VERIFICATION OF PUNCHING SHEAR STRENGTH USING THE SURFACE OF MINIMUM SHEAR RESISTANCE METHOD
Gabriella P. Valentim1; Rafael de A. Sobral1; Renata S. P. Dal Pont1; Isabela M. C. Gomes1; Manoel J. M. Pereira Filho1; Marcos H. de Oliveira1; Maurício de P. Ferreira2
1 Universidade de Brasília; 2 Universidade Federal do Pará
doi:10.20906/CPS/CILAMCE2017-0539
Resumo
Punching shear failure is a brittle rupture that can cause progressive collapse in the structure. The best way to prevent it is by using shear reinforcement around the columns. Although the Brazilian, American and European design code recommendations verify the punching shear strength in flat slabs for internal rupture in the region of the shear reinforcement, these recommendations are not accurate as to the location of the rupture surface. The Surface of Minimum Shear Resistance (SMSR) method presents an iterative method that checks the possible failure surfaces by varying their slope (ө) in order to determine the minimum shear resistance (VR,cs), which is composed by the concrete resistance (VR,c) and the shear reinforcement strength (VR,s), both as a function of ө. This paper presents a numerical analysis in Visual Basic for Applications that does what is proposed on the SMSR method. In order to estimate more accurately the force in each layer of the shear reinforcement, the parcel of strength from the steel VR,s was determined by the CCD Method. The routine was applied in a database with 35 slabs reinforced with studs or stud rails with symmetric loading. Besides the SMSR Method, the NBR 6118:2014 and the Eurocode 2:2014 were also used to predict the ultimate punching shear resistance for the slabs. The results from these 3 methods were compared with the ultimate rupture load verified experimentally.
Palavras-chave: Reinforced Concrete; Flat Slabs; Punching Shear; Shear Reinforcement