Numerical Investigation of Shape-Memory Alloy–Reinforced Bridge Columns Subjected to Lateral Impact Loads

Abstract

This paper numerically investigates the dynamic behavior of bridge piers reinforced with shape-memory alloy (SMA) rebar when subjected to lateral impact loads. Performance of SMA reinforced pier is compared with column reinforced by conventional steel rebar by performing finite-element (FE) simulations in LS-DYNA. The impact performance of the columns is evaluated by considering variations in different structural- and loading-related parameters including the type of SMA rebar, the length of SMA rebar (LSMA), the impact velocity (Vimp), and the axial load ratio (ALR). From the FE simulations, it is found that the use of SMA rebars at the plastic hinge regions and the impact loading height of the columns significantly enhances the impact resistance and the recoverability of the columns by reducing their damage levels and residual displacements. Also, the failure modes of the columns tend to govern by flexure by using SMA rebars, and the columns reinforced with Cu-based (Cu–Al–Mn) SMA rebars are more likely to fail in flexural modes compared to those reinforced with Ni-based (Ni–Ti) SMA rebars. However, the negative influences of SMA rebars on the impact resistance of the columns are found when LSMA exceeds 0.5 under impact loads with velocities greater than 15 m/s. In addition, an ALR greater than 0.1 considerably increases the impact resistance of the columns.