Fracture Model Evaluation of Dam Concrete

Abstract

The following fracture models are assessed on the basis of an extensive testing program of large wedge‐splitting specimens: Bažant's size effect law; Hil‐lerborg's fictitious crack model; Carpinteri's brittleness model; and Shah and Jenq's two‐parameter model. Experimental data reinforce the validity of the size effect law with respect to specimen sizes. Fracture toughness values determined through the compliance method are compared with the model predictions. Results are discussed regarding specimen size requirement for linear elastic fracture mechanics (LEFM) applicability. On the basis of the size effect law and the fictitious crack model, the wedge‐splitting specimen sizes used are still too small for a classical LEFM analysis to be valid. The fracture models and their corresponding brittleness number are compared and found to be related to each other. They can be traced to Griffith's linear elastic fracture mechanics theory. The experimental results are then extrapolated to large structures, such as dams, and the limits of validity of both linear elastic and nonlinear fracture mechanics structural analyses are discussed.