受压加肋焊接空心球节点抗火试验研究

为研究火灾下受压加肋焊接空心球节点的性能，对2个足尺节点进行受火试验。通过试验得到了加肋焊接空心球节点在标准火灾下的节点表面温度场、不同荷载下节点的耐火时间、破坏形式以及位移特征。根据欧洲规范，建立了三维加肋焊接空心球节点的有限元模型，分析了火灾下节点温度发展规律及位移特征。有限元分析结果与试验结果的对比验证了有限元分析的正确性。研究结果表明：升温过程中，加肋焊接空心球节点中远离加劲肋处的球壳温度最高，靠近加劲肋以及钢管连接处的球壳温度较低；火灾下受压加肋焊接空心球节点的破坏具有突然性，破坏发生在钢管与球节点的连接处；荷载比大的球节点耐火时间短。

Experimental study on stiffened welded hollow spherical joints subjected to compression and fire

In order to study the performance of the stiffened welded hollow spherical joints subjected to compression under fire, tests were conducted on two full-scale specimens. The temperature field of hollow sphere, the ultimate fire resistant duration under different load ratios, failure mode and the displacement characteristics of the joint were obtained. According to the Eurocode, a three-dimensional finite element model of stiffened welded hollow spherical joint was established, and the temperature development and displacement characteristics of the joints were analyzed. The finite element analysis result was compared with the test result to verify the accuracy of finite element analysis. The results show that during the heating process, the highest temperature appears at the hollow sphere where is away from the stiffener. The temperature of hollow sphere near the stiffener and the connection between the sphere and the steel pipe is lower. The failure of the stiffened welded hollow spherical joints under fire and pressure is sudden. The damage occurs at the junction of the steel pipe and the joint. The fire resistant duration of the joint with large load ratio is shorter.