Assessment of punching shear capacity of reinforced concrete flat slabs with openings based on selected theoretical studies

Abstract

Reinforced concrete (RC) flat slabs are widely used in modern construction due to their architectural flexibility and construction efficiency. However, the presence of openings near columns can significantly reduce punching shear capacity and increase the risk of brittle failure. This study evaluates the predictive accuracy of existing methods by comparing seven international design codes (ACI 318-19, Eurocode 2, BS 8110-1997, TS500, ECP 203-2018, NBR 6118, and JSCE) with one analytical model, namely Model Code 2010 (MC2010) and three empirical models developed by Teng, El-Shafiey, and Köroğlu. The calculated results are validated against two independent experimental datasets reported by Anil et al. and El-Shafiey et al. The results reveal significant inconsistencies among the methods. For the Anil dataset, the Vexp/Vcal ratio ranges from 0.57 to 1.09 and is predominantly below 1.0, indicating a tendency toward unconservative predictions. In contrast, for the El-Shafiey dataset, the ratio varies between 0.93 and 1.26, reflecting a more conservative trend. Notably, the mean deviation reaches up to 88.33% for MC2010 (LoA-II), highlighting the limitations of current approaches. These findings indicate that the conventional critical perimeter reduction approach fails to fully capture the combined effects of opening location, size, and shape on stress distribution and load transfer mechanisms. Therefore, there is a clear need to develop new predictive models with a stronger mechanical basis that explicitly incorporate the geometric characteristics of openings.