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异形柱框架结构与普通框架结构抗震性能对比分析
A Comparison of Seismic Behavior between Specially Shaped and Rectangular Column Frame Structures
【作者】 刘红星;
【导师】 黄宗明;
【作者基本信息】 重庆大学 , 结构工程, 2008, 硕士
【摘要】 钢筋混凝土异形柱结构体系是以L形、T形和十形等异形截面柱代替传统矩形柱作为竖向支承构件而构成的结构,其主要特点就是柱肢厚度与墙体厚度一致,避免框架柱在室内突出、少占建筑空间,因而被广泛应用于住宅建筑。近年来对异形柱构件的理论分析和试验研究已经比较系统、成熟,目前对异形柱框架结构抗震性能的研究主要通过弹性模拟分析和结构试验进行,且试验研究主要集中在构件层次或者平面框架层次,而对在设防地震和罕遇地震下,整体结构进入非线性阶段的抗震性能缺乏定量的分析研究。本文研究内容是国家自然科学基金项目“异形柱结构空间非线性动力反应分析方法和整体抗震性能研究”(项目编号50478067)中的一个组成部分,主要目标是采用基于有限单元柔度法的纤维模型梁柱单元编制的钢筋混凝土框架三维非线性地震反应分析程序,对依现行规范和技术规程设计的钢筋混凝土异形柱框架结构进行非线性动力时程反应分析,不仅考察了结构整体抗震性能,还从纤维层次对构件的内力和变形进行了分析,为异形柱结构的抗震设计和相应规程的补充修订提供重要的参考依据,同时依据对异形柱框架结构和矩形柱框架结构三维非线性地震反应分析的结果,比较了两类结构的抗震性能。围绕上述目标,本文主要完成了以下工作:①对低周反复荷载作用下的钢筋混凝土矩形柱、L形柱、T形柱和十形柱在不同加载方向不同轴压比下的受力性能,采用基于有限单元柔度法的纤维模型梁柱单元,进行了模拟分析,并从延性、刚度方面进行了比较。②按照现行抗震设计规范及异形柱结构技术规程,设计了一典型异形柱框架结构,并分别按照等结构初始刚度以及与相应的异形柱等截面面积、等截面惯性矩的原则选取了矩形柱截面,设计了3个矩形柱框架结构。③采用基于有限单元柔度法的纤维模型梁柱单元,对所设计的结构进行了单向水平地震作用下的三维非线性地震反应分析,考察了异形柱框架结构在设防和罕遇地震水准下的抗震性能,并和矩形柱框架结构进行了对比。利用构件截面纤维的弯矩-曲率关系曲线和应力-应变数据更加细致地考察了异形柱结构构件在不同水准地震作用下的开裂、屈服规律,对比了两类结构的非线性抗震性能演化规律。
【Abstract】 The reinforced concrete structure system with specially shaped columns is a system widely adopted in residential structures due to no exposed beams and columns in the room. Presently, theoretical research and experimental study on specially shaped column units are systematical and mature. The research on seismic performance of the specially shaped column structure is mainly carried out through structural experiment and elastic analysis. The experiment mainly focused on columns or planar structures. The quantitative research on seismic performance of the integrated structure under different degrees of intensity is far from enough.This paper is part of the National Natural Science Fund project″researches on 3D nonlinear seismic response analysis methods and integrated seismic performance of reinforced concrete structure with specially shaped columns″(Project No. 50478067). Based on the program for 3D nonlinear seismic response analysis of RC frames which developed on the beam-column element of fiber model, it aims to carry out the 3D nonlinear seismic response analysis on RC frames with specially shaped columns designed by the code and specification, examine integrated seismic performance under the fortification and rare seismic actions, analyze the forces and deformations of the fibers in the units, and offer some reference data for the seismic design on RC frames with specially shaped columns. Meanwhile, by the 3D nonlinear seismic performance results of the structure with specially shaped columns and structures with rectangular columns, the seismic behavior of the two types of structures is compared.This paper centers on problems mentioned above, the following tasks are conducted:①By the beam-column element of fiber model based on nonlinear finite element flexibility method, the RC L,T,十-shaped columns of different axial compressions and directions under cyclic loading have been analyzed throughout the process and the analysis results have been compared with the rectangular columns.②According to the current Chinese code and technical specification, some frame structures with rectangular columns and specially shaped columns are designed respectively based on the criterion of the same section area, moment of inertia, initial rigidity of the specially shaped frame structure.③Using the program of fiber beam-column element based on flexibility method of finite element, nonlinear dynamic analysis is taken to analyze the two types of structures. The response of structures (such as story drift and torsion varying rules) is obtained under the fortification and rare grand motion. Still, the crack and yield rules of the main elements of the structures are compared by analyzing the stress and strain data of section fibers. So the change rules of the nonlinear seismic behavior of the two kinds of structures are obtained and some advices are provided for the seismic design of the specially shaped column structures and revising of the related specifications.
【Key words】 Specially shaped columns; Reinforced concrete frame; Seismic performance; nonlinear seismic response analysis; Fiber model;