分布式连接全装配钢筋混凝土楼盖板缝节点平面内受力性能试验研究

Experimental study on in-plane mechanical behavior of slab connections of discretely connected precast RC diaphragms

为研究分布式连接全装配RC楼盖板缝节点平面内受力性能,进行了5种共18个板缝节点在平面内水平单调荷载、低周反复荷载和拉剪复合作用下的足尺模型试验,对板缝节点的受剪承载能力、破坏形态、滞回曲线、位移延性、耗能能力和拉剪复合受力性能进行了较为系统的研究。研究表明:除SPC和SP-CPC节点外其他3种板缝节点均具有较好的受剪承载力和刚度,且节点承载力可由叠加法简化计算;HPC节点、CPC节点和HP-CPC混合式节点具有较好的滞回性能、耗能能力和位移延性,是较为合理的板缝连接节点形式;拉力的存在削弱了板缝节点受剪承载力,且拉剪比越大削弱程度越高;高拉剪比下节点的延性较差,在极限荷载下易发生类似螺栓群连接中的"连锁破坏反应",设计时需对高拉剪比区的连接件进行改进和加强,以满足楼盖对板缝节点延性的要求。

An experimental program consisting of prototype tests of eighteen slab joint connections (five kinds)was conducted to evaluate the in-plane mechanical behavior of the proposed slab connections used in discretely connected precast RC diaphragms (DCNPD)under in-plane monotonic load,cyclic load and combined shear and tension load. Performance of the test specimens was evaluated in terms of the shear bearing capacity,failure mode,ductility,energy dissipation,among others.The test results show that the connections possess high shear bearing capacity and stiffness except the SPC and SP-CPC connections,and their shear bearing capacity can be predicted using a simple superposition method;the HPC,CPC and HP-CPC connections have good hysteristic behavior,energy-dissipation capacity and displacement ductility,and are thus suitable slab joints for DCNPD ;the presence of tension decreases the shear bearing capacity of slab connections,and as the tension to shear force ratio increases,the weakening effect becomes more evident ;the ductility of slab connections is poor under high tension to shear force ratio,and the domino effect is likely to happen under extreme loading conditions.Slab joint connections under high tension to shear force ratio should be improved and strengthened to meet the connections'displacement ductility requirement.