Smart Lead Rubber Bearings Equipped with Ferrous Shape Memory Alloy Wires for Seismically Isolating Highway Bridges

Shape memory alloys (SMA) can substantially improve the damping capacity and re-centering capability of elastomeric isolators. The objective of this study is to assess the seismic performance of smart lead rubber bearings (LRBs) equipped with double cross ferrous SMA wires. Hysteretic shear response of SMA wire-based LRB is determined using finite element method. The seismic response of a multispan continuous steel girder bridge isolated by SMA-LRB is evaluated. Hybrid SMA-LRB bearing exhibits a significantly lower shear strain demand (up to 46% reduction) and a higher energy dissipation capacity (up to 31% increase) compared to the LRB.     

Seismic Fragility Curves for Un-Anchored On-Grade Steel Storage Tanks: Bayesian Approach

In this article, Bayesian approach is used for estimation of seismic fragility of un-anchored on‐grade steel storage tanks based on historical data and American Lifeline Alliance tanks database. The approach properly accounts for epistemic as well as aleatory uncertainties. The point and interval estimates of the fragility are formulated based on structural reliability method that implicitly or explicitly reflects the influence of epistemic uncertainty. The fragility curves developed herein are compared to corresponding relations currently available in the technical literature, the comparison suggest that actual tank performance is better than that predicted in the literature. Finally, application of fragilities in loss estimation methodology is investigated and showing a considerable scatter in the results corresponding to different fragilities.