Ductility and Cracking of Slabs As Part of Continuous Composite Beams in Regions with Hogging Bending Moments

In order to investigate the influence of reinforcement on the development of cracks and the behaviour of composite slabs as part of composite beams in hogging bending areas, experimental investigations and parameter studies by calculation have been carried out at the University of Kaiserslautem. These studies are described in (1, 2, 3, 4). In this paper the main results of the studies are described. The results in details show. 1) The development of cracking in slabs as part of composite beams is decisively influenced by the transverse reinforcement. Proposals to determine the minimum reinforcement with reference to the service load and to calculate the crack width in dependance on the transverse reinforcement must be determined. 2) The experimental investigations with composite beams showed, that in view of the load-bearing capacity different kinds of minimum reinforcement exist: one to reach the plastic moment and one to make the application of the plastic hinge theory possible. Conditions for composite beams to reach both kinds of minimum reinforcement are determined.