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动力实测对周期折减系数的修正
UPDATING OF CYCLE REDUCTION FACTOR BASED ON IN-SITU STRUCTURAL DYNAMIC MEASUREMENT
【摘要】 选取5幢短肢剪力墙结构进行环境激励下的结构脉动响应实测,基于实测加速度响应,统计识别了结构的前三阶固有周期。分别采用Satwe和SAP2000对动力实测结果进行数值分析,结果表明,结构的计算周期(Tc)较实测周期(Tm)大。引起计算与实测周期差异(δi)的主要因素是填充墙对结构抗侧刚度的贡献,由于实测结构长、短轴方向的填充墙占比不同,相应于两个方向的δx和δy亦不同,δy均在10%以内,而δx普遍较大,最大值达到45.1%,此时不宜采用单一地震作用方向的周期折减系数进行结构双向的抗震设计。为此,通过进一步分析比较,提出应根据结构两正交轴向填充墙的实际布置情况,分别选取各自方向的周期折减系数进行二次地震作用分析,以同时达到安全性和经济性的双重抗震设计目标。
【Abstract】 In-situ vibration measuring for 5 short-pier shearwall structures under ambient excitation was carried out.The first three order natural periods of the structures were identified statistically based on acquired acceleration responses data.Next,numerical models of the above 5 real structures were established by Satwe software and SAP2000 software,respectively.The eigenvalues analyzing results showed numerical simulation periods(Tc) were bigger than the in-situ measuring periods(Tm).Differences(δ) between Tc and Tm were caused mainly by the lateral stiffness contribution of infilled walls.In addition,δx and δycorresponding to the long and minor axis of the structures were asymmetric because the amounts of the infilled walls for two axis were not uniform.As a result,δy of all 5 buildings was within 10%,whereas,the maximum of δx was up to 35%.As far as for this condition,it is unreasonable when only single cycle reduction factor was used for bi-direction aseismic design.So it was suggested that based on the real arrangement of the infilled walls,the cycle reduction factor should be selected in each direction and analyzed twice for aseismic design goal.
【Key words】 in-situ vibration measurement; dynamic characteristics identification; natural period; cycle reduction factor; short-pier shearwall structure;
- 【文献出处】 工业建筑 ,Industrial Construction , 编辑部邮箱 ,2013年S1期
- 【分类号】TU398.2
- 【下载频次】58