Evaluation of shear strength in RC beams from experimental database and design codes

The shear behaviour of reinforced concrete (RC) structures has been extensively studied, yet a unified understanding of failure mechanisms and a universally accepted shear strength model remain elusive. Several design codes propose different empirical equations for shear strength prediction, necessitating a critical evaluation of their accuracy against experimental databases. Therefore, the current study addresses key gaps in shear strength prediction for RC beams through a comprehensive parametric analysis of 960 experimentally tested beams reported in the literature, examining the influence of governing parameters on the accuracy of empirical models adopted in major international design codes. In addition, the predictions of nine design codes were validated against 16 tested beams grouped by shear span-to-depth ratio (a/d) to systematically assess the effect of a/d on predictive accuracy. The study identified beam depth and width as the most influential parameters and, among the evaluated models, the Australian and Hong Kong codes consistently provided the most accurate and reliable predictions across different beam geometries and a/d ratios; however, ACI (American Concrete Institute) and British standards tend to be overly conservative. Experimental and parametric analyses further confirm the significant influence of the a/d ratio on failure modes, highlighting the need to refine existing code design equations.