Highway bridge built of composites.
Composites, typically used to construct submarines, fighter aircraft, and spacecraft, will be used to build a cable-stayed highway bridge. Lockheed Palo Alto Research Laboratories has joined a consortium headed by the University of California at San Diego (UCSD) to design and build the 450-foot-long bridge across Interstate 5 at the university campus.
The proposed bridge will be made in segments. Lockheed expertise in nondestructive testing, developed for military applications such as the F-22 fighter aircraft program and satellite buses, will allow each segment to be examined radiographically for integrity after manufacture. Lockheed's capability in design, analysis, and optimization of composite structures will help make the segments as light as possible. They would then be trucked to the site for rapid assembly. Transporting and lifting them into place is possible because a composite segment can be more than 10 times lighter than a segment of concrete and steel that would carry an equivalent load. Usually made of glass, carbon, and polymer fibers, advanced composite materials are lighter, stronger, and more corrosion-resistant than conventional building materials such as steel and concrete.
UCSD, Lockheed, and other members of the Advanced Composite Technology Transfer Consortium will pool their expertise to identify, analyze, and evaluate composite materials, configurations, and fabrication and joining methods critical to the development of the proposed bridge. They are expected to complete the research and development phase of the project in three years. Construction approval will then be sought from various local, state, and federal agencies and from UCSD. Actual construction of the bridge should take about a year.
Alan K. Miller, a principal Lockheed engineer involved in the bridge project since its inception, said "An innovative filament winding process developed here facilitates a high rate of composite material deposition without the need to cure the component in large autoclaves."
The cost of composite material is approximately $20 per pound, as compared to concrete and steel, which cost $1 per pound. One of the goals of this project is to bring the cost of composites down to $5 or $10 per pound. This would be for the overall finished product, not just for materials. The weight of the material required, reduced on-site labor, and life-cycle costs would be considered part of the bargain.
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|Title Annotation:||bridge at the University of California at San Diego|
|Date:||Jul 1, 1993|
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