带非对称阻尼器的柔性支撑框架主余震作用分析  

An asymmetrical damper to improve tension-only braced frame performance under mainshock and aftershocks coupling strikes

作　　者：谷子 樊圆 袁苗苗[1] 卢文胜[1] GU Zi;FAN Yuan;YUAN Miaomiao;LU Wensheng(Department of Disaster Mitigation for Structures,Collage of Civil Engineering,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学土木工程学院结构防灾减灾工程系,上海200092

出　　处：《振动与冲击》2023年第4期1-9,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金面上项目(52178501);山东省高校协同创新中心重点课题(XTZ201903)。

摘　　要：研究主余震耦合作用下具有非对称弹塑性特征的非对称摩擦阻尼器(asymmetrical friction damper, AFD)对柔性支撑框架结构的减震作用。传统扁钢柔性支撑(tension-only brace, TOB)存在松弛问题导致柔性支撑结构在主余震耦合作用下性能严重退化。研究表明:AFD适用于柔性支撑结构,具有非对称弹塑性特征,静摩擦阶段发挥非线性“自拉紧”效应,提供较大的恢复力;在滑动摩擦阶段提供稳定的附加阻尼。该研究对静摩擦阶段和滑动摩擦阶段分别给出了简化模型,对滑动摩擦阶段给出附加阻尼比计算方法,提出了基于AFD的拉紧保护模式和阻尼耗能模式。对比分析柔性支撑框架结构TOB方案和2种AFD方案的主震和主余震耦合弹塑性时程反应,TOB方案在中震主余震及大震主震下屈服,而在大震主余震分析下松弛导致结构破坏,证实柔性支撑结构在主余震耦合作用下存在较大风险;而2种AFD方案可有效保护结构,拉紧保护模式为结构提供更高的减震上限,阻尼耗能模式同样有效防止TOB过度松弛,在主余震作用下提升结构减震性能。An asymmetrical friction damper(AFD) with asymmetrical elastic-plastic feature was studied to improve the tension-only braced frames under mainshock and aftershocks coupling strikes. Traditional tension-only braces(TOBs) have the slackness problem that can result in severe structural performance degradation under the coupling of mainshock and aftershocks. Testing and analysis results reveal that the AFD is suitable to apply into tension-only braced frames, with asymmetrical elastic-plastic feature, providing large nonlinear restoring force with “self-tensioning” effect in static friction phase, and stable additional damping after sliding friction phase occurs. Theoretical models of static friction and sliding friction phase as well as the calculation method of additional damping ratio were proposed. Self-tensioning and damping protection modes based on AFD were developed. Comparison between nonlinear time history analysis on tension-only braced frame structures with TOBs and AFDs of two protection modes were conducted. The TOBs yielded under the design basis and rare mainshock, and caused structural failure due to their slackness under the rare mainshock and aftershocks, which verifies the risk of TOBs under mainshock and aftershocks coupling strikes. Two tension-only braced structures with protection modes of AFD can improve the structure under mainshock and aftershocks coupling strikes, in which self-tensioning mode strengthens aseismic performance and damping protection mode prevents slackness, enhancing damping ability under mainshock and aftershocks.

关 键 词：非对称阻尼器 非对称弹塑性模型 柔性支撑(TOB) 主余震耦合 非线性动力分析 

分 类 号：TU352.1[建筑科学—结构工程]