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

通过试验和分析研究，对钢梁柱节点的断裂性能进行了研究。并从节点强度和变形能力的角度对断裂节点的结构改进进行了研究。采用三维有限元方法对影响矩形空心柱与宽翼缘截面梁焊接梁腹板节点的弹塑性弯曲性能进行了分析，认为这是影响节点断裂性能和变形能力的因素之一。研究了矩形空心柱的宽厚比对焊接梁腹板节点抗弯强度的影响，并提出了计算公式。通过试验研究，研究了钢梁柱节点的脆性断裂行为，试验变量为柱截面(矩形空心截面和宽翼缘截面)、端部连接类型(车间焊接型和现场焊接型)以及钢材(低韧性材料和高韧性材料)的断裂韧度。通过实验再现了日本玄武地震和Northrige地震中观察到的脆性断裂模式，并用有限元方法分析了脆性断裂热点处的应变集中。节点的脆性断裂强度受脆性断裂热点处断裂韧性的影响。本研究试验的断口结构改进为水平和竖直两种形式。通过考虑节点的应力传递机制，估算了改进后节点的最大强度。脆性断裂热点处的断裂韧性影响着改性节点的断裂强度和变形能力。

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.