近断层地震动特性对RC框架结构地震反应影响

发布时间：2018-02-26 00:25

本文关键词： 近断层框架结构地震动特性竖向地震动脉冲地震动　出处：《中国地震局工程力学研究所》2015年硕士论文　论文类型：学位论文

【摘要】：框架结构由于空间布置灵活、受力简单明确、节省材料等诸多优点而被广泛采用。自然界中对建筑造成损害最大的便是频发的地震,而地震中经济财产损失和伤亡人数大多集中在近断层处。因此,对近断层框架结构的破坏方式和机理的总结和分析十分必要,为近断层附近建造的该类结构的抗震设计和相应的减灾措施奠定基础。本文工作内容如下:1.首先对近断层地震动特性进行了总结。近断层地震动特性主要包括两个方面:一是不可忽略的竖向地震动,竖向地震动的峰值加速度有时达到或超过水平地震动的峰值加速度;二是近断层地震动表现出明显的脉冲性,根据近断层脉冲地震动产生机理,分为前方向性脉冲和滑冲效应脉冲。为了研究脉冲地震动特性对结构地震作用的影响,本文对比分析了脉冲地震动和非脉冲地震动的反应谱和能量流,以及前方向性脉冲地震动和滑冲效应地震动反应谱。2.设计了 4层和8层典型RC框架结构,采用ABAQUS计算软件建立了分析模型,分别分析了两栋框架结构在竖向地震动和脉冲地震动作用下的反应,分析了两种近断层地震动特性对框架结构地表反应的影响。对于竖向地震动的影响,分别选取汶川地震、帝谷地震和集集地震中各一条地震动,调整竖向峰值加速度和水平峰值加速度比为1、0.5和0。分析竖向地震动对框架结构水平方向位移、框架底层外柱和内柱的轴力、弯矩和剪力的影响。结果表明,竖向地震动对结构水平方向的位移几乎没有影响;竖向地震动对框架各层中柱轴力影响非常大,而对各层边柱并没有太大的影响,同时由于竖向地震动的作用,框架结构柱会出现拉力;竖向地震动对抗弯能力没有太大影响,而对柱,尤其是中柱的抗剪能力有着很大的影响。对于脉冲地震动的影响,根据前方向性脉冲地震动、滑冲脉冲地震动和非脉冲地震动三种类型一共选取9条地震动。分析脉冲地震动对框架结构水平方向位移、框架底层外柱和内柱的轴力、弯矩和剪力的影响。结果表明,脉冲地震动对层间位移角有放大作用,对于4层结构,前方向性脉冲地震动和滑冲脉冲地震动作用下结构最大层间位移发生在底层,对于8层结构,前方向脉冲地震动的水平层间位移在特性上已和非脉冲地震动无异,滑冲地震动将最大层间从前两者的第4层移至第2层;脉冲地震动对柱剪力、弯矩的影响大于其对柱轴力的影响,对于4层结构,脉冲地震动对柱轴力、剪力、弯矩的影响随着楼层的增加迅速减小,脉冲地震动对柱轴力的影响甚微。对于8层结构,脉冲地震动对轴力、剪力的影响随着楼层减小而减小,对弯矩的影响先是增大,然后减小;脉冲地震动使框架柱很容易达到柱的抗弯能力,却对柱的抗剪能力影响甚微。
[Abstract]:The frame structure is widely used because of its flexible space arrangement, simple and clear force, saving materials and so on. In nature, frequent earthquakes cause the greatest damage to buildings. However, most of the economic property loss and casualties in the earthquake are concentrated near the fault. Therefore, it is necessary to summarize and analyze the failure mode and mechanism of the near-fault frame structure. The work of this paper is as follows: 1. Firstly, the seismic characteristics of near fault ground are summarized. The seismic characteristics of near fault layer mainly include two parts. First, the vertical ground motion, which cannot be ignored, The peak acceleration of vertical ground motion sometimes reaches or exceeds the peak acceleration of horizontal ground motion. In order to study the effect of impulse ground motion on structural earthquake, the response spectrum and energy flow of pulsed ground motion and non-pulse ground motion are compared and analyzed. And the response spectrum of forward directional impulse ground motion and sliding motion. 2. The typical RC frame structure with four and eight layers is designed, and the analysis model is established by using ABAQUS software. The responses of two frame structures under vertical ground motion and pulsed ground motion are analyzed, and the effects of two near-fault seismic characteristics on the surface response of frame structures are analyzed. For the vertical ground motion, the Wenchuan earthquake is selected respectively. In Digu earthquake and Jiji earthquake, the ratio of vertical peak acceleration and horizontal peak acceleration is adjusted to be 10.5 and 0.0.The horizontal displacement of frame structure by vertical ground motion and the axial force of outer column and inner column at bottom of frame are analyzed. The results show that the vertical ground motion has little effect on the horizontal displacement of the structure, and the vertical ground motion has a great effect on the axial force of the column in each layer of the frame, but has no great effect on the lateral column of each layer. At the same time, because of the vertical ground motion, the frame structure column will appear tensile force, the vertical ground motion has no great influence on the bending ability, but has a great influence on the shear resistance of the column, especially the middle column. A total of 9 ground motions are selected according to the three types of forward directional ground motion, sliding impulse ground motion and non-pulse ground motion. The horizontal displacement of the frame structure caused by the pulse ground motion, the axial force of the outer column and the inner column at the bottom of the frame are analyzed. The results show that the interstory displacement angle is magnified by the pulsed ground motion. For the four-story structure, the maximum interstory displacement occurs at the bottom of the structure under the action of the front directional pulse ground motion and the sliding impulse ground motion. For the 8-story structure, the horizontal displacement of the front direction pulsed ground motion is no different from that of the non-pulse ground motion, and the sliding ground motion moves the maximum interlayer from the fourth layer of the first two layers to the second layer; the shearing force of the pulsed ground motion to the column, The influence of impulse ground motion on axial force, shear force and bending moment of column decreases rapidly with the increase of floor, and the influence of impulse ground motion on axial force of column is little for four-story structure, and for 8 story structure, the influence of impulse ground motion on axial force of column is less than that on axial force of column, and the influence of impulse ground motion on axial force of column is less than that on axial force of column. The effect of pulsed ground motion on axial force and shear force decreases with the decrease of floor, and the effect on bending moment increases and then decreases.
【学位授予单位】：中国地震局工程力学研究所
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU375.4;TU311.3

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