PREDICTION OF PUNCHING SHEAR RESISTANCE OF PRESTRESSED CONCRETE FLAT SLABS

2011 ◽  
Vol 14 (1) ◽  
pp. 180-196
Author(s):  
A M Elshihy ◽  
H A ShehabEldeen ◽  
O Shaalan ◽  
R S Mahmoud
Keyword(s):  
Prestressed Concrete ◽  
Shear Resistance ◽  
Punching Shear ◽  
Flat Slabs

Enhanced reliability assessment of punching shear resistance models for flat slabs without shear reinforcement

2021 ◽  
Vol 226 ◽  
pp. 111319
Author(s):  
Marcus Ricker ◽  
Tânia Feiri ◽  
Konstantin Nille-Hauf ◽  
Viviane Adam ◽  
Josef Hegger
Keyword(s):  
Reliability Assessment ◽  
Shear Resistance ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Flat Slabs

scholarly journals Investigation of the effects of opening size and location on punching shear resistance of flat slabs using Abaqus

2021 ◽  
Vol 15 (4) ◽  
pp. 136-147
Author(s):  
Nguyen Tuan Trung ◽  
Pham Thanh Tung
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Numerical Study ◽  
Shear Resistance ◽  
Design Principles ◽  
Numerical Results ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Flat Slabs ◽  
Abaqus Model

The paper presents a numerical study on the effects of opening size and location on punching shear resistance of flat slabs without drop panels and shear reinforcement using ABAQUS. The study proposes an ABAQUS model that is enable to predict the punching shear resistance of flat slabs with openings. The model is validated well with the experimental data in literature. Using the validated numerical model, the effects of opening size and location on the punching shear resistance of flat slabs are then investigated, and the numerical results are compared with those predicted by ACI 318-19 and TCVN 5574:2018. The comparison between experimental and numerical results shows that the ABAQUS model is reliable. The punching shear resistances calculated by ACI 318-19 and TCVN 5574:2018 with different opening sizes and locations are agreed well to each other, since the design principles between two codes now are similar.

scholarly journals Theoretical prediction of punching shear capacity of flat slabs without shear reinforcement strengthened by concrete topping

2021 ◽  
Vol 1203 (2) ◽  
pp. 022108
Author(s):  
Daniel Čereš ◽  
Katarína Gajdošová
Keyword(s):  
Shear Resistance ◽  
Design Guidelines ◽  
Shear Capacity ◽  
Reinforcement Ratio ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Model Code ◽  
Flat Slabs ◽  
Eurocode 2 ◽  
Model Code 2010

Abstract The main reasons for strengthening flat slabs are the change of the use of a building, increase in the value of loads, degradation of the concrete cover layer, or insufficient reinforcement. This paper is focused on the assessment of punching shear capacity of the strengthened flat slabs without shear reinforcement. One of the possibilities how to enhance punching shear capacity is the addition of reinforced concrete topping. The main goal of this paper is to compare the possibilities for calculation of the increase in the punching shear capacity by investigation of the influence of different thicknesses of concrete toppings and different reinforcement ratio. A reference specimen is represented by a fragment of a flat slab with the thickness of h = 200 mm supported by circular column with the diameter of 250 mm. Three different thicknesses (50 mm, 100 mm, 150 mm) of concrete toppings were considered together with three different reinforcement ratios for each thickness of concrete overlay. Theoretical predictions of the punching shear resistance of flat slabs were evaluated by design guidelines according to the relevant standards: Eurocode 2 (EN 1992-1-1), Model Code 2010 and draft of the second generation of Eurocode 2 (prEN 1992-1-1). The differences in the influence of reinforcement ratio are significant. In Model Code 2010 the reinforcement ratio in concrete topping was considered in equation of moment of resistance. This is unlike in both of the mentioned Eurocodes, where the reinforcement ratio was assumed as a geometric average value of the original reinforcement ratio in the slab before strengthening and of the reinforcement ratio of concrete topping. All the predicted theoretical calculations are based on the perfect connection and bond between the original and new layer of concrete. These predictions should be verified by experimental investigation, which is going to be prepared shortly. By the additional increase in the thickness of concrete topping or in the amount of added reinforcement the attention should be payed to the limitation of the punching shear resistance by the value of the maximum punching shear resistance in the compression concrete strut.

Punching shear provisions for reinforced and presfressed concrete flat slabs

1996 ◽  
Vol 23 (2) ◽  
pp. 502-510 ◽  
Author(s):  
N. J. Gardner
Keyword(s):  
Reinforced Concrete ◽  
Correction Factor ◽  
Prestressed Concrete ◽  
Shear Capacity ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Flat Slabs ◽  
Reinforced Concrete Slabs ◽  
Unbonded Tendons ◽  
Effective Depth

The validity of the CSA A23.3-94 code provisions for punching shear were compared with the punching shear results of 142 reinforced concrete flat slabs, 16 prestressed concrete flat slabs with unbonded tendons, and 17 flat slabs with unbonded prestressed and supplementary bonded reinforcement. The code prediction equations are not capable of direct verification against experimental results without using a correction factor. Using a justifiable correction factor, the CSA A23.3-94 provisions are appropriately conservative for reinforced concrete slabs but the scatter is large. However, it was concluded that the CSA A23.3-94 provisions are not conservative for prestressed concrete flat slabs. An equation is proposed to calculate the punching shear capacity of reinforced concrete and prestressed concrete slabs, which has a smaller coefficient of variation than the punching shear provisions of CSA A23.3-94, for symmetrically loaded interior columns. The critical section of the proposed method is the perimeter of the column, which is easier to justify than an arbitrary critical perimeter half the effective depth of slab from the column. Key words: reinforced concrete, prestressed concrete, flab slabs, punching shear.

Study of Flat Slabs Strengthening against Punching Shear

2016 ◽  
Vol 249 ◽  
pp. 221-226 ◽  
Author(s):  
Jan Nováček ◽  
Miloš Zich
Keyword(s):  
Shear Crack ◽  
3D Models ◽  
Shear Resistance ◽  
Material Nonlinearity ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Design Code ◽  
Shear Strengthening ◽  
Absolute Value ◽  
Flat Slabs

The paper focuses on punching shear strengthening of flat slabs. In the study, different, in practice commonly used systems of strengthening are introduced, systems used less frequently are also mentioned. Chosen methods of strengthening are modeled using FEM software considering material nonlinearity and crack development in structures. 3D models with brick finite elements and discrete modeling of reinforcement are used. The way of modeling of the structure itself is verified against known results of tests of concrete slabs under punching shear. Comparison of individual systems of strengthening is performed from the viewpoint of absolute value of punching shear resistance and it is supplemented by calculation of punching shear resistance according to design code EC 1992. Simultaneously, results are compared to the approach of Critical Shear Crack Theory that places great emphasis on deformation capacity of the slab itself, which can be easily determined from FEM models which allow for material nonlinearity.

scholarly journals Punching shear in flat slabs by strut and tie model

2021 ◽  
Vol 14 (5) ◽  
Author(s):  
Ricardo José Carvalho Silva ◽  
Dênio Ramam Carvalho de Oliveira ◽  
Nívea Gabriela Benevides de Albuquerque ◽  
Thiago Andrade Gomes ◽  
Aaron Kadima Lukanu Lwa Nzambi
Keyword(s):  
Shear Resistance ◽  
Punching Shear ◽  
Strength Prediction ◽  
Design Codes ◽  
Test Results ◽  
Main Design ◽  
Strut And Tie ◽  
Flat Slabs ◽  
The One ◽  
Strut And Tie Model

Abstract Research on behavior of flat slabs under punching shear, performed by Kinnunen, Regan and Muttoni influenced the main design recommendations. Meanwhile, studies about strut and tie model developed by Schlaich for beams, deep beams and corbels also influenced these design codes. This work aimed to adapt the strut and tie model for the punching shear resistance analysis in flat slabs. The punching shear resistance of 30 flat slabs verified through strut and tie model was compared to the one designed following Brazilian, American and European codes recommendation. Subsequently, this same model was validated by comparing the test results of 32 flat slabs. The strut and tie model results, when compared with the test results, showed a better average than those from codes, and the modified strut and tie model can become an alternative for punching shear strength prediction.

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