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| Vol. 18, No. 10 | Nov. 5, 1998 |
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| Vol. 18, No. 10 | Nov. 5, 1998 |
A section of the new composite bridge deck is set in place.
Bridge 1-351, as it is known on Delaware's highway system, is one of the first state-owned, all-composite bridges in the nation.
The project demonstrates a new technology with the potential to solve a major problem facing Delaware and the nation as a whole-deterioration of aging infrastructure.
Other partners in the project are the Delaware Department of Transportation (DelDOT), the Federal Highway Administration and local industry, including Hardcore Composites, Anholt Technologies and contractor James Julian Inc. of Delaware.
According to DelDOT's Chao Hu, close to 30 percent of America's 600,000 public bridges are either structurally deficient or functionally obsolete, with the rehabilitation/ replacement cost estimated at close to $150 billion.
"This new composites technology will enable us to deal with the deficiencies in a more effective way," he said. "We are also hopeful that it will enable us to build new bridges to last longer, thus reducing the backlog of deficient bridges in the long run."
UD researchers have shown that advanced composites are a very promising alternative, offering many benefits over such traditional construction materials as steel and concrete.
"These materials don't corrode, can be fabricated to near-net shape, and can incorporate innovative design features," John W. Gillespie Jr., civil and environmental engineering and Center for Composite Materials, said.
The technology builds on the University team's fundamental understanding of composites processing, material behavior and long-term performance, culminating in new design and analysis tools that have been experimentally validated in the Department of Civil and Environmental Engineering's large-scale testing facility.
According to Michael J. Chajes, civil and environmental engineering, the new bridge is composed of a two-part FRP deck connected by a unique, longitudinal joint and covered with a latex-modified concrete wearing surface. The overall structure is 32 feet long, 26 feet wide and 30 inches thick. Each deck section weighs 14,000 pounds. The FRP material used to construct the deck is about one-tenth the weight of concrete.
"This is an important consideration in bridge deck replacement," Chajes said, "because any weight that can be saved in the deck itself translates into increased load-carrying capacity."
The bridge, designed in accordance with AASHTO (American Association of State Highway and Transportation Officials) specifications, was fully tested at the University.
"This is essential to future application of the technology to bridge design and construction," said Dennis R. Mertz, civil and environmental engineering, an expert in bridge design. "This project has positioned us to take the next step in codifying the use of composites for bridge rehabilitation and construction."
Critical to the success of the project was the University's holistic "systems" approach to the research.
"Forming an alliance among the University, DelDOT and industry enabled us to demonstrate this technology through application on a state-owned bridge rather than as just a private project," according to Scott A. Sabol, Delaware Transportation Institute. "The success of the project is due largely to our combined expertise in advanced materials and bridge design, augmented by our understanding of transportation practices."
The presence of the University on the team brought an educational component to the project, taking it beyond mere demonstration. Civil and environmental engineering doctoral candidate Douglas A. Eckel II made substantial contributions to the design and testing of the bridge deck sections.
"It has been a wonderful experience for me as a graduate student to be involved in a hands-on project starting at the design stage and progressing through manufacturing and erection of the bridge in the field," Eckel said.
Another facet of the project involves long-term monitoring of the bridge by University researchers. The use of advanced sensor technology will yield a wealth of information regarding the performance of the bridge under actual service conditions. This feedback will enable optimization of future deck designs.
"The University of Delaware is emerging as a national leader in the application of composite materials to infrastructure renewal," President David P. Roselle, said. "This project demonstrates our ability to form partnerships for education, research and technology transfer in an area that has the potential to benefit the entire nation."
-Diane Kukich
Photo by Jack Buxbaum
