UC San Diego

The deterioration of steel in aging reinforced concrete bridges is a continual problem which could benefit from improved rehabilitation techniques that take advantage of enhanced and more durable materials such as fiber reinforced polymer (FRP) composites. Appropriately designed hybrid material systems benefit from the performance and durability advantages of FRP materials yet remain more cost effective than comparable all-composite systems. Development of rapid rehabilitation systems for the decks of concrete box girder bridges, which are increasingly common throughout the United States, is presented. One goal of this research is to assess and validate the use of FRP composite panels for use as both stay-in-place formwork and as the bottom longitudinal and transverse reinforcement in the deck of concrete box girder bridges. Performance assessments for full-scale two -cell box girder bridge specimens through monotonic and extensive cyclic loading provided validation for the FRP panel system bridge deck as a viable rehabilitation solution for box girder bridge decks. The FRP panel system performed comparably to a conventionally reinforced concrete bridge deck in terms of serviceability, deflection profiles, and system level structural interaction and performed superior to the RC bridge deck in terms of residual deflections, and structural response under cyclic loading. Assessment of a damaged FRP panel bridge deck system, which was repaired using a resin injection technique, showed superior performance for the repaired system in terms of integrity of the FRP panel interface and cyclic response. Rapid rehabilitation techniques for strengthening reinforced concrete box girder bridge deck overhangs using near-surface-mounted (NSM) carbon fiber reinforced polymer (CFRP) were also evaluated. Analytical predictions of load carrying capacity and deflections provided correlation with experimental results, and the developed analysis methods provide an effective design tool for future research. Results from the laboratory testing of a bridge deck overhang strengthened with FRP showed significant increases in load carrying capacity as well as deformation capacity as compared to the as-built specimen without FRP. This research provides enhanced understanding of hybrid structures and indicates significant potential for rehabilitation applications to concrete box girder bridges.