为了研究行波效应对于多跨大跨结构随机地震响应的影响机理,本文首先以两跨结构简化模型为研究对象,选取柱顶相对位移作为计算响应量,采用多点虚拟激励法对结构的响应功率谱公式进行推导,求得结构响应极值随行波频率的变化规律,最后将此方法拓展至多跨结构,分析不同跨数以及不同支承形式对于多点激励下结构地震响应的变化规律。计算结果表明:受拟静力响应影响,多跨结构中柱柱顶相对位移受行波效应影响更加显著,在大跨结构抗震设计中应该引起重视;随着跨数增加结构响应极值并没有明显提升,但不同支承形式可能导致结构受多点激励效应影响不同,针对具体的支承形式结构进行具体分析是必要的。
Abstract
This paper aimed at studying the influence mechanism of the seismic response of large multi-span structures to wave-passage effect. A simplified two span structural model is firstly used as the research object and the relative displacement of columns are used as the calculated response. The response power spectrum density formulae are derived by the multi-support pseudo excitation method. The changing law of the structural seismic peak response with wave-passage frequency is also calculated. These procedures are extended to multi-span structures to study the influence of different amounts of spans and different supporting forms to the structural seismic response. The result shows that: due to the pseudo static response, the relative displacement of the middle columns is larger than the corner columns that should be paid more attention in structural seismic design; the peak response does not increase a lot with the increasing amount of spans, however, different supporting forms may lead to distinct response. It is necessary to calculate the structural response to multi-support excitations according a specific supporting form.
关键词
行波效应 /
多跨大跨结构 /
虚拟激励法 /
柱顶相对位移 /
不同支承形式
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Key words
wave-passage effect /
large multi-span structures /
pseudo excitation method /
the relative displacement of columns /
different supporting forms
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脚注
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