Pretensioned, Rocking Bridge Columns for Accelerated Construction and Enhanced Seismic Performance

A new precast bridge bent system has been developed that accelerates on-site construction activities, minimizes residual displacements even after large seismic events and reduces post- earthquake damage. The connections are the key to the system’s seismic performance. They were tested under quasi-static conditions and found to perform exceptionally well with nearly zero strength degradation and little concrete damage, even after being loaded cyclically up to drift ratios of 10%. The restoring properties of the system were evaluated through multi-shaking table tests conducted on a quarter-scale, two-span bridge specimen. The maximum residual drift ratio during testing was 0.4%, even after excursions to drift ratios exceeding 13%. This paper describes the new system, compares its performance to that of more conventional cast-in-place construction, and describes key aspects of its design philosophy.