Toward combined local-average stress field modeling of reinforced concrete

• Local mechanisms are investigated in determination of total response of RC members.
• A slip–strain relation is proposed to determine the strain distribution on rebar.
• A post-process procedure is proposed to locally enhance the smeared crack approach.
• Averaged smeared models are improved in the presence of local mechanisms.
• Nonlinear finite element program (ESMARC) is developed for analysis of RC members.

Local mechanisms in RC domain are highly related to cracking initiation/propagation and reinforcement arrangement. These mechanisms and their significant role in the determination of average constitutive models are investigated in this paper. Developing a FORTRAN-based nonlinear finite element program, effects of changing local mechanisms’ state during loading procedure are introduced into average tension-softening/stiffening behavior of concrete and average yield strength of steel bar. Adopting a “post-process” procedure, a combined local-average finite element modeling of RC members is conceivable. Accordingly, adequate displacement values are detected at the crack plane and accurate displacement-based constitutive models are applied instead of simplified strain-based ones.