圆弧扩大头和梁翼缘圆孔削弱型箱型中柱-H型钢梁节点循环加载试验研究

Low-cycle reversed loading tests on inner diaphragm joints of H-style steel beam-square steel tubular column with enlarged juncture and opening holes at beam flanges

对1个隔板贯通式箱型中柱-H型钢梁常规节点和3个圆弧扩大头及梁翼缘网孔削弱型节点进行了低周往复循环加载试验．试验结果表明，常规节点在梁翼缘对接焊缝处脆断，节点塑性转角约为0．016rad；网弧扩大头及圆孔削弱型节点在梁翼缘圆孔削弱处断裂，裂纹起始于圆孔侧边，塑性转角较常规节点提高约19％，承载力较常规节点降低5．5％～9．4％，滞回曲线的包络面积（耗能性能）较常规节点约提高0．2％～9．0％．圆弧扩大头构造降低了梁翼缘对接焊缝的应力集中程度，避免了对接焊缝过早脆断；圆孔削弱构造促使梁削弱截面形成塑性铰．

Low-cycle reversed loading tests were performed on inner diaphragm joints of H-style steel bean〉square steel tubular column, including one conventional joint and three joints with enlarged juncture near butt weld and opening holes at beam flanges. The test results show that, for the conventional joint, butt weld at beam flange brittle fracture and the plastic rotation is about 0.016 rad. For the joints with enlarged juncture near butt weld and opening holes at beam flanges, the crack initiates at the edge of the circular hole and fracture occurs at the reduced beam section. The plastic rotation of the joints with enlarged juncture near butt weld and opening holes at beam flanges increases by 19%, the loading capacity decreases by 5.5% -9.4% and the area enveloped by hysteretic curves increase by 0.2%-9.0% compared with that of the conventional joint. The stress concentration at butt weld is remarkably mitigated and therefore the immature fracture is brittle avoid by using of enlarged juncture. The plastic hinge is formed at the reduced beam section due to the opening holes at beam flanges.