SMA-VED混合自复位支撑钢框架地震易损性与风险分析

本文提出了一种新型形状记忆合金（Shape Memory Alloy，SMA）-黏弹性阻尼器（ViscoelasticDamper，VED）自复位支撑，设计了普通预应力筋自复位支撑钢框架与SMA-VED自复位支撑钢框架。采用组合模型以及改进材料模型准确模拟了支撑的力学行为，详细讨论了考虑构件失效的模拟方法，通过试验确定了VED的失效应变范围，最后基于概率统计方法进行了易损性分析以及全周期风险分析。研究发现: SMA-VED自复位支撑可显著提升框架抗震性能；倒塌风险以及残余变形超越概率均显著低于普通预应力筋自复位支撑钢框架，下降比例最高超过50%。预应力筋断裂失效导致框架倒塌风险可提高5倍以上； SMA-VED自复位支撑失效会造成残余变形超越概率有所上升但幅度不大。总体来说，SMA-VED自复位支撑钢框架具备更好的地震鲁棒性。

Seismic fragility analysis and risk assessment of SMA-VED hybrid self-centering braced steel frames

An innovative shape memory alloy（SMA）-viscoelastic damper（VED）self-centering brace is proposed in this paper. Steel frames with prestressed tendon-based self-centering braces and SMA-VED self-centering braces are designed. Composite models and modified material model are adopted to capture the hysteretic behavior of the two types of braces，and the simulation of failure of elements is also discussed. Tests are conducted to confirm the failure strain ranges of VED. Finally，fragility analysis and risk assessment are carried out based on the probability methods. The results show that the SMA-VED self-centering brace could significantly improve the seismic performance of the frame. The collapse risk and probability of residual deformation exceedance of the SMA-VED self-centering braced frame is much lower than that of the frame with prestressed tendon braces，and the largest decreasing ratio is more than 50%. The collapse risk of the frame is increased by more than 5 times when the failure of prestressed tendons is considered. The failure of SMA-VED self-centering brace would cause a small increase in the probability of residual deformation exceedance. In general，the SMA-VED self-centering braced steel frame has better seismic robustness.