steel Bridge
Construction and Integral
Abutments in the USA
Presented by:
Harry L. White 2nd, PE
New York State DOT
Transportation Research and Development Bureau
Lecture Outline
Accelerated Bridge Construction (ABC)
– Why use it?
– What is it?
– How is it being done in the USA?
Integral Abutment Bridges
– What are they?
– What are the benefits/risks?
– How is it being done in the USA?
Why Use ABC?
There Are Hidden Costs
Traffic Disruption
Wasted Fuel/Time
Danger to Drivers/Construction Workers
Lost Business
Noise for Local Residents
Increase in Stress for all involved
Often, these hidden costs can exceed
the cost of the actual structure.
What is ABC?
What is ABC?
“ABC is bridge construction that uses
innovative planning, design, materials,
and construction methods in a safe and
cost-effective manner to reduce the onsite
construction time that occurs when
building new bridges or replacing and
rehabilitating existing bridges.”
- Federal Highway Administration
In Other Words…
Accelerated Bridge
Construction takes less
time than normal.
Accelerated Bridge Construction
Federal Highway Administration Initiative
– “Get In. Get Out. Stay Out.”
Prefabricated Bridge Elements (PBE)
– Manufactured Away From Construction Site
– Stored Until Ready
– Delivered When Needed
– Installed Quickly
How Does the USA Use ABC?
Precast Footings
Splice-Sleeve Connector
Precast Pier Elements
Precast Deck Panels
Ultra-High Performance
Concrete (UHPC)
Three Separate Components
– Bagged Cement Powder
– Steel Fiber Reinforcement
– Chemical Admixtures
Compressive Strength: 150 MPa (22 ksi)
Post-Cracking Tensile Strength: 5 MPa
19 mm diameter reinforcing bar fully
developed with only 100 mm embedment
Test Slabs - NYSDOT
Entire Superstructures
SPMT – Self Propelled Modular Transports
– Requires assembly area
– Requires clearance
– Requires level under road access
Float-In
– Assembly area does not need to be nearby
– Requires waterway
Sufficient depth
Sufficient clearance
Self-Propelled
Modular Transports
Willis Avenue, New York City
Float-In
Integral Abutments
No Joints
No Bearings
Single Row of Piles
Lower Initial Cost
Less Maintenance
More Durable
Fully Integral Abutment Bridges
Fully Integral Abutment Bridges
Design Consistency
“Informed Art” not “Absolute Science”
No Approved Design Methodology
Rules of One Agency Ignored by Others
– 46% Orient piles in weak-axis bending
– 33% Orient Piles in strong-axis bending
– 8% No preference for pile orientation
– 13% Require use of symmetrical piles
Design Considerations
Translation is Primary Abutment
Movement
Rotation of Abutment Depends on:
– Abutment height
– Beam depth and connection details
– Span length
– Backfill compaction – ‘Soil Ratcheting’
Design Considerations
Most States Limit Span Lengths
– Longest steel span 318 m in Colorado, USA
– Longest cast-in-place concrete span 290 m
(Colorado, USA)
– Longest prestressed concrete span 358 m
(Tennessee, USA)
Span Lengths Usually Based on Experience
Design Considerations (cont.)
Typical Beam Designed Simply-Supported
– Conservative
– Provides safety-factor for abutment rotations
Actual Connection of Superstructure and
Abutment is Between Pinned and Fixed
Beam depth
Beam material
Connection details
Steel Superstructures
PBES Integral Abutment
Conclusions
Integral Abutments are:
– Inexpensive on a first cost basis
– Inexpensive on a life-cycle basis
– Redundant and robust for extreme events
– Enhanced load distribution at girder ends
– Rapid construction
– Larger tolerances
– Preferred abutment type for most agencies
ABC May Improve:
Total Construction Time
– Multiple elements may be fabricated at once
Material Quality and Durability
– Fabricated in a controlled environment
Work-Zone Safety
– Less time on-site reduces chance of accidents
ABC May Reduce:
Traffic Impacts
– Prefabricated elements install quickly
Weather-Related Time Delays
– Prefabrication permits a predictable schedule
Environmental Impacts
– Fabrication in a controlled environment
Interference With Nearby Utilities
Thank You