Hoek-Brown Strength Criterion for Actively Confined Concrete

Abstract

The application of the Hoek–Brown empirical strength criterion to actively confined concrete is investigated. A large database of experimental results on hydraulically and triaxially confined concrete is reviewed and analyzed. The normalized two-parameter Hoek–Brown criterion provides a simpler and more robust fit than theoretical and empirical models previously proposed in the literature for actively confined concrete. The Hoek–Brown curved failure surface is used to predict the failure angles that are experimentally observed in the brittle mode. A residual stress lower bound is proposed based on the brittle fracture mechanism. The analysis of this residual stress lower bound allows the formal identification of the transition between the brittle and the ductile failure modes in confined concrete. The modeling results are compared with the available published data and good agreement is found between the experimental observations and the predictions of the model. Recommendations for the integration of the Hoek–Brown model in the concrete design equations are also provided.