空间预应力板柱结构动态倒塌响应分析

Analysis on Dynamic Collapse Response of Spatial Prestressed Slab-Column Structure

为研究预应力板柱结构在不同位置结构柱突然失效后的动态倒塌响应,利用有限元软件ANSYS/LS-DYNA开展了数值模拟分析。在验证建模方法合理的基础上,建立了一足尺3层2×2跨无粘结空间预应力板柱结构,分别研究了结构在拆除内柱、拆除角柱和拆除边柱3种不同工况下的裂缝发展模式、动态位移响应以及内力重分布过程。结果表明:在1.0(DL+LL)的设计荷载作用下,满足规范要求的预应力板柱结构在单独拆除内柱或边柱后不会发生倒塌,而单独拆除角柱则会使结构发生倒塌破坏。结构柱失效后,大部分不平衡荷载将沿最短路径传递至相邻柱,内柱失效工况下,96%的不平衡荷载将分配至4个边柱;边柱失效工况下,64%的不平衡荷载将传递至两相邻角柱;角柱失效工况下,68%的不平衡荷载将传递至两相邻边柱。在设计荷载作用下,3种柱失效工况下结构的预应力筋均未发生断裂,底层柱均未发生剪切破坏。不平衡荷载沿位于失效柱上的板带传递时,钢筋为主要承担者,其贡献可高达86.5%,但当结构变形较剧烈时,预应力筋的贡献将提升。

To study the dynamic collapse performance of the unbonded prestressed slab-column structure(UPS)under different column failure scenarios,the finite element software ANSYS/LS-DYNA was used to carry out numerical simulation analysis.On the basis of verifying the reasonableness of the modeling method,a full-scale three-story 2×2 span UPS was established.The crack patterns,dynamic displacement response and internal force redistribution process of the structure were discussed under three different column removal scenario.The results show that:under the design loadof 1.0(DL+LL),the UPS meets the requirements of the code will not collapse after the inner column or side column is removed separately,while the UPS will collapse after the removal of the corner column.After the failure of the inner column,96%of the unbalanced load will be distributed to the 4 side columns in the short direction.After the failure of the side column,64%of the unbalanced load will be distributed to the 2 corner columns.After the failure of the corner column,68%of the unbalanced load well be distributed to each 2 side columns.After the failure of the column,the prestressed tendons of the UPS will not be fractured,and the bottom column will not be sheared.Reinforcement is the main bearer of the unbalanced loads transmitted laterally within the column strip of the failure column,and their contribution can be as high as 86.5%.However,when the structural deformation is severe,the contribution of prestressed tendons will increase.