Through the transient test on two welded hollow spherical joints subjected to compression under fire, the temperature distribution, displacement characteristics, failure mode and ultimate fire resistance time of the joint under different load ratios were obtained under standard fire. The three-dimensional finite element model of welded hollow spherical joints was established, and the performance of the joints subjected to compression under fire was analyzed. Compared with the test results, the correctness of finite element simulation analysis was verified. The results showed that during the heating process, the surface temperature of the sphere inside the steel pipe is the lowest. The surface temperature of the sphere is low at the intersection with the steel tube and is highest at the middle-latitude of the sphere. The surface temperature of sphere is lower than ISO-834 standard heating curve. Failure mode of axially compressed welded hollow spherical joints under fire is concave failure. Failure position is at the sphere connected with the steel pipe. Failure process is short. Fire resistance time of load-ratio 0.35 specimen is more than 20% longer than that of load-ratio 0.6 specimen. The critical temperature of the current fire protection code is smaller than the results of the finite element.

通过对两个焊接空心球型接头在火中受压的瞬态试验，得到了标准火力条件下不同载荷比下接头的温度分布，位移特性，破坏模式和极限耐火时间。建立了空心焊接球形接头的三维有限元模型，并分析了在火灾下受压接头的性能。与测试结果进行比较，验证了有限元模拟分析的正确性。结果表明，在加热过程中，钢管内部球体的表面温度最低。球的表面温度在与钢管的交点处较低，而在球的中纬度处最高。球的表面温度低于ISO-834标准加热曲线。着火条件下轴向压缩焊接空心球面接头的失效方式为凹形失效。失效位置在与钢管连接的球体上。失败过程很短。荷重比为0.35的试样的耐火时间比荷重比为0.6的试样的耐火时间长20％以上。当前防火规范的临界温度小于有限元的结果。