Predicting Uniaxial Cyclic Compressive Behavior of Brick Masonry: New Analytical Model

A constitutive model for simulating the compressive response of unreinforced brick masonry subjected to cyclic loading is presented and discussed. The developed formulations are consistent with the smeared rotating crack approach and may be easily implemented in finite element codes for nonlinear analysis. The analysis approach includes different features such as nonlinear curves for capturing the shape of the unloading/reloading branches, both in case of full unloading from the envelope curve and partial unloading/reloading. A unified model for predicting the residual plastic strain as a function of the strain recovered during unloading is also proposed. Particular attention is paid to the stiffness degradation occurring during reloading and to the prediction of the stress and strain values at which the reloading branch intersects the envelope. The calibration of most of the proposed formulations is based on experimental results reported in the literature, as well as from two uniaxial cyclic compression tests carried out within the present work. Finally, the model effectiveness is tested with some verification examples.