基于替代路径法的结构抗连续倒塌能力研究

发布时间：2018-06-05 06:12

本文选题：连续倒塌 + 混凝土结构　；参考：《天津大学》2014年博士论文

【摘要】：结构连续倒塌是由于偶然意外荷载等产生的结构局部破坏，并导致结构破坏向其他部分发展，最终导致结构大范围倒塌。由于初始破坏无法预测，本研究的目的不是如何控制或削弱初始破坏，而是在初始破坏发生的情况下，判断结构发生连续倒塌的可能性，以及提出结构抵抗连续倒塌的措施。本文以规则建筑和不规则建筑为结构模型，采用替代路径法对其抗连续倒塌能力进行了评价，在此基础上提出了多种抗连续倒塌措施，主要研究内容及结论如下： 1、对于规则混凝土结构，结构中上层单柱失效比结构底层相同位置单柱失效引发结构连续倒塌的风险较高。底层（或中上部楼层）角柱或中上部楼层长边边柱失效都会引发结构自上而下的连续倒塌，内柱或短边边柱失效不会引发结构的连续倒塌。 2、按照DoD2010中动力放大系数进行非线性静力分析能较好的反映单柱失效瞬时结构的响应，而无法反映塑性铰的发展过程以及竖向位移的最终结果。 3、在竖向承重构件失效情况下，X型拉结可以为结构提供替代荷载传递路径，有效减小柱失效瞬时结构的位移，抑制部分结构变形的发展，提高结构的抗连续倒塌能力。DoD2010中楼板内布置拉结有利于发挥楼板的薄膜效应，优于DoD2005中沿着梁布置水平拉结。后两种拉结方案对单柱失效瞬时节点竖向位移的影响不太显著，但能有效地抑制结构变形的进一步发展，具有一定的抗连续倒塌能力，但效果不如X型拉结显著。 4、对于L型不规则混凝土结构，首层外凸角处角柱失效比首层内凹角处角柱失效更容易引发结构的连续倒塌。在首层两个外柱同时失效情况下，梁、柱破坏，楼板发生坍塌，，竖向位移呈加速增大的趋势，结构发生连续倒塌。首层内凹角处双柱失效后，相邻楼板容易发生坠落，从而引发局部连续倒塌，但破坏程度不及两个外柱失效工况。 5、对于L型不规则混凝土结构，在顶层增加钢桁架可以提高结构的整体性，增强结构在局部破坏后的荷载重分布能力，从而提高其抗连续倒塌性能。增加梁柱配筋可以提高构件的强度，降低竖向承重构件失效的风险，同时降低结构在单柱失效情况发生连续倒塌的风险，但其效果不及在顶层增加钢桁架。
[Abstract]:The continuous collapse of the structure is caused by accidental and accidental loads, which leads to the development of the structure to other parts, and finally to the collapse of the structure on a large scale. Because the initial failure can not be predicted, the purpose of this study is not to control or weaken the initial failure, but to judge the possibility of continuous collapse of the structure under the condition of the initial failure, and to put forward the measures to resist the continuous collapse of the structure. In this paper, taking regular building and irregular building as structural model, the ability to resist continuous collapse is evaluated by alternative path method. On this basis, several measures to resist continuous collapse are put forward. The main research contents and conclusions are as follows: 1. For regular concrete structures, the risk of continuous collapse caused by single column failure in upper layer is higher than that in the same position at the bottom of the structure. Failure of the bottom (or upper floor) corner column or the long side column of the upper and middle floor will cause the continuous collapse of the structure from top to bottom, while the failure of the inner column or the short edge column will not cause the continuous collapse of the structure. 2. The nonlinear static analysis based on the dynamic magnification factor in DoD2010 can well reflect the response of a single column failure instantaneous structure, but can not reflect the development process of plastic hinge and the final result of vertical displacement. 3. Under the failure condition of vertical load-bearing member, the X-type tie can provide alternative load transfer path for the structure, reduce the displacement of the instantaneous structure of column failure effectively, and restrain the development of partial structural deformation. To improve the continuous collapse resistance of the structure. In DoD2010, the layout of the floor is advantageous to exert the thin film effect of the floor, which is superior to the horizontal tie along the beam arrangement in DoD2005. The latter two schemes have little effect on the vertical displacement of single column failure instant joints, but they can effectively restrain the further development of structural deformation and have a certain ability to resist continuous collapse, but the effect is not as significant as that of X-type joints. 4. For L-type irregular concrete structure, the failure of corner column at the outer convex corner of the first layer is more likely to cause the continuous collapse of the structure than the failure of the corner column at the inner concave corner of the first story. In the case of simultaneous failure of two external columns on the first floor, the beam and column are destroyed, the floor collapses, the vertical displacement increases rapidly, and the structure collapses continuously. After the failure of the two columns at the inner concave corner of the first floor, the adjacent slabs are prone to fall, thus causing local continuous collapse, but the degree of failure is less than that of the two external columns. 5. For L-type irregular concrete structures, adding steel truss to the top floor can improve the integrity of the structure and enhance the load redistribution ability of the structure after local failure, thus improving its continuous collapse resistance. Increasing Liang Zhu reinforcement can increase the strength of the members and reduce the risk of failure of vertical load-bearing members, and reduce the risk of continuous collapse of the structure in single column failure, but its effect is not as good as adding steel truss on the top floor.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU312.3

【参考文献】