Design of RC solids using stress analysis

Modelling of structures using linear-elastic 3D solid modelling is well established and can be used to considerable advantage in the design of reinforced concrete structures. It is not intuitive, however, on how to dimension the reinforcing steel in 3D solids to meet the stress demands of the applied tractions obtained from a linear FE analysis. One method is to place adequate reinforcing steel in the direction of any principal tension stress and to ensure that the concrete has sufficient strength to meet all principal compressive stress demands. However, placing reinforcement in principal directions is not always convenient and placement in the local structural or global directions is preferred. The question is then how to dimension reinforcement for any set of orthogonal axes for the 6 components of any applied stress tensor that defines the stresses at a point. The answer to this question is presented in this paper.