MODELING PUNCHING SHEAR OF REINFORCED-CONCRETE SLABS USING LAYERED FINITE-ELEMENTS

The paper examines the applicability of the finite element, layered sh ell formulation in the global analysis of reinforced concrete slabs wh en subjected to high, concentrated transverse loads. The formulation i ncorporates quadratic, degenerate, isoparametric shell elements. A sig nificant feature of these elements is their ability to take into accou nt out-of-plane shear response. This allows the implementation of a th ree-dimensional constitutive model for the evaluation of the stiffness matrix: The proposed formulation allows the use of out-of-plane reinf orcement in the elements. Through the consideration of the three-dimen sional states of strain and stress in each layer, the model can predic t the failure of structures caused by either flexure or punching shea, : The paper presents and discusses the essential features of the propo sed formulation which are related to the transverse shear model. The f ormulation has been checked against experimental results of tests on s labs subjected to punching shear: A parametric study has also been und ertaken to determine the influence of several parameters on the behavi or of slabs with and without stirrups.