Punching shear tests of post‐tensioned flat slabs supported on edge columns

Abstract

This paper describes an experimental study of the punching resistance of unbonded post tensioned flat slabs supported on edge columns. Fifteen slabs rectangular in plain, with sides of 2 m by 1.2 m and 120 mm thick were tested, supported on square columns with sides of 200 mm and with length of 600 mm at the top and at the bottom. The main variables are the eccentricity (Mu/Vu) of the shear force, which is obtained varying the relation between loads parallel and perpendicular to the free edge; the amount of unbonded tendons (4 or 6 tendons perpendicular to the free edge and 3 or 2 tendons parallel to the free edge with the column); and the non‐prestressed flexural reinforcement detailing. The behavior of slabs is discussed in terms of vertical displacements, strains on concrete and on non‐prestressed rebars, forces on the unbonded tendons, cracking pattern and ultimate shear forces. The increase of the eccentricity (Mu/Vu) changes the failure mode from punching to flexure and torsion associated to punching.

Predicting Embodied Carbon and Cost Effectiveness of Post-Tensioned Slabs Using Novel Hybrid Firefly ANN

“…In 1990, Foutch et al [5] pointed out the advantages of using PT RC slab solutions according to design strength considerations. Previous research has confirmed that prestressing substantially improves the resistance of flat concrete slabs to punching shear [6][7][8]. From the sustainability perspective, the research conducted by Dane Miller [9] confirmed that by increasing the span length in PT slabs from 6.67 to 13.3 m, the consumption of concrete and steel reinforcement can be decreased by 21.5 and 34.4%, respectively.…”

“…The punching shear strength of flat RC slabs is typically controlled by the compressive strength of the slab and column concrete and their geometric parameters. In a flat slab without shear reinforcement subjected to a cantered axial load by an isolated column, two categories of orthogonal bending moments, M ϕ producing tangential stresses and Mr producing radial stresses, are developed due to the bidirectional flexural action of the slab, as depicted in Figure 18 [6]. The normal stresses, σ ϕ, and σ r , developed by the above-mentioned orthogonal bending moments, respectively, stretch the top and compress the bottom of the slab.…”

A strength and deformation model for prestressed lightweight concrete slabs under two-way shear

“…The two-way shear strength of PCS has been experimentally by many researchers (Amir et al, 2016;Barba´n et al, 2019;Burns and Hemakon, 1977;Correa, 2001;Eid, 2013;Franklin and Long, 1982;Gerber and Burns, 1971;Grow and Vanderbilt, 1967;Hasssanzadeh, 1998;Kordina and Nolting, 1984;Koust, 1977;Mao and Yaung, 2012;Melges, 2000;Moreillon, 2008;Mostafaei et al, 2011;Moussa and Salama, 2008;Nylander et al, 1977;Pralong et al, 1979;Ragab et al, 2014;Ramos and Lucio, 2006;Ramos et al, 2008Ramos et al, , 2011Regan, 1983;Rezai Kallage, 1993;Saleh and Suaris, 2009;Scordelis et al, 1958;Shehata, 1982;Silva, 2005;Smith and Burns, 1974). Only two studies focused on PLCS.…”

“…In addition, that the twoway shear strength predicted by most international codes is overly conservative. Barba´n et al (2019) tested 15 eccentric slab-column connections, where the slab was rectangle 2 3 1.2 m and 120 mm thickness. The investigated parameters were the loading eccentricity and the flexural reinforcement ratio.…”