BURLINGAME, CALIF.-Four bridge deck plates of various advanced composites will be tested this spring in a roadway carrying heavy trucks and transit buses on the University of California, San Diego, campus. ``This demonstration case represents a worst-case environment, and the technology can only get cheaper and lighter in eventual commercial applications,'' said Frank Belknap, program manager at UCSD for the federal Advanced Research Pro-jects Agency.
Belknap noted that a standard highway application has 7-8 feet between girders, rather than the 15 feet in the demonstration.
Lockheed Martin Corp. and DuPont Co. ventures are making duplicate sets of the 71/2-by-15-foot plates. One set of each type plate will go into the 15-by-30-foot roadway opening, with electronic monitors feeding data constantly to UCSD's nearby Powell Struc-tural Research Laboratories. The other set will undergo myriad structural, dynamic and destructive tests.
``We are looking at both bridge deck replacement and whole bridges,'' said Philip Underwood, structures laboratory manager at the Lockheed Martin Missiles and Space unit's advanced technology center in Palo Alto, Calif.
The deck combines polyester and vinyl ester with fiberglass.
``We have a triangular truss configuration and mold the section using SCRIMP technology,'' said Karl Bernetich, infrastructure programs manager for joint-venture Hardcore DuPont Com-posites LLC of New Castle, Del.
SCRIMP stands for Seemann Composites Resin Infusion Mold-ing Process, a low-cost way to make large composite parts.
Amoco Corp.'s Performance Products unit in Alpharetta, Ga., will install a polymer concrete surface consisting of polyester resin, sand, aggregate and milled carbon fibers to cover the deck plates and provide a friction and wear surface for the road, according to Mike Michno, governments contracts manager with Amoco Performance Products.
The demonstration at UCSD may advance a bridge-deck technology in its infancy for vehicular traffic.
``I haven't seen any composite bridge deck that is really near the market, although there is a lot of prototyping and testing,'' said W. Brandt Goldsworthy, an industry consultant in Torrance, Calif. ``The departments of transportation need to have their comfort level raised.''
Goldsworthy was interviewed at the Wilson Forum on Existing & Potential Applications of Com-posite Materials in the Infrastruc-ture, held March 11-12 in Burlin-game.
Craig Ballinger, an industry consultant in Vienna, Va., agreed that no bridge decks of polymer composites have reached the commercial market yet.
Jim Roberts, director of the engineering service center for the California Transportation Depart-ment, renewed his call for composite bridge decks in his March 11 keynote speech to the Wilson Forum.
Roberts sees composites as a noncorrosive deck-replacement solution in the Midwest and Northeast, where frequent applications of salt eventually can destroy concrete surfaces, and he has committed Caltrans funds to help develop design specifications.
Specifically, Caltrans plans by June to request qualifications for design, testing and installation of an advanced composite deck on the Schuyler Heim Bridge near Long Beach, Calif., to replace a failing open-grated steel deck. The one-year contract will have a value of about $1 million.
Several Wilson Forum presentations reported on designs proposing to use composite materials in bridge superstructures and decks.
Lockheed Martin staff scientist Chris Dumlao described development of a superstructure prototype, but highway department questions about material testing and acceptance criteria appear to be delaying a real-world installation of the polymer-composite short-span bridge.
``We have offered the bridge to a few agencies for field testing,'' Underwood said.
A busload of Wilson Forum attendees viewed the demonstration bridge March 11 at the center in Palo Alto.
The 30-by-18-foot bridge in-cludes sandwich panel deck plates of E-glass and polyester resin, underlying pultruded 4-inch-square tubes of E-glass roving and mat reinforcing polyester resin, and hand-layup, U-shaped support beams of stitched, nonwoven E-glass and a formulation of isophthalic polyester and vinyl ester resin. Lockheed Mar-tin funded the $250,000 development, which was completed in August.
Highway officials rely on construction-based material specifications and deal mostly with steel and concrete.
The composite bridge was assembled using finished-product performance specifications with aerospace origins. Underwood declined to identify the agency contacts.
In another Wilson Forum presentation, Capt. Paul Yantha, a lecturer at Royal Military College in Kingston, Ontario, described a vehicle bridge of glass-fiber-reinforced plastics with pultruded structural channels.
I. Dennis Parsons, associate professor at the University of Illinois in Urbana, Ill., reviewed a concept to filament wind inner shells and an outer shell in fabricating a fiber-reinforced bridge deck.
``Shells are extremely efficient structural elements,'' he said.
