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

通过试验和分析研究，对钢梁柱连接的断裂行为进行了研究。并从接头强度和变形能力的角度对断裂接头的结构改造进行了研究。采用三维有限元法分析了矩形空心截面柱与宽翼缘截面梁焊接梁腹板节点的弹塑性受弯性能，这是影响节点断裂性能和变形能力的因素之一。提出了矩形空心截面柱宽厚比对焊接梁腹板节点抗弯强度的影响，并给出了估算公式。以柱截面（矩形空心截面和宽法兰截面）、组端连接类型（车间焊接类型和现场焊接类型）和钢材料（低韧性材料和高韧性材料）的断裂韧性为实验变量，对钢梁柱连接的脆性断裂行为进行了研究。利用这些实验再现了在Hyogoken-nambu地震和Northrige地震中观测到的脆性断裂模式，并采用有限元方法分析了脆性断裂热点处的应变集中。接头的脆性断裂强度受脆性断裂热点处断裂韧性的影响。本研究中试验的骨折连接的结构修改为水平和垂直后腿型。考虑连接的应力传递机制，对改进后连接的最大强度进行了估计。改性接头的断裂强度和变形能力受脆性断裂热点处断裂韧性的影响。

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.