MATERIAL MODEL FOR CONCRETE IN CRACKED AND UNCRACKED STATES

An elastoplastic model for concrete is presented that covers the nonli near triaxial behavior of concrete under compressive and tensile loadi ng, compressive failure, and tensile cracking. In all the states, the model is based on the same concept. For the description of the prefail ure behavior, two different hardening functions are introduced that co ntrol the expansion and the transposition of the ''yield surface.'' To simulate tensile cracking, a ''smeared-crack approach'' is chosen. Th e elastoplastic concept is extended, whereas the anisotropic behavior of cracked concrete is taken into account. By introducing a new combin ation of isotropic expansion and kinematic transposition of the ''yiel d surface,'' steady transitions between compression and tension zones are obtained both in cracked and uncracked states. Comparisons with te st results show the very good capacity of the proposed model to cover the material behavior both in the pre- and postfailure regions. By app lying the method of finite elements, the analysis of notched beams dem onstrates that the model is very well suited to predict the response o f concrete structures.