Earthquake response of a three-span, simply supported bridge to near-field pulse and permanent-displacement step

Wave passage and differential motions at multiple supports of long structures result in excessive demands in the near field of strong earthquakes. These demands are caused mainly by pseudo-static deformations imposed by differential ground motions. As would be expected, replacing continuous bridge girders with multiple short segments, interconnected by structural joints reduces the large pseudo-static forces in the piers. In this paper, these reductions are quantified for a three-span simply supported bridge. It is shown that the shear forces in the joint keys, as well as the drifts of piers, for out-of-plane response are reduced in the high frequency band in the structural system that is made flexible by placement of joints over the piers.

► Out-of-plane response of a simply supported, three-span bridge.
► Reduction of shear forces in joint keys of the bridge.
► Reduction of pseudo-static actions by girder joints.