Seismic performance of benchmark base-isolated bridges with superelastic Cu-Al-Be restraining damping device

摘要

This paper presents a simulation-based benchmark control study in which shape memory alloy (SMA)-based displacement restraining damping devices are proposed to control the seismic response of a full-scale three-dimensional seismically excited highway bridge. In this Phase II benchmark problem, the bridge is fully isolated at both the abutments and the central pier location using nonlinear hysteretic bearings with a lead core on the inside and an elastomer surrounding the lead core. The SMA restraining damping device is a passive control device employing superelastic Cu-Al-Be alloy wires as its core re-centering component, which restrains the base-isolated bridge from excessive displacement responses, especially under extreme earthquake events. In this benchmark study, a total of 20 such passive control devices are supposed to be installed at the isolation level between the deck and the isolators on bridge piers and center column at 10 locations, each location consisting of a single orthogonal pair to control the responses in both directions. The performance of the passive control devices is analyzed in terms of the performance indices in the benchmark problem definition at a variety of ambient environment temperatures at 23, 0, -25 and - 50℃, respectively. The results of this simulation-based benchmark control study show that the proposed passive control device can effectively reduce the excessive displacement responses and permanent bearing deformations of the benchmark base-isolated bridge subjected to strong ground motions, and temperature seems to have little effect on the performance of the superelastic Cu-Al-Be restraining damping device in bridge response control.