本文报道了九个支管三通和两个普通管的试验结果。模型暴露于单独的载荷:内部压力和外部耦合及其组合。施加的载荷远远超出了弹性极限，并讨论了模型的弹塑性响应。确定了各模型的试验极限或屈服点荷载，并绘制了相互作用曲线。对于单个载荷，面外耦合是关键情况。然而，内部压力的存在增加了外部耦合的阻力。归一化极限偶（平面外或平面内）随直径比的增大而减小。所有模型均显示出超出实验确定的极限荷载的相当大的储备能力。

Experimental results of nine branch-pipe tee connections and two plain pipes are reported. The models were exposed to individual loadings: internal pressure and external couples and their combination. The loads were applied well beyond the elastic limit, and the elasto-plastic response of the models are discussed. Experimental limit or yield-point load of each model is determined, and the interaction curves are plotted. For the individual loadings, the out-of-plane couple is the critical case. However, presence of the internal pressure increases the resistance to the external couple. Normalized limit couple (out-of-plane or in-plane) decreases with the increase of diameter ratio. All models showed considerable reserve capacity beyond the experimentally determined limit loads.