Seismic fragility assessment of concrete bridge pier reinforced with shape memory alloy considering residual displacement

Abstract

Post-earthquake rapid recovery of bridge is one of the prime objectives for performance based design. Shape Memory Alloy (SMA) has the unique ability to undergo large deformation, but can regain its undeformed shape through stress removal (i.e. superelasticity), which brings about an added advantage in seismic regions. In an attempt to reduce permanent damage of concrete bridges, a hybrid RC bridge pier configuration is presented here. In the proposed configurations of bridge piers, the plastic hinge region is reinforced with SMA and the remaining portion with regular steel. Residual displacement is a critical parameter for performance based earthquake engineering as it dictates the functionality of a member after an earthquake. This paper evaluates fragility-based seismic vulnerability of SMA reinforced concrete bridge pier considering residual displacement. Fragility curves have also been used to assess the relative performance of SMA with conventional steel RC bridge pier. Probabilistic Seismic Demand Model (PSDM) has been used in generating the fragility functions. The development of these fragility curves for bridge piers aid in expressing the potential impact of SMA on the bridge pier vulnerability.