MODELING OF BIAXIAL BENDING OF RC MEMBERS BASED ON FRACTURE MECHANICS

摘要

This paper describes the modeling of the biaxial bending of RC frames within a new framework called Lumped Damage Mechanics. In this alternative approach, the models are based on the methods of Fracture Mechanics and the concept of Plastic Hinge. Cracks due to biaxial bending are lumped at plastic hinges by the introduction of the adequate damage variables. The expressions of the energy release rates of an inelastic hinge are then derived and crack propagation is characterized via the Griffith criterion. The plastic behavior is described using the interaction surface proposed by Bresler and a limited normality rule. The result is a model conceptually simple and nevertheless accurate enough for engineering purposes. In order to validate the model, some numerical simulations of tests reported in the literature are presented. In the tests, columns built as a cantilever were subjected to axial load and two lateral actions. A good agreement between tests and model can be observed.