scholarly journals Behavior of composite pre-flat slabs in resisting punching shear forces

2020 ◽  
Vol 59 (1) ◽  
pp. 333-347
Author(s):  
Wajdi J. Baniya ◽  
Wael Zaki ◽  
C-M. Rabie Farrag ◽  
D- Ahmed Rashed
Keyword(s):  
Punching Shear ◽  
Shear Forces ◽  
Flat Slabs

Contribution of Settlement of a High-Rise Building with Recession in a Ground Plan to Punching Shear

2017 ◽  
Vol 259 ◽  
pp. 198-202
Author(s):  
Jan Nováček ◽  
Miloš Zich
Keyword(s):  
Punching Shear ◽  
Vertical Shear ◽  
Shear Forces ◽  
Current Time ◽  
High Rise ◽  
Exact Approach ◽  
Ground Plan ◽  
Flat Slabs ◽  
Different Types ◽  
Current Standards

Construction systems with recession in their ground plan along increasing height of a building are often used in current time. This lay-out is advantageous for the global stability of a building, which acts as a vertical cantilever with a widen socle. Attention must be paid with this type of global lay-out solution, because significant shear forces appear thanks to various types of grand plan. Usually buildings with massive elements, which can bear major of shear forces, don’t have any problem with the global vertical shear forces. Contrarily buildings with slight construction system such as flat slabs supported by columns could be unsafe designed if this effect is not taken account. There is no recommendation or exact approach to this problem in current standards and therefore it only depends on the designer’s approach and their experience. In the paper different types of approaches to the analysis of vertical shear forces and their distribution are presented. They are demonstrated on models with various levels of detailing. The scope of models starts at very simple linear model of whole structure and ends by models which take account of non-linear base supports and construction stages.

Design of Flat Slabs Height

2015 ◽  
Vol 1106 ◽  
pp. 221-224
Author(s):  
Ľudovít Fillo ◽  
Jana Labudková ◽  
Ján Hanzel
Keyword(s):  
Shear Resistance ◽  
Punching Shear ◽  
Shear Forces ◽  
Flat Slabs

Results of latest experiments have revealed that the maximum punching resistance defined from crushing of concrete struts at the perimeter of a column is an insufficient criterion for limitation of maximum shear forces at the vicinity of the columns. Therefore further limitation has been recommended by CEN TC250 SC2 and introduced in STN EN 1992-1-1/NA [1]. The paper will deal with the new requirements concerning the maximum punching shear resistance, based on the kmax factor and design of min flat slabs height.

The Analysis of Shear Forces Flow around the Supports of Flat Slabs

2020 ◽  
Vol 309 ◽  
pp. 216-221
Author(s):  
Simona Šarvaicová ◽  
Viktor Borzovič
Keyword(s):  
Cross Section ◽  
Shear Resistance ◽  
Linear Analysis ◽  
Punching Shear ◽  
Shear Forces ◽  
Flat Slab ◽  
Flat Slabs ◽  
Eurocode 2 ◽  
Non Linear ◽  
Linear Shear

This paper deals with both linear and non-linear analysis of shear forces distribution in the area near the supports of the flat slabs. With a cross-section ratio of cmax / cmin > 3, the main amount of the shear stress is concentrated near the column or wall corners bases. As a consequence of this phenomenon, it is necessary to reduce the control perimeter when evaluating the punching shear resistance of a flat slab. The fragments of the flat slabs with the thickness of 200 mm supported by a wall with various loading conditions were analyzed. The results according to the Eurocode 2 were compared to a non-linear shear resistance evaluation that was calibrated based on the results from the previous experiments. Based on thus evaluated punching shear resistances, the theoretical reduced control perimeter was determined and subsequently it was compared to design model Eurocode 2. The physical basis for determining reduced control perimeters is based on the shear force concentration near the support.

scholarly journals Influence of the Shear Cap Size and Stiffness on the Distribution of Shear Forces in Flat Slabs

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 188
Author(s):  
Maciej Grabski ◽  
Andrzej Ambroziak
Keyword(s):  
Load Capacity ◽  
Punching Shear ◽  
Effective Control ◽  
Reinforced Concrete Structure ◽  
Calculation Methods ◽  
Shear Forces ◽  
Flat Slabs ◽  
Internal Forces ◽  
Effect Of Support ◽  
High Flexibility

The scope of this paper is to investigate analytically and numerically the influence of shear cap size and stiffness on the distribution of shear forces in flat slabs in a slab–column-connections-reinforced concrete structure. The effect of support (shear cap) stiffness on the calculation of the length of the shear control perimeter according to the available methods is presented. Based on the analysis, the authors indicate in what range of support stiffness the corner concentrations become important in the calculation of the punching resistance. For shear caps with high flexibility (α1 ≤ 0.5), the concentration of internal forces in the corners does not occur. The authors compare the numerical results obtained from the calculation methods and indicate the correlations, which can be useful guidance for structural designers. In the case of large shear caps, the simplified MC2010 method gives a significantly lower value of the effective control perimeter length compared to more accurate methods. This paper is intended to provide scientists, civil engineers, and designers with guidelines on which factors influence punching shear load capacity of the slab–column connections with shear caps.

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

Moment and shear transfer between columns and concrete slabs

1990 ◽  
Vol 17 (4) ◽  
pp. 621-628
Author(s):  
Amin Ghali ◽  
Adel A. Elgabry
Keyword(s):  
Shear Strength ◽  
Structural Design ◽  
American Concrete Institute ◽  
Punching Shear ◽  
Vertical Shear ◽  
Concrete Slabs ◽  
Finite Element Analyses ◽  
Shear Transfer ◽  
Flat Slabs ◽  
Punching Failure

Gravity and horizontal forces cause the transfer of vertical shear and moments between concrete flat slabs and their supporting columns. These forces can cause punching failure. Design equations for safety against punching given in the Canadian Standards Association and the American Concrete Institute codes are critically reviewed. It is shown that the equations give in some cases incorrect stresses which do not satisfy equilibrium. A modification is suggested which makes the equations applicable to all cases. The paper also discusses the codes' approach of sharing the resistance to transferred moment between resistances by flexure and by eccentricity of shear, using the coefficient γv. Comparisons are made with the result of finite element analyses. It is concluded that the code equations, with the suggested modification, are adequate, provided that appropriate values are used for the coefficient γv. Key words: columns, connections, flat concrete plates, moments, punching shear, reinforced concrete, shear strength, slabs, structural design.

Numerische Untersuchungen zur Durchstanztragfähigkeit von Flachdeckensystemen/Numerical investigations on punching shear capacity of continuous flat slabs

Bauingenieur ◽  
2018 ◽  
Vol 93 (04) ◽  
pp. 141-151
Author(s):  
D. Kueres ◽  
P. Schmidt ◽  
S. Bosbach ◽  
M. Classen ◽  
M. Herbrand ◽  
...  
Keyword(s):  
Shear Capacity ◽  
Punching Shear ◽  
Numerical Investigations ◽  
Flat Slabs ◽  
Finite Elemente

Das Durchstanztragverhalten von Stahlbetonplatten wird seit mehreren Jahrzehnten experimentell erforscht. Aufgrund des hohen Kosten- und Arbeitsaufwandes von Durchstanzversuchen an Flachdeckensystemen wurde der Großteil der vorhandenen Durchstanzversuche an isolierten Flachdeckenausschnitten durchgeführt. Die Geometrie der Versuchskörper wurde dabei mit dem Ziel gewählt, den Stützmomentbereich um die jeweils betrachtete Decke-Stütze-Verbindung zu simulieren. Günstige Einflüsse, die sich in Flachdeckensystemen zum Beispiel aus Momentenumlagerungen oder Druckmembrantragwirkung ergeben, können in diesen Versuchen nicht auftreten. Daher eignen sich die vorhandenen Versuche in erster Linie zur sicheren Abschätzung der Durchstanztragfähigkeit.   Aufbauend auf theoretischen und experimentellen Untersuchungen aus der Literatur, wird in diesem Beitrag die Durchstanztragfähigkeit von Flachdeckensystemen anhand von nicht-linearen Finite-Elemente-Simulationen genauer untersucht. Das verwendete numerische Modell wird zunächst anhand von Durchstanzversuchen validiert. Nachfolgend wird das Modell für weiterführende Parameterstudien verwendet, um die Unterschiede zwischen Flachdeckensystemen und –ausschnitten genauer zu analysieren. Die Ergebnisse der numerischen Untersuchungen werden abschließend dafür genutzt, einen praxistauglichen Ansatz zur Bestimmung der Durchstanztragfähigkeit von Flachdeckensystemen im Bereich von Innenstützen abzuleiten.

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