University of Delaware
Office of Public Relations
UpDate - Vol. 16, No. 17, Jan. 23, 1997
Composites research helps save bridges for the future

     Three faculty members, along with a number of graduate and
undergraduate engineering students, are building bridges for the
future and saving bridges from the past.
     Using the latest in composites technology, Michael Chajes
and Dennis Mertz, associate professors in civil and environmental
engineering, and Jack Gillespie, technical director of the Center
for Composite Materials and an associate professor in materials
science with a joint appointment in civil engineering, are
working closely with industry, government transportation
agencies, private contractors and construction companies to apply
the latest technology to age-old problems.
     The team is focusing on using composites to repair old
structures and build new ones.
     The joint initiative, formally called "Applications of
Advanced Materials to Civil Infrastructure," started in the early
1990s, when the UD engineers decided to address a major problem
facing Delaware and the nation- deterioration of the aging
infrastructure, particularly road and highway bridges.
     As a result of collaboration among the University, the
Delaware Department of Transportation (DelDOT), the Federal
Highway Administration (FHWA) the Delaware River and Bay
Authority (DRBA) and Hardcore-DuPont, several cooperative
projects are in progress.
     According to Chajes, composite materials-which are lighter,
more transportable, easier to work with and longer lasting-are
being tested in the campus laboratory and at field sites to
determine the possibility of replacing traditional steel and
concrete in bridge construction and repair.
     While composite materials may seem more expensive initially,
the UD team is attempting prove in the laboratory that the new
materials have a longer life span. The team also believes that
the use of composites will lower construction costs by allowing
projects to be completed in a shorter amount of time than those
using traditional methods and materials.
     According to Mertz, explaining the benefits of composite
materials to contracting companies and their employees is another
area that the UD research team must address.
     Even skeptics, however, were impressed with the findings of
a study that showed how the demolition of a 1940s era
Pennsylvania bridge, and construction of an entirely new one,
might have been avoided by applying composite materials now being
tested for structural bridge repair in UD laboratories.
     Demolition of the old structure and the new construction
that followed cost several million dollars. Not only would the
repair with composites materials have cost less, it also would
have been accomplished more quickly. This would have minimized
disruptions in the traffic pattern and shortened the length of
construction, Mertz said.
     Gillespie said they've discovered that when composites are
applied to bridges that need repair, their load-carrying
capabilities are increased and, in some cases, they can support
more weight than when they were originally built. In fact,
Gillespie added, the application of composites can increase the
capabilities of bridges in good condition.
     In the Du Pont Hall laboratory, corroded and cracked steel
beams taken from deteriorating roadways have had carbon fiber
composites bonded to them. Some are 1/4" thick strips, while
others look like sheets of thin black wallpaper, measuring as
little as 5/1000 of an inch in thickness.
     According to Chajes, when the paper thin sheets of carbon
fiber composites were applied with an epoxy to the underside of a
bridge on Foulk Road, north of Wilmington, the longitudinal
cracks that had formed on the beams were arrested. The bridge has
shown no signs of deterioration since it was repaired two years
ago.
     Although this entire research initiative is in the early
stages, GIllespie said three major field applications are being
planned in collaboration with DRBA, DelDOT, FHWA and Hardcore-
DuPont. They include a 70-foot-long bridge near the Delaware
Memorial Bridge, a 30-foot-long bridge near Glasgow, Del., on
Route 896, and an overpass over Interstate 295 in Delaware.
     Gillespie pointed out that a significant amount of
information and education must be directed toward the
construction companies and workers who eventually will use these
new materials. In the past, mainly steel and concrete have been
used in bridge construction. In UD's upcoming bridge projects,
about 75 percent of the structures will be made of composite
materials.
     "Our efforts with the departments of transportation,"
Gillespie said, "will affect the culture of construction, use of
materials and activities in the work force. The use of
composites, and the potential for their widespread utilization,
will have a dramatic effect on the traditional labor force. We're
trying to put ourselves in their position as we develop our
methods and procedures, so these materials can be applied by the
typical construction worker."
     Because of his background as a bridge designer, Mertz has
devoted a good portion of his time explaining the project team's
plans to bridge engineers and fabricators and incorporating their
comments and suggestions into the UD initiative's procedures and
planning.
     A number of civil and environmental engineering students
also are involved in the program. Gillespie and Chajes pointed
out that the presence of students-who are using their involvement
for research-is important to the University.
     Working on such an innovative project will give the UD
graduates an advantage in the job market, since the use of
composites in building and construction will definitely increase
in the future.
     Gillespie explained that as word spreads about what the
University is doing, and because of UD's reputation as a
recognized leader in composites and their practical application,
the University will find it easier to attract the best students.
     If the projects are successful in the state of Delaware,
Chajes said, then application of this technology will increase
nationwide.
     In such projects, cost always is a major factor.
     "We hope that the initial cost is comparable to using
traditional materials and construction techniques," Gillespie
said. "And, we believe that over the life span of the structure
the cost will be less. Departments of transportation, which in
the past would look only at the initial costs of a project, are
now starting to look at the long-term, life-cycle cost."
     Gillespie said he finds the work exciting and far reaching.
All the components are present for the University to become a
national leader in this area. He said there is supportive
cooperation with the state, a local industry that can produce
composite materials and excellent research talent at the
University.
                                             -Ed Okonowicz