Numerical investigation on the behaviour of socket connections in GFRP-reinforced precast concrete

Precast socket connections involve connecting precast columns and beams through prefabricated pockets. This method is widely used in the precast concrete industry due to its ability to accelerate construction and provide strong connections. To enhance their benefits and ensure durability in harsh environments, noncorrodible Glass Fibre Reinforced Polymers (GFRP) reinforcement is commonly employed as an effective reinforcement solution. The current numerical study investigates the performance of GFRP precast socket connections using epoxy resin for assembly. Finite element models were developed and verified against the experimental results of three specimens. The numerical model was then employed to investigate the influence of several key parameters influencing the behaviour of precast GFRP socket connections. It was found that the performance of the connection depends on the socket depth, concrete depth under the socket, size of the beam, and socket-filling material. Additionally, the stiffness and capacity of the connection were found to be strongly affected by the column reinforcement ratio. The study reveals that the maximum capacity of the connection can be achieved using a socket depth equal to 1.4 times the thickness of the column. Moreover, the socket region should be properly confined by concrete of thickness at least 0.8 of the column thickness at the overhanging side of the beam and 0.5 times the column width in the transverse direction as well as the bottom of the socket, to ensure the development of the full capacity at the connection. Although epoxy resin has many advantages, including nonshrinkage, high workability, and high strength, it was found that replacing the epoxy resin with ultra-highperformance concrete improves the connection performance, and hence the required depth of the socket can be reduced. The results of this study can be used to safely work out the minimum size and detailing of the GFRPRC socket connections using epoxy resin for assembly.