In this paper, the stress concentration factors (SCFs) in tubular T/Y-connections strengthened with fiber reinforced polymer (FRP) under OPB are investigated. For this aim, 263 FE models of T/Y-joints with FRP were generated and analyzed. In the FE models, the contact between the FRP sheets and the members was modeled. By using the generated FE models, the effect of the FRP layers, the brace inclination angle, and the joint geometry on the SCF ratios of the reinforced to the corresponding un-reinforced joints were investigated. Results showed that the SCF of an FRP strengthened joint can be down to 29% of the SCF of the associated un-strengthened joint. Moreover, the increase of the FRP layer number results in a considerable decrease of the SCFs. Also, this phenomenon is more significant in the joints with larger γ. Moreover, the increase of the elastic modulus of FRP along the fibers results in the remarkable decrease of the SCF ratios. Finally, the FE results were used to propose a design equation for determining the SCFs in T/Y-joints reinforced with different FRP materials under OPB load.

在本文中，研究了在OPB下用纤维增强聚合物（FRP）增强的管状T / Y连接中的应力集中因子（SCF）。为此，生成并分析了263个带有FRP的T / Y接头的有限元模型。在有限元模型中，对FRP板材与构件之间的接触进行了建模。通过使用生成的有限元模型，研究了FRP层，撑杆倾斜角度和接头几何形状对钢筋与相应的非钢筋接头的SCF比的影响。结果表明，FRP加固接头的SCF可以降低到相关未加固接头的SCF的29％。此外，FRP层数的增加导致SCF的显着减少。同样，这种现象在具有较大γ的接头中更为明显。而且，FRP沿纤维的弹性模量的增加导致SCF比的显着降低。最后，有限元结果被用来提出一个设计方程，以确定在OPB载荷下不同FRP材料加固的T / Y接头中的SCF。