工程力学7
第27卷第10期 Vol.27 No.10 2010年 10 月 Oct. 2010 文章编号:1000-4750(2010)10-0007-07
工 程 力 学 ENGINEERING MECHANICS
7
铅芯橡胶支座微分型恢复力模型
屈服前刚度的研究
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金建敏1,2,周福霖2,谭 平2
(1. 西安建筑科技大学土木工程学院,陕西,西安 710055;2. 广州大学工程抗震研究中心,广东,广州 510405)
摘 要:该文简介了微分型恢复力模型(Bouc-Wen模型)的发展过程及其在铅芯橡胶支座中的应用,基于两个不同规格支座的压剪试验比较了不同屈服前刚度K1(K1=5Kd―40Kd)的微分型恢复力模型与实测结果的差异,发现了一些有益的规律。之后,计算分析了一个上部结构为8层的隔震模型,铅芯橡胶支座屈服前刚度K1分别取10Kd―40Kd,对于不同的屈服前刚度K1,上部结构底层的水平刚度分别设为100Kd、300Kd、500Kd,用以比较屈服前刚度K1对不同周期结构的地震响应的影响。通过以上对比和计算,对隔震设计中铅芯橡胶支座屈服前刚度的取值给出了合理建议。
关键词:铅芯橡胶支座;微分型恢复力模型;压剪试验;屈服前刚度;隔震设计 中图分类号:TU352.1 文献标识码:A
STUDY ON PRE-YIELD SHEAR STIFFNESS OF DIFFERENTIAL RESTORING FORCE MODEL FOR LEAD RUBBER BEARING
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JIN Jian-min1,2 , ZHOU Fu-lin2, TAN Ping2
(1. School of Civil Engineering, Xi’an University of Architecture and Technology, Xi’an, Shaanxi 710055, China; 2. Earthquake Engineering Research &Test Center, Guangzhou University, Guangzhou, Guangdong 510405, China)
Abstract: The paper introduces the development of differential restoring model (Bouc-Wen model) and its application in lead rubber bearing. Based on the compression-shear tests of two different LRBs, the differential restoring force model with various pre-yield shear stiffness ranging from 5Kd to 40Kd is considered and compared with the experimental results, and some important conclusions can be drawn from the results. An isolated eight-story super-structure is used as the numerical example. Its pre-yield shear stiffness of the LRB is chosen to be 10Kd and 40Kd, meanwhile the stiffness of the bottom floor of the super-structure is 100Kd, 300Kd and 500Kd for different shear pre-yield stiffness of the LRB. Thus the effect of different pre-yield shear stiffness on the structure with various natural periods can be considered and compared. Finally, a reasonable value of the pre-yield shear stiffness of the lead rubber bearing is given for the design of isolated buildings.
Key words: lead rubber bearing; differential restoring model; compression-shear test; pre-yield shear stiffness;
seismic-isolation design
铅芯橡胶支座(LRB)是在普通橡胶支座中央插入铅芯而构成,铅芯直径一般为橡胶支座外径的
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收稿日期:2009-03-23;修改日期:2009-09-21
基金项目:国家自然科学基金重点项目(90815027);减震控制与结构安全开放实验室开放基金
作者简介:∗金建敏(1973―),男,湖北襄樊人,高工,博士生,从事工程抗震、结构隔震、减震研究(E-mail: [email protected]); 周福霖(1939―),男,广东广州人,教授,中国工程院院士,从事工程抗震、隔震、减震研究(E-mail: [email protected]); 1/5―1/7,铅的特点是屈服应力约为8.33kN/mm2(环境温度为15℃时),与变形速度有关,具有受力终
8 工 程 力 学
止时可恢复的特征,在地震中反复消耗地震能量。铅芯橡胶支座使隔震支座和阻尼器的功能一体化,可以单独在隔震系统中使用,而无须另设阻尼器,使隔震系统的组成变得比较简单。目前,铅芯橡胶支座已成为应用最广泛的隔震装置之一[1]。
1 微分型恢复力模型
用微分方程来描述光滑滞回恢复力过程是Bouc于1967[2]年首先研究的,Wen(1976)[3]、Park、Wen和Ang(1986)等人[4]将这种方法一般化,得到了能概括较大一类光滑恢复力特点的滞变微分方程,可以较好地模拟铅芯橡胶支座的恢复力特性。
Wen(1976)提出非线性滞回体系的恢复力q由下式表示:
q(x,x