Constitutive model for biaxial cyclic loading of concrete

An incremental type of stress-strain relationship is proposed for simulating the hysteretic response of concrete, subjected to biaxial cyclic loading. The behavior of concrete is represented by an infinite number of Theological elastic-plastic type of elements connected in parallel. The strain at elastic limit and maximum plastic strain values of each element are assumed to be stochastically distributed. It is possible to simulate with sufficient accuracy, the strain softening, the path dependency and the hysteretic response using this model. The model is computationally efficient and the relatively few parameters needed can be calibrated from the monotonic, uniaxial response and from the biaxial failure envelope. Shear stresses and rotation of loading axes cannot yet be handled with this model.