Determination of yielding point by means a probabilistic method on acoustic emission signals for application to health monitoring of reinforced concrete structures

2018 ◽  
pp. e2305
Author(s):  
R. Vidya Sagar ◽  
Gyaneshwar Kumar ◽  
Gaurav Prasad ◽  
Elisabet Suarez ◽  
Antolino Gallego
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Health Monitoring ◽  
Probabilistic Method ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Yielding Point

Improvement Of Curvilinear Diagrams Of Concrete Deformation

2019 ◽  
pp. 99-104
Keyword(s):  
Reinforced Concrete ◽  
Peak Load ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Deformation Model ◽  
Reinforced Concrete Structures ◽  
Significant Difference ◽  
Deformation Diagrams

Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.

EXPERIMENTAL STUDIES OF REINFORCED CONCRETE STRUCTURES WITH CROSS-SHAPED SPATIAL CRACK UNDER TORSION WITH BENDING

2020 ◽  
Vol 92 (6) ◽  
pp. 13-25
Author(s):  
Vl.I. KOLCHUNOV ◽  
◽  
A.I. DEMYANOV ◽  
M.M. MIHAILOV ◽  
◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Experimental Determination ◽  
Calculation Method ◽  
Experimental Studies ◽  
Concrete Structures ◽  
Design Parameters ◽  
Reinforced Concrete Structures ◽  
Experimental Scheme

The article offers a method and program for experimental studies of reinforced concrete structures with cross-shaped spatial crack under torsion with bending, the main purpose of which is to check the design assumptions and experimental determination of the design parameters of the proposed calculation method. The conducted experimental studies provide an opportunity to test the proposed calculation apparatus and clarify the regularities for determining deflections, angles of rotation of extreme sections, and stresses in the compressed zone of concrete. For analysis, the article presents a typical experimental scheme for the formation and development of cracks in the form of a sweep, as well as characteristic graphs of the dependence of the angles of rotation of end sections.

Integration and evaluation of multiple piezo configurations for optimal health monitoring of reinforced concrete structures

2017 ◽  
Vol 28 (19) ◽  
pp. 2717-2736 ◽  
Author(s):  
Naveet Kaur ◽  
Lingfang Li ◽  
Suresh Bhalla ◽  
Yong Xia ◽  
Pinghe Ni ◽  
...  
Keyword(s):  
Reinforced Concrete ◽  
Health Monitoring ◽  
Concrete Structures ◽  
Mechanical Impedance ◽  
Metal Wire ◽  
Small Range ◽  
Reinforced Concrete Structures ◽  
Complex Behaviour ◽  
Damage Level ◽  
Impedance Technique

Since the last two decades, the electro-mechanical impedance technique has undergone extensive theoretical and experimental transformations coupled with the evolution of newer practical adaptations and variants. Notable among these are the metal wire–based variant, the dual piezo configuration and the embedded configuration, over and above the conventional surface-bonded configuration. Although there is a plethora of electro-mechanical impedance–related research devoted to metallic structures, only a limited number of studies are available for reinforced concrete structures, which are characterized by more complex behaviour and pose multiple problems for the electro-mechanical impedance sensors such as small range and high damping due to heterogeneous constitution. This article presents, for the first time, a comprehensive comparative study covering four different variants, namely, the surface-bonded single piezo configuration, the embedded single piezo configuration and the metal wire single piezo configuration in electro-mechanical impedance technique for structural health monitoring of a real-life-sized reinforced concrete beam subjected to destructive testing. The article also proposes a modified and more practical version of the dual piezo configuration called the modified dual piezo configuration, employing concrete vibration sensors. It is found that the modified dual piezo configuration is the most expedient among all variants in capturing the damage with respect to the first occurrence of cracks and the final warning of ultimate failure. Metal wire single piezo configuration is good in detecting the first level of damage; however, its efficiency ceases thereafter when crack size increases. It can be considered as an alternative to surface-bonded single piezo configuration in the scenarios where the damage level is incipient. The sensitivity of the modified dual piezo configuration increases with increasing number of actuators connected in parallel due to an increase in the output current. Also, contrary to the surface-bonded single piezo configuration, the susceptance signature of the modified dual piezo configuration is equally sensitive to damage due to the absence of capacitance part in its admittance signature. Hence, its susceptance can also be used for damage severity measurement for incipient damage level in reinforced concrete structures. The surface-bonded single piezo configuration is found to be best in quantifying damage severity in terms of the equivalent stiffness parameter. Embedded single piezo configuration and metal wire single piezo configuration, on the other hand, correlate well with the global dynamic stiffness of the structure. Overall, the proposed integration enables an early detection of damage, its propagation and improved severity measurement for reinforced concrete structures, thus contributing to new application protocols.

scholarly journals Deformability of Short Steel Reinforced Concrete Structures on Light Concrete

2018 ◽  
Vol 7 (3.2) ◽  
pp. 370 ◽  
Author(s):  
Oleksandr Semko ◽  
Viktor Dariienko ◽  
Vitaliy Sirobaba
Keyword(s):  
Reinforced Concrete ◽  
Sheet Metal ◽  
Experimental Research ◽  
Lightweight Concrete ◽  
Structural Parameters ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Steel Reinforced Concrete ◽  
Thin Walled

The calculation, modeling and experimental research of steel-concrete tubular elements made of thin-walled galvanized sheet metal and lightweight concrete have been carried out. The proposed type of structures can be used as a separate structure in the form of a column or a pillar, and one of the types of the reinforcement of a certain light structure. The basic technological and constructive requirements for manufacturing and further exploitation of structures are given. For determination of actual work’s indexes of constructions experimental research of standards are undertaken, and recommendations on adjustment of well-known calculation formulas of close constructions as for structural parameters are given. The design (modeling) was performed in MSC / Nastran software. An analysis of the proposed structures use is carried out with the corresponding conclusions. 

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