Ply angle effect on fiber composite wrapped reinforced concrete beam–column connections under combined axial and cyclic loads

This paper presents a numerical analysis to investigate the effect of ply angle on the improvement of shear capacity and ductility of beam–column connections strengthened with carbon fiber-reinforced polymer (CFRP) wraps under combined axial and cyclic loads. Three-dimensional nonlinear finite element models for the beam–column connections were developed and simulated with the Marc.Mentat™ 2001 finite element analysis (FEA) software. An experimental study on an FRP-wrapped beam–column connection, which was previously reported in the literature, was utilized to validate the accuracy of the proposed finite element models. The FEA study entailed profiling the behavior of three beam–column connections that were strengthened through the CFRP wrapping with various ply angle configurations. Analysis results indicated that four layers of wrapping placed successively at ±45° ply angles with respect to the horizontal axis is the most suitable upgrade scheme for improving shear capacity and ductility of beam–column connections under combined axial and cyclic loads.