Experimental evaluation of effective width in steel-concrete composite beams

The paper deals with the evaluation of effective width for elastic and plastic analysis of steel–concrete composite beams. The study is performed through experimental tests performed at the University of Trieste on four specimens. Both cases of sagging and hogging bending moments are investigated, as well as the influence of the beam-to-column joint. It is shown that for all specimens the effective width increases with the load, approaching the width of the whole slab near the collapse. The presence of a beam-to-column joint does not affect this result. The comparison with the Eurocode 4 formulation demonstrates that such approach is adequate for elastic analyses, whereas it may be too restrictive for plastic analyses. A simple modification of the Eurocode 4 proposal is therefore presented for collapse analyses of composite beams under hogging bending moment.