地下室约束方式对非周边约束大底盘对称双塔结构小震抗震性能的影响研究

发布时间：2018-04-11 14:56

本文选题：对称双塔结构 + 非周边约束　；参考：《长沙理工大学》2015年硕士论文

【摘要】：近年来,大底盘多塔楼结构在我国得到了广泛的应用。随着人们要求的日益多样化,大底盘多塔楼结构的结构形式也日趋复杂,其中亟待解决的问题也逐渐增多。一般结构地下室会受到土的良好约束,在进行建模分析时,按照规范方法通常通过嵌固地下室某层,来模拟该约束作用。对于大底盘多塔结构来说,一般底盘平面尺寸比较大,加上实际场地地形存在不确定性,可能会出现地下室非周边约束的情况,即有一个面或几面没有土的约束。目前我国规范尚未规定此类情况下对结构进行建模分析时,如何模拟周围土体对地下室的约束作用。从现有文献来看,关于地下室非周边约束问题的研究相对较少。少数几篇研究该问题的文献也仅讨论了单塔楼的情况,且研究得不够深入。因此,对多塔结构开展此类研究显得非常必要。本文旨在研究地下室仅有三侧有土约束的情况下,不同的地下室约束建模方式对对称双塔结构抗震性能的影响。笔者应用Midas/Building有限元分析软件,建立了36组底盘跨数不同的算例模型。每组算例模型分为结构布置完全一样但底盘约束方式不一样的3个模型。3个模型分别采用“基础嵌固”、“底盘嵌固”约束方式和本文参考桩基规范而来的“土弹簧”约束方式。总计108个模型。各模型对称的两个塔楼均为24层。对36组模型进行反应谱分析和配筋计算得到以下结论:(1)三类模型的结构动力特性差异很小,基本周期由大到小的顺序为:基础嵌固模型、土弹簧约束模型、底盘嵌固模型,差值很小,在0.06s内,实际工程中可以忽略;(2)塔楼最大层间位移角大小顺序跟基本周期相同。前两者差值在30%以内,后两者在19%以内。从变形方面来看,采用底盘嵌固模型进行设计与土弹簧约束模型结果更加相近,但偏于不安全。笔者建议如果条件允许,采用土弹簧约束模型进行设计更为合理,否则建议采用更为保守的基础嵌固模型。(3)塔楼底层剪力大小顺序也同基本周期一样。前两者差值在20%以内,后两者在35%以内。基础嵌固模型求得的底层剪力更接近土弹簧约束模型值。从地震力方面来说,笔者建议实际工程中,如果条件允许,采用土弹簧约束模型进行设计更合理,不然建议采用较保守的基础嵌固模型进行设计。(4)计算用钢量从大到小的顺序也与基本周期顺序一样。差别较小,在2%以内。对实际工程的经济性影响比较小。
[Abstract]:In recent years, large chassis multi-tower structure has been widely used in China.With the increasing diversification of people's demands, the structural forms of large chassis and multi-tower structures are becoming more and more complex, and the problems that need to be solved gradually increase.Generally, the basement of structure is constrained by soil. In modeling and analysis, the constraint is simulated by embedding a certain layer of basement according to the specification method.For the large chassis multi-tower structure, the plane size of the general chassis is relatively large, and the actual site topography is uncertain, which may lead to the non-peripheral constraints of the basement, that is, there is no soil constraint on one or several sides.At present, the code of our country has not stipulated how to simulate the restraint of surrounding soil to the basement when modeling and analyzing the structure in this case.According to the existing literature, there are few researches on the non-peripheral constraint problem of basement.A few papers on this problem only discuss the case of single tower, and the research is not enough.Therefore, it is very necessary to carry out this kind of research on the multi-tower structure.The purpose of this paper is to study the effect of different basement constraint modeling methods on the seismic performance of symmetrical twin towers under the condition of only three sides of the basement with soil constraints.By using Midas/Building finite element analysis software, 36 groups of example models with different span number of chassis are established.Each example model is divided into three models with the same structure arrangement but different constraint mode of chassis. The three models are respectively "base embedded".In this paper, the "earth spring" constraint mode based on the specification of pile foundation is referred to.Total 108 models.Each model of the two symmetrical towers are 24 stories.From the response spectrum analysis and reinforcement calculation of 36 groups of models, the following conclusions are drawn: (1) there is little difference in the structural dynamic characteristics of the three kinds of models, and the order of the basic period from large to small is: the foundation embedded model, the soil spring constrained model, the chassis embedded model.The difference is very small, within 0.06s, the order of the maximum interstory displacement angle of the tower is the same as that of the basic period.The difference between the former and the latter is less than 30% and 19% respectively.From the point of view of deformation, the results of design based on the chassis embedded model are more similar to those of the soil spring constraint model, but the results are not safe.The author suggests that if conditions permit, it is more reasonable to use the soil spring constraint model for design, otherwise, it is suggested to adopt a more conservative foundation inlay model. The order of shear at the bottom of the tower is the same as that of the basic period.The difference between the former and the latter is less than 20% and 35% respectively.The underlying shear force obtained by the foundation embedded model is closer to the value of the soil spring constrained model.From the aspect of seismic force, the author suggests that it is more reasonable to use the soil spring constraint model to design in practical engineering, if conditions permit,Otherwise, it is suggested that the order of steel quantity from large to small is the same as the order of basic period.The difference is less than 2%.The economic impact on the actual project is relatively small.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU973.31

【参考文献】