An Experimental and numerical study of the load distribution effect on composite slab shear resistance

Abstract

The design codes prescribe “a close simulation” of the uniformly distributed loads for bending tests, since, applying an ideal uniform load on the slab surface, is not technically as simple as applying concentrated loads by spreader beams. The 4-point bending test used in both standard methods m-k and PCM to determine the shear resistance of composite slabs is currently the most conventional loading arrangement. This article presents the comparison between the 4-point bending and uniform load results, obtained from both experimental tests and numerical simulations. Two groups of specimens, made with a common trapezoidal steel profile and concrete, including short and long spans, have been tested under the two loading setups. The numerical analysis of these slabs has been carried out through modelling the realistic interaction of steel and concrete. For the 4-point bending simulation, predefined vertical cracks are modelled representing the real crack inducers, whereas, for the uniform load case, the Willam-Warnke model is used. Both the experimental and the numerical results indicated that the 4-point bending test provides higher shear strength than uniform load. The experimental part was conducted by LERMA (Universitat Politècnica de Catalunya – BarcelonaTech) in collaboration with AdMaS-BUT at Brno University of Technology. The 3D FEM of composite slabs has been made through ANSYS software.