Parametric study of curved in plan composite steel-concrete beams

There are situations in which a composite steel-concrete beam is subjected to torsion, such as members that are curved in plan or straight edge beams. The concrete slab and steel beam contribute to the torsional strength and stiffness of a composite steel-concrete beam, but this composite action is usually ignored in design codes of practice, which leads to conservative designs or in some cases premature failure. Therefore, this paper provides a 3-Dimensional (3-D) finite element model of the curved in plan steel-concrete composite beams. This model has been validated with previous experimental tests from Tan and Uy (2009). It was used to simulate the structural behaviour and study the characteristic properties of the curved in plan composite steel-concrete beams subjected to combined torsion and flexure. Parametric studies were also carried out with several composite steel-concrete beams' variation such as the size of steel beam, the length of the composite steel-concrete beam, stud spacing, and different horizontal curvatures. From the parametric studies, the structural behaviour of the curved in plan composite steel-concrete beams has been plotted. From the flexure-torsion interaction relationship diagrams, the structural strength of the curved in plan composite steel-concrete beams actually weaken as higher horizontal curvature was introduced. Additionally, there was an increase in their torsional moment capacities for the curved in plan composite steel-concrete beams in the presence of flexure. This rate of increase in torsional moment capacity increased with the increase in span length. This increase was resulted from the increase in the compressive stresses induced to the concrete slab. Nevertheless, there was a limit to which the rate could increase due to the dimension limitation of the concrete slab, the span length of the composite steel-concrete beams and premature failure of the steel beams. Partial shear connection has also proven to be beneficial compared to full shear connection in this paper.