scholarly journals Investigation of longitudinal reinforcement contribution in shear punching of reinforced concrete flat slabs without transverse reinforcement

2019 ◽  
Vol 279 ◽  
pp. 02005
Author(s):  
Vladimir Alekhin ◽  
Alexander Budarin ◽  
Maxim Pletnev ◽  
Liubov Avdonina
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Load Capacity ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Factors Affecting ◽  
Codes Of Practice ◽  
Reinforced Concrete Slabs

The shear punching of the reinforced concrete slabs is a complex process occurring when considerable force is concentrated on the relatively small area of a column-slab connection. An incorrect assessment of load capacity of slab under the punching shear may lead to an accident. One of the most significant factors affecting the slab capacity is longitudinal reinforcement. In this article much attention is given to the analysis of the longitudinal rebar impact on the maximum loading capacity of reinforced concrete slabs without transverse reinforcement affected by punching shear force using the finite element method. The results obtained via the finite element simulation are compared with laboratory tests and manual calculations carried-out using various methods represented in different national building Codes of practice.

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.

Data Base for Punching Shear Strength of Reinforced Concrete Slabs and Evaluation for CCES Equation

2011 ◽  
Vol 90-93 ◽  
pp. 933-939 ◽  
Author(s):  
Qiu Ning Yang ◽  
Ming Jie Mao ◽  
Sumio Hamada
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Factors Affecting ◽  
Reinforced Concrete Slabs ◽  
Numerous Test ◽  
Rc Slabs

Several equations for punching shear strength of the reinforced concrete slab have been proposed in the world. These equations have their own factors affecting the strength. There are numerous test data for punching shear strength of RC slabs, which have been obtained by numerous researchers. A database with approximately 300 specimens has been structured through the present study. In the present study seven equations for punching shear strength are evaluated based on the database. CCES equation is also evaluated from the present database.

scholarly journals Nonlinear finite element analysis of punching shear strength of reinforced concrete slabs supported on L-shaped columns

2020 ◽  
Vol 19 (4) ◽  
pp. 125-138
Author(s):  
Qing Zhang ◽  
Graeme J. Milligan ◽  
Maria Anna Polak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Nonlinear Finite Element ◽  
Punching Shear ◽  
Shear Behaviour ◽  
Concrete Slabs ◽  
Shear Stresses ◽  
Element Analysis ◽  
Reinforced Concrete Slabs

Most current concrete design codes include provisions for punching shear of reinforced concrete slabs supported on columns with L, T, and cruciform shapes. Reference studies verifying the accuracy of these code provisions are typically not provided. Empirical data of punching failures of slabs supported on columns with L, T, and cruciform shapes are limited due to the cost and time required to test specimens with slab thicknesses and column sizes commonly used in practice. In this paper, the punching shear behaviour of five interior L-shaped slab-column connections, one without a slab opening and four with slab openings, subjected to static concentric loading are analyzed using a plasticity-based nonlinear finite element model (FEM) in ABAQUS. The FEM is similar to models previously calibrated at the University of Waterloo and are calibrated considering nine slabs that are tested to study the impact of column rectangularity on the punching shear behaviour of reinforced concrete slabs. The finite element analysis results indicate that shear stresses primarily concentrate around the ends of the L, and that current code predictions from ACI 318-19 and Eurocode 2 may be unconservative due to the assumed critical perimeters around L-shaped columns.

scholarly journals Experimental and numerical studies on punching shear strength of concrete slabs containing sintered fly ash aggregates

2021 ◽  
Vol 20 (1) ◽  
pp. 15-25
Author(s):  
Ranjith Babu B. ◽  
◽  
Thenmozhi R ◽  
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Fly Ash ◽  
Constitutive Modelling ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs ◽  
Rc Slabs ◽  
Plate Connection ◽  
Ash Aggregates

This paper presents experimental and numerical investigations on M30 Grade of concrete containing 40% of sintered fly ash aggregates (SFAs) on the punching behaviour of reinforced concrete (RC) slabs. Two 1000 x 1000 x 100 mm reinforced concrete slabs were cast and subjected to punching tests. The experimental results were compared with creating a nonlinear finite element programme using ABAQUS. This 3D Finite element analyses were performed with the appropriate modelling of element size and the constitutive modelling of concrete. The material parameters of the damaged plasticity model in ABAQUS were calibrated based on the test results of slab – plate connection. The comparison between experimental and numerical results indicates that the calibrated model correctly predicts the punching shear response of the slabs. A modification of 0.4 is introduced in MC2010 code.

scholarly journals NUMERICAL STUDY OF THE PUNCHING SHEAR MECHANISM FOR THIN AND THICK REINFORCED CONCRETE SLABS

2021 ◽  
Vol 17 (4) ◽  
pp. 91-105
Author(s):  
Oleg Kabantsev ◽  
Sergey Krylov ◽  
Sergey Trofimov
Keyword(s):  
Reinforced Concrete ◽  
Experimental Studies ◽  
Great Influence ◽  
Shear Capacity ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Longitudinal Reinforcement ◽  
Shear Mechanism ◽  
Reinforced Concrete Slabs ◽  
The Difference

The assessment of the punching shear capacity for reinforced concrete slabs, carried out according to the regulatorydocuments of a number of countries, leads to significantly various results. At the same time, the results of thecalculated forecast may have great differences from the experimental data. A great influence on the accuracy of the resultsof the calculated forecast is exerted by the thickness of the examined slabs, as well as the value of longitudinal reinforcement.These parameters determine the features of the mechanisms of destruction of slabs in case of the punching shearmechanism, as indicated by individual interpretations of the results of experimental studies. In order to determine thefeatures of the punching shear mechanism of reinforced concrete slabs of various thicknesses, numerical studies of theprocess of cracking and destruction of slabs of different thicknesses have been performed. Differences in the mechanismof formation and development of cracks in thin and thick slabs are revealed. The paper shows that the behavior of thinand thick slabs has qualitative distinctions at the initial stages of formation and development of the cracks leading todestruction. The authors have also shown the difference between stress-strain state of thick and thin slabs before destruction.In conclusion, it was established that the influence of longitudinal reinforcement on the strength during punching inthick slabs is much less than in thin ones.When evaluating the punching shear capacity of reinforced concrete slabs, the regulatory documents of different countries give significantly different results. In this case, the calculation results may differ significantly from the experimental data. The deterioration of the thickness of the calculated slabs, as well as the value of the longitudinal reinforcement has a great influence on the accuracy of the calculation results. These parameters determine the features of the destruction mechanisms of slabs under punching. This fact is indicated by some interpretations of the results of experimental studies. In order to establish the peculiarities of the punching shear mechanism of reinforced concrete slabs of different thicknesses, a numerical investigation of the cracking and destruction of slabs of different thicknesses have been performed. Differences in the mechanism of formation and development of cracks in thin and thick slabs have been revealed. The paper shows that the behavior of thin and thick slabs has qualitative differences at the initial stages of the cracks formation and development that leads to destruction. The difference between stress-strain state of thick and thin slabs before breaking have been shown. It was found that the effect of longitudinal reinforcement on the punching shear strength in thick slabs is much less than in thin ones.

scholarly journals The analysis of the effectiveness of different types of punching shear reinforcement not fully anchored

2013 ◽  
Vol 12 (1) ◽  
pp. 195-202
Author(s):  
Tadeusz Urban ◽  
Michał Gołdyn ◽  
Łukasz Krawczyk
Keyword(s):  
Load Capacity ◽  
Point Of View ◽  
Experimental Results ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Transverse Reinforcement ◽  
Longitudinal Reinforcement ◽  
Flat Plates ◽  
Eurocode 2 ◽  
Different Types

The paper discusses the issue of load capacity of flat plates with transverse reinforcement situated between the longitudinal reinforcement. Using this types of reinforcement is much more convenient from the installation point of view, however, it does not guarantee complete embedment, as efficient as traditional stirrups that comprise longitudinal reinforcement in compression and the tension zone. The transverse rods do not comprise the main reinforcement, so their slide out of the concrete slabs or cracks parallel to the plane of the longitudinal reinforcement and delamination of the slab can occur. The different types of transverse reinforcement were presented: system consisting of  ready-made bolts, reinforcement baskets or ladders. Experimental results of plates with  these types of reinforcement are presented. The analysis of effectiveness of reinforcement anchorage indicates that transverse bolts can be used to increase the punching shear load capacity of the plates. The resulting capacity was only of about 20% lower than result elements with complete embedment Experimental results were similar to the theoretical capacity resulting from the consideration by Eurocode 2.

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