Seismic Behavior and Structural Modification of Steel Beam-to-Column Connection

通过试验和理论分析，研究了钢框架梁柱节点的断裂性能。并从连接件的强度和变形能力的角度研究了断裂连接件的结构修改。采用三维有限元方法，分析了矩形空心柱与宽翼缘梁焊接梁腹板节点的弹塑性受弯性能，该性能是影响节点断裂性能和变形能力的因素之一。研究了矩形截面柱宽厚比对焊接梁腹板节点抗弯承载力的影响，并提出了计算公式.以柱截面（矩形空心截面和宽翼缘截面）、端部连接形式（工厂焊接和现场焊接）和钢材（低韧性材料和高韧性材料）的断裂韧性为试验变量，对钢梁柱节点的脆性断裂行为进行了试验研究。通过这些实验再现了在兵库县南部地震和北岭地震中观察到的脆性断裂模式，并通过有限元方法分析了脆性断裂热点处的应变集中。连接件的脆性断裂强度受脆性断裂热点处的断裂韧性影响.本研究中所试验的裂缝连接的结构修改为水平加腋型和垂直加腋型。通过考虑节点的应力传递机制，估算了节点的最大承载力。脆性断裂热点处的断裂韧性对接头的断裂强度和变形能力有影响。

The fracture behaviors or the steel beam-to-column connections were investigated by the experimental and analytical research works. And the structural modifications of the fractured connections were also investigated from the viewpoints of the strength and deformability of the connections1. The elastic-plastic flexural behavior of the welded beam web joint between rectangular hollow section column and wide flange section beam, which is one of the influencing factors of the fracture behaviors and deformability of the connections, was analyzed by the three-dimensional finite element method. The flexural strength of the welded beam web joint is influenced by the width-to-thickness ratio of the rectangular hollow section column and the estimation formula was proposed.2. The brittle fracture behaviors or the steel beam-to-column connections were investigated by the experimental research works, in which the experimental variables were the column section (rectangular hollow section and wide flange section), the type or team end connection (shop welding type and field welding type) and the fracture toughness of the steel materials (low toughness material and high toughness material). The brittle fracture modes observed in the Hyogoken-nambu earthquake and Northrige earthquake were reproduced by these experiments, and the strain concentration at the hot spot of brittle fracture was analyzed by the finite element method. And the brittle fracture strength of the connection is influenced by the fracture toughness at the hot spot of brittle fracture.3. The structural modification of the fractured connection experimented in this study was the horizontal and vertical haunch types. The maximum strength of the modified connection was estimated by taking account of the stress transfer mechanism of the connections. The fracture strength and deformability of the modified connections are influenced by the fracture toughness at the hot spot of brittle fracture.