What can we do with multiscale modelling of reinforced concrete structures

In this paper, recent developments in application of multiscale modelling techniques to reinforced concrete structures are presented. More specifically, reinforced concrete Representative Volume Elements (RVEs) are upscaled to a few commonly used structural models such as a solid in plane stress, an Euler-Bernoulli beam, and a Kirchhoff-Love plate. At the large-scale, reinforced concrete is assumed to be a homogeneous material, while the subscale response comprises cracking of plain concrete, plasticity of reinforcement and bond-slip action in the steel/concrete interface. The upscaling procedure, based on computational homogenisation is later used in the multiscale scheme, more commonly known as the FE2 method, where the response at every structural integration point is obtained from the results of the RVE analyses. The application of the method is illustrated by modelling the response of a few different reinforced concrete structures such as a deep beam in four-point bending, beam in uniaxial tension and bending, and part of a slab subjected to membrane and bending loads. The results show that general structural behaviour in terms of load-deflection and moment-curvature relations can be well captured by the multiscale models. It is also possible to produce local results such as crack widths, making the developed two-scale models a potentially suitable tool for efficient analyses of large-scale reinforced concrete structures. Additionally, thanks to parallel computing, the developed multiscale models can potentially shorten the computational time in comparison to conventional single-scale analyses.