Moment-shear-axial force interaction in composite beams

Composite steel-concrete beams are frequently used in situations where axial forces are introduced. Some examples include the use in cable-stayed bridges or inclined members in stadia and bridge approach spans. In these situations, the beam may be subjected to any combination of flexure, shear and axial loads. However, modern steel and composite construction codes currently do not address the effects of these combined actions. This study presents an analysis of composite beams subjected to combined loading. A finite element model (FEM) has been developed and the results derived from the model show excellent agreement with existing FEM and experimental results. The effect of compression and tension loads on a member subjected to flexure and shear is also explored. Design models are proposed for estimating the flexure and shear interaction of an axially loaded member.