Design of simply-supported and continuous beams in steel-concrete composite construction

Abstract

This chapter provides an overview of the design of simply-supported and continuous beams in steel-concrete composite construction in Australia. Current Australian practice supports composite beams with web-side-plate connections, which are assumed to behave as nominally pinned joints. If the connections do behave as pins, the resulting high end rotations can cause unacceptable cracking of the concrete surface and there are a number of composite carparks in Australia that are excessively cracked due to inadequate reinforcement over the connection. Continuous composite beams offer better crack control and lower deflections, even when the depth of the steel section is less than that required for the equivalent simply-supported beam. Continuity in a composite beam may be achieved either with internal supports, or by the use of suitable connections within a frame. Continuous beams provide the designer with greater scope to vary design parameters, such as positive moment shear connection and negative moment reinforcement levels, to find the optimum solution for each situation. A rigorous cost-benefit analysis may show that continuous and semicontinuous composite beams should be the preferred construction option.