Simplified and Advanced Analysis of Membrane Action of Concrete Slabs

This paper presents a comparison between a simple analytical approach based on rigid-plastic behavior with a change of geometry, an advanced finite element model (FEM), and 14 tests on horizontally-unrestrained concrete slabs that reached vertical displacements up to 10 times the effective depth of the slab. Both analytical approaches predicted the membrane behavior of the slabs, comprising compressive membrane action around the slab's perimeter and tensile membrane action in the central span region of the slab. The simple approach produced good predictions of the load-displacement response toward the end of the test, whereas the FEM produced reasonable predictions over the full. history of the test. By considering the magnitude and pattern of the stresses within the FEM, the assuniptions adopted within the simple approach were investigated and are discussed. Overall, the comparison of the simple approach against the FEM and test results shows that it can safely be used for predicting the load-carrying capacity, due to membrane action, of concrete slabs under large displacements.