Study of composite steel frame with reinforced-concrete infill

This paper describes the development of a three-dimensional, non-linear finite-element model for evaluating the response of composite structural systems consisting of steel frames with reinforced-concrete infill walls subjected to a combination of gravity and in-plane lateral loading. Several sensitivity studies, taking into account both material characteristics and geometrical non-linearities were performed in order to investigate parameters such as the shear retention factors, Coulomb's coefficient for steel–concrete contacts and different load–slip relationships for modelling the shear behaviour of headed studs. Appropriate experimental data sourced from the literature were utilised to verify the proposed numerical model. A series of parametric studies was conducted to explore the effect of transverse and longitudinal confinement reinforcement, reinforcing bar diameter and steel strength. In order to investigate the composite interaction effect, several numerical models were developed, with emphasis on the configuration of shear connectors along the interface between the steel members and the reinforced-concrete infills. The analysis results demonstrated that the developed finite-element model captured and predicted the force–drift response of the system and revealed that the presence of shear connectors had a critical effect on the overall behaviour of the system.