Title:
Shape Memory Alloy Based Dampers used for Seismic Retrofit of Continuous Bridges with Unequal Height Piers
Author(s):
Nailiang Xiang
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/17/2021
Abstract:
Continuous bridges with unequal height piers are highly vulnerable to seismic hazards with the shorter (stiffer) piers prone to suffer severe damages due to the unbalanced inertia force distributions among the unequal piers. One of the common retrofit measures for such irregular bridges is that flexible devices like rubber bearings or metallic steel dampers are inserted at the shorter piers to mitigate the seismic forces imposed on piers, while simultaneously, share a certain amount of force with the taller piers. However, such devices can hardly show both recentering and energy dissipation characteristics that have been proved to be very important factors for seismic damage mitigation of structures. This study investigates the possibility of using shape memory alloy (SMA)-based dampers for seismic retrofit of unequal height continuous bridges. First, a static pushover analysis is conducted on the bridges with and without SMA retrofit measures, to reveal the progressive damage mechanism and sequences of different structural components. The design parameters of the SMA dampers can be adjusted accordingly to obtain a satisfactory damage development pattern. After that, nonlinear incremental dynamic analysis (IDA) as well as probabilistic fragility analysis is then performed to verify the results from the static analysis. The results indicate that SMA dampers can not only well balance the seismic forces between the unequal piers to lead to a uniform damage across the piers, but also show high effectiveness in seismic resilience enhancement by minimizing the post-earthquake residual displacements of the bridges.