Mander et al. nonlinear concrete model - con_ma

This is a uniaxial nonlinear constant confinement model, initially programmed by Madas [1993], that follows the constitutive relationship proposed by Mander et al. [1988] and the cyclic rules proposed by Martinez-Rueda and Elnashai [1997]. The confinement effects provided by the lateral transverse reinforcement are incorporated through the rules proposed by Mander et al. [1988] whereby constant confining pressure is assumed throughout the entire stress-strain range.

Users have to assign the mean value of concrete strength and the mean value minus the standard deviation or the characteristic value in order to describe the mechanical characteristics of the existing or the new material respectively.

Note: The confinement factor employed by this material type is a constant confinement factor. It is defined as the ratio between the confined and unconfined compressive stress of the concrete, and used to scale up the stress-strain relationship throughout the entire strain range. Although it may be computed through the use of any confinement model available in the literature [e.g. Ahmad and Shah, 1982; Sheikh and Uzumeri, 1982; Eurocode 8, 2004; Penelis and Kappos, 1997], the Mander et al. [1989] is used by the program. Its value usually fluctuates between the values of 1.0 and 2.0 for reinforced concrete.