Influence of width-to-effective depth ratio on shear strength of reinforced concrete elements without web reinforcement

It is well-known that the shear strength of reinforced concrete elements without web reinforcement is affected by different factors. Among them, tensile strength of concrete, longitudinal reinforcement ratio, shear span-depth ratio, size effect, axial force, and maximum aggregate size seem to be the most important. Concerning other parameters-for example, the width-to-effective depth ratio (b/d)-there is still disagreement within the research community about its possible influence on shear bearing capacity. In this context, the present research evaluates the influence of both the b/d and bar spacing-to-effective depth ratio (s/d) on the shear strength by means of an experimental program on 17 full-scale specimens characterized by b/d ranging from 0.5 to 3.5 and an s/d from 0.24 to 0.71. Results showed that, for b/d > 1, an increase in the b/d determines a non-negligible increment in the shear strength, whereas the s/d (in the considered range) does not affect the shear bearing capacity.