Quantifying Arch Action in Intermediate Shear Span RC Beams: A Coefficient-Based Approach for Shear Strength Prediction

Accurately predicting the ultimate shear strength of RC beams, especially those with intermediate shear spans, presents a significant challenge. This complexity arises from the intricate interplay of flexural and shear behaviors within these structures. Although extensively researched, the contribution of arch action to the shear strength of these beams has frequently been underestimated. This study reexamines and quantifies the shear force contribution from arch action in intermediate reinforced concrete beams by introducing the arch action coefficient, α. This coefficient is determined using two analytical approaches: the compatibility method and the differential method. Both methods are subsequently validated through experimental testing on reinforced concrete beams. To simplify the calculation of ultimate shear strength, α charts are developed through finite-element analysis, incorporating the influences of yield strength, stirrup ratio, longitudinal reinforcement ratio, and span-to-depth ratio on α. Furthermore, theoretical models have been developed to consider the combined contributions of concrete and stirrup in beam action calculations. Generally, comparisons between these combined theoretical predictions (for beam action) and numerical simulations (for arch action) against experimental results show strong agreement.