Evaluation of continuum modelling approaches for reinforced concrete in geotechnical applications

Modelling the structural response of reinforced concrete (RC) elements in geotechnical applications has been implemented using various numerical approaches with different levels of confidence; ranging from simple linear elastic approximations to non-linear section behaviour using embedded beams with moment-curvature (M-κ) relationships within dummy elements. However, the non-linear structural response of continuum RC approaches has not been widely employed in the geotechnical analysis of soil-structure interaction problems. This paper evaluates and compares different combinations of modelling approaches for the concrete and reinforcement, as implemented within the FE code PLAXIS 2D, to simulate the structural response of RC beams using the continuum approach for the concrete with discretely modelled reinforcement. The Concrete Model ‘CM’ and an equivalent Mohr-Coulomb ‘MC’ approach are compared for the concrete alongside the use of either embedded plates (with interfaces) or embedded beam rows to efficiently simulate the reinforcement. These approaches are validated against well-documented experimental data of singly and doubly reinforced concrete beams obtained from the literature. The results can be utilised to improve structural precision in Finite Element models in various soil-structure interaction problems (e.g., piles, shallow foundations, retaining walls, tunnel linings) within an integrated geotechnical environment.