宁波国际会展中心网架结构多维多点激励地震响应分析及隔震研究

发布时间：2018-04-21 15:21

本文选题：地震响应 + 模态分析　；参考：《华南理工大学》2010年硕士论文

【摘要】： 大跨网架结构广泛用于体育馆、机场等大型公共场所。如何提高该结构的抗震能力是研究的热点之一。本文以宁波国际会展中心(二期)大跨度平板网架结构为例,采用数值分析方法,研究了多维多点地震作用下,网架结构的动力响应,比较了地震动输入方式对结构地震响应的影响。研究了隔震支座设置方式的优化。本文主要完成以下工作: 1、利用有限元软件ANSYS建立结构的计算模型,进行了结构的静力分析。选取九种形式的杆件截面和五种网架高度,通过分析位移和应力响应计算结果,发现通过杆件截面优化可以有效地降低网架结构在设计荷载作用下的位移,随着网架结构高度的增大,节点的位移减小。 2、模态分析结果表明随着结构自振阶次的增加,自振频率将递增。取三种地震波,对网架结构进行一致输入,研究表明:三向地震作用时得到的结构响应最大。 3、在网架结构的八个支座处虚拟相同质量的大质量块。比较了9度多遇地震和罕遇地震对结构的不同作用效果。不考虑行波效应时,采用同一地震加速度时程,对各质量块输入惯性力,分析网架结构在各方向地震作用下的位移响应等。考虑行波效应时,根据各支座的间距,选取合理的加速度时程,分析结构的响应。结果表明:单点一致输入地震作用所得结构位移小于多点输入情形,即单点输入将高估结构的抗震能力。取网架前20阶模态,由规范规定的地震影响系数曲线得到加速度反应谱,分单点和多点两种激励方式分析网架抗震性能。将加速度时程转成功率谱密度函数,并将之运用于抗震分析。分别对三种地震波进行比较,结果发现三种地震波所得网架结构(均方根)位移和支座反力相差不大。 4、在原有网架模型的支座处增设8根钢筋混凝土柱。分析了铅芯橡胶隔震支座GZY300的三种分布情形,发现隔震支座的设置方式对网架的位移响应有较大影响。分别采用上部隔震和下部隔震措施,比较三种地震波作用时结构的位移。将隔震支座设在网架支撑柱上部,隔震所得结构响应小于下部隔震情形。同时还分析了普通橡胶隔震支座对网架的位移响应,并与GZY300支座进行比较。考虑不同截面尺寸支撑柱对结构的轴力时程的影响,亦证明了采用上部隔震对支撑柱的安全是有利的。
[Abstract]:Long-span truss structure is widely used in gymnasium, airport and other large public places. How to improve the seismic capacity of the structure is one of the hot research topics. In this paper, the dynamic response of the grid structure under the action of multi-dimensional and multi-point earthquakes is studied with the example of the large-span flat space truss structure of Ningbo International Conference and Exhibition Center (second phase), and the numerical analysis method is used to study the dynamic response of the latticed truss structure. The effect of seismic input mode on seismic response of structure is compared. The optimization of isolation support is studied. The main work of this paper is as follows: 1. The finite element software ANSYS is used to establish the calculation model of the structure, and the static analysis of the structure is carried out. Through analyzing the results of displacement and stress response calculation, it is found that the displacement of space truss structure under design load can be effectively reduced by the optimization of the member cross section by selecting nine kinds of member sections and five kinds of grid height. With the increase of the height of the grid structure, the displacement of the node decreases. 2. The modal analysis results show that the natural vibration frequency will increase with the increase of the natural vibration order of the structure. Three kinds of seismic waves are used to input the truss structure uniformly. The results show that the structure response is the largest under the action of triaxial earthquake. A large mass block of the same quality is virtual at the eight supports of the grid structure. The effects of 9 degree frequent earthquakes and rare earthquakes on structures are compared. When the traveling wave effect is not considered, the inertia force is input to each mass block by using the same seismic acceleration time history, and the displacement response of the grid structure under the earthquake action in all directions is analyzed. Considering the traveling wave effect, the response of the structure is analyzed by selecting a reasonable acceleration time history according to the distance between the supports. The results show that the displacement of the structure is smaller than that of the multi-point input, that is, the seismic capacity of the structure will be overestimated by the single point input. Taking the first 20 modes of the grid frame, the acceleration response spectrum is obtained from the seismic influence coefficient curve specified in the code, and the seismic performance of the grid frame is analyzed by two excitation modes: single point and multiple points. The spectral density function of acceleration time history transition success rate is applied to seismic analysis. The results show that the displacement of the grid structure (root mean square) and the reaction force of the support are not different from each other. 4. Add 8 reinforced concrete columns to the support of the original grid model. Three kinds of GZY300 distribution of lead-rubber isolation bearing are analyzed. It is found that the setting mode of the isolation bearing has a great influence on the displacement response of the grid frame. The displacements of the structures subjected to three kinds of seismic waves were compared by means of upper isolation and lower isolation respectively. The isolation support is located at the upper part of the grid bracing column, and the response of the isolated structure is smaller than that of the lower one. At the same time, the displacement response of the ordinary rubber isolation bearing to the grid frame is analyzed and compared with the GZY300 bearing. Considering the influence of supporting columns with different cross-section sizes on the axial force history of the structure, it is also proved that the use of upper seismic isolation is beneficial to the safety of the braced columns.
【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TU311.3;TU356

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