Failure Analysis of Initially Cracked Concrete Structures

Abstract

Fracture mechanics is very often employed in analyses of cracked structural components. We present here another technique that is based on the equivalence between a crack, its process zone, and a distribution of damage. It is a simplified method aimed at approximating the distribution of damage around an existing crack. This approximation is based on the analysis of localization with a nonlocal damage model. Finite-element calculations on a compact tension concrete specimen for several initial crack lengths are presented and compared with experiments. The method is shown to yield errors less than 20% on the prediction of the load reduction factor as a function of the initial crack length. The method is also extended to the prediction of the response of fiber-reinforced components with initial damage. The response of cracked fiber-reinforced concrete (FRC) beams is computed and compared with the results of original experiments, where the loading conditions that created the initial crack are different from those leading to failure.