Numerical study of the shear performance of pultruded square glass fibre reinforced polymer connectors in composite prefabricated concrete sandwich panels

Shear resistance of the glass fibre reinforced polymer (GFRP) connectors is critical for the design of composite prefabricated concrete sandwich panels (PCSP). This study investigates the shear performance of recently proposed pultruded square GFRP tubular shear connectors in composite PCSP using finite element (FE) modelling. At first, the FE model was established and validated against experimental results in terms of connectors’ shear force vs. slip responses, peak shear force, stiffness and failure modes. With the validated FE model, parametric studies were carried out to examine key parameters affecting the shear performance of connectors. The results revealed that increasing longitudinal tensile strength and shear strength of the GFRP enhances the connectors’ shear force resistance, with a more pronounced effect in +45°/-45° fibre orientation than in 0°/90°. Furthermore, the connectors’ stiffness increases significantly with higher GFRP shear modulus and by orienting the fibres at +45°/-45°. The variation in the design of shear test specimen was also found to have a small impact on the connectors’ resistance, suggesting a need for establishing a standard double shear test method. Increasing the insulation thickness reduced the shear force resistance and stiffness of the connectors, but connectors in tension could resist greater shear force than the straight connectors. Moreover, larger and thicker connectors exhibited improved shear resistance regardless of insulation thickness. The empirical equations in predicting shear strength and stiffness of the connectors were derived from regression analysis and showed reasonable accuracy with an R 2 coefficient between 0.95 and 1.00, enabling their application in the design and optimisation of composite PCSPs. • Shear performance of newly proposed connectors is investigated using FEA. • Influence of GFRP mechanical properties on shear connector performance is examined. • Fibre orientation is shown to have a strong influence on connector shear performance. • Design variations in shear test specimens are found to greatly affect connector shear resistance. • Empirical equations are proposed to predict their shear strength and stiffness.