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Steel-Free
Concrete Bridge Deck
The Need
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Steel-free concrete
replaces reinforced concrete in bridge decks and similar
structures in marine environments and in northern climates
having snow and ice. It is to eliminate the source of
deterioration, the steel reinforcing bars in slabs exposed to
deicing salts. Eliminating corrosion makes concrete deck slabs
virtually maintenance-free, which makes life cycle costs of
steel-free concrete decks much lower than reinforced concrete
decks. |
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The Technology
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Shear connectors
make the steel-free concrete deck composite with the steel
girders that support it. Top flanges of girders attempt to
displace outward when a truck drives across the deck. External
transverse steel straps below the bridge deck and between the
bridge girders prevent this outward displacement by providing
a lateral restraining force to the girder and concrete deck.
In response, compressive membrane forces develop in the
concrete deck. Ultimate load can be greater than the load at
which the same deck would fail if it were reinforced
conventionally. In fact, the tension capacity of the steel
straps in the steel-free deck replaces conventional
reinforcing steel. The external steel straps can be inspected
and maintained in a similar fashion to steel girders. |
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The Benefits
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The benefits from
implementing this system are:
- Improvement of quality and
durability by eliminating corrosion caused by de-icing
salts
- Maintenance and repairs
without the normal disruption of traffic
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Status
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Two
versions are available: 1. The cast-in-place version 2.The
pre-cast ArchPanelTM version.
The
cast-in-place deck slab is now in the Canadian Highway Bridge
Design Code (CHBDC), currently in the press. Japan is
reviewing the technology. Meeting with American Association
State Highway Transportation Officials (AASHTO) Code Committee
are in progress.
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Points of Contact
Dr. Aftab A. Mufti,
P.Eng.
President ISIS Canada, The University of Manitoba,
Administrative Centre, 227 Engineering Building, Winnipeg, Manitoba, Canada R3T 5V6
Phone: 204 474 8506 Fax: 204 474 7519 e-mail: muftia@cc.umanitoba.ca
References
- News Release, 2000
Nova Award Nominations
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. |
JK1
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