圆弧扩大头狗骨隔板贯通方钢管混凝土柱-H形钢梁节点抗震性能分析

对圆弧扩大头狗骨隔板贯通方钢管混凝土中柱-H形钢梁节点和常规节点进行了循环加载试验,对比研究了圆弧扩大头狗骨隔板对方钢管混凝土柱-H形钢梁节点抗震性能的影响,对节点试验试件进行了基于结构钢椭球面断裂模型和屈服模型的强震灾变分析。结果表明,隔板贯通方钢管混凝土中柱-H形钢梁节点起裂于梁腹板工艺孔处,节点域核心区混凝土形成"斜压短柱"效应,直至节点破坏时,核心混凝土未发生压碎或拉裂破坏。常规节点脆断于几何变化剧烈、应力高度集中的梁翼缘对接焊缝边缘,节点塑性转角约为0.016 rad。圆弧扩大头狗骨隔板构造消除了梁翼缘对接焊缝处的几何突变,促使塑性铰形成于远离节点区的梁削弱截面。圆弧扩大头狗骨节点的塑性转角可达到0.033 rad~0.041 rad,耗能性能和承载力较常规节点分别提高72%~86%和下降9.6%~12.6%。

Seismic performance of diaphragm-through type joints between concrete-filled square steel tubular column and H-section steel beam with enlarged arc and dog-bone junctures

In order to study the effects of enlarged arc and dog-bone junctures on seismic performance of diaphragm-through type joints between concrete-filled square steel tubular column and H-section steel beams, low-reversed loading tests were performed on joints with enlarged arc and dog-bone junctures as well as conventional joints. Disaster mechanism analysis was performed on the specimens based on an elliptical fracture envelop and a generalized yield model of constructional steel. The results of tests and fracture analysis reveal that crack initiates at the edges of constructional welding holes of beam web. The core concrete in panel zone acts as a baroclinic short column and does not crack or crush until joints failure. The conventional joint exhibits brittle fractures at the edges of butt weld between the beam flange and the diaphragm rib with the sharply changed geometry where the stress concentration is serious. The plastic rotation of the conventional joint is about 0.016 rad. For the joints with enlarged arc and dog-bone junctures, the plastic hinge is formed at the reduced beam section far away from panel zone while the sharply changed geometry and stress concentration at butt weld of beam flanges are mitigated. The plastic rotation of joints with enlarged arc and dog-bone junctures may range from 0.033 rad to 0.041 rad, and the energy dissipation capacity increases by 72%~86% while the load bearing capacity decreases by 9.6%~12.6%, compared with that of conventional joints.