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梁柱全焊节点在建筑钢结构中广泛应用,其火灾后受力性能对整个结构灾后承载安全至关重要。通过5个梁柱全焊节点试件高温冷却后的低周反复加载试验,研究了高温过火对其承载力、延性和耗能能力的影响规律。试验过火温度介于500~800℃之间,冷却方式为自然冷却。试验结果表明,所有试件均发生梁柱翼缘对接焊缝处的断裂破坏。高温冷却后试件的抗弯承载力较未过火试件有所降低,延性和耗能能力有所提升,变化幅度统一呈现随过火温度的升高先增大后减小的变化规律。当过火温度为700℃时,节点承载力降低最大,降低幅度约为20%;同时节点延性和耗能能力提升最多,增大幅度分别约为14%和13%。研究成果可为火灾后钢结构安全性鉴定提供参考。
Beam-column welded joints are widely used in the construction of steel structures, and the post-fire force performance is crucial to the safety of the entire structure after the disaster. The influence of high temperature overheating on the bearing capacity, ductility and energy dissipation capacity was studied by low-cycle repeated loading test after all the five welded joints were welded. Test over-temperature between 500 ~ 800 ℃, the cooling method for natural cooling. The test results show that all the specimens have the fracture damage of the butt flange weld. The flexural capacity of specimens after high temperature cooling is lower than that of specimens without overheating, and the ductility and energy dissipation capacity are improved. The variation range shows the variation that firstly increases and then decreases with the increase of overfire temperature. When the overfire temperature is 700 ℃, the bearing capacity of joints decreases the most, about 20%. At the same time, the ductility and energy dissipation of joints increase most, about 14% and 13% respectively. The research results can provide a reference for the safety evaluation of steel structure after fire.