Earthquake response of a three-span bridge, with mid-span supported by isolators, to near-field pulse and permanent-displacement step

In our previous work, it was confirmed that replacing continuous bridge girders with multiple short segments interconnected by structural joints leads to reduction of the large, pseudo-static forces in the piers and also reduces the overall seismic demands in the intermediate and moderately high-frequency band of ∼2 Hz to ∼10 Hz. In this paper, essentially the same three-span bridge is studied, but in this instance for the case in which the mid-span is supported by isolators. With nonlinear isolators, and without designed limits on their relative displacement, the system periods become longer than the periods of the same bridge with decks interconnected by pins with shear keys, but the overall dynamic behavior remains similar.

► Out-of-plane response of a three-span bridge to propagating seismic waves. ► Spatial seismic effects cased by delayed excitation of bridge piers. ► Reduction of drifts and of pseudo-static actions by flexibility of bridge deck. ► Lead rubber bearing isolators with bilinear stiffness. ► Response of bridge to near-fault ground motion.