In this paper,a multi-scale approach is presented to model important characteristics of the behavior of reinforced concrete structural frame elements: appearance of permanent deformations, loss of stiffness and strain softening. The formulation developed is consistent with thermodynamical and variational principles. Three scales are defined: i) the structure corresponds to the macroscale, ii) the materials (concrete and steel) are separated at the mesoscale, and iii) the heterogeneity of concrete is considered at the so-called microscale. The finite el- ements method is employed at both macroscale and mesoscale. To reach an equilibrium state along the load-deformation path, a computational strategy is elaborated to impose strong coupling among the interacting modelling scales. The displacement field at mesoscale is enhanced to integrate information coming from the microscale.