Experimental investigation on seismic performance of energy dissipation subsidiary piers for long-span cable-stayed bridges

The concept of structural damage control is that easily replaceable sacrificial elements deform plastically to dissipate seismic energy while primary components remain elastic or are subjected to minor damage. According to that the seismic performance of long-span cable-stayed bridges depends mainly on their structural systems, a new damage control strategy, namely reducing the damage of the towers by means of sacrificing the subsidiary piers, was proposed. Three large-scale reinforced concrete models with rectangular hollow sections were tested under cyclic quasi-static loads to investigate seismic performance of the subsidiary piers. The first specimen was a single-column pier designed originally, while the others were twin-column piers. Shear links (SLs) and buckling restrained braces (BRBs) were installed between the two columns as a series of energy dissipation elements. Failure patterns, hysteretic curves, displacement ductility and energy dissipation capacity, skeleton curves and stiffness degradation of the specimens which were under cyclic loading, and deformation capacity of the energy dissipation elements, were investigated. The results show that compared with the single-column pier, the energy dissipation elements increase the stiffness and strength of the twin-column piers and improve their seismic performance.