Live-Load Test Results of Missouri’s First High-Performance Concrete Superstructure Bridge

For its significant economical savings and greater design flexibility, high-performance concrete (HPC) is becoming more widely used in highway bridge structures. High-performance bridges with HPC and large-diameter prestressed strands are becoming attractive to designers. Bridge A6130 is the first fully HPC superstructure bridge in Missouri. The bridge has HPC cast-in-place deck and high-strength concrete girders reinforced with 15.2-mm (0.6-in.) diameter strands. The bridge was instrumented with embedded strain gauges and thermocouples to monitor the early-age and later-age behavior of the structures from construction through service. To investigate the overall behavior of the bridge under live load, a static live-load test was developed and carried out. During the live-load test, 64 embedded vibrating wire strain gauges and 14 embedded electrical-resistance strain gauges were used to acquire the changing strain rate in the bridge caused by the varying live-load conditions. Girder deflections and rotations were also recorded with external sensors and a data acquisition system. Based on the test results, the load distribution to the girders was studied. The AASHTO specifications live-load distribution factor recommended for design was compared with the measured value and found to be overly conservative. The AASHTO load and resistance factor design live-load distribution factors recommended for design were found to be comparable to measured values. Two finite element models were developed with ANSYS and compared with measured values to investigate the continuity level of the Missouri Department of Transportation interior bent detail.