高温后正面角焊缝抗拉剪切强度的试验

Experiment on tensile and shear strength of front fillet welded joint post-high-temperatures

为了研究高温后正面角焊缝抗拉剪切强度变化规律,对双盖板角焊缝试件加热至不同高温,再采用自然冷却和喷水冷却两种方式冷却到常温,然后进行拉伸试验.试验表明,经历高温不超过500℃的试件冷却后破坏方式为中间钢板母材拉断.经历高温超过500℃后冷却的试件都在角焊缝焊喉处脆性断裂;经高温冷却后正面角焊缝抗拉剪切强度受所经历最高温度值、冷却方式影响较大,900℃以内最大降低10%.根据试验结果,建立了高温后正面角焊缝抗拉剪切强度计算公式.结果可供火灾后钢结构损伤评估和加固分析时参考.

In order to investigate the characteristics of tensile and shear strength of front fillet welded joint post-high-temperatures,the tension tests for double strapped front fillet welded joint were conducted after cooling down from different high temperatures.The tests indicate that specimens are fractured at the middle of steel plate as the maximum temperature undergone below 500 ℃ and brittle fractured at the throat of fillet weld as the maximum temperatures undergone above 500 ℃.The maximum temperature undergone and the cooling pattern are major factors influencing tensile and shear strength of front fillet welded joint post-high-temperatures.Based on the experimental results,this paper proposes the calculation formulas of tensile and shear strength of front fillet welded joint post-high-temperatures.The conclusions supply references for evaluation damage and reinforcement of steel structure post fire.