Inherent robustness of RC slabs and beams

The paper starts with a brief review of provisions in Eurocode 2 concerning minimum reinforcement. Next, two cases of inherent robustness of concrete structures are investigated i.e. membrane action in RC slabs and the effect of minimum reinforcement on the structural behaviour of continuous beams. Models for membrane action in rectangular RC slabs have been developed in the early 1960's and recently gained attention again in the framework of accidental loading situations. Both compressive membrane action (small displacement) and tensile membrane action (large displacements) are discussed. The effect of minimum secondary reinforcement in a two span RC beam when the central support is removed, was analysed through a full 3D FE analysis. Both compressive arching and tensile catenary action could be observed. When the central support was removed the beam was able to sustain the design load through catenary action