有限长度预拉杆部分自复位PEC柱组合框架中间层抗震性能试验研究

为研究部分包裹混凝土（partial encased concrete，PEC)柱-钢梁有限长度预拉杆部分自复位连接组合框架中间层抗震机理，考虑耗能件形式和PEC柱布置方式，设计制作了3榀1∶2缩尺比例组合框架中间层子结构试件并进行水平低周往复荷载试验。基于试验结果，对试件的滞回特征、自复位功效、耗能能力进行了对比分析。研究表明：T形件螺栓孔的合理设置可有效实现“设计地震水平下通过耗能件耗能减震，大震水平下连接转化为承压型受力模式”的设计目标；部分自复位连接预拉杆预应力决定自复位功效，而辅助耗能件仅影响其耗能发展进程； PEC柱布置方式对部分自复位功效和耗能能力影响较小，验证了卷边PEC柱较好地改善了双向刚度的差异；T形件对穿螺栓与预拉杆传力方式促使节点区混凝土更好地形成斜压带传力模式和节点加强板增强了节点区混凝土约束的双重作用使得节点区较好地达到了“强节点”抗震要求；所有试件加载至设计地震水平下层间侧移限值1/50时，其整体与层间残余侧移最大值分别为0.21%和0.11%，基本满足了自复位结构残余侧移0.2%的要求，而加载超过大震水平下层间侧移限值的1/30时，所有试件承载能力仍继续增大，其整体与层间残余侧移最大值分别为0.86%和0.42%，即所有试件层间仍具有良好的自复位功效。

Experimental study on seismic performance of inter-story substructure of PEC column-steel beam frame with limited length pretension bar-partial self-centering connection

To study the seismic mechanism of inter-story substructure of PEC column-steel beam frame with limited length pre-stressed bar and partial self-centering connection, three 1∶2 scaled PEC column-steel beam frame test assemblages considering different energy dissipations and PEC column layouts were tested under low cyclic lateral loading. Based on test results, the hysteretic characteristics, self-centering capability and energy-dissipation capacity were analyzed and compared. The results indicate that the force-transfer mechanism of “partial self-centering connection at moderate earthquake level and bearing-type connection at major earthquake level” can be effectively achieved if the bolt slotted hole is set up rationally. Self-centering capability is depended on the pre-stress value of pre-tensioned bar, while the process of energy dissipation is only influenced by the type of energy-dissipation component. Approximately equal bi-stiffness of PEC column is verified resulted from little effect of PEC column layout. The force-transfer mechanism of confinced concrete equivalent strut was formed in the panel zone due to penetrating bolts and pre-tensioned bars and reinforced gusset plate, which basically meets the seismic requirement for “strong joint”. When loading to the inter-story drift limit of 1/50 for frame structure at design earthquake level, the maximum residual drifts of global specimen and inter-story structure are 0.21% and 0.11%, respectively, which basically meeting the residual drifts requirement of 0.2% for self-centering structures. While loading to the inter-story drift limit of 1/30 for frame structure at maximum-considered earthquake level, the bearing capacity of all specimens are still increasing, and the maximum residual drifts of global specimen and inter-story structure are 0.86% and 0.42%, respectively. Overall, all the specimens persist superior inters-story self-centering capability.