Load Testing and Load Distribution of Fiber Reinforced, Polymer Strengthened Bridges: Multi-year, Post Construction/Post Retrofit Performance Evaluation

Abstract

Fiber-Reinforced Polymer (FRP) strengthening of structural systems has increased in applications over recent years. The many benefits that the technology offers are significant. Field validation of FRP-strengthened bridges through load testing provides a means of measuring the performance of a bridge over time. Non-contact optical surveying equipment is one such method that can measure the deflection of bridges subjected to a static load. Since 1999, more than 25 FRP bridges in Missouri have either been repaired or constructed using FRP products to serve as demonstration and case study projects. A remaining question related to this technology is their long-term field performance. This work presents the load testing results of four bridges located in Morgan County, Crawford County, Iron County, and Dallas County, Missouri. These bridges were originally strengthened in 2003 with different FRP technologies and subsequently load tested biennially. The investigation focused primarily on determining if the bridges had undergone any degradation in the FRP material properties based upon the structures’ response to loading. Deflection and load distribution between girders was monitored. Pre- and post-load testing results were compared to better understand the performance over time and study structural degradation. Finally, the visual inspection results of these bridges by the researchers are presented. FRP is slowly making strides within the Civil Engineering community. The widespread acceptance of these materials is hampered by their unproven long-term reliability. Monitoring deflections of bridges constructed with FRP technologies under static load testing can help validate the long term performance of these materials.