scholarly journals Methods of analysis of a reinforced concrete section under bending with axial force in the post-yield range

2014 ◽  
Vol 13 (3) ◽  
pp. 119-126
Author(s):  
Jacek Korentz
Keyword(s):  
Reinforced Concrete ◽  
Axial Force ◽  
Concrete Cover ◽  
Reinforcing Bars ◽  
Concrete Members ◽  
Extreme Loads ◽  
Concrete Confinement ◽  
The Moment ◽  
The Relationship ◽  
Concrete Section

Predicting the behaviour of plastic hinges subjected to large inelastic deformations caused by extreme loads such as earthquakes plays an important role in assessing maximum stable deformation capacities of framed concrete structures. This paper presents the analytical procedure for analysing the behaviour of a reinforced concrete section under bending with axial force in the post-yield range. The following stages of section behaviour are defined: the uncracked, first cracked, yielding, cover crushing, cover spalling, buckling of bars and limit stages. The relationship between the moment and curvature in these stages, including the effects of concrete confinement, the spalling of the concrete cover, and the inelastic buckling of the reinforcing bars, is considered. The presented method makes it possible to estimate the ductility of reinforced concrete members with various longitudinal and transverse reinforcement.

scholarly journals The method of analysis of a reinforced concrete section under bending in the post-yield range

2013 ◽  
Vol 12 (1) ◽  
pp. 123-130
Author(s):  
Jacek Korentz
Keyword(s):  
Reinforced Concrete ◽  
Analytical Procedure ◽  
Concrete Cover ◽  
Transverse Reinforcement ◽  
Concrete Members ◽  
Extreme Loads ◽  
Concrete Confinement ◽  
The Moment ◽  
The Relationship ◽  
Concrete Section

Predicting the behavior of plastic hinges subjected to large inelastic deformations caused by extreme loads such as earthquakes plays an important role in assessing maximum stable deformation capacities of framed concrete structures. This paper presents an analytical procedure for analysing the behaviour of a reinforced concrete section under bending in the post-yield range. The following stages of section behaviour are defined as the uncracked; first cracked; yielding; cover crushing; cover spalling; buckling of bars; and limit stages. The relationship between the moment and curvature in these stages, including the effects of concrete confinement, the spalling of the concrete cover, and the inelastic buckling of the reinforced bars, are considered. The results obtained from analytical calculations have are compared to the results obtained from a computer analysis. The presented method makes it possible to estimate the ductility of reinforced concrete members with various longitudinal and transverse reinforcement.

Numerical Interpretation of Bond Between Steel and Concrete in Presence of Corrosion and Cyclic Action

2009 ◽  
Vol 417-418 ◽  
pp. 349-352 ◽  
Author(s):  
Luca Giordano ◽  
Giuseppe Mancini ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Stress Transfer ◽  
Experimental Tests ◽  
Radial Pressure ◽  
Mechanical Action ◽  
Concrete Cover ◽  
Reinforcing Bars ◽  
Cyclic Action ◽  
Bond Slip

Bond between steel and concrete in reinforced concrete structures plays a fundamental role. The stress transfer mechanism depends on the condition of the contact surface between the two materials, the mechanical characteristics of concrete near the rebar and on the available level of confinement. Corrosion of reinforcing bars in concrete structures modifies those three factors. Because of corrosion, on the rebar surface a granular oxide layer is present and with its expansion it generates a significant radial pressure; consequently tensile stresses grow till cracking of the concrete cover with a subsequent reduction of the confinement effect. Moreover the presence of a mechanical action modifies the resisting mechanism producing an increasing damage. In this study, a model is presented for the numerical simulation of experimental tests on r.c. ties subjected to mechanical action; furthermore some considerations on reinforced concrete ties subjected also to corrosion effect are reported. From those analyses it is possible to estimate a modified bond-slip law between the reinforcing bars and the concrete, in order to take into account the level of damage.

scholarly journals New warning sensors to detect corrosion risk in reinforced concrete

2019 ◽  
Vol 289 ◽  
pp. 06002
Author(s):  
Mahdi Khadra ◽  
Elisabeth Marie-Victoire ◽  
Myriam Bouichou ◽  
Christian Crémona ◽  
Stéphanie Vildaer
Keyword(s):  
Reinforced Concrete ◽  
Concrete Cover ◽  
Chloride Ions ◽  
Cultural Value ◽  
Original Material ◽  
Reinforcing Bars ◽  
First Results ◽  
Corrosion Risk ◽  
Deterioration Mechanism ◽  
Different Depths

Corrosion is the most frequent but also the most deleterious deterioration mechanism affecting reinforced concrete. In addition to the economic impact of the repair works, for historical concrete structures, corrosion can generate irreversible losses of original material of great cultural value. If the usual non-destructive electrochemical methods have highlighted their efficiency in evaluating on-going corrosion activity, they also have pointed out their drawbacks for accurate extrapolation and prevention. To prevent the corrosion phenomenon, by detecting the penetration of aggressive agents, a new warning sensor system has been developed. The principle of the technique is to embed thin metallic sheets (called orphan blades) in the concrete cover, at different distances from the surface to the reinforcing bars. Then the corrosion of those very reactive orphan blades is followed during the propagation of the carbonation front and/or the penetration of chloride ions using stimulated infrared thermography. The corrosion of the sensors at different depths is indicative of the ingress speed of the front and can alert about the risk of corrosion of reinforcing bars in the concrete. The purpose of this study is to present this new technique and the first results obtained in the laboratory on corroded and non-corroded sensors.

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