Punching Resistance of Flat Slabs with Openings – Experimental Investigation

Abstract

Flat slabs are commonly used structures in contemporary architecture. Although their common use there is still problem in design of these structures. The openings adjacent to a column are often used for plumbing and such a position of the openings increases shear stresses in the flat slab near the column. This paper deals with experimental work focused on the punching shear resistance of the flat slab specimens with openings adjacent to column compared to the flat slab specimens without openings. The opening influence is determined experimentally and by using models for the assessment of punching resistance from relevant standards and codes. The material properties of concrete and reinforcing steel were obtained from the laboratory tests.

The influence of a column shape cross-section on the punching capacity

“…The fracture-mechanics parameters of the numerical model are based on work (Kadlec & Cervenka, 2015) and (Augustin, Fillo, Halvonik, & Marčiš, 2018). The five finite elements on the thickness of the slab were chosen, because no changes in the trend (5-10 elements) of the load-deflection curve or the ultimate resistance were noticed (Kadlec & Cervenka, 2015) and (Augustin et al, 2018). Also the combination of tetra and brick elements is not recommended, leading to the underes-timation of the ultimate resistance.…”

“…The individual column dimensions were in the range of 1 cmax/cmin  7. The results from previous experiments(Augustin et al, 2018),(Guandalini et al, 2009) were used to calibrate the models in non-linear program Atena.…”

Non-linear analysis of slab-column connections with openings

“…The fracture-mechanics parameters of the numerical model are based on work (Kadlec & Cervenka, 2015) and (Augustin et al, 2018). For calibration of the numerical model, a specimen without openings was used.…”

“…The five finite elements on the thickness of the slab were chosen, because no changes in the trend (5 -10 elements) of the load-deflection curve or the ultimate resistance were noticed (Kadlec & Cervenka, 2015) and (Augustin et al, 2018). Also, the combination of tetra and brick elements is not recommended, leading to the underestimation of the ultimate resistance.…”

“…EL-Shafiey tested seven slab specimens with a thickness of 150 mm, one reference slab, three slabs with square openings with different dimension located at the face of the column and three slabs with openings at the column corner. Eight slabs with symmetrically placed openings tested (Augustin, Fillo, Halvonik, & Marčiš, 2018). The slabs had thickness of 250 mm, two slabs were reference without openings and six slabs were tested with three different positions of the openings.…”