Unified Failure Model of Reinforced Concrete Members Subjected to Hazard Loads II: Brittle Failure Analysis

A simple and unified failure model is proposed for rectangular reinforced concrete (RC) members subjected to axial loads, bending, shear force and torsion. There are two distinct types of failure mechanisms, ductile failure and brittle failure. In the present paper, a lower-bound limit analysis of brittle failure is proposed. The normal-section at failure is considered intact and stress distributions at failure can be presumed. Then, the interaction relationship can be deducted when stress distributions reach the failure criterion of concrete and RC members fails at the same time. Combined with the ductile failure analysis proposed in part I, a unified failure model is obtained and it is in good agreement with experimental results. Not only can this unified failure model explicitly explain failure mechanisms, but ultimate bearing capacities also can be easily calculated and the failure mechanism can be quickly determined. Overall, this model is significant for the analyses of reinforced concrete structures in engineering.