Optimum Reinforcement Design in Concrete Membrane Elements

During the last three decades many design criteria have been proposed to evaluate the ultimate bearing capacity of reinforced concrete membrane elements. Some of these theories allow for the design of reinforcement once a linear elastic analysis is performed. The approach suggested by the new Model Code 2010 and based on the research developed by the authors at the beginning of 2000, leads to the calculation of the required reinforcement and to the verification of concrete stresses once the compression field direction at ultimate limit state is known. The optimum reinforcement can be determined in accordance to this approach finding the compression field direction by solving a nonlinear equation. Following the Model Code approach, the interaction surfaces for the design of membrane elements are presented in this paper.