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传统抗弯框架的楼板构造限制节点处的裂缝发展,导致了自定心楼板承载力的降低,进而影响了它在后张预应力钢框架中的应用。提出了2种方案来减小对后张预应力框架抗震性能的限制。第1种方案在抗弯框架中对楼板进行改进,在节点附近,金属楼板不连续且纵梁与混凝土脱离,以减小楼板约束。第2种方案仅在后张预应力框架的某刚性层用桁架单元连接楼板和梁,将内力从楼板传递至框架。在框架横向楼板梁的一端设置滑动装置,可得出楼板的滑动位移。通过4组节点试验,对普通节点和第1种方案节点的循环性能进行比较。通过框架组件试验,对刚性层如何影响框架性能、柱剪力和梁轴力分布、节点处裂缝发展状况进行分析。结果表明:用两种方案改进的后张预应力框架,均有很大的变形能力,且残余变形很小。采用本方法,还可确定柱剪力和梁轴力。
The traditional flexural frame floor structure restricts the development of cracks in the joints, which leads to the decrease of the bearing capacity of the self-centering floor slab, thus affecting its application in the post-tensioned prestressed steel frame. Two schemes are proposed to reduce the limit of the seismic performance of the post-tensioned prestressed frame. The first solution is to improve the floor in flexural frames. Near the nodes, the metal floor is discontinuous and the stringers are separated from the concrete to reduce floor restraints. The second option connects the floor slab and the girder with truss elements only at a rigid layer of the post-tensioned prestressed frame to transfer the internal forces from the floor to the frame. A sliding device is arranged at one end of the transverse beam of the frame to obtain the sliding displacement of the floor. Through four groups of node tests, the cycle performance of the common node and the first scheme node are compared. Through the testing of frame components, the influence of the rigid layer on the performance of the frame, the distribution of column shear force and beam axial force, and the development of cracks at the joints were analyzed. The results show that the post-tensioned prestressed frames modified by the two schemes have great deformability and little residual deformation. Using this method, column shear and beam axial forces can also be determined.