The 20th century brought about many innovative changes to the world of construction. While concrete and steel tend to be the materials of choice, technology has introduced a material, which may become the material of choice for future designs. This material is Fiber Reinforced Polymer (FRP). Composites being both light and strong, are being introduced to many applications, including bridge construction.
In an effort to speed construction and increase service life of a bridge, the North Carolina Department of Transportation (NCDOT) looked to composites. A deteriorating bridge in Union County presented the opportunity to test this new concept in bridge construction. Bridge #89-022 over Mill Creek on New Salem Road (SR1627) needed to be removed and rebuilt, so it was chosen to receive the first composite deck in the State of North Carolina. Martin Marietta Composites division, producer of the FRP DuraSpanTM system, was contracted to produce the panels required for the bridge replacement.
The construction of this bridge was funded in large part through a discretionary grant from the FHWA through the Innovative Bridge Research and Construction Program. Evaluation of this structure continues as a part of the NCDOT Research Project2002-12 titled "Evaluation of Bridge Analysis vis-à-vis Performance". The results of this evaluation will therefore be contained in the final report for this research to be concluded in the summer of 2003.
First, the existing structure was removed, and the new steel girders were installed. Then, angles were welded to the girders to support the panel and to provide room for grout injection. After the angles were welded in place, the panels were placed in accordance with the Martin Marietta Installation Guide by NCDOT personnel, and under the supervision of Martin Marietta representatives. After the deck panels were placed, a combination of shear studs and grout were used to permanently attach the panels to the girders. Once this attachment was made, the rebar and forms for the endwalls were placed, and the concrete was poured. The asphalt overlay was then placed followed by the guardrail. The last item on the agenda was the load testing of the bridge. Once testing was completed, the bridge was opened to traffic.
