Fracture-Based Method to Determine Flexural Capacity of Concrete Beams on Soil

A method to predict the fracture response of concrete beams utilizing cohesive crack elements was expanded from a three-point bending beam to a beam on soil boundary condition. The simulations were compared with monotonic three-point bending beam and beam on soil tests, verifying the cohesive elements with a bilinear softening curve defined by the concrete's fracture and tensile strength properties can effectively predict the flexural capacity and post-peak behavior of both specimen configurations. Vertical and horizontal springs idealized the soil support to the beams. Whether the springs were linear or nonlinear elastic had a limited effect on the peak load capacity of the concrete beams on soil. At pre-peak and peak load levels, the two concrete beam configurations had similar stress patterns and crack propagation levels in spite of the different boundary conditions. The method simplicity and accuracy under different boundary conditions offers a promising approach that can be extended to predicting the flexural capacity of concrete slabs.