Shake table studies and analysis of a two-span RC bridge model subjected to a fault rupture

The objective of this study was to investigate the fault rupture effects on the seismic response of a bridge system crossing an active fault. A large-scale two-span bridge model supported on three bents, one on each of the University of Nevada, Reno (UNR), shake tables, was tested under earthquakes with incoherent motions that simulated fault rupture. The results were compared with those from an identical bridge model subjected to coherent ground motions in a previous shake table study. It was found that fault rupture substantially affected the damage type and location in the bridge bents. The most severely damaged bent in the current bridge was a relatively flexible bent near the fault. However, under coherent motions, the shortest bent experienced the severest damage. Linear static and nonlinear dynamic analyses of the test model revealed that existing analytical techniques are adequate in estimating the response of the most critical bent subjected to fault rupture.