Device uncertainty propagation in low-ductility RC frames retrofitted with BRBs for seismic risk mitigation
Device uncertainty propagation in low-ductility RC frames retrofitted with BRBs for seismic risk mitigation
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DOI：
10.1002/eqe.3456
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发表时间：
2021-04-09
影响因子：
4.5
通讯作者：
Raghunandan, Meera
中科院分区：
文献类型：
--
作者：
Freddi, Fabio;Ghosh, Jayadipta;Raghunandan, Meera
被动控制系统，如抗屈曲支撑（brb），通过赋予建筑物强度和刚度，同时提供额外的高而稳定的能量耗散能力，已经成为新结构和现有结构地震反应控制的有效工具。配备brb的系统已在文献中进行了广泛的研究；然而，通常只考虑brb属性的确定性描述。这些特性由制造商提供，并根据基于代码的公差限制依次通过资格控制测试进行验证。因此，结构中引入的设备性能可能与其标称设计估计不同，从而可能导致不期望的抗震性能。本研究提出了一个概率评估框架来评估brb的不确定性对加固RC框架地震反应的影响。在案例研究中，考虑了一个基准的三层RC抗弯矩框架，其中brb的不确定性定义与设备质量控制测试的标准化公差限制相兼容。这种不确定性是通过两级析因设计策略和拉丁超立方体采样技术实现的。云分析和概率地震需求模型用于开发裸露和改造框架的四种损伤状态的易损性函数，同时也考虑了brb属性的不确定性。对三个案例研究区域进行了风险评估。结果表明，对于考虑的案例研究结构，这些不确定性可能导致脆弱性增加21%，地震风险估计变化高达56%。
Passive control systems, such as buckling-restrained braces (BRBs), have emerged as efficient tools for seismic response control of new and existing structures by imparting strength and stiffness to buildings, while providing additional high and stable energy dissipation capacity. Systems equipped with BRBs have been widely investigated in literature; however, only a deterministic description of the BRBs' properties is typically considered. These properties are provided by the manufacturer and are successively validated by qualification control tests according to code-based tolerance limits. Therefore, the device properties introduced within the structure could differ from their nominal design estimates, potentially leading to an undesired seismic performance. This study proposes a probabilistic assessment framework to evaluate the influence of BRBs' uncertainty on the seismic response of a retrofitted RC frame. For the case study, a benchmark three-story RC moment-resisting frame is considered where BRBs' uncertainty is defined compatible to the standardized tolerance limits of devices' quality control tests. This uncertainty is implemented through a two-level factorial design strategy and Latin hypercube sampling technique. Cloud analysis and probabilistic seismic demand models are used to develop fragility functions for the bare and retrofitted frame for four damage states while also accounting for the uncertainty in the property of BRBs. Risk estimates are successively evaluated for three case study regions. The results show that, for the considered case study structure, these uncertainties could lead to an increase of fragility up to 21% and a variation in seismic risk estimates up to 56%.