Incremental dynamic analysis of highway bridges with novel shape memory alloy isolators

Base isolators are commonly used to protect highway bridges from severe seismic damage. A novel self-centering isolator based on superelastic shape memory alloy (SMA) has been proposed to be installed between the piers and decks of highway bridges. This paper systematically evaluates the seismic performance of SMA isolators via the incremental dynamic analysis (IDA) of a prototype highway bridge with SMA isolators. The multi-span reinforced concrete highway bridge and the corresponding SMA isolators are designed according to an ad hoc displacement-based design (DBD) approach. The seismic analyses are conducted under different seismic intensity levels using the computation program DRAIN2DX. IDA results indicate that the SMA isolators can effectively protect the superstructure of the highway bridge and minimize the post-earthquake residual deformation. The properly designed highway bridges with SMA isolators are subjected to limited damage under frequent and design basis earthquakes.