Soft Projectile Impacts on Thin Reinforced Concrete Slabs: Tests, Modelling and Simulations

2011 ◽  
Vol 82 ◽  
pp. 503-508
Author(s):  
Christophe Pontiroli ◽  
Alain Rouquand
Keyword(s):  
Reinforced Concrete ◽  
Research Effort ◽  
Concrete Structures ◽  
Numerical Procedure ◽  
Heterogeneous Material ◽  
Material Model ◽  
Concrete Slabs ◽  
Reinforced Concrete Slabs ◽  
Stress Strain Relation ◽  
Dynamic Loadings

Numerical simulations of reinforced concrete structures subjected to high velocity impacts and explosions remain a difficult task today. Since ten years and more now, the CEA-Gramat has maintained a continuous research effort with the help of different French universities in order to overcome encountered difficulties in modelling the behaviour of concrete structures under severe loading. These difficulties are related to numerical aspects (convergence difficulties of the non linear stress strain relation in 3D configuration, efficiency of the numerical procedure and robustness), but also due to the ability of the material model to simulate the accurately behaviour of a very complex and heterogeneous material like concrete. A new concrete model, named PRM model, has been developed at CEA-Gramat (Pontiroli, Rouquand & Mazars, [1], [2], [3]) to predict the concrete response under a large range of dynamic loadings.

Modelling the Response of Simply-Supported Two-Way Reinforced Concrete Slabs Exposed to Fire

2016 ◽  
Vol 711 ◽  
pp. 588-595
Author(s):  
Emran Baharudin ◽  
Luke Bisby ◽  
Tim Stratford
Keyword(s):  
Reinforced Concrete ◽  
Computational Study ◽  
Concrete Structures ◽  
Structural Response ◽  
Concrete Slabs ◽  
Structural Behaviour ◽  
Fire Engineering ◽  
Reinforced Concrete Slabs ◽  
Structural Fire Engineering ◽  
Fire Codes

The historically good performance of concrete structures in real fires, and the lack of urgent drivers for the concrete industry to support research on the fire performance of concrete structures, means that research on the full frame response of concrete buildings to fires has received much less attention than for steel-framed structures. However, a credible understanding of, and ability to model, the response of concrete structures under fire exposure is crucial to make further progress in the field of structural fire engineering, and to make best use of the flexibility enabled by performance-based fire codes. This paper presents a computational study on the structural behaviour of reinforced concrete slabs during fire tests undertaken by Zhang et al.[16]. The distribution of stresses in the slabs is discussed, as is the need for further research to better understand structural response during fire. Amongst other factors, the assumed tensile strength of the concrete is crucial to accurately predict response. The results corroborate the existing consensus that concrete slabs in real buildings can, in some cases, withstand fires for longer than expected; this is due to mobilisation of membrane actions, amongst other factors.

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 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.

Numerical Analysis of the Influence of the Parameter of Ductility of Reinforcing Steel on the Behaviour of Narrow Three-Span Reinforced Concrete Slabs from the Point of View of Experimental Investigations

2015 ◽  
Vol 769 ◽  
pp. 133-138
Author(s):  
Mirosław Wieczorek
Keyword(s):  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Laboratory Tests ◽  
Numerical Models ◽  
Material Model ◽  
Point Of View ◽  
Experimental Investigations ◽  
Concrete Slabs ◽  
Building Structures ◽  
Reinforced Concrete Slabs

In the time of exploitation of building structures frequently situations do occur, in which due to failures they are exposed to much higher loads than originally predicted. The subject matter of the performed investigations and a numerical analysis are models of four narrow reinforced concrete slabs with the dimensions 7140×500×190 mm. The paper presents the results of the numerical analysis, the aim of which was to reflect and to provide detailed information about phenomena occurring in the course of laboratory tests. Numerical models were constructed according to the system ANSYS, applying volumetric elements SOLID65 and bars LINK8. In order to determine the relation σ-ε of steel an isotropic model of strengthening in the system ANSYS was used, constructed by Misses. The behaviour of concrete was represented by the material model Concrete. The parameters applied in the material models had been obtained in laboratory tests of the material. The paper quotes the results of calculations compared with the results obtained in laboratory tests.

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.

scholarly journals Case study on the mineralogical and petrophysical analysis of reinforced concrete slabs of a highway viaduct of the S.G.C. Orte-Ravenna

2021 ◽  
Vol 3 (6) ◽  
Author(s):  
Elena Marrocchino ◽  
Chiara Telloli ◽  
Alessandra Aprile ◽  
Domenico Capuani ◽  
Davide Malaguti ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slabs ◽  
Petrophysical Analysis ◽  
Reinforced Concrete Slabs
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