Experimental Studies on Seismic Performance of Subsidiary Piers for Long Span Cable-Stayed Bridge with Energy Dissipation

Abstract

This paper studied a damage-controlled RC bridge pier, which is a sacrificial subsidiary pier, 60 m in height, of a trial designed cable-stayed bridge with a main span of 1400 m. The previous studies have demonstrated that the bridge towers would have tow-hinge type failure, namely plastic hinges occurred both at the tower bottom section and around the cables anchorage section on the upper part of tower, when suffered from strong earthquakes in the longitudinal direction of the bridge. The simulations have illustrated that the damage of bridge towers can be reduced to an acceptable level if the subsidiary piers can be redesigned as energy dissipation structural components. In this study, three 1/10 scale subsidiary pier models, which are one single RC column and two twin RC columns connected by energy dissipation elements, were tested under cyclic quasi-static loads. The energy dissipation members adopted in the subsidiary piers are shear links (SLs) and buckling restrained braces (BRBs). From the experiments, it is found that: 1) Compared to the single column model, the energy dissipation capacity of the twin-column models with energy dissipation members, SLs or BRBs, can be improved significantly. In this study, the deformation capacity of the twin-column model with SLs is better than that with BRBs, indicating that the twin-column pier connected by SLs has the largest energy dissipation capacity among all tested models. 2) The twin-column piers suffer from less damage than the single column pier does due to the helps of energy dissipation members. The energy dissipation capacity of the twin-column piers tested can satisfy the seismic demand of the long span cable-stayed bridge investigated under strong earthquakes.