Does capacity design do the job?: An examination of higher mode effects in cantilever walls
Does capacity design do the job?: An examination of higher mode effects in cantilever walls
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容量设计能起到作用吗？：悬臂墙高模态效应的检验
DOI：
10.5459/bnzsee.36.4.276-292
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
M. Priestley
中科院分区：
文献类型：
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作者：
M. Priestley
新西兰荷载规范中关于悬臂墙建筑物中弯矩和剪力的动态放大的现行规定进行了严格的审查。通过对6个2 ~ 20层墙体结构的时程分析，发现无论是等效侧力法还是振型反应谱法都不能充分反映高层振型效应。时程分析结果表明，动力放大系数既取决于初始阶段，也取决于预期的位移延性水平。提出了两种不同的方法来考虑悬臂墙的高次模态效应。第一种是基于一个简单的修改的模态反应谱法，而第二种是适合于单模态设计方法，如等效侧向力法。两者都被发现给预期的反应很好的代表性。结果表明，在设计地震烈度下提供容量保护并不能确保在高于设计水平的烈度下不受不良破坏模式的影响。这对医院等关键设施的设计具有重要意义。
Current provisions in the New Zealand Loadings code for dynamic amplification of moment and shear force in cantilever wall buildings are critically examined. Based on time-history analyses of six wall structures, from two- to twenty-storeys, it is found that higher mode effects are inadequately represented by either the equivalent lateral force or modal response spectrum design methods. The time-history results indicate that dynamic amplification is dependent on both initial period, and expected displacement ductility level. Two different methods for consideration of higher mode effects in cantilever walls are proposed. The first is based on a simple modification of the modal response spectrum method, while the second is appropriate for single-mode design approaches such as the equivalent lateral force method. Both are found to give excellent representation of expected response. It is shown that providing capacity protection at the design seismic intensity does not ensure against undesirable failure modes at intensities higher than the design level. This has significance for the design of critical facilities, such as hospitals.