Shear Capacity of Doubly Skinned Composite Beams with Lacings

Abstract

The provision of shear stirrups/connectors is found to enhance the shear capacity of beams, thus preventing the brittle mode of failure. A doubly skinned composite system consists of steel cover plates on either side of infill material that are connected by means of shear connectors. Laced steel-concrete composite (LSCC) is a recently developed doubly skinned composite structural system, which is found to possess high ductility. In this paper, a model to predict the shear capacity of LSCC beams is proposed. Applicability of the model is verified through the experimental response. The performance of LSCC beams in terms of nominal failure shear stress is compared with that of laced reinforced concrete (LRC) beams and steel-concrete composite (SCC) beams with other forms of shear connectors such as through-through and J-hook connectors. Shear capacities of LSCC beams are found to be about 25% more than that of laced reinforced concrete (LRC) beams with a shear span to depth ratio of 2.0, while they are found to be equal to that of LRC beams with a shear span to depth ratio of 1.5. The predicted linear strains in lacing compare well with that measured in experiments.