Prediction of Failure Strength of Reinforced Concrete Deep Beams using Two-dimensional Grid Strut-Tie Model Method

Abstract

It is difficult to form a rational strut-tie model that represents a true load transfer mechanism of structural concrete with disturbed stressed region(s). To overcome the difficulty and handle numerous load cases with just one strut-tie model, a two-dimensional grid strut-tie model method was proposed previously. However, the validity of the method was not fully examined, although the incorporated basic concepts and new methods regarding the effective strength of concrete strut, load carrying capacity of struts and ties, and geometrical compatibility of grid strut-tie model were explained in detail. In this study, for accurate strength analysis and reliable design of reinforced concrete deep beams, the appropriateness of the two-dimensional grid strut-tie model method is verified. For this, the failure strength of 237 reinforced concrete deep beams, tested to shear failure, is predicted by the two-dimensional grid strut-tie model method, and the results are compared with those obtained by the sectional shear design methods and conventional strut-tie model methods of current design codes.