Accuracy of building code formulations in predicting shear strength of exterior RC beam-column joints

This study evaluates the accuracy of current building code and literature-based formulations for predicting shear strength in exterior reinforced concrete (RC) beam column joints and proposes a simplified empirical model. Through analysis of experimental results from the literature, four predictive models are assessed: the joint shear strength model proposed by Fardis (2021), which was adopted in a superseded draft of the second-generation Eurocode 8, EN-1998-1-2004, NZS 3101 1:2006, and ACI 352 R 02. The study includes correlation analysis of key parameters affecting shear strength, including concrete compressive strength, joint geometry, axial load, and joint shear reinforcement ratios. Results indicate that the Fardis (2021) model provides good accuracy with a slight underestimation of experimental joint shear strength. ACI 352 R 02 demonstrates the highest consistency and lowest coefficient of variation in its predictions. EN-1998-1-2004 shows moderate predictive capability, while NZS 3101 1:2006 exhibits the highest variability and least consistency. Based on these findings, a new simplified empirical formulation is proposed that incorporates the parameters identified as most influential. The new model, validated through Monte Carlo cross validation, demonstrates the best prediction capability across the analysed dataset.