The aim of this research project is to enable a full numerical rigid-plastic approach to the analysis and design of solid concrete structures. This will be achieved by the establishment of a validated framework for finite element limit analysis of 3D concrete structures. The validation work includes advanced numerical studies and physical experiments on different scales. The expected scientific outcomes will be a theoretical basis for numerical analysis and design of 3D reinforced concrete structures; new knowledge on the mechanical behavior of reinforced concrete in the tri-axial stress states and valuable empirical insight into the behavior of solid structures through full scale testing. The scientific outcomes results in a number of specific deliverables, which potentially will have a broad impact on how design of solid concrete structures will take place in the future. The deliverables include a computer-based tool for more efficient and optimal design of solid concrete structures as well as research based design guidelines, such as provisions for minimum reinforcement and effective strength parameters when designing pile caps.