Performance-based seismic loss assessment of isolated simply-supported highway bridges retrofitted with different shape memory alloy cable restrainers in a life-cycle context
Performance-based seismic loss assessment of isolated simply-supported highway bridges retrofitted with different shape memory alloy cable restrainers in a life-cycle context
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在生命周期背景下对采用不同形状记忆合金电缆限制器改造的孤立简支公路桥梁进行基于性能的地震损失评估
DOI：
10.1177/1045389x20906018
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发表时间：
2020-03-04
影响因子：
2.7
通讯作者：
Alam, M. Shahria
中科院分区：
文献类型：
--
作者：
Li, Shuai;Dezfuli, Farshad Hedayati;Alam, M. Shahria
形状记忆合金电缆已经成为传统钢索约束器的替代品，用于防止桥梁在极端地震中脱臼。高成本的NiTi形状记忆合金约束器在桥梁改造中的可行性进行了数值研究，并发表了令人鼓舞的结果；然而，考虑到经济影响，不同类型的形状记忆合金，如铜基和铁基形状记忆合金抑制剂的效果尚未得到讨论。本研究的目的是详细解决这一问题，以提出最具成本效益的适合桥梁工程应用的形状记忆合金约束器。本文对一座采用四种形状记忆合金（NiTi、FeNiCoAlTaB、CuAlMn和FeMnAlNi）加固的孤立简支桥进行了地震易损性和生命周期损失（直接和间接）评估。结果表明：对于在设计位移范围内进行的所有桥梁，形状记忆合金类型对桥梁的损伤概率和长期地震损失的影响是显著的。所有安装了形状记忆合金约束器的桥梁的倒塌概率都很低（小于7%）。此外，还发现铁基形状记忆合金阻抑剂（SMA-II和SMA-IV）的桥架性能优于其他情况。在CHBDC-2014规定的设计地震事件下，与不加约束器和加装NiTi形状记忆合金约束器的桥梁相比，铁基形状记忆合金约束器可以分别减少约87%和11%的长期损失。对公路桥梁进行形状记忆合金约束器改造的概率风险分析，有助于为这种智能材料在结构应用中的广泛应用铺平道路。
Shape memory alloy cables have emerged as an alternative to conventional steel cable restrainers for preventing the bridge spans from unseating during an extreme earthquake. Feasibility of high-cost NiTi shape memory alloy restrainers in retrofitting the bridges has been numerically investigated, and promising results have been published; however, considering the economic impacts, the effect of different types of shape memory alloy such as Cu-based and Fe-based shape memory alloy restrainers has not been discussed yet. The objective of this study is to address this problem in detail in order to propose the most cost-effective shape memory alloy restrainer suitable for bridge engineering applications. Seismic fragility and life-cycle loss (both direct and indirect) assessments are analytically performed on an isolated simply-supported highway bridge retrofitted by four types of shape memory alloy restrainers (i.e. NiTi, FeNiCoAlTaB, CuAlMn, and FeMnAlNi). Results showed that for all retrofitted bridges performed in the range of design displacement, the effect of type of shape memory alloy is significant on the damage probability and long-term seismic loss of the bridges. All the bridges retrofitted with shape memory alloy restrainers have a very low probability of collapse (less than 7%). It is also found that the bridge retrofitted with Fe-based shape memory alloy restrainers (SMA-II and SMA-IV) performed better as compared to the other cases. Compared to the bridge without restrainers and with NiTi shape memory alloy restrainers, Fe-based shape memory alloy restrainers can reduce the long-term loss by about 87% and 11%, respectively, at the design earthquake event specified in CHBDC-2014. The probabilistic risk analysis of highway bridges retrofitted with shape memory alloy restrainers can aid in paving the way toward widespread application of such smart materials in structural applications.