Finite Element Modelling of Pultruded FRP Beam-to-Column Joints

This study presents a finite element investigation of bolted beam-to-column connections in pultruded fibre-reinforced polymer (FRP) profiles using FRP cleats and steel bolts. Numerical simulations were performed in ABAQUS under monotonic and cyclic loading to evaluate moment–rotation behaviour, initial stiffness, and delamination initiation at the fillet radius of FRP cleats. Progressive damage modelling was implemented using Hashin’s failure criterion with fracture energies derived from standard ASTM tests. The model was validated against experimental results, demonstrating close agreement in stiffness, moment resistance, and failure modes. A subsequent parametric study examined the influence of cleat dimensions, bolt size, and bolt-hole clearance. The findings show that while moment resistance remains largely unaffected by these parameters, joint stiffness is sensitive to cleat geometry and bolt characteristics. The validated numerical framework provides a reliable tool for predicting the behaviour of FRP joints, reducing reliance on costly experimental testing, and supporting the design of practical FRP structures.