Atefeh Jahanmohammadi - phd Candidate, Structural Engineering, Tarbiat Modares University
Masoud Soltani Mohammadi - Associate professor, Earthquake Engineering, Tarbiat Modares University

Average stress field concept, mainly adopted in the common smeared crack approach, is enhanced by introducing the local stress field concept into the computational procedure. Defining a general slip- strain relation, the distribution of local strain along a reinforcing steel bar is determined. Compatible assumptions are adopted to define the displacement-strain correlation, so the local mechanisms,specifically related to the shear mechanism and its’ components, are investigated with much more accuracy in definition and modeling. Besides, with the aid of local and average stress equilibrium conditions, the average constitutive models are updated and the average response of a RC member is evaluated in the presence of local information. Introducing the main algorithm, the accuracy of the approach in the nonlinear analysis of RC members and its’ efficiency in problems with highly localized characteristics, is discussed.

Keywords: smeared crack, local stress field, slip-strain relation, nonlinear finite element