Short-span polymer-matrix-composite bridges entering service in Ohio and Idaho may give Martin Marietta Materials Inc. an entree to transportation and infrastructure markets.
Butler County in Ohio this week plans to open a permanent replacement for a concrete bridge on a two-lane road over a creek in Hamilton. A prototype span is scheduled for use in Idaho beginning in early August.
In each case, Martin Marietta of Raleigh, N.C., is supplying the bridge without charge. Mechanical and fiber-optic devices will monitor material performance and provide a base line for future structures.
An opening ceremony for ``Ohio's first all-composite vehicle bridge'' is set for July 25.
A civil engineering firm dealt with site details, including substructure and railings.
``We treated the pieces from California as we would precast or prestressed concrete members,'' said Mark Henderson, structural engineer in the Cincinnati office of Lockwood Jones & Beals Engineers & Architects Inc.
Henderson credited John Mistretta, an Air Force materials engineer, with bringing together the composite bridge developer and county engineer and serving as a central coordinator. Wright Laboratory's materials directorate at Wright Patterson Air Force Base in Ohio, along with Martin Marietta, is providing principal funding for installation of the sensors and follow-up monitoring.
Generally, however, more interaction is needed to overcome a ``huge communication gap between aerospace and civil structural engineering communities,'' Henderson said. The gap accounts, in part, for slow adoption of advanced materials for traditional infrastructure applications.
Aspects of the Ohio installation are a generation removed from the original design.
The deeper, stiffer tube construction uses ``the heaviest fabric ever to be pultruded,'' said Barry White, sales manager of Glasforms Inc., based in San Jose, Calif.
Glasforms pultrudes trapezoidal tubes that are combined into 12-inch-by-6-inch rectangles, each with an interior angle brace running the bridge's length. White said Johnston Industries Inc. of Phoenix City, Ala., supplied the four layers of 60-ounce-per-square-yard, triaxial- fiber-orientation fiber.
Under a one-year program beginning in August, the Idaho installation will carry two-way traffic on a route to the refueling station at the Idaho National Engineering and Environmental Laboratory's transportation complex, about 45 miles west of Idaho Falls.
``All government vehicles out here will go over the bridge every day,'' Julio Rodriguez, project manager at the Energy Department site, said in a telephone interview.
``It won't be permanent. Martin Marietta wants to use the bridge elsewhere,'' possibly in a salt-water environment in Florida, he added.
Idaho Falls contractor Northwestern Technology is handling the installation, bolting together sections of the 30-foot-by-18-foot prototype.