Fracture Modeling of Concrete and Steel

Abstract

A new relationship between the fracture energy of concrete, the tensile strength, and the ultimate crack width has been developed by considering the postcracking strength or softening of concrete. Linear, power, and exponential mathematical models were used to describe the descending branch of the stress-strain diagram. A nonlinear finite-element model was developed, using smeared cracks for a layered model approach. This facilitated the representation of the reinforced concrete and composite (steel and concrete) members that were analyzed to verify the modeling of the materials and a range of structures. The predictions of the load-deflection behavior of a reinforced concrete slab and a continuous composite beam in the elastic and inelastic range incorporated the fracture energy model, and the correlation between the theoretical and experimental results was very good. In a final evaluation, the fracture criteria of concrete and metals have been compared, and excellent correlation has been established between the inelastic behavior of the two very different materials.