PSI - Issue 44

Francesca Barbagallo et al. / Procedia Structural Integrity 44 (2023) 363–370 Francesca Barbagallo et al. / Structural Integrity Procedia 00 (2022) 000 – 000

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model, horizontal and vertical joint reinforcements are considered yielded. This modification leads to equations “apparently” equal to those of Fardis capacity model , but much simpler in application. Indeed, Fardis model requires the preliminary calculation of the stresses in steel reinforcements by means of a set of equilibrium and compatibility equations that have to be applied in sequence and iteratively. Instead, in the equations of the proposed model, the stresses of steel reinforcement are known a priori and equal to the steel yield strength, which allows the determination of the value  corresponding to the maximum shear resistance by means of a closed form relation and in turns the direct determination of this maximum shear resistance. The shear strength provided by the proposed capacity model is determined in the paper for a set of RC joints and compared to that obtained by the Fardis capacity model. The difference between the two obtained strengths is negligible (less than 1%) in most of the analyzed cases and never larger than 7%, which demonstrates the accuracy of the proposed capacity model. The closed form formulation of the capacity model allows the designer to equate shear demand to shear strength, thus obtaining equations that can be analytically solved to design the required horizontal and vertical joint reinforcements. References CEN European Standard EN1998-1:2005 Eurocode 8: Design of Structures for Earthquake Resistance. Comité Européen de Normalisation, Brussels, 2005. CEN European Standard EN1998-1-2:2020 Eurocode 8: Design of Structures for Earthquake Resistance – Part 1-2: Rules for new buildings. Comité Européen de Normalisation, Brussels, 2020. Hwang S.J, Lee H.J., 1999, Analytical Model for Predicting Shear Strengths of Exterior Reinforced Concrete Beam-Column Joints for Seismic Resistance. ACI Structural Journal, 96, 846-858. Hwang S.J, Lee H.J., 2000, Analytical Model for Predicting Shear Strengths of Interior Reinforced Concrete Beam-Column Joints for Seismic Resistance. ACI Structural Journal, 97, 35-44. Fardis M.N., 2021a, A level of approximation approach to seismic de-sign or assessment of beam-column joints in shear. Structural Concrete, 22, 1259-1284. https://doi.org/10.1002/suco.202000336 Fardis M.N., 2021b, Shear strength model RC joints, consistent with the shear design rules for prismatic members in the second-generation Eurocodes. Bulletin of Earthquake Engineering, 19, 889-917. https://doi.org/10.1007/s10518-020-01000-0.

Norme Tecniche per le Costruzioni, D.M. 14 gennaio 2008, G.U. 4/2/2008. Norme Tecniche per le Costruzioni, D.M. 17 gennaio 2018, G.U. 20/2/2018.