大底盘隔震结构若干问题分析与应用研究

发布时间：2018-04-03 05:29

本文选题：大底盘　切入点：隔震　出处：《福州大学》2014年硕士论文

【摘要】：隔震技术是能够降低结构地震响应的有效手段之一,但是长期以来主要应用于中低层较规则的建筑。近年来,大底盘结构广泛应用于城市综合体等公用建筑中,而采用隔震技术能够较好的改善大底盘结构竖向不规则性在水平地震作用下所带来的复杂内力分布的问题,因此将隔震技术应用到大底盘结构对于推广隔震技术和提高大底盘结构安全性都具有现实意义。基于此,本文围绕大底盘结构隔震设计中的若干问题和工程应用进行了如下方面的研究：(1)以Bouc—Wen模型作为整个结构的弹塑性恢复力模型,考虑质心和刚心的偏心影响,建立大底盘隔震结构的振动模型,推导其运动方程。(2)当塔楼间竖向隔离缝的宽度受到建筑构造等因素限制而不能取到现行规范规定的限值,为消除“塔楼间可能存在碰撞”的担忧,以新疆某一大底盘双塔楼结构为背景,建立三种较为常用的隔震方案,考察双塔楼各层最近点的相对位移,比较各方案塔楼间的相对运动状态；结果表明：对于双塔楼较对称的大底盘结构,塔楼的动力特性相似,双塔间的相对位移很小,按现行规范规定取值较为保守；此外,还研究了塔楼的不对称性对双塔相同层最近点间的相对位移的影响。结果表明：随着双塔结构不对称性的增加,隔震结构双塔楼出现碰撞的可能性增大。(3)为研究隔震结构较可能的倾覆失效模式,基于隔震支座竖向拉压刚度相同与不同两个假定,以新疆某一大底盘双塔楼隔震结构为背景,以大震下隔震支座的极大面压和极小面压为考察对象,研究两种假定下隔震结构倾覆失效模式,提出隔震结构较可能出现的是大震下隔震支座发生受压破坏导致的结构倾覆失效模式。(4)在基本风压较大的地区,为使得上部结构达到较好的减震效果而减小铅芯橡胶支座的使用数量,进而导致隔震层抗风承载能力不足,本文基于有限元软件Etabs和Abaqus,考虑叠层橡胶隔震支座和抗风支座的组合隔震形式来实现上部塔楼结构减震效果适中、隔震层位移在合理范围和隔震层抗风承载力满足要求三者的平衡。(5)基于现行抗震规范,系统的总结了隔震设计要点、设计流程,对新疆某一大底盘三塔楼隔震工程实例进行隔震设计,对相关问题进行分析,给出设计建议。
[Abstract]:Isolation technology is one of the effective methods to reduce the seismic response of structures, but it has been mainly used in regular buildings with low and middle stories for a long time.In recent years, large chassis structures have been widely used in public buildings such as urban complexes, and the problem of complex internal force distribution caused by vertical irregularity of large chassis structures under horizontal earthquake can be improved by using isolation technology.Therefore, the application of isolation technology to large chassis structures is of practical significance for popularizing the isolation technology and improving the safety of large chassis structures.Based on this, some problems and engineering applications in isolation design of large chassis structures are studied in this paper as follows: (1) the Bouc-Wen model is used as the elastoplastic restoring force model of the whole structure, and the eccentricity of the center of mass and the rigid center is considered.The vibration model of isolation structure with large chassis is established, and its motion equation is deduced. When the width of vertical isolation joint between towers is restricted by building structure and other factors, the limit value stipulated in current code can not be obtained.In order to eliminate the concern that there may be a collision between towers, taking a large chassis double tower structure in Xinjiang as the background, three more commonly used isolation schemes are established to investigate the relative displacement of the nearest points of each floor of the double towers.The results show that the dynamic characteristics of the two towers are similar, the relative displacement between the two towers is very small, and the values are conservative according to the current code, the results show that the dynamic characteristics of the two towers are similar, and the relative displacement between the two towers is very small.The influence of the asymmetry of the tower on the relative displacement between the nearest points of the two towers is also studied.The results show that with the increase of the asymmetry of the double tower structure, the possibility of collision of the two towers of the isolated structure increases. (3) in order to study the more likely overturning failure mode of the isolated structure, the vertical tension and compression stiffness of the isolation support is the same as that of the two different assumptions.Taking a large base double tower isolated structure in Xinjiang as the background, taking the maximum surface pressure and minimal surface pressure of the isolation bearing under a large earthquake as the object of investigation, the overturning failure modes of two hypothetical isolation structures are studied.It is suggested that the overturning failure mode of the isolated structure caused by the compression failure of the isolated bearing under the strong earthquake is more likely to occur in the area where the basic wind pressure is high.In order to reduce the number of lead-core rubber bearings in order to make the superstructure achieve better damping effect, the wind bearing capacity of the isolation layer is insufficient.In this paper, based on the finite element software Etabs and Abaqus, the combination of laminated rubber isolation bearing and wind-resistant bearing is considered to achieve moderate shock absorption effect of the upper tower structure.Based on the current seismic code, the main points of isolation design and the design flow are systematically summarized.The isolation design of a large base three tower isolation project in Xinjiang is carried out. The related problems are analyzed and the design suggestions are given.
【学位授予单位】：福州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU352.12

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