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Structural system influence on the shear capacity of wide members without shear reinforcement

Abstract:

Most shear strength models used to estimate the shear capacity of wide reinforced concrete members without shear reinforcement do not consider the structural system or the support conditions. However, some experimental results indicate that members with predominant flexural action, such as cantilever beams, may benefit from higher bending moments at the support. These results suggest that the structural system or the support conditions can influence the shear strength. In this paper, we investigate the structural system influence on the shear strength of wide members. For this purpose, we review the available test results that varied the structural system, and we compared the accuracy and precision level of shear strength models from the literature according to the structural system of the members. In the analyses, we observed that the ratio of tested to pbkp_redicted shear capacity is 5 - 10 % smaller for cantilever members than for simply supported beams. On the other hand, the ratio of tested to pbkp_redicted shear capacity is 10-20% larger in continuous members than in simply supported ones. Although these results may indicate some influence of the structural system in the shear behavior, in this study, we did not identify physical reasons to validate this hypothesis. In this way, this tendency of results could be addressed to some bias in the database. However, we verified that the correlation between the shear capacities of wide members could be better correlated with the shear slenderness by taking into account that the behavior of some continuous members under uniformly distributed loads is similar to the simply supported ones with a reduced span length.