Effectiveness of Negative Stiffness System in the Benchmark Structural-Control Problem for Seismically Excited Highway Bridges

The effectiveness of a novel negative stiffness device (NSD) and damper system for reduction of the seismic response of highway bridges was investigated in this study. To this end, a Phase II benchmark highway bridge was employed for the numerical evaluation. By engaging the NSD at an appropriate apparent yield displacement, the combination of isolation system and NSD device behaves like a softening system, resulting in an increase in the combined system displacement response. The increased deformation of the combined system is reduced by additional passive damping in parallel with the NSD. An analytical model for the NSD was developed. Experimental results are presented to verify the analytical model of the NSD. The effectiveness of the proposed NSD in response control was evaluated by numerical simulation of the benchmark highway bridge, and the results demonstrate that the proposed passive NSD and damper system is beneficial in controlling the seismic response of base-isolated bridges and provides performance comparable to the sample semiactive control but by passive means. (C) 2018 American Society of Civil Engineers.