scholarly journals ALGORITHM FOR DEFORMATION ANALYSIS AND EXPERIMENTAL STUDY OF REINFORCED CONCRETE SLABS WITH UNILATERAL BONDS

2017 ◽  
Vol 21 (2) ◽  
pp. 99-109
Author(s):  
I. N. Serpik ◽  
K. V. Muymarov ◽  
S. N. Shvachko
Keyword(s):  
Reinforced Concrete ◽  
Finite Elements ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Thin Layers ◽  
Secant Method ◽  
Deformation Analysis ◽  
Concrete Slabs ◽  
Transverse Cracks ◽  
Reinforced Concrete Slabs

A computation scheme for the analysis of reinforced concrete slabs using the finite element method providing possibility to consider unilateral connections has been developed. The stress-strain state of a slab is modeled taking into account physically nonlinear behavior of concrete and reinforcement, reinforcement discreteness, formation of transverse cracks in concrete. Kirchhoff hypotheses are considered to be true for a slab as a whole. It is believed that reinforcement out of cracks has a perfect adhesion with concrete. Concrete is represented by a system of thin layers, each of which is in a two-dimensional stress state. Approximation of displacements in this multilayer scheme is performed using triangular plate finite elements. Deformation of the reinforcement is described by means of rods working only in tension or compression. Unilateral connections are the contact finite elements. Concrete strength is evaluated according to Karpenko criterion. Deformation of concrete between cracks is described in accordance with Murashev’s approach.On the basis of the principle of virtual displacements assembling of elements takes place. A secant method case providing the convergence of the iterative process for a complex nonlinear problem of this type is proposed. At the first stage, a step-by-step increase of external forces is provided until the actual level of loading is achieved. Only one iteration of the secant method is performed at each step. Then, the iterative solution of the problem with repeated change of secant modulus is applied. The efficiency of this algorithm is confirmed on the basis of theoretical analysis and experiment for a rectangular in terms of bending reinforced concrete slab with free bearing on three sides, and not fixed on the fourth side. Three slab samples were tested and formation of cracks was monitored, measurement of deformations and displacements were performed

scholarly journals Effect of the Geometrical Constraints to the Wenner Four-Point Electrical Resistivity Test of Reinforced Concrete Slabs

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4622
Author(s):  
Kevin Paolo V. Robles ◽  
Jurng-Jae Yee ◽  
Seong-Hoon Kee
Keyword(s):  
Experimental Investigation ◽  
Electrical Resistivity ◽  
Reinforced Concrete ◽  
Concrete Slab ◽  
Plain Concrete ◽  
Electrode Spacing ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs ◽  
Spacing Ratio ◽  
Geometrical Constraints

The main objectives of this study are to evaluate the effect of geometrical constraints of plain concrete and reinforced concrete slabs on the Wenner four-point concrete electrical resistivity (ER) test through numerical and experimental investigation and to propose measurement recommendations for laboratory and field specimens. First, a series of numerical simulations was performed using a 3D finite element model to investigate the effects of geometrical constraints (the dimension of concrete slabs, the electrode spacing and configuration, and the distance of the electrode to the edges of concrete slabs) on ER measurements of concrete. Next, a reinforced concrete slab specimen (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) was used for experimental investigation and validation of the numerical simulation results. Based on the analytical and experimental results, it is concluded that measured ER values of regularly shaped concrete elements are strongly dependent on the distance-to-spacing ratio of ER probes (i.e., distance of the electrode in ER probes to the edges and/or the bottom of the concrete slabs normalized by the electrode spacing). For the plain concrete, it is inferred that the thickness of the concrete member should be at least three times the electrode spacing. In addition, the distance should be more than twice the electrode spacing to make the edge effect almost negligible. It is observed that the findings from the plain concrete are also valid for the reinforced concrete. However, for the reinforced concrete, the ER values are also affected by the presence of reinforcing steel and saturation of concrete, which could cause disruptions in ER measurements

Critical shear crack theory-based punching shear model for FRP-reinforced concrete slabs

2020 ◽  
pp. 136943322097814
Author(s):  
Xing-lang Fan ◽  
Sheng-jie Gu ◽  
Xi Wu ◽  
Jia-fei Jiang
Keyword(s):  
Shear Strength ◽  
Reinforced Concrete ◽  
Shear Crack ◽  
Concrete Strength ◽  
Weight Ratio ◽  
Punching Shear ◽  
Concrete Slabs ◽  
Crack Theory ◽  
Reinforced Concrete Slabs ◽  
Rc Slabs

Owing to their high strength-to-weight ratio, superior corrosion resistance, and convenience in manufacture, fiber-reinforced polymer (FRP) bars can be used as a good alternative to steel bars to solve the durability issue in reinforced concrete (RC) structures, especially for seawater sea-sand concrete. In this paper, a theoretical model for predicting the punching shear strength of FRP-RC slabs is developed. In this model, the punching shear strength is determined by the intersection of capacity and demanding curve of FRP-RC slabs. The capacity curve is employed based on critical shear crack theory, while the demand curve is derived with the help of a simplified tri-linear moment-curvature relationship. After the validity of the proposed model is verified with experimental data collected from the literature, the effects of concrete strength, loading area, FRP reinforcement ratio, and effective depth of concrete slabs are evaluated quantitatively.

Numerical Analysis of Anti-Impact Performances of the Reinforced Concrete Slab

2012 ◽  
Vol 249-250 ◽  
pp. 1063-1068
Author(s):  
Qian Ma ◽  
Dan Wu ◽  
Xu Dong Shi ◽  
Xiu Gen Jiang
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Concrete Strength ◽  
Impact Resistance ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs ◽  
Steel Bar ◽  
Parameterized Modeling ◽  
Element Theory ◽  
Bar Diameter

The influence of the structure parameters on the anti-impact performances of the reinforced concrete slab is studied in the article. The reinforced concrete model is established by using ANSYS 13.0/LS-DYNA and nonlinear finite element theory and the parameterized modeling is achieved. The results show that the increase of the thickness of the slab and the steel bar diameter result in the enhancement of impact resistant capability of the slab; a appropriate quantity of reinforcement is significant; Increasing the concrete strength has a distinct impact on the slab’s impact resistance when using relatively low strength concrete. However the influence becomes weak after the concrete strength comes to C60 and higher. The fruits are useful to the designing of reinforced concrete slabs.

Critical Review of Design Procedures for Reinforced Concrete Slabs as per IRC 112-2011

2019 ◽  
Vol 969 ◽  
pp. 349-354 ◽  
Author(s):  
J. Chithra ◽  
Praveen Nagarajan ◽  
A.S. Sajith ◽  
R.A. Roshan
Keyword(s):  
Reinforced Concrete ◽  
Critical Review ◽  
Concrete Slab ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Finite Element Software ◽  
Reinforced Concrete Slabs ◽  
Distributed Load ◽  
Uniformly Distributed Load ◽  
Sandwich Model

Nowadays finite element software is used for the design and analysis of reinforced concrete slabs. This paper intends to have a critical review based on a comparison study between the three design methods and to estimate the amount of reinforcement to be provided in each case. The three methods discussed are; the three-layer sandwich model (IRC 112-2011), Wood Armer method (EN1992-1-1:2004) and the conventional design method as per IS 456-2000. In the recently revised code for bridges IRC 112-2011, there is a recommendation to adopt three-layer sandwich model for the design of reinforced concrete slab. In this paper, a critical review of this method is done, and it is used for slabs subjected to uniformly distributed load. This method is illustrated by considering the design of rectangular slab subjected to uniformly distributed load. The results of this method are compared with the results obtained using Wood Armer method and using the moment coefficients suggested in IS 456-2000.

OPTIMAL DESIGN OF RIGID PAVEMENT MADE OF PREFABRICATED REINFORCED CONCRETE SLABS BASED ON THE RESULTS OF THE CALCULATION OF THE SHEAR RESISTANCE BY FINITE ELEMENTS METHOD

2018 ◽  
Vol 8 (3) ◽  
pp. 4-7
Author(s):  
Anton O. GLAZACHEV ◽  
Liliya Y. GIMADETDINOVA ◽  
Alexey P. GONCHARUK ◽  
Igor V. NEDOSEKO
Keyword(s):  
Reinforced Concrete ◽  
Comparative Analysis ◽  
Optimal Design ◽  
Finite Elements ◽  
Shear Resistance ◽  
Numerical Calculations ◽  
Concrete Slabs ◽  
Design Tools ◽  
Rigid Pavement ◽  
Reinforced Concrete Slabs

The article presents a comparative analysis of the results of the calculation of rigid pavement on the shear stability obtained by the classical engineering method and using numerical calculations. The conclusion is made about the possibility of using modern design tools to select the optimal design of rigid pavement.

THE EFFECT OF IMPACT LOADS ON PRESTRESSED CONCRETE SLABS

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Youmn Al Rawi ◽  
Yehya Temsah ◽  
Hassan Ghanem ◽  
Ali Jahami ◽  
Mohamad Elani
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
Concrete Slabs ◽  
Shear Mode ◽  
Reinforced Concrete Slab ◽  
Finite Element Program ◽  
Reinforced Concrete Slabs ◽  
The Impact

Many research studies have been conducted on the effect of impact loading on structures, and design procedures were proposed for reinforced concrete (RC) slabs; however the availability of these studies and procedures are limited for prestressed slabs. The proposed research will examine, using numerical analysis, the impact of rock fall on prestressed concrete slabs with equivalent moment capacity reinforced concrete slabs. It is expected that prestressed concrete slabs will have different behavior to resist impact loading compared with traditional reinforced concrete slabs. The thickness of the prestressed concrete slab will be 25cm whereas that of the reinforced concrete slab will be 30cm. The impact loading consists of 500Kg drop weight. The drop height will be 10m, 15m and 20m.The structural analysis is performed using a Finite Element program "ABAQUS". A comparison will be done between both slab types in terms of failure mode, damage, and deflection. It has been found that both slabs failed in punching. However, the RC slab performed better than the prestressed concrete slab with respect to the value of the deflection at mid-span, while both showed punching shear mode of failure.

BEHAVIOR OF REINFORCED CONCRETE SLABS UNDER ACCIDENTAL IMPACTS

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Shamsoon Fareed
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
High Mass ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs ◽  
Numerical Predictions ◽  
Operational Life ◽  
The Impact

Loads resulting from activities such as rock fall, heavy drop weights (for e.g. equipment's, heavy machines during installation), missile and aircraft interaction with slabs may results in loading intensity which have higher magnitude as compared to static loading. Based on the velocity of the impacting object at the time of contact, these activities may result in impact loading. Therefore, slabs designed should provide resistance to these accidental loading during their entire operational life. In this study, a dynamic non-linear finite element analyses were conducted to investigate the behavior of the reinforced concrete slabs subjected to high-mass low-velocity impacts. For this purpose, initially an already published impact test results were used to validate the numerical predictions. Following validation, a study was conducted to investigate the influence of the impact velocity on the behavior of the reinforced concrete slab. Based on the numerical investigation, it was found that the velocity of the impacting object has a significant influence on the behavior exhibited by slab under impact loading. Furthermore, it was also found that the behavior of slab under impact is both local and global. Local behavior is associated with the damage caused at the contact area of the slab and the impactor, whereas global behavior refers to the overall deformation of the slab when stress waves move away from the impact zone and travel towards the supports.

scholarly journals Upper Bound Method for Yield Design of Reinforced Concrete Slabs Using Conic Programming and an Adaptive Remeshing Strategy

2019 ◽  
Author(s):  
Hector Andres Tinoco
Keyword(s):  
Reinforced Concrete ◽  
Finite Elements ◽  
Upper Bound ◽  
Limit State ◽  
Standard Form ◽  
Numerical Procedure ◽  
Concrete Slabs ◽  
Flow Rule ◽  
Adaptive Remeshing ◽  
Reinforced Concrete Slabs

This study presents a numerical procedure for the analysis of reinforced concrete slabs (RCS) that obey Nielsen's yield criterion (slabs orthogonally reinforced). An upper bound formulation combined with finite elements was established to solve the kinematic theorem as a conic optimization problem with the aim to determine the maximum bearing capacity of RCS. Discrete Kirchhoff finite elements were implemented and adapted to establish a limit state problem for the yield design. By using Nielsen´s criterion, a kinematic criterion was established applying the flow rule of plasticity. The kinematic criterion was included in the upper bound formulation with the aim to constraint the curvatures of the slab. The upper bound formulation was organized in the standard form of a second order cone programming (SOCP) problem since the kinematic criterion was formulated in conic form. Numerical examples were proposed to test the accuracy of the method including the adaptive remeshing strategy.

scholarly journals Performance of Self-Compacted Reactive Powder Concrete Slab Under Harmonic Dynamic Loading

2019 ◽  
Vol 26 (1) ◽  
pp. 89-99
Author(s):  
Mohammad Makki Abbass Bilal ◽  
Mohamad Adnan Mohamad
Keyword(s):  
Reinforced Concrete ◽  
Dynamic Loading ◽  
Static Loading ◽  
Concrete Slab ◽  
Reactive Powder Concrete ◽  
Concrete Slabs ◽  
Dynamic Resistance ◽  
Structural Element ◽  
Reinforced Concrete Slabs ◽  
Reactive Powder

Many types of loading the structure must sustain in addition to dead and live loads according to the function of structural element type that must be taken in analysis.  Dynamic resistance to loading of reinforced concrete slabs using self-compact reactive powder concrete, with different boundary conditions at the sides in addition of static loading was studied. The reinforced concrete slabs were designed under static load according to ACI-318R-2014 and then the adequacy was checked under harmonic dynamic loading. The static loading consists of dead load and residential live load considering according to ASCE-07-2010. Modeling analysis was performed to determine the eigenvalues and eigenvectors values and then frequency response analyses of the slab by finite elements method that adopted for analysis. The results indicated that in case of self-compacted reactive powder concrete rather than normal concrete gave deflection less and also there was a different result of deflection according the type of slab boundary condition supports.

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