NONLINEAR FINITE-ELEMENT ANALYSIS OF CONCRETE DEEP BEAMS

The salient features and concepts of a model developed recently are re viewed. The parameters of the model arc the peak compressive stress of concrete, initial elastic modulus, and tangential Poisson's ratio. Th e peak stress is assumed equal to the compressive strength of standard cylindrical concrete specimens, the Poisson's ratio is calculated by a proposed empirical equation. Predictions of the model compare favora bly with experimental data on small specimens reported by various inve stigators. The model was implemented with the finite element method an d several deep beams were analyzed and compared with experimental data . The strain softening characteristics of the model allowed satisfacto ry predictions of the response up to failure. The areas where cracks d eveloped and the propagation of the crack zones up to the final collap se of the beam were predicted and compared with experimental data. Fin ally the model was used to predict the behavior of square panels subje cted to in-plane axial and shear forces as well as pure shear. The pre dictions are satisfactory.