无粘结预应力混凝土平板-T形中柱节点抗震性能试验研究

Experimental study on seismic behavior of unbonded prestressed concrete flat plate slab- T- shaped interior column connections

在6个1:1.5缩尺无粘结预应力混凝土平板-T形中柱节点试件的试验基础上,本文对各试件在低周反复荷载作用下的受力过程和破坏特性进行描述,分析了无粘结预应力钢筋应力增量变化特点、板暗梁面筋和节点区附近板暗梁箍筋的应力变化特点,对比了T形柱不同截面参数和不平衡弯矩不同加载方向对该节点抗震性能和不平衡弯矩分配的影响,对该节点的抗震性能进行了评价。试验结果表明,节点的不平衡弯矩主要靠板的弯曲作用来传递,T形柱腹板长度c1对节点的抗震性能和不平衡弯矩分配系数等方面具有决定作用。文中采用隔离体方法对板柱节点进行受力分析,推导了节点剪力传递弯矩系数的计算公式,提出了节点理论抗弯承载力的计算方法。试验结果对工程设计有一定的参考价值。

Based on the experimental study of six 1:1.5 scale unbonded prestressed concrete flat slab T shaped interior column connections, the failure features of the connections under low cycle reversed loads were analyzed, the stress increments of unbonded prestressing steel bar during the test were analyzed, the stress variations of the top flexural reinforcement and the stirrups of the concealed beam near connection in slab were investigated, the different section parameters of T shaped interior column and the unbalanced moment in different directions that influence the seismic behavior of the connections and the distribution coefficient of unbalanced moment were studied with the seismic behavior of the connections evaluated. The test result showed that the transfer of unbalanced moment of the connection is mainly depended on the bending of the slab. And the web length c1 of T shaped interior column has decisive effect on the seismic behavior of the connection and the distribution coefficient of unbalanced moment. The work of the connection under loads was analyzed by free body method. The formula for calculating distribution coefficient of unbalanced moment by shear was derived and the method for calculating flexural capacity of the connection was put forward. The test results may serve as a reference for project design.