Theoretical prediction of the shear strength of reinforced concrete slabs under concentrated loads close to linear supports

Abstract

A mechanical model has been developed by the authors in order to predict the shear strength of reinforced concrete slabs under concentrated loads close to linear supports. Such situation takes place very often in bridge slabs and cantilever sections of bridge decks under concentrated heavy vehicle loads. The model takes into account a significant number of variables involved in the phenomenon, such as the clear shear span, the concrete compressive strength, the reinforcement ratio, the effective depth, the load spreading angle, the size effect and the size of the loaded area. It is applicable to simply supported slabs, cantilever slabs and situations with partial restraint to the rotation, such as intermediate supports. It has been validated with a database of 90 shear test in slabs subjected to a single concentrated load in different supporting conditions, yielding results on the safe side and showing low scatter. A parametric analysis of the model is also presented, detailing how the different involved variables affect the shear strength. These results, along with the simplified expressions developed for the shear strength calculation, provide a useful tool for the assessment of the shear strength of RC solid slabs in daily engineering.