Effect of Aggregate Size on Punching Strength of Reinforced Concrete Slabs

2016 ◽  
Vol 835 ◽  
pp. 450-454
Author(s):  
Dickson Fong Wen Jing ◽  
Lau Teck Leong
Keyword(s):  
Shear Failure ◽  
Aggregate Size ◽  
Retention Factor ◽  
Shear Capacity ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Shear Stresses ◽  
Shear Cracks ◽  
Normal Concrete ◽  
Reinforced Concrete Slabs

This paper reports test results of flat slab cast from micro-concrete and normal concrete subjected to concentric punching shear. Although the punching shear failure mechanism of micro-concrete slabs was very similar to that of normal-concrete slabs, the punching shear capacity is reduced to about 73% due to the reduction in transferred shear stresses across shear cracks by aggregate interlock. Therefore, a shear retention factor of 0.7 is suggested to be applied in estimating the punching shear strength of micro-concrete slabs.

A REVIEW TO PUNCHING SHEAR CAPACTY OF NORMAL AND HIGH PERFORMANCE FIBER CEMENTIOUSE COMPOSITES

2021 ◽  
Vol 25 (Special) ◽  
pp. 4-115-4-126
Author(s):  
Liwaa Abd Alhussen ◽  
◽  
Layth A. Al-jaberi ◽  
Ra’id F. Abbas ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
High Performance ◽  
Shear Failure ◽  
High Performance Concrete ◽  
Shear Capacity ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Slab Thickness ◽  
Shear Stresses ◽  
Reinforced Concrete Slabs

The reaction of column to flat slabs may cause what is known as “punching shear stresses” when the stress is normally concentrated within the perimeter around the loaded area. In general, the reinforced concrete slabs are not designed for any shear failure due to the sudden nature of this type of failure. Many solutions can be followed to overcome such issue like increasing the depth of slab and diameter of columns. Increasing the slab thickness may add extensive dead loads and can breaks the economy justifications of this structural member. On the other hand, increasing the diameter of any column may un accepted due to architectural purposes. The high performance concrete is such type of concrete that illustrate high levels of mechanical performance “structural behavior as a consequence” if compared with normal concrete. Due to that, the high performance concrete may give good alternative an exceeds the problem of punching as a result. The basic aim of this study is to propose a brief review regarding this field of research. However, this study is divided to three parts, the first is devoted to view a suitable background about the punching shear capacity of traditional concrete slabs. The second part is registered to view the past experience in reinforced concrete slabs punching capacity and have steel fibers while the second part is devoted to present the state of art concerning the punching shear of high performance concrete slabs.

scholarly journals Modeling Punching Shear Capacity of Fiber-Reinforced Polymer Concrete Slabs: A Comparative Study of Instance-Based and Neural Network Learning

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Nhat-Duc Hoang ◽  
Duy-Thang Vu ◽  
Xuan-Linh Tran ◽  
Van-Duc Tran
Keyword(s):  
Neural Network ◽  
Regression Model ◽  
Shear Capacity ◽  
Fiber Reinforced Polymer ◽  
Punching Shear ◽  
Polymer Concrete ◽  
Concrete Slabs ◽  
Fiber Reinforced ◽  
Reinforced Concrete Slabs ◽  
Reinforced Polymer

This study investigates an adaptive-weighted instanced-based learning, for the prediction of the ultimate punching shear capacity (UPSC) of fiber-reinforced polymer- (FRP-) reinforced slabs. The concept of the new method is to employ the Differential Evolution to construct an adaptive instance-based regression model. The performance of the proposed model is compared to those of Artificial Neural Network (ANN) and traditional formula-based methods. A dataset which contains the testing results of FRP-reinforced concrete slabs has been collected to establish and verify new approach. This study shows that the investigated instance-based regression model is capable of delivering the prediction result which is far more accurate than traditional formulas and very competitive with the black-box approach of ANN. Furthermore, the proposed adaptive-weighted instanced-based learning provides a means for quantifying the relevancy of each factor used for the prediction of UPSC of FRP-reinforced slabs.

scholarly journals Prediction of Punching Shear Capacity of Two-Ways FRP Reinforced Concrete Slabs

2017 ◽  
Vol 5 (2) ◽  
pp. 1-7
Author(s):  
Ilker Kara ◽  
Besian Sinani
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Shear Capacity ◽  
Reinforced Concrete Beams ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Design Standards ◽  
Concrete Members ◽  
Reinforced Concrete Slabs ◽  
Frp Reinforcement

An innovative solution to the corrosion problem is the use of fiber-reinforced polymer (FRP) as an alternative reinforcing material in concrete structures. In addition to the non corrodible nature of FRP materials, they also have a high strength-to-weight ratio that makes them attractive as reinforcement for concrete structures. Extensive research programs have been carried out to investigate the flexural behavior of concrete members reinforced with FRP reinforcement. On the other hand, the shear behavior of concrete members, especially punching shear of two-way slabs, reinforced with FRP bars has not yet been fully explored. The existing provisions for punching of slabs in most international design standards for reinforced concrete are based on tests of steel reinforced slabs. The elastic stiffness and bonding characteristics of FRP reinforcement are sufficiently different from those of steel to affect punching strength. In the present study, the equations of existing design standards for shear capacity of FRP reinforced concrete beams have been evaluated using the large database collected. The experimental punching shear strengths were compared with the available theoretical predictions, including the CSA S806 (CSA 2012), ACI-440.1R-15 (ACI 2015), BS 8110 (BSI 1997), JSCE (1997) a number of models proposed by some researchers in the literature. The existing design methods for FRP reinforced concrete slabs give conservative predictions for the specimens in the database. This paper also presents a simple yet improved model to calculate the punching shear capacity of FRPreinforced concrete slabs. The proposed model provides the accurate results in calculating the punching shear strengths of FRP-reinforced concrete slender slabs.

scholarly journals Punching Shear Behavior of Reinforced Concrete Slabs under Fire using Finite Elements

2020 ◽  
Vol 26 (5) ◽  
pp. 106-127
Author(s):  
Athraa H. Gharbi ◽  
Akram S. Mahmoud
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Shear Failure ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Mechanical And Thermal Properties ◽  
Element Analysis ◽  
Reinforced Concrete Slabs ◽  
Fire Condition ◽  
Increasing Temperature

The main aim of this paper is studied the punching shear and behavior of reinforced concrete slabs exposed to fires, the possibility of punching shear failure occurred as a result of the fires and their inability to withstand the loads. Simulation by finite element analysis is made to predict the type of failure, distribution temperature through the thickness of the slabs, deformation and punching strength. Nonlinear finite element transient thermal-structural analysis at fire conditions are analyzed by ANSYS package. The validity of the modeling is performed for the mechanical and thermal properties of materials from earlier works from literature to decrease the uncertainties in data used in the analysis. A parametric study was adopted in this study,  it has many factors such as the ratios of length to thickness, fire temperature, time exposed to fire, concrete compressive strength, area exposed to fires and type of support. It can be concluded from this research the significant factors that affect the punching shear strength. However, the increasing ratio of length to thickness may be lead to increasing the deflection more than 123% at fire condition. Also, the increasing temperature leads to increasing the deflection about 40% at fire condition.

scholarly journals Resisting punching shear stress in reinforced concrete slabs

2018 ◽  
Vol 162 ◽  
pp. 04025
Author(s):  
Ebada Ahmed ◽  
Boshra Eltaly ◽  
Fatma El-Zhraa ◽  
Magdy Tayel
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Shear Capacity ◽  
Punching Shear ◽  
Shear Reinforcement ◽  
Reinforcement System ◽  
Strength Concrete ◽  
Reinforced Concrete Slabs ◽  
The Difference ◽  
Compact Strength

Punching shear failure is a major problem encountered in the design of reinforced concrete flat slabs. The utilization of shear reinforcement via shear studs or other means has become a choice for improving the punching shear capacity. In this study, a new alternative of reinforcement modalities were tested and demonstrated the effect of self-compact concrete on the punching shear capacity, beside that compared between the difference codes to identify the suitable one for determining the position of critical section of punching shear. Nevertheless, in this investigation, the proposed reinforcement system is examined for interior columns only. An experimental work consisting of six specimens: five of them were cast with normal reinforced concrete and one was cast with self-compact strength concrete. The obtained results indicate that the proposed shear reinforcement system has a positive effect in the enhancement of the punching shear capacity of interior slab–column connection of self-compact strength concrete.

Effect of Column Dimensions on the Punching Shear of Flat Slab

2019 ◽  
pp. 378-393
Author(s):  
Hamid Abdulmahdi Faris ◽  
Lubna Mohammed Abd
Keyword(s):  
Reinforced Concrete ◽  
Shear Failure ◽  
Concrete Slab ◽  
The Other ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Flat Slab ◽  
Interior Edge ◽  
Reinforced Concrete Slabs

The "flat slab" is a reinforced concrete slab bolstered, by a number of columns. Punching, shear is a category for collapse for reinforced concrete slabs exposed to great confined forces. In "flat slab" constructions the shear failure happens, at column bolster joints. To avoid this, collapse two methods are used, first method is increasing the column dimensions and, the other is to use drop panel if the first method leads to uneconomical, design. Two examples are used to find the effect, of column dimensions, increase on the punching shear failure of "flat slab". The first example, is a "flat slab" of span (5 by 5) m and the other is of span (6 by 6) m. The column which examined is the interior, edge and corner columns, and the interior column is the most dangerous case. It is concluded that, the increase of column dimensions are lead to avoid of punching shear failure in "flat slab" and the drop panel is enlarge the area of the critical shear perimeter and this avoiding punching shear failure.

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.

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