Magnetic variation in construction steels under tensile stress. Empirical research with Helmholtz coils

2021 ◽  
Vol 71 (341) ◽  
pp. e243
Author(s):  
D. Ferrández ◽  
C. Morón ◽  
P. Saiz ◽  
A. Morón

Steel is responsible for providing resistance to flexotraction to reinforced concrete structures. Steel is responsible for providing reinforced concrete structures with a flexural strength. For this reason, it is important to study its behaviour under different tensile states. This study used measuring equipment that was able to determine variations in magnetic properties of B500-SD steel bars during standard tensile tests. The magnetic field generated by a Helmholtz coil was collected through a secondary circuit. This enables the induced electromotive force to relate with the steel deflection stages when subjected to the tests. Moreover, it was possible to determine the variation of magnetic permeability when submitting 12mm and 16mm diameter bars to different tensile states. This method could prove extremely useful in determining the tensile state of ribbed steel bars that are embedded into the concrete structure.

2013 ◽  
Vol 470 ◽  
pp. 921-924
Author(s):  
Hai Chao Tan

As the progress of theory and computer technology, nonlinear analysis is widely applied in civil engineering. Strip method, as one of the numerical methods, is used widely especially in the analysis of beams, columns and shell structures. The first half of this paper introduces the theoretical model and the basic assumptions of the strip method; the latter half of this paper compiles the strip method into computer program using FORTRAN language. At last, using beams with rectangular cross-section of reinforced concrete structures as an example, the paper analyze the factors, such as the strength of the steel bars, which have an impact on the bearing capacity of reinforced concrete structures.


2006 ◽  
Vol 321-323 ◽  
pp. 377-380 ◽  
Author(s):  
Hong C. Rhim ◽  
Bo Hwan Oh ◽  
Hyo Seon Park

An attempt has been made to measure existing steel stress using magnetoelasticity. A device has been developed and used for the measurement of magnetism in response to the deformation of a steel bar. The proposed technique can be used for the assessment of existing reinforced concrete structures by the measurements of steel stress embedded inside concrete. A traditional technique requires to break the existing steel bar to measure existing strain. However, the proposed technique is developed to measure the stress without damaging the steel bar. A successful application of magnetoelasticity depends on the establishment of relationship between elastic and magnetic response due to loading. To investigate the correlation between the two, steel bars are loaded in tension under uniaxial loading while the magnetic reading is recorded. Based on the test results, equations are suggested to predict stress for steel bars with different diameters.


Author(s):  
Nour Eldeen Abo Nassar

Reinforced concrete (RC) structures have the ability to be extremely durable and able to withstand a diversity of different environmental cases. However, failure in these structures still happens due to precocious reinforcement erosion. If steel reinforcement corrodes in concrete structures, this leads to a decrease in the lifetime and durability of these structures, which cause early failure of the structures, costing significantly to inspect and maintain the deteriorating structures. Then, monitoring of reinforcement corrosion is of great importance to prevent early failure of structures. Structures corrosion can be decreased through correct monitoring and taking appropriate control measures in the appropriate period of time. When steel bars corrode, the formation of rust causes the concrete to be separated from the steel and then thereafter. In case this issue is not addressed, it may influence the entire structure. This paper attempts to present a comprehensive review of corrosion of rebar in RC structures, its mechanisms, monitoring and prevention.


2019 ◽  
pp. 185-190
Author(s):  
Yu. L. Kuzmin ◽  
O. A. Stavitsky

The paper analyzes ways to ensure long service life (up to 50 years) of reinforced concrete marine structures. It has been established that durability and maintenance-free operation of floating and coastal offshore structures for 50 and more years depend on corrosion of steel reinforcement which could be avoided by applying electrochemical protection. The parameters of electrochemical protection against corrosion of steel fittings are given.


2018 ◽  
Vol 11 (6) ◽  
pp. 1326-1353
Author(s):  
V. G. CHIARI ◽  
A. L. MORENO JUNIOR

Abstract The use of mechanical splices to connect steel bars is an important solution in many infrastructure projects worldwide. In Brazil, this system is rarely used. The Brazilian standards regarding this subject are old and out of date; particularly with regard to the performance evaluation test methods for these splices in the laboratory. This paper presents and discusses the test procedure proposed in the international standard ISO 15835 [1] in light of the current procedure defined by Brazilian Standard ABNT NBR 8548 [2], applied to types of mechanical splices commonly used in Brazil: taper threaded and bolted couplers. Performance parameters for these mechanical splicing systems related to structural integrity in reinforced concrete structures are evaluated on the basis of the results obtained in these tests. In the end, it is intended that this paper provide support for discussion of design procedures and laboratory performance evaluation of couplers for mechanical splices of steel bars in reinforced concrete structures in future reviews of Brazilian standard ABNT NBR 8548 [2].


Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 979 ◽  
Author(s):  
Margherita Pauletta ◽  
Nicola Rovere ◽  
Norbert Randl ◽  
Gaetano Russo

Maintenance of reinforced concrete structures is a prevailing topic, especially with regard to lifeline structures and bridges, many of which are now designed with a service life beyond 100 years. Reinforcement made of ordinary (carbon) steel may corrode in aggressive environments. Stainless steel, being much more resistant to corrosion, is a valid solution to facilitate the protection of the works, increasing the service life and reducing the need for repair and maintenance. Despite the potential for stainless steel to reduce maintenance costs, studies investigating the influence of stainless steel on the behavior of reinforced concrete structures are limited. This study investigated the bond behavior of stainless steel rebars by means of experimental tests on reinforced concrete specimens with different concrete cover thicknesses, concrete strengths, and bar diameters. In each case, identical specimens with carbon steel reinforcement were tested for comparison. The failure modes of the specimens were examined, and a bond stress–slip relationship for stainless steel bars was established. This research shows that the bond behavior of stainless steel rebars is comparable to that of carbon steel bars.


2015 ◽  
Vol 1 (2) ◽  
pp. 42
Author(s):  
E. Moreno ◽  
M. I. Prieto ◽  
M. N. González ◽  
N. Llauradó

ResumenLa carbonatación del hormigón o la intrusión de cloruros en suficiente cantidad para alcanzar el nivel de las barras, es desencadenante de la corrosión de la armadura. Uno de los efectos más significativos de la corrosión del acero de refuerzo en estructuras de hormigón armado es la disminución de las propiedades relacionadas con la ductilidad del acero. El reforzamiento tiene un efecto decisivo en la ductilidad global de las estructuras de hormigón armado. Se utilizan diferentes códigos para clasificar el tipo de acero en función de su ductilidad usando los valores mínimos de varios parámetros. El uso de indicadores de ductilidad asociados a diferentes propiedades puede ser ventajoso en muchas ocasiones. Se considera necesario para definir la ductilidad por medio de un solo parámetro que tiene en cuenta los valores de resistencia y deformación simultáneamente. Hay una serie de criterios para definir la ductilidad del acero mediante un único parámetro. El presente estudio experimental se ocupa de la variación en la ductilidad de las barras de acero embebido en hormigón cuando se expone a la corrosión acelerada. Este trabajo analiza la idoneidad de un nuevo indicador de la ductilidad utilizado en barras corroídas. AbstractThe carbonation of concrete or the chlorides ingress in such quantity to reach the level of bars is triggers of reinforcement corrosion. One of the most significant effects of reinforcing steel corrosion on reinforced concrete structures is the decline in the ductility-related properties of the steel. Reinforcement ductility has a decisive effect on the overall ductility of reinforced concrete structures. Different Codes classify the type of steel depending on their ductility defined by the minimum values of several parameters. Using indicators of ductility associating different properties can be advantageous on many occasions. It is considered necessary to define the ductility by means of a single parameter that considers strength values and deformation simultaneously. There are a number of criteria for defining steel ductility by a single parameter. The present experimental study addresses the variation in the ductility of concrete-embedded steel bars when exposed to accelerated corrosion. This paper analyzes the suitability of a new indicator of ductility used in corroded bars.


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