A novel lever-based-inerter-enhanced self-centering damping system to retrofit double-column bridge bent

Abstract

Research has demonstrated that the self-centering dampers (SCDs) can mitigate the maximum and residual displacement of multi-column bridge bents under seismic excitation. Application of SCDs also increases the stiffness of bridge bents, which could intensify other seismic responses, such as base shear and acceleration. In order to alleviate the increments of these responses, a novel inerter-enhanced self-centering damping system (ISCDS) is proposed by adding a lever-based inerter (LBI) to the shape-memory alloy-based SCD in parallel. The displacement design spectrum, including the effect of the inerter, is developed based on an existing design acceleration spectrum. Two double-column bridge bents retrofitted with ISCDS and SCD are then designed by direct displacement-based design (DDBD) method, and their seismic performance is examined and compared by elastic-plastic time history analysis. The results show the bridge bent retrofitted with ISCDS has obvious advantages in terms of reducing the use of self-centering material, maximum acceleration and maximum base shear compared to bridge bent with SCD under the premise of the similar control performance of maximum and residual displacement. Finally, the effects of the inertance-mass-ratio and amplification factor on the seismic performances of the retrofitted bridge are investigated, and the reasonable values of the two parameters are suggested.