竖向地震作用下型钢混凝土长悬挑结构的抗震性能分析

发布时间：2018-12-31 22:26

【摘要】：型钢混凝土长悬挑结构一方面以诸多优点在现代复杂高层建筑的快速发展中占据举足轻重的地位,另一方面因其往往造成建筑结构质量及刚度分布不均匀,受力复杂,使此类结构的抗震性能分析和研究难度增大。大量地震记录表明,高烈度区地震动竖向加速度分量对建筑物的破坏作用十分显著的,所以对高烈度地区型钢混凝土长悬挑结构进行竖向地震作用下的抗震性能研究就显得十分必要。本文以某超高层混凝土结构的型钢混凝土长悬挑连廊为研究对象,应用ETABS2015软件建立整个结构的有限元模型。首先对其进行模态分析,表明考虑竖向地震时高阶模态影响显著;然后采用振型分解反应谱法分别计算结构在水平双向地震作用和三向地震作用下的地震反应。结果表明:竖向地震作用对结构水平位移基本没有影响,而对节点和梁跨中竖向位移影响较大。竖向地震对柱轴力和斜撑轴力影响显著,框架梁端弯矩和跨中弯矩在竖向地震作用下明显增大。本文再选取了EL-centro波、TAFT波及人工波三条地震波对其进行了弹性时程分析,分析结构在相应两种工况下的反应,并与以上振型分解反应谱法所得结果进行比较。结果表明:反应谱法和时程分析法得出类似的结论,具体表现为结构在两种工况下的节点水平位移曲线、梁跨中水平位移曲线基本重合,即竖向地震对节点和梁跨中水平位移几乎没有影响,而对节点和跨中竖向位移增大作用明显,与双向水平输出结果相比,悬臂端节点及梁跨中竖向位移显著增大;竖向地震对框架柱轴力影响显著,并且随着高度的增加,影响逐渐减小;斜撑的轴力及梁端弯矩、梁跨中弯矩在竖向地震作用下也有较大增加,且梁跨度越大,竖向地震影响越明显。弹性反应谱分析分析和时程分析都表明对于此类结构,竖向地震作用影响较大,设计中应足够重视,以确保其安全性和适用性,本文研究结果可为类似结构的设计和施工提供参考。
[Abstract]:On the one hand, the long cantilever steel concrete structure occupies a pivotal position in the rapid development of modern complex high-rise buildings with many advantages, on the other hand, it often results in uneven distribution of the quality and stiffness of the building structure and complex forces. It is more difficult to analyze and study the seismic behavior of this kind of structures. A large number of seismic records show that the vertical acceleration component of ground motion in high intensity area has a very significant effect on the destruction of buildings. So it is necessary to study the seismic behavior of long cantilever steel reinforced concrete structures in high intensity area under vertical earthquake. In this paper, the finite element model of the whole structure is established by using ETABS2015 software, taking the steel reinforced concrete long cantilever corridor of a super tall concrete structure as the research object. The modal analysis shows that the influence of high order modes is significant when vertical earthquakes are considered, and then the seismic response of structures under horizontal and three direction earthquakes is calculated by mode decomposition response spectrum method. The results show that the vertical earthquake has no effect on the horizontal displacement of the structure, but has a great effect on the vertical displacement of the joint and beam span. The vertical earthquake has a significant effect on the axial force of column and the axial force of inclined braces, and the bending moment at the end of the frame beam and the moment in the span are obviously increased under the action of vertical earthquake. In this paper, three seismic waves of EL-centro wave, TAFT wave and artificial wave are selected for elastic time-history analysis, and the response of the structure under two conditions is analyzed, and the results are compared with those obtained by the above modal decomposition response spectrum method. The results show that the response spectrum method and the time history analysis method have similar conclusions, which are shown as the horizontal displacement curves of the joints and the horizontal displacement curves of the beams in the middle of the beam span. That is, the vertical earthquake has little effect on the horizontal displacement of the joint and beam span, but it has obvious effect on the increase of the vertical displacement of the joint and span. Compared with the results of the bi-directional horizontal output, the vertical displacement of the cantilever end joint and the beam span increases significantly. The vertical earthquake has a significant effect on the axial force of the frame column, and with the increase of the height, the influence decreases gradually. The axial force of inclined brace and the bending moment at the end of beam and the moment in the middle of beam span also increase greatly under the action of vertical earthquake, and the bigger the span of beam is, the more obvious the effect of vertical earthquake is. Both the elastic response spectrum analysis and the time history analysis show that the vertical earthquake has a great influence on such structures, which should be paid enough attention in the design to ensure their safety and applicability. The results of this paper can provide reference for the design and construction of similar structures.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU973.31

【参考文献】