A Full-Scale, Single-Column Bridge Bent Tested by Shake-Table Excitation
A landmark test of a reinforced concrete bridge column was conducted on the George E. Brown, Jr. Network for Earthquake Engineering SimulationÃ¢Â€Â™s shake table at U.C. San Diego. This was the first full-scale shake table test of a bridge column designed to current US seismic design provisions and tested under dynamic conditions. Caltrans seismic design guidelines were followed for the design and detailing of the 1.2-m (4-ft) diameter column. The flexurally dominant test specimen was subjected to ten significant ground motions and tested to impending collapse. The results provide the basis for comparison with a small scale shake table test to evaluate the reliability of small scale testing and significance of scale effects under dynamic conditions. The column exhibited a ductile response with a well formed plastic hinge within one column diameter from the base. Concrete spalling was observed after a simulated design level earthquake. Longitudinal bar buckling, longitudinal bar fractures, and concrete core crushing were mechanisms for deteriorating strength and stiffness, but were induced in the later stages of testing after stable response to repeated demands beyond the design level event.