Lattice discrete particle model for reinforced concrete structures: A novel geometrically consistent approach

The interaction between steel and concrete is critical in the performance of Reinforced Concrete (RC) structures. Yet, the complexity of bond-slip behavior and the heterogeneous nature of concrete creates challenges for accurately predicting fracture behavior, particularly in the simulation of failure patterns. In this context, novel modifications to the Lattice Discrete Particle Model (LDPM) are proposed herein for simulating RC structures, with a particular focus on the bond-slip behavior governing the rebar-concrete interactions. A new geometrically consistent strategy is proposed to materialize steel rebar in the simulations, enabling the realistic definition of bond elements within the LDPM framework. A bond stress-strain constitutive law and a compressive behavior model for bond elements within the LDPM framework are presented. Additionally, to realistically simulate radial stresses due to rib-induced dilation, the introduction of a local rotation angle is proposed. The derived LDPM framework is extensively validated through comparisons with experimental results from pull-out tests on unconfined and confined cylinders, as well as flexural bending tests on RC beams with lap splices. The approach is shown to accurately capture important mechanical behaviors in different types of RC elements, including load-displacement responses, cracking patterns, failure mechanisms, and bond-slip behavior at the steel-concrete interface. Further validation is shown for RC beams with varying reinforcement layouts under four-point bending loads, revealing that the proposed approach can be applicable to large-scale RC structures with varying reinforcement configurations. Lastly, a parametric analysis presents the effects of key influencing factors, including the particle distribution, local rotation angle, bond strength, and critical bond strain, on the overall nonlinear response of RC structures. • A Lattice Discrete Particle Model implementation for reinforced concrete structures. • Accurate predictions of the steel-rebar interaction are demonstrated. • Rebar-rib mechanical interlock is captured via introduction of a local rotation angle. • Extensive validation is presented by means of experimental data on independent tests.