An accurate and reliable three dimensional finite element model has been developed to investigate the behaviour of simply supported steel–concrete composite beams with HSFGB shear connectors. The commercial finite element software ABAQUS was used for the modelling, and which required strategies to be implemented in the study. The structural components of the composite beam and their interactions were fully simulated, with the material non-linearity of the concrete slab, steel beam and HSFGB shear connector and the corresponding failure criteria being taken into consideration. The quasi-static finite element analysis using the dynamic explicit procedure was adopted for the analysis. The results obtained from the finite element analyses were verified against available test results. It was shown that the developed finite element model was capable of capturing the fundamental behaviour of the composite beam accurately.
Invoking the validated model, the typical mechanical behaviour of a composite beam with HSFGB shear connectors was able to be elucidated. The composite beam was shown to exhibit benign structural performance in terms of stiffness, ultimate strength and ductility under either uniformly distributed or concentrated loading. Five characteristic points on the full range load–defection curve can be defined. Parametric studies of composite beams with different bolt spacing, diameter of their pre-fabricated hole, bolt post-tension and spacing of longitudinal reinforcement were performed using the finite element model. The reduction in the bolt spacing (so increasing the number of bolts in the shear span) leads to an increase in the ultimate strength of the composite beam. A composite beam with low degree of shear connection still achieves a much higher ultimate strength than its non-composite counterpart, with considerable ductility arising from the high shear resistance and slip capacity of the HSFGB shear connectors. By maintaining a constant bolt size, increasing the diameter of the pre-fabricated hole causes a decrease in the stiffness and ultimate load of the beam, particularly for the beam with an oversized hole. Locating the shear connectors near the support is an effective approach to improve the performance of composite beams with such oversized holes.