预应力混凝土空间节点抗震性能试验研究

Experimental study on seismic performance of prestressed concrete spatial joints

通过4个模型节点的低周反复荷载试验,对预应力混凝土空间节点的破坏形态、特征荷载、恢复力模型、延性、耗能能力、变形恢复能力等进行了较为系统的研究。研究表明:核心区水平剪力-剪切角滞回曲线呈反S形,有一定的捏拢效应;节点核心区开裂较早,裂缝多且宽;环梁和环向预应力的约束能有效地改善空间节点的延性;双向地震作用下的预应力混凝土空间节点具有较大的水平受剪承载力以及良好的延性、耗能能力和变形恢复能力,但比相应的平面节点稍差;空间加载节点在主轴方向的受剪承载力小于相应的平面加载节点。

Based on experiments of four model joints under low reversed cyclic loading, the failure patterns, characteristic loads, hysteretic model, ductility, energy dissipation and deformation restoring capacity of the prestressed concrete spatial joints were systemically studied. Studies show that pinching could obviously be observed in the horizontal shear versus shear angle hysteresis loops, which exhibited reverse-S shape. More and wider cracks could be observed, which appear early in spatial joints. The restraints applied on the circumferential beam and the prestress could significantly improve the ductility of spatial joints. The seismic performance such as horizontal shear capacity, ductility, energy dissipation and deformation restoring capacity of model joints was larger under bidirectional low reversed cyclic loading, but less than the planal joints. The shear capacity of the two principal axes of joints under spatial loading was lower than that of the corresponding joints under planal loading.