Cracking and Punching Shear Failure Analysis of RC Flat Plates

Abstract

This paper presents a nonlinear layered finite element method capable of analyzing cracking and punching shear failure of reinforced concrete flat plates with spandrel beams or torsion strips. Incorporating a layered approach with transverse shear capabilities, the procedure takes into account the full interaction between the spandrel beam and the adjoining slab (in bending, shear, and torsion). The formulation of the nonlinear cracking and failure analysis is discussed in some detail. A comparative study based on a series of 11 half-scale reinforced concrete flat plate models and four single slab-column specimens confirms the method's ability to satisfactorily predict the punching shear strengths, the deflections, and the crack patterns, as well as the collapse loads, of the models. Also included in the comparison is a semiempirical procedure, along with those recommended by the American Concrete Institute, the British Standards Institution, and the Standards Association of Australia. Results show that the proposed method and the semiempirical formulas are more accurate and reliable than those of the three national codes of practice.