方钢管混凝土柱-钢梁外隔板节点拟静力试验研究

Quasi-static experimental study of outer diaphragm connections between square concrete filled steel tube columns and steel beams

通过对2个方钢管混凝土柱-工字钢梁外隔板式节点试件进行的拟静力加载试验,研究节点在反复循环荷载作用下的滞回性能、耗能能力、延性、应力分布和传力机制。试验结果表明,节点具有较高的承载力以及较好的延性和耗能能力,外隔板式节点的梁端弯矩一部分通过柱腹板两侧隔板传递到柱钢管腹板和核心混凝土,另一部分则主要通过柱角两内侧各0.25倍柱宽范围内的隔板直接传递给柱钢管翼缘和核心混凝土。柱角附近的隔板出现严重的应力集中,影响节点的耗能和延性。对节点建立同时考虑几何非线性和材料非线性的有限元分析模型,模拟分析了节点的受力性能。结果表明,由有限元分析所得的位移曲线与试验所得的骨架曲线极为相似,由有限元模型所得的应变分布规律与试验结果一致。

Through quasi-static tests on two outer diaphragm connections between square concrete filled steel tube columns and H shape steel beams, the hysteretic behavior, energy dissipation capacity, ductility, stress distribution and force transfer mechanism of the joints under low cycle reversed loads are studied. The results indicate that such joints have higher carrying capacity, better ductility and energy dissipation behaviors. Some of the end moments of the beams were transferred to the column web and the core concrete at the panel zone by the outer diaphragm connected to the column web. Other end moments were directly transferred to the column flange and the core concrete by the diaphragm near the column corner. Serious stress concentration occurred in the diaphragm near the column corner. Nonlinear FEM models of the outer diaphragm connection between concrete-filled square tubular columns and steel beams involving large deformation and material nonlinearity are presented. Joint behaviors and stress distributions were analyzed. The results indicate that the load-displacement curves, stress distribution from the FEM agree well with framework curves of the cyclic behavior from the low-cycle reversed loading tests.