异形柱空间框架撤柱动力响应及数值模拟

发布时间：2018-03-16 14:15

本文选题：异形柱框架　切入点：连续倒塌　出处：《天津大学》2014年硕士论文　论文类型：学位论文

【摘要】：连续倒塌是指由于意外事件的突然发生造成结构的子结构损伤或者结构局部破坏,继而导致连锁反应的产生,引起破坏向结构的其它部分扩散,最终使结构发生大范围的倒塌破坏。异形柱框架结构相对于传统矩形柱框架结构,由于其柱肢薄弱且节点容易发生破坏,在意外荷载作用下更容易发生连续倒塌。本文以异形柱结构为研究对象,对空间异形柱框架进行撤柱试验,并进行结构抗倒塌的动力响应分析。为研究混凝土异形柱框架的抗连续倒塌动力响应,进行了一个1/3缩尺比的两层3×2跨混凝土异形柱空间框架撤柱试验,试验共包含两个工况:底层角柱撤除试验和短边中柱撤除试验。试验结果显示两工况下,与失效柱相连梁转角最大值分别为1.45×10-4rad和1.46×10-4rad,均小于倒塌判定标准值0.105rad,表明混凝土异形柱框架结构在底层框架柱撤除后具有较好的抗倒塌性能。基于有限元软件ANSYS/LS-DYNA建立混凝土异形柱试验框架的有限元分析模型,采用替代路径法进行底层关键柱失效的结构非线性动力分析。通过对比分析失效柱柱顶竖向位移及钢筋应变的计算值和试验值,二者吻合较好,表明基于ANSYS/LS-DYNA软件采用替代路径法研究异形柱空间框架的抗连续倒塌性能是合理的。在此基础上研究试验两种不同撤柱工况下与失效柱相连梁端混凝土应变变化情况,结果显示两工况的梁端混凝土应力值均未超过混凝土轴心抗拉强度或轴心抗压强度,混凝土不会发生开裂或压碎,与试验中观察到的撤柱后未发现裂缝是一致的,进一步说明利用LS-DYNA进行数值模拟分析是可靠的。在此基础上,利用ANSYS/LS-DYNA软件对试验异形柱空间框架进行底层内柱突然失效工况和两个相邻框架柱同时失效的三种最可能工况下的结构非线性动力分析,分析表明两个相邻框架柱突然失效后剩余框架不会发生连续倒塌,但会产生显著的动力效应。
[Abstract]:Continuous collapse refers to the damage to the substructure or local damage of the structure caused by the sudden occurrence of an accident, which leads to a chain reaction, which causes the damage to spread to other parts of the structure. Compared with the traditional rectangular column frame structure, the special-shaped column frame structure is vulnerable to damage because of its weak column limb and the joint. Continuous collapse is more likely to occur under the action of accidental load. In this paper, the special shaped column structure is taken as the research object, and the column withdrawal test is carried out on the spatial special-shaped column frame. In order to study the dynamic response of concrete special-shaped column frame against continuous collapse, a two-story 3 脳 2 span spatial frame with a scale ratio of 1/3 is carried out. The test consists of two working conditions: the bottom corner column removal test and the short side column removal test. The maximum rotation angles of beams connected with failure columns are 1.45 脳 10 ~ (-4) rad and 1.46 脳 10 ~ (-4) radrespectively, which are less than the standard value of collapse determination 0.105 rad. it shows that the concrete frame structure with special-shaped columns has better anti-collapse performance after the removal of the bottom frame column. Based on the finite element software ANSYS/LS-DYNA, the structure is built on the basis of the finite element software ANSYS/LS-DYNA. Finite element Analysis Model of Test frame for Special shaped column of Vertical concrete, The structural nonlinear dynamic analysis of the failure of the bottom key column is carried out by using the alternative path method. The calculated and experimental values of the vertical displacement and the strain of the steel bar on the top of the failure column are compared with each other, and the results are in good agreement with each other. The results show that it is reasonable to study the continuous collapse resistance of spatial frame with special-shaped columns based on the alternative path method based on ANSYS/LS-DYNA software. On this basis, the strain variation of concrete at the end of the beam connected to the failure column under two different column withdrawal conditions is studied. The results show that the stress values of concrete at the end of the beam under two working conditions are not higher than the axial tensile strength or compressive strength of the concrete, and the concrete will not crack or crush, which is consistent with the observed cracks after the column withdrawal. It is further proved that the numerical simulation analysis using LS-DYNA is reliable. Using ANSYS/LS-DYNA software, the nonlinear dynamic analysis of the structure under the three most probable failure conditions of the inner column of the bottom layer and the failure of two adjacent columns at the same time is carried out on the spatial frame with special shaped columns. The analysis shows that the residual frame will not collapse continuously after the failure of two adjacent frame columns, but it will have significant dynamic effect.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU398.9;TU311.3

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