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FRP
Deck - Rehabilitation of a Steel Truss Bridge
The Need
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To
avoid a costly bridge replacement project, the New York State Department
of Transportation partnered with private industry to rehabilitate a steel
truss bridge using lightweight composites. Reducing dead load
on the bridge by 265 tons, the application of composite deck
technology
doubled the load ratings (to a level higher than the original
design) and allowed weight restrictions to be removed, while
saving $1.4 million. This was the first time this type of
rehabilitation was accomplished in the U.S.
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The Technology
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Bentley's Bridge, located near
Elmira, New York, was installed in September 1999. Before
reconstruction, the structure had a steel reinforced concrete
deck cast over steel stringers. Due to deterioration of the
bridge, load restrictions were posted. Reconstruction of the
bridge with FRP (fiber reinforced polymer) composite deck
panels fabricated an AASHTO HS25 design load for the bridge
deck. Panels are fabricated using Vacuum Assisted Resin
Transfer Molding to produce a lightweight celular core panels. |
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| The construction included six
composite bridge deck panels, with composite curbs and shims,
measuring 140' span by 25’ width.
Also included in the project was the construction of
replacement pedestrian walkways with composite walkway panels.
The
lightweight deck and walkway replacement enabled New York
State Department of Transportation to double the bridge's load
ratings while allowing vehicle weight restrictions to be
removed. Most important, it avoided a costly bridge replacement project by
rehabilitating a steel truss bridge using lightweight
composites. Reducing dead load on the bridge by 265 tons, the
application of this technology doubled the load ratings to a
level higher than the original design and allowed weight
restrictions to be removed, while saving $1.4 million in the
process. It demonstrates the tremendous
savings in time, money and weight to be gained from the use of
large composite structures. The total cost of the project was
just $800,000, versus a projected $2.2 million for replacing
the bridge. As a result of reducing the dead load on the
bridge to 32 pounds per square foot from 170 pounds per square
foot, contractor was able to raise the load rating on the
bridge to a much higher level than the original design and
save the original superstructure. And the installation -
completed in September, 1999 - was responsible for only one
month of downtime for the bridge, instead of several. |
The Benefits
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- Allow
vehicle weight restrictions to be removed
- Eliminate
the need for a costly and time-consuming bridge replacement
project along a heavily trafficked road.
- Reduce the deck dead load on the structure by 265
tons.
- Prolong the life of steel truss bridges.
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Status
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NEW
CASTLE, DELAWARE - August 24th, 2000 - Hardcore Composites has
been named by the Civil Engineering Research Foundation in
this year's Charles Pankow Award, the Foundation's highest
award for innovation, for the rehabilitation of an aging steel
truss bridge in Wellsburg, New York, using fiber-reinforced
composites. Hardcore Composites manufactured the key component
in the project - a lightweight but super-strong all-composite
deck. Over the past four years,
Hardcore Composites has manufactured and installed twenty
traffic-bearing bridges or bridge decks.
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Barriers
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The major barriers facing the application of composite materials in
construction are:
1. Limited information on Life cycle costs
2. Limited information on Life cycle performance
3. Limited information on benefits/cost analysis of replacing
conventional materials with composites
4. For this particular technology (HCI panels) sometimes a vertical
uplift between the panels is noticed. This could be because the thin
splice plates that are used to join the two adjacent panels did not provide
adequate stiffness to prevent this movement. This problem can be rectified by clamping down the decks. However, the preparation and assembly of the tongue pieces as well as the extra efforts of clamping down the decks could be difficult and time consuming. |
Points of Contact
- Mark Ewen,
Business Director. 618 Lambsons Lane New Castle, DE 19720. Tel:
(302) 442-5900
References
- Hardcore Composite Press Release
Disclaimer Statement
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Neither the Construction
Industry Institute nor Purdue University in any way endorses this
technology or represents
that the information presented can be relied upon without further investigation. |
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