scholarly journals Bridges maintainability evaluation peculiarities as part of hydraulic structures

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Boris Bondarev ◽  
Vladimir Erofeev ◽  
Alexandr Bondarev ◽  
Anastasia Korneeva ◽  
Mihail Gavrilov ◽  
...  
Keyword(s):  
Concrete Strength ◽  
Technical Condition ◽  
Hydraulic Structures ◽  
Actual State ◽  
Final Report ◽  
Shock Pulse ◽  
Structural Elements ◽  
Monitoring Method ◽  
Elastic Rebound

Introduction: the article is dedicated to assessing the condition with respect to use for traffic methods of bridges as part of hydraulic structures (dams, hydroelectric power stations, locks). The main factors affecting the structural element’s durability included in the composition of the hydraulic structures are dynamic loads (applied repeatedly and repeated) affecting the bay due to the hydrodynamic effect; temporary, moving loads from passing highway transportation, along the top of the structure (along the roadway); harmful chemical impurities contained in the water passing through the structure. Under the influence of the above-mentioned factors, defects and damage occur in the hydraulic facilities’ structural elements. Methods: the authors assessed the actual state of the material of the operating structure. To assess structures and materials actual state during the bridge structure inspection work, the following instrumental measurements were performed on as-built structural elements: leveling the top of the sidewalks and the roadway; materials strength determination of the main supporting structures by nondestructive methods; thickness measuring the asphalt concrete pavement of the roadway; determination of the degree of carbonation of concrete; identification of defects in the elements of the bridge. The actual structure’s concrete strength was determined by nondestructive testing methods: (1) by the method of the elastic rebound; (2) by the shock pulse monitoring method; (3) an indirect method of concrete strength ultrasonic testing based on the revealed relationship between the method of separation with shear test and methods – shock pulse and elastic rebound. Results: technical condition and bridge safety indicators calculation as a hydraulic structure element was executed. Discussion: technical examination results of the bridge structural elements and instrumental studies confirm the conclusion about the repair measures need with high-strength concretes and protective coatings based on polymer composite materials. Final report: following the emergency scenarios a numerical estimate table for the quantitative and qualitative parameters list was made, parameters corresponding to a particular structure state. Thus, according to the scenario related to the 3rd accident group, the bridge technical condition is assessed as limited operable, and the safety level is reduced.

MODELING THE PROCESS OF INSPECTION OF REINFORCED CONCRETE SUPPORTS OF TECHNOLOGICAL OVERPASSES

2021 ◽  
Vol 14 (1) ◽  
pp. 68-73
Author(s):  
N Rogov ◽  
S. Nikolenko ◽  
Svetlana Sazonova
Keyword(s):  
Reinforced Concrete ◽  
Concrete Strength ◽  
Technical Condition ◽  
Concrete Cover ◽  
Magnetic Method ◽  
Strength Of Materials ◽  
Elastic Rebound ◽  
Cover Thickness ◽  
Non Destructive

The paper presents the process of assessing the technical condition of reinforced concrete supports of existing technological overpasses. The characteristics of overpasses are given. Defects identified in the process of assessing the technical condition are shown. The paper describes the control of concrete strength by the non-destructive method of elastic rebound using the Digi Shmidt 2000 device and the determination of the concrete cover thickness and the location of reinforcement by the magnetic method using the Profometer-5S device. The layout of the working reinforcement in the reinforced concrete supports of the overpass section has been determined. The results of verification calculations of the structures of technological ramps are given, taking into account the revealed defects and damages, the strength of materials and the specified actual loads. Proposals are given for improving the performance of concrete of reinforced concrete supports of overpasses.

Examination of State of the Cable Insulation by the Return Voltage

2018 ◽  
Vol 19 (6) ◽  
Author(s):  
Dmitry Semenov ◽  
Anna Sidorova ◽  
Pavel Romanov ◽  
Aleksey Kuvshinov
Keyword(s):  
Residual Life ◽  
Technical Condition ◽  
Actual State ◽  
Power Cables ◽  
Insulation Resistance ◽  
Cable Lines ◽  
P Factor ◽  
Paper Insulation ◽  
New System

Abstract The relevance of the study is conditioned by the need to determine the state and residual life duration of high-voltage cable lines to identify faulty and maintainable cables. The aim of the article is to determine a reliable scientifically grounded criterion for assessment of insulation characteristics of the cables in use and to perform a comparative analysis of the results obtained by the traditional method of diagnosing insulation with the results of a new method of assessment by the return voltage. In this regard, the article deals with the issues related to the testing of cables having oil-impregnated paper insulation, as well as with the issue of switching from planned replacement of cables to assessment of their actual state and period of residual life. The authors propose to use the method of examining the cables by the return voltage using the device for testing electrical insulation “UDEI-1” developed at the department of Electrification and Automation of the Nizhny Novgorod State University of Engineering and Economics. The article presents the results of measuring the return voltage of three cables that operated under different conditions. The cables had different technical state. The analysis of the estimation of the residual life of cables by the return voltage was carried out using such criteria as the PIRV polarization index, the LIRV electrical conductivity index, and the P-factor. The P-factor is the physical criterion demonstrating the aging of paper-oil insulation by the shape of the return voltage curve. It represents such characteristics of insulation aging as moistening. To compare the results of testing the cables by the return voltage with the conventional methods of diagnostics and to determine the actual technical condition of power cables, the authors applied the method of spatiotemporal reflectometry and the method of measuring insulation resistance with the determination of such indicators of state as insulation resistance normalized per one kilometer, absorption coefficient, and polarization index. The results of this article confirm that the return voltage gives a qualitative assessment of the state and degree of aging of cables with impregnated paper insulation. The authors proposed a new system for evaluation of cable condition by weighting coefficients. In this approach, the determination of residual life of cables with impregnated paper insulation is based on the values of the return voltage. Application of the new system gives opportunity to improve reliability of the power lines. Recommendations for the further operation of the studied cables are given. The materials of the article are of practical value for carrying out complex assessment of the technical condition of power cables by the return voltage and can be useful for drawing up a schedule for replacement or repair of cable lines depending on their actual state.

scholarly journals THE ALGORITHM OF COMPLEX DIAGNOSTICS OF TECHNICAL CONDITION OF BUILDING STRUCTURES ON THERMOGRAMS ANALYSIS

2020 ◽  
pp. 23-28
Author(s):  
D. Karpov
Keyword(s):  
Construction Projects ◽  
Thermal Power ◽  
Technical Condition ◽  
Building Structures ◽  
Structural Elements ◽  
Highly Qualified ◽  
Energy Survey ◽  
Measurement Base ◽  
Actual Mass

the algorithm of complex diagnostics of a technical condition of building constructions and structures on the analysis of thermograms is offered. An attempt is made to systematize and logically build a sequence of stages of energy inspection of heat-consuming and heat-generating construction projects and their structural elements. The presented algorithm includes the main stages performed in such surveys. It differs from the known technologies of energy monitoring of buildings and structures by the presence of two additional stages, which are an integral part of any energy survey: determination of the relative surface humidity of building structures and the actual mass flow of coolant through the heating device for the analysis of thermal images. The implementation of energy (thermal imaging) and technical inspections according to the presented structural scheme requires not only the presence of appropriate instrumentation and measurement base, but also the involvement of highly qualified specialists (civil engineers, thermal power engineers, thermal physicists, operators-thermographers, etc.).

scholarly journals Nalysis of Changes to Steel Footbridge Geometry Within 25 Years in Service

2018 ◽  
Vol 28 (2) ◽  
pp. 164-176
Author(s):  
Jacek Sztubecki ◽  
Adam Bujarkiewic ◽  
Justyna Sobczak-Piąstka ◽  
Tomasz Janiak ◽  
Jarosław Gajewski
Keyword(s):  
Service Life ◽  
Technical Condition ◽  
Frame Of Reference ◽  
General Analysis ◽  
Bridge Structure ◽  
Structural Elements ◽  
Bridge Structures ◽  
Special Value ◽  
Static Operation

Abstract Identification of the technical condition of bridge structures should be supplemented by determination of structural displacements in relation to the adopted frame of reference and measurement of changes to the geometry of its individual elements. Of special value are the results of measurements of the same values obtained along an extended service life. They provide an opportunity to compare results, track down tendencies, and more quickly recognise signs of aggravating technical condition of structures. The paper presents an analysis of changes to the geometry of a bridge structure – a cable– stayed footbridge used for pedestrian and bicycle traffic across the Brda river in Bydgoszcz. Measurements were made by means of surveying techniques within a period of 25 years of the structure service life. The collected data enabled numerous comparative analyses to be conducted. Displacements of footbridge structural elements observed across time led to formulation of recommendations for further use of the footbridge. For instance, recommendations for footbridge adjustment, including improvement of its geometry, were provided. In addition, a general analysis of the effect of footbridge displacements on its static operation was conducted.

Digital assessment of reliability of production system of power subjects

2018 ◽  
Vol 11 (2) ◽  
pp. 109-116
Author(s):  
S. V. Mishcheryakov
Keyword(s):  
Human Capital ◽  
Production System ◽  
Target Function ◽  
Technical Condition ◽  
The State ◽  
Actual State ◽  
Fuel Supply ◽  
Digital Assessment ◽  
Optimal Values

The article outlines scientifi c approaches to the formation of digital technologies for managing the main factors of energy production. The assessment of the state of the production system is based on the index of the state of the production system of the power facility. Its target function is formulated, including dimensionless indices of fuel supply, the state of material and human capital assets. The author has formulated and solved the problem of finding the optimal values of a function using the mathematical apparatus of fuzzy sets. The indices characterizing the factors of production are defined as the solution of the optimization problem using ranking by values and weight coefficients determined by Saaty’s method. The determination of the fuel supply index and the technical condition of assets is carried out on the basis of the methods adopted in the energy sector, taking into account their actual state, provided that the reliability of the functioning of the UES is ensured. The article discusses in detail the technologies for assessing the company's human capital, shows the investment benefits of its development, presents the rational ranges of these investments, and provides statistical data that support the theoretical conclusions.

scholarly journals DETERMINATION OF TECHNICAL CONDITION OF BUILDING CONSTRUCTIONS BASED ON COMPREHENSIVE ASSESSMENT OF BUILDING PRODUCTION

2019 ◽  
pp. 22-27
Author(s):  
А. Малахов ◽  
A. Malahov ◽  
В. Косинов ◽  
Viktor Kosinov
Keyword(s):  
Technical Condition ◽  
Comprehensive Assessment ◽  
Structural Elements ◽  
Industrial Facilities ◽  
Engineering Research ◽  
Industrial Buildings ◽  
Metal Frame ◽  
Capital Construction ◽  
Instrumental Control

The article deals with the issues related to the assessment of the technical condition of structural elements, taking into account the stages of engineering research, design and installation. The importance of the topic under consideration is due to a large number of accidents at civil and industrial facilities that occur before the exhaustion of the bearing capacity. The analysis of the object (the metal frame of industrial buildings) is carried out on the basis of project documentation, data obtained by a full-scale survey, visual and instrumental control, numerical methods of research. The qualitative and quantitative parameters of the capital construction object necessary for assessing the technical condition are presented. They include design schemes of frame structures, materials, their characteristics, defects and parameters. The study shows the importance of comprehensive assessment of capital construction facilities in terms of constructive safety. Identification of errors at each stage of construction allows to prevent emergencies that lead to the destruction of the load-bearing system and to develop measures to establish the possibility (impossibility) of repair or reconstruction

scholarly journals Development of Devices for the System of Monitoring the Strength Features of Concrete in Operated Buildings and Structures Based on the Ultrasonic Pulse Method

2019 ◽  
pp. 22-27
Author(s):  
Ya. Serikov
Keyword(s):  
Building Materials ◽  
Pulse Method ◽  
Ultrasonic Pulse ◽  
Technical Condition ◽  
Structural Elements ◽  
Survey Results ◽  
Static And Dynamic Loads ◽  
Object Material ◽  
Negative Factors

  Operation of buildings and structures for various purposes is accompanied by an impact on their structural elements, building materials, and a complex of negative factors. These factors include the lifespan, climatic parameters, static and dynamic loads, dustiness, air pollution, etc. Their action worsens the physico-mechanical characteristics, the structure of concrete. This reduces the reliability of structural elements, reduces the life of the construction object. In DBN V. 1.2-14-2009 «The system of ensuring the reliability and safety of construction objects» set the classification of construction objects by classes of consequences in the event of an accident. The estimated lifetimes of each type of construction objects are also determined. Extension of life is allowed only after inspection and evaluation of the technical condition of the construction object, material characteristics, through the determination of the degree of their compliance with regulatory requirements. The importance of obtaining reliable survey results requires the improvement of relevant instruments and metrology. The described developed system of monitoring of construction objects, as well as instrumentation and system based on the ultrasonic pulse method. They are designed to control the physico-mecha-nical characteristics, the structure of concrete and other building materials. The developed devices and system are characterized by increased accuracy, reliability and reliability of measurements.

scholarly journals DETERMINATION OF A TECHNICAL CONDITION OF THE EQUIPMENT OF THE LINE OF A DRIVE OF ROLLING ROLLS ON THE SPEED OF PROPAGATION OF THE SHOCK PULSE

2021 ◽  
pp. 21-24
Author(s):  
Andriy Baglai
Keyword(s):  
Delay Time ◽  
Impact Load ◽  
Technical Condition ◽  
Pulse Velocity ◽  
Diagnostic Feature ◽  
Shock Pulse ◽  
Intermediate Shaft ◽  
Speed Of Propagation ◽  
The Impact

One of the ways to determine the technical condition of the equipment of the line working rolls - spindles - gear cage - root coupling - reducer - intermediate shaft - engine is considered. In each connection there is wear of contact elements, for example, bronze inserts of spindles, teeth of gears. According to the known method, the amount of current wear of the elements and the gaps caused by them at the same time is determined by the time of delay of the reaction of sections of the line to the impact load during the capture of the strip by rolls. The greater the wear, the longer the delay time. The option of determining the state of the nodes of the line by determining the speed of propagation of the shock pulse from the rolling stand to the engine is considered. An example of measuring the reaction delay time of three sections of one of the stands with calculations of the pulse rate in these sections is given. It is shown that with increasing wear, the pulse velocity decreases significantly. Therefore, this speed characterizes the technical condition of the sites, ie has a diagnostic feature. Additionally, the influence of the presence of oil, scale, and contamination in the joints is considered. It is also recommended to use the ratio of the base speed of the shock pulse in the solid shaft to the actual speed in the nodes to determine their technical condition.

DETERMINE THE EFFECT OF DESTRUCTION OF ELEMENTS OF THE BASE ON GENERAL TECHNICAL CONDITION OF HOUSING FACILITIES

2014 ◽  
Vol 2 (3) ◽  
pp. 0-0
Author(s):  
Марина Шутова ◽  
Marina Shutova ◽  
Анатолий Субботин ◽  
Anatoliy Subbotin ◽  
Сергей Болдарев ◽  
...  
Keyword(s):  
Construction Projects ◽  
Standard Procedure ◽  
Technical Condition ◽  
Actual State ◽  
Technical Inspection ◽  
Physical Deterioration ◽  
General Technical ◽  
Housing Facilities

The article is devoted compared the results of determination of physical deterioration and condition of foundations housing facilities according to the standard procedure and the actual state of foundations, estimated by the results of a full technical inspection of construction projects

scholarly journals On the calibration dependencies designing for concrete strength testing by sclerometric nondestructive metods

2020 ◽  
pp. 16-25
Author(s):  
D. Snezhkov
Keyword(s):  
Concrete Strength ◽  
Pulse Method ◽  
Interaction Force ◽  
Test Methods ◽  
Additional Parameter ◽  
Shock Pulse ◽  
Parameter Calibration ◽  
Elastic Rebound ◽  
Under Construction ◽  
Two Parameter

Sclerometric methods of testing concrete, in particular, the rebound hammer testing, retain their positions as the most common indirect methods for concrete strength determining in situ. They are used as a means for technological testing during the buildings construction, as well as during their inspection during maintenance. Indirect parameters of current sclerometric devices are usually point-values: the rebound index, the diameter and depth of the print, the duration of the indenter insertion process, and the maximum interaction force. However, the lack of an unambiguous relationship between these parameters and the strength of concrete leads to additional uncertainty of the test result, which is one of the problems of sclerometric methods of concrete control. The instability of the calibration dependencies of the method is also observed. Even strict compliance with the requirements of the procedure does not guarantee the repeatability of the obtained dependencies.The article considers the possibility of improving metrological indicators of calibration dependencies of sclerometric methods by introducing an additional parameter-concrete humidity. The possibility of combining two sclerometric methods – the elastic rebound method and the shock pulse method is also considered. Data were obtained on concrete samples with a curing time of 25..60 days. Two-parameter calibration dependencies, including concrete humidity as an additional parameter, allowed for all experimental series of samples to reduce the residual mean square deviation of the calibration dependence of elastic rebound and shock pulse methods by 10%..16%, and to consistently provide the minimum acceptable value of the correlation coefficient r = 0.7 for the studied concrete compositions. The influence of concrete heterogeneity on the readings of sclerometric test methods is considered.The developed method of constructing two-parameter calibration dependencies can be recommended for inclusion in the current standards governing the determination of the strength of concrete structures under construction.

Sign in / Sign up

Export Citation Format

Share Document