Experimental Evaluation of Corrosion Effect on Bond Between Steel and Concrete in Presence of Cyclic Action

2009 ◽  
Vol 417-418 ◽  
pp. 345-348 ◽  
Author(s):  
Luca Giordano ◽  
Giuseppe Mancini ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Cyclic Load ◽  
Crack Opening ◽  
Concrete Structures ◽  
Electrochemical Corrosion ◽  
Reinforced Concrete Structures ◽  
Reinforcing Bars ◽  
Cyclic Action ◽  
In Series ◽  
Ultimate Condition

Corrosion modifies the steel-concrete interface in reinforced concrete structures. The efficiency of the connection between the two materials is reduced and the structural behavior both in service and in ultimate condition is affected. Moreover in structures subjected to cyclic load, a simultaneous mechanical deterioration due to the load is present. In this work an experimental analysis on reinforced concrete structures under both cyclic load and corrosion of reinforcing bars is presented. Three couples of reinforced concrete ties are connected in series and subjected to the same stress variation in order to produce the cracking conditions and to activate the bond mechanism. However, while one of the two reinforced concrete ties is only subjected to cyclic load, the second one is also corroded using an accelerated electrochemical corrosion process. The simultaneous effect of the cyclic load and corrosion is evaluated monitoring the crack opening on the structures during the test and by means of visual inspection of the sample. The test results show the correlation between the mechanism of bond and the average level of stresses for an amplified stress range.

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.

Crack Width Evolution of R/C Structures Subject to Corrosion and Fatigue

2010 ◽  
Vol 452-453 ◽  
pp. 417-420
Author(s):  
Luca Giordano ◽  
Francesco Tondolo
Keyword(s):  
Reinforced Concrete ◽  
Service Life ◽  
Crack Width ◽  
Cyclic Load ◽  
Crack Opening ◽  
Reinforced Concrete Structures ◽  
Chemical Attack ◽  
Experimental Campaign ◽  
Simultaneous Loading ◽  
Concrete Interface

Corrosion modifies the steel-concrete interface in reinforced concrete structures. Moreover in structures subjected to cyclic load, a simultaneous mechanical deterioration due to the load is present. Both phenomena can lead to an evolution of cracks width during the service life. In order to evaluate the crack openings increase, an experimental campaign on reinforced concrete ties subjected to simultaneous loading and corrosion have been realized. Transversal crack opening, initially due to loading and longitudinal corrosion cracks evolution is monitored. Results highlight the differences in terms of corroded and uncorroded specimens, static and cycling test and also different loading amplitude. Finally it can be observed as the growing of the damage is significantly different when a cycling action, combined with a chemical attack is present.

scholarly journals Distributed Fiber Optics Sensing and Coda Wave Interferometry Techniques for Damage Monitoring in Concrete Structures

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 356 ◽  
Author(s):  
Antoine Bassil ◽  
Xin Wang ◽  
Xavier Chapeleau ◽  
Ernst Niederleithinger ◽  
Odile Abraham ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Fiber Optics ◽  
Asset Management ◽  
Crack Opening ◽  
Concrete Structures ◽  
Reinforced Concrete Beam ◽  
Coda Wave ◽  
Reinforced Concrete Structures ◽  
Detection And Localization ◽  
Coda Wave Interferometry

The assessment of Coda Wave Interferometry (CWI) and Distributed Fiber Optics Sensing (DFOS) techniques for the detection of damages in a laboratory size reinforced concrete beam is presented in this paper. The sensitivity of these two novel techniques to micro cracks is discussed and compared to standard traditional sensors. Moreover, the capacity of a DFOS technique to localize cracks and quantify crack openings is also assessed. The results show that the implementation of CWI and DFOS techniques allow the detection of early subtle changes in reinforced concrete structures until crack formation. With their ability to quantify the crack opening, following early detection and localization, DFOS techniques can achieve more effective monitoring of reinforced concrete structures. Contrary to discrete sensors, CWI and DFOS techniques cover larger areas and thus provide more efficient infrastructures asset management and maintenance operations throughout the lifetime of the structure.

scholarly journals Nonlinear calculation of reinforced concrete structures to the impact of the air shock wave

Vestnik MGSU ◽  
2019 ◽  
pp. 33-45 ◽  
Author(s):  
Anton Y. Savenkov ◽  
Oleg V. Mkrtychev
Keyword(s):  
Numerical Simulation ◽  
Shock Wave ◽  
Reinforced Concrete ◽  
Nonlinear Dynamic ◽  
Software Package ◽  
Crack Opening ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Advantages And Disadvantages ◽  
The Impact

Introduction. Researched methods of accounting for the nonlinear operation of reinforced concrete structures on the example of an industrial structure, when exposed to an air shock wave using modern software systems based on the finite element method. The calculation of reinforced concrete construction to the impact of an air shock wave, if no increased requirements for tightness are presented to it, in accordance with current regulatory documents, must be carried out taking into account the elastic-plastic work, crack opening in the stretched zone of concrete and plastic deformations of reinforcement are allowed. Reviewed by new coupling approach to determining the dynamic loads of a shock wave, implemented in the LS-DYNA software package, which allows to take into account the effects of a long-range explosion and wave-wrapping around a structure. Materials and methods. The study of the stress-strain state of the structures was carried out using numerical simulation. For the nonlinear equivalent-static method, a step-by-step calculation algorithm is used, with gradual accumulation and distribution of stresses, implemented in the LIRA-SAPR software package. For the nonlinear dynamic method, the Lagrangian-Eulerian formulation is used using the methods of gas dynamics in the LS-DYNA software package. Results. As a result of numerical simulation, the following was done analysis of existing methods of nonlinear calculations; analysis of the existing loads during the flow of shock waves around the structure; analysis of the forces and movements in the bearing elements, as well as pictures of the destruction of concrete and reinforcement. Conclusions. According to the results of the comparison of the two approaches, conclusions are drawn about the advantages and disadvantages of the methods. Advantages of nonlinear dynamic calculation methods are noted compared to the equivalent-static ones. Use of the combined approach to the description of the shock wave front gives a reduction in time and allows us to describe the interaction of the wave with the structure with sufficient accuracy. The findings indicate the relevance of the study and provide an opportunity to move to more reasonable computational models.

Probable Calculation of Reinforced Concrete Elements by Deformation

2019 ◽  
Vol 974 ◽  
pp. 614-619
Author(s):  
Valeria A. Pshenichkina ◽  
Fedor F. Leychu ◽  
Kseniya N. Sukhina ◽  
Vyacheslav V. Drozdov
Keyword(s):  
Reinforced Concrete ◽  
Building Material ◽  
Crack Opening ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Uniform Deformation ◽  
Operation Stage ◽  
High Degree ◽  
Concrete Elements ◽  
Degree Of Heterogeneity

The article discusses the methodology for the reinforced concrete structures’ probabilistic deformation calculation. The uniform deformation criteria for assessing the reliability of reinforced concrete structures in the operation stage for strength, stiffness and crack opening are proposed. Taking into consideration the relatively high degree of heterogeneity of reinforced concrete as a building material, each criterion is determined with a predetermined provision.

Interaction between Flexure and Shear on the Debonding of RC Beams Retrofitted with Compression Face Plates

2002 ◽  
Vol 5 (4) ◽  
pp. 223-230 ◽  
Author(s):  
M.S. Mohamed Ali ◽  
D.J. Oehlers ◽  
M.A. Bradford
Keyword(s):  
Reinforced Concrete ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Rc Beams ◽  
Reinforcing Bars ◽  
Stress Concentrations ◽  
Deep Beams ◽  
Continuous Beams ◽  
The Subject

Steel and FRP plating reinforced concrete structures is increasingly being used for retrofitting. Plates can be bonded to any surface of a beam or slab, although it is common practice to adhesively bond plates to the tension faces. The addition of these tension face plates reduces the sectional ductility of the beam. Furthermore, these tension face plates are prone to premature debonding because the stress concentrations induced by these plates overlap with those induced by the tension reinforcing bars adjacent to the plate. Solutions to these two problems, which are the subject of this paper, consist of: adhesively bonding plates to the compression faces to counterbalance the tension face plates and, hence, improve the beam sectional ductility; and to extend the tension face plates, in continuous beams, past the points of contraflexure so that they terminate in a compression face. In this paper, eleven new tests on 340 mm deep beams are presented that show that compression face plates are less prone to debonding than tension face plates.

scholarly journals Method of the Finite-Element Model Formation Containing the 3D Elements for Structural Calculations of the Reinforced Concrete Structures Considering the Crack Opening

2021 ◽  
Vol 23 (1) ◽  
pp. D15-D25
Author(s):  
Sergei N. Nazarenko ◽  
Galina A. Grudcina
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Crack Opening ◽  
Concrete Structures ◽  
Analytical Calculation ◽  
Element Model ◽  
Data File ◽  
Reinforced Concrete Beam ◽  
Reinforced Concrete Structures ◽  
3D Elements

This article presents the 3D computational modeling method for reinforced concrete structures. An example of calculation of the reinforced concrete beam, using the Finite Element Method in SCAD++ following proposed algorithm, is given. Results comparison to the analytical calculation of the model with selected reinforcement is presented. For concrete, the 3D solid Finite Elements are used and the 3D beam elements for reinforcement. The model is formed using AutoCAD and AutoLISP, which creates a text data file in SCAD format for the description of model. In addition, computation of the 3D model of the crossbar with a crack is performed. Crack sizes are set in the stretched zone based on data from initial calculation. Graphic results obtained in SCAD++ are presented.

RESULTS OF EXPERIMENTAL STUDIES OF REINFORCED CONCRETE STRUCTURES WITH SQUARE CROSS SECTIONS IN TORSION WITH BENDING

2020 ◽  
Vol 91 (5) ◽  
pp. 3-12
Author(s):  
Vl.I. KOLCHUNOV ◽  
◽  
A.I. DEMYANOV ◽  
I.V. PECHENEV ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Cross Section ◽  
Cross Sections ◽  
Crack Formation ◽  
Rectangular Cross Section ◽  
Crack Opening ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Strain Gauges ◽  
Reinforced Concrete Structures

The article presents the results of experimental studies of the complex resistance of reinforced concrete structures with a square cross-section, made of B25 heavy-concrete, which includes graphs of deflection and rotation angles, as well as the dependence of concrete deformations obtained from the indications of strain gauges. The main deformations of elongation (and shortening) of concrete were determined using data, obtained from the proposed scheme for installing strain gauges. Rebar for experimental samples was selected in such a way that it achieved yield stress in the stage before destruction. The obtained experimental data is required for evaluation of proposed methods for calculation of structures with a rectangle cross section structures in the considered stress-strain state, for example, to check the values of the general load of crack appearing, its value relative to the distruction load; distance between cracks at different levels of crack formation, width of cracks opening at the level of the main reinforcement axis and at the distance of two diameters from the reinforcement axis, coordinates of spatial cracks formation, schemes of crack formation, crack development and crack opening. It was found, that in the tested structures the width of crack opening at the level of the main reinforcement axis is two to three times less than at a distance of two diameters from the main longitudal (or transverse) reinforcement axis. The parameters and crack patterns established during the experiments allow us to clarify the accepted working hypotheses for constructing a calculation model of the resistance in reinforced concrete structures of rectangular cross-section under torsion with bending.

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