Lattice Discrete Particle Modeling of Reinforced Concrete Flexural Behavior

Modern structural design relies heavily on accurate numerical simulations of materials and structures. For concrete and RC, however, available computational models, although successful for many applications, fail to a large extent to correctly capture complex failure mechanisms. This is the case, for example, for failures occurring in regions in which the assumptions of classical structural theories do not apply and for situations characterized by extensive fracture and size effect. To overcome this issue, this paper investigates the use of a discrete mesoscale model, the so-called lattice discrete particle model (LDPM), for simulation of the flexural behavior of RC structural elements. LDPM captures naturally complex fracture phenomena in a variety of loading conditions because it simulates material heterogeneity. This is obtained by replacing the actual concrete internal structure with a system of polyhedral cells interacting through nonlinear and fracturing lattice struts. The results presented in this paper show that LDPM can be used to predict with great accuracy the ultimate flexural behavior of RC beams with a wide range of main and secondary reinforcements. LDPM predicts very well the transition from ductile to brittle behavior for increasing reinforcement ratios in slender and stocky beams, and, most importantly, predicts the quasi-brittle characteristics of failure and the associated size effect.