Considerable work has been undertaken over the past 20, or so, years on non-linear modelling of reinforced cocrete membranes with incremental progression towards a fully rational model using a smeard crack approach. Investigators have adopted either a fixed crack or rotating formulation, each with advantages and disadvantages. If a fixed crack approach is adopted then something needs to be known about the shear stiffness of the concrete after cracking as principal stress and principal strain directions need not be coincident. This has typically required the introduction of a shear retention factor, empirically set such that the FE model is calibrated against data from large scale model tests.
