Six-Year Performance Evaluation of St. James, Missouri, Composite Bridges

Field validation of FRP bridges through load tests provides a means of measuring the performance of a bridge over time. Non-contact optical surveying equipment is one such method that can be utilized to measure the deflection of bridges under a static truck load. Four bridges located in St. James, Missouri were originally constructed in 2001 with FRP technologies and subsequently load tested. Each bridge utilized FRP in its construction in a different way. One bridge consisted entirely of FRP sandwich panels whereas two other bridges utilized FRP panels for the decks with steel beams for girders. The final bridge employed CFRP and GFRP bars within precast concrete panels. Deflection readings were measured using DCVTs mounted on tripods within the creek beds. These bridges were recently reevaluated (2007) utilizing high precision surveying equipment with a very similar truck loaded to a comparable weight. The investigation primarily focused on determining if the bridges had undergone any degradation in the FRP material properties. In addition the load distribution between girders and/or panels was monitored. These results were then compared to the existing data from the original load tests to better understand the performance over time and study structural degradation.