Experimental Study of Reinforced Concrete Bridge Columns Subjected to Near-Fault Ground Motions

Recorded fault normal, near-fault earthquakes typically exhibit a high-velocity pulse due to the superposition of S-waves. Shake table tests were conducted to investigate the effects of near-fault ground motions on the seismic performance of bridge columns that are designed for near-fault earthquakes. Four large-scale reinforced concrete circular columns with different initial periods were tested The design spectra included the current California Department of Transportation spectrum and a new spectrum developed in this study. The most distinct measured column response was the relatively large residual displacements even tender moderate levels of motion. Tire shake table test results revealed that it is necessary to control residual displacement at the design stage. The data also showed that the plastic hinge length in sufficiently confined columns subjected to near-fault earthquakes is comparable to that of columns experiencing far-field motions.