Shear resistance of reinforced concrete elements according to Model Code 2020

Abstract

1. Evolution of methods for determining shear resistance in reinforced concrete structural elements led to the approach proposed in the new Model Code 2020. It is based on the strut-and-tie model and allows for verification on three levels of approximation. In this paper, the new approach is presented and illustrated for three levels of approximation, I, IIa, and IIb, and then compared with Eurocode 2. For the calculation of the design shear resistance according to Eurocode 2, the inclination of the concrete compression strut was assumed to be the same as for Model Code 2020. The prediction of shear resistance was studied on a rectangular cross-section, assuming two concrete classes and two types of vertical stirrups with varying spacing. To facilitate the interpretation of the results, they were scaled using coefficients and plotted. The most severe criteria for the support zone are obtained using Eurocode 2 and Model Code 2020, level of approximation I. The detailed analysis using Model Code 2020 level of approximation IIb leads to the smallest amount of the shear reinforcement, because it accounts for the participation of concrete in the design shear resistance. More advanced design approaches yield economic benefits but require more expensive designs.