Experimental and analytical analysis of punching shear in flat slabs supported on column topped with concrete head

Abstract

An experimental laboraatory test of the two series of slab-column elements topped with drop panels of varying sizes is described in this paper. The scope of the paper is to investigate the influence of the drop panel size and stiffness on the behaviour of the connection between the flat slab and the column topped by the concrete head. The impact of the head size and stiffness is analysed analytically and experimentally. The experimental test results show that at a ratio hsh/lsh≤0.55 the heads are too flexible to cause punching shear outside the head, confirm significant concentrations of shear forces at the corners of the large support, and show a significant contribution of the linear parts of the control perimeter to the ultimate force transmitted by the slab-column joint. The authors compare the experimental test results with the considered standard calculation methods and indicate the correlations. The paper provides new experimental results and proposals for the application of a reduction factor for permissible shear stresses in the EC2 standard that depends on the dimension of the support. Simultaneously, the experimental results and the comparison with the standard calculations indicate a further need for research on the connection of a slab to a column topped by a drop panel.