Use of pseudo-negative stiffness dampers for reducing the seismic response of bridges: a benchmark study

Seismic response control of the benchmark Highway Bridge with a variable damper employing pseudo-negative stiffness (PNS) control algorithm; referred as PNS damper is investigated under the six earthquake ground motions. PNS damper is used as a semi-active control device. The study is based on the finite-element model of the 91/5 highway bridge located in Southern California. The prime aim of the study is to investigate the effectiveness of PNS damper for seismic response mitigation of the benchmark highway bridge. Numerical simulations are conducted by installing the control devices between the deck-end and abutments of the bridge. The response of the bridge with PNS damper is compared with the corresponding uncontrolled response and the sample controllers. Combined effect of the PNS damper and elastic stiffness of the existing structural member produces a broad hysteresis loop, leading to higher seismic energy dissipation at low control force. From the results of the numerical simulations, it is concluded that PNS dampers are quite effective in reducing the pier base shear, deck displacement, acceleration and bearing displacements, thereby reducing damages during near-fault earthquake ground motions.