ULTIMATE STRENGTH ANALYSIS OF STRUCTURAL CONCRETE DEEP BEAMS USING STRUT-TIE MODELS

This paper presents an ultimate strength analysis of two reinforced and one prestressed concrete deep beams tested to failure. A nonlinear strut-tie model approach implemented with an interactive computer graphics program was utilized to evaluate the ultimate strength and nonlinear behavior of the beams. Different types of strut-tie models for the beams were selected based on the principal compressive stress trajectories, actual specimen detailing, and loading and support conditions. The present study shows that the nonlinear strut-tie model approach can provide simple and effective solutions for a large number of analysis situations by describing the essential structural behavior aspects and evaluating the strength of structural concrete. It also allows for the conceptual representation of the complex concrete and reinforcing steel interactions, and permits the study of localized effects through the bearing capacity evaluation of nodal zones. The framework provided by the nonlinear strut-tie model approach for considering combined actions is strongly suggested in the ultimate strength analysis of structural concrete deep beams.