This paper presents the development of a three-dimensional finite element model of composite beams by using ABAQUS, commercially available finite element modelling and analysis software. The developed model can predict the behaviour of long-span continuous beams subjected to combined gravity and fire loading effects. Temperature-dependent material properties such as stress-strain, conductivity, thermal expansion, and specific heat are adopted from Eurocode. The model was benchmarked with experimental data from the literature. A parametric study has been conducted by altering the quantity of continuity bar in the beam and analysed the change in the behaviour of the beam. It was observed that the amount of continuity rebar has a significant influence in failure time of composite beams. © 2020, Springer Nature Singapore Pte Ltd.