scholarly journals THE RELEVANCE OF CHANGING THE DESIGN SOLUTION COVERAGE WITHOUT STRENGTHENING EXISTING FOUNDATIONS

2019 ◽  
Vol 7 (2) ◽  
pp. 42-49
Author(s):  
Ольга Хрянина ◽  
Ol'ga Hryanina ◽  
Мария Колесникова ◽  
Maria Kolesnikova

The authors carried out the study of raw materials and their analysis, which allowed to identify the engineering-geological conditions of the construction site and outline the program of scientific and survey works. Full-scale and instrumental examination of the technical condition of the bearing and enclosing structures of the building. It is established that the building structures during operation have not received deformations that prevent normal operating conditions and are currently in satisfactory condition. The strength of concrete Foundation organoleptic and instrumental methods, which showed compliance with the design values. Analysis of verification calculations of the base, a satisfactory condition of the building structures showed that the structural solution of the coating can be changed and performed in kind without strengthening the existing foundations.

2021 ◽  
pp. 28-37
Author(s):  
Leonid Shyrin ◽  
Rostislav Yehorchenko ◽  
Мykola Sergienko

The purpose of the paper is to analyze a deformation mechanism of the mine degassing pipelines to forecast their spatial changes in terms of intensification of underground mining of coal-gas seams. Methodology. The paper deals with expert assessment of the available approaches to diagnostics of technical condition of mine degassing pipelines, which are constructed within the in-seam underground mine workings with the floor rocks prone to heaving. The results of scheduled surveying measurements of technical condition of in-seam development workings have helped identify the potentially hazardous zones of rock mass deformation and indices of changes in spatial location of section degassing pipelines mounted in those mine workings. To determine the operating modes of a degassing pipeline under such operating conditions, a computer model of interaction of the elements of transport-technological system “mine gas pipeline – mine working” has been developed Findings. Diagnostics of technical conditions of the mine gas transmission lines and examination of their dismantled components have helped understand that deflections, mainly resulting in water accumulation zones, intensive corrosion of internal pipe walls, and mechanical depositions of coal and rock dust take place right within the flange connection areas. Formation of such zones is argued by health of the degassing pipeline as well as mine air inflow. Availability of internal corrosion, water accumulations, and mine air inflow decreases substantially capacity of the underground gas transmission line inclusive of qualitative characteristics of the captured methane-air mixture and efficiency of MDS on the whole. Originality. New approaches to diagnostics of technical condition of mine degassing gas pipeline in difficult mining and geological conditions of development of gas-bearing coal seams are substantiated and it is offered to consider indicators of their functioning as interacting in space and time transport-technological system "mine gas pipeline - mining". Practical implications. The operational parameters of mine degassing systems notes that the equipment performance with the least underpressure losses created by vacuum pipes requires that the degassing pipeline should have minimum hydraulic resistance of the gas transmission network. Pipeline aeration from the mine workings and water accumulations should be prevented by means of qualitative hermetic sealing of its flange connections as well as the pipeline straightness with the corresponding pitches. Consequently, the basic requirements for operating mine degassing pipelines involve their design profile, tightness of flange connections of pipes as well as operative control of the facility health.


2013 ◽  
Vol 588 ◽  
pp. 281-289 ◽  
Author(s):  
Jan Warczek ◽  
Rafał Burdzik ◽  
Grzegorz Peruń

The modern commercial vehicle with a weight of more than 3,5 [Mg] is a complex design solution, which contains many of mechatronic systems. The standard equipment are the ability of the driver assistance systems such as ABS (Anti-Lock Braking System), ESP (Electronic Stability Program), ASR (Acceleration Slip Regulation). The technical condition of the modern car's suspension determines the value of the indicators of road safety. An essential element of the suspension system, whose function is to change the mechanical vibration energy into thermal energy, is the shock absorber. Incorrect functioning of shock absorbers affects the quality of the operation of these systems improve safety. In the case of gradually wears of shock absorber even an experienced driver is able to notice this phenomenon. For this reason it becomes necessary the need for regular technical condition monitoring of dampers. Diagnostic dampers on buses and trucks are limited to the organoleptic examination and propose based on intermediate symptoms such as accelerated tire wear. The paper describes the method for estimating the suspension damping characteristics of commercial vehicle in operating conditions.


2019 ◽  
Vol 265 ◽  
pp. 05003
Author(s):  
Nicolay Perminov ◽  
Andrey Perminov

In the article, on the basis of extensive theoretical and experimental research carried out, innovative geotechnology for repair of culverts is presented, which provides an improvement in the conditions for interaction between the body of the structure and the soil massif with increasing technogenic impacts. The analysis of the technical condition of the culvert transport and engineering structures under special operating conditions is given. Factors determining their premature emergency condition and interfering with stable functioning under increasing loads and impacts have been studied. On the basis of many years of experimental and theoretical and experimental design work, geotechnology «Saturn» has been proposed, suitable for repairing all types of culverts on railroads and highways, engineering infrastructure facilities, and especially for repair and reconstruction of pipes under conditions of a constant intensive watercourse with nonstandard (atypical) constructive solutions, as well as located in hard-to-reach and difficult for the organization of the construction site sections of the route. The experience of successful application of the developed technology "Saturn" on the railroad during the repair and reconstruction of long-maintained culverts of stone and concrete pipes under the conditions of a constant intensive watercourse and at water disposal facilities during repair of deep tunnels without their decommissioning is described.


2021 ◽  
Vol 11 (7) ◽  
pp. 2984
Author(s):  
Pietro Croce ◽  
Paolo Formichi ◽  
Filippo Landi

In modern structural codes, the reference value of the snow load on roofs is commonly given as the product of the characteristic value of the ground snow load at the construction site multiplied by the shape coefficient. The shape coefficient is a conversion factor which depends on the roof geometry, its wind exposure, and its thermal properties. In the Eurocodes, the characteristic roof snow load is either defined as the value corresponding to an annual probability of exceedance of 0.02 or as a nominal value. In this paper, an improved methodology to evaluate the roof snow load characterized by a given probability of exceedance (e.g., p=0.02 in one year) is presented based on appropriate probability density functions for ground snow loads and shape coefficients, duly taking into account the influence of the roof’s geometry and its exposure to wind. In that context, the curves for the design values of the shape coefficients are provided as a function of the coefficient of variation (COVg) of the yearly maxima of the snow load on the ground expected at a given site, considering three relevant wind exposure conditions: sheltered or non-exposed, semi-sheltered or normal, and windswept or exposed. The design shape coefficients for flat and pitched roofs, obtained considering roof snow load measurements collected in Europe during the European Snow Load Research Project (ESLRP) and in Norway, are finally compared with the roof snow load provisions given in the relevant existing Eurocode EN1991-1-3:2003 and in the new version being developed (prEN1991-1-3:2020) for the “second generation” of the Eurocodes.


Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4008
Author(s):  
Błażej Doroszuk ◽  
Robert Król ◽  
Jarosław Wajs

This paper addresses the problem of conveyor transfer station design in harsh operating conditions, aiming to identify and eliminate a failure phenomenon which interrupts aggregate supply. The analyzed transfer station is located in a Polish granite quarry. The study employs laser scanning and reverse engineering methods to map the existing transfer station and its geometry. Next, a discrete element method (DEM) model of granite aggregate has been created and used for simulating current operating conditions. The arch formation has been identified as the main reason for breakdowns. Alternative design solutions for transfer stations were tested in DEM simulations. The most uncomplicated design for manufacturing incorporated an impact plate, and a straight chute has been selected as the best solution. The study also involved identifying areas of the new station most exposed to wear phenomena. A new transfer point was implemented in the quarry and resolved the problem of blockages.


2012 ◽  
Vol 461 ◽  
pp. 652-655
Author(s):  
Ying Wu ◽  
Peng Zhang ◽  
Xiao Li

Directional drilling technology is an important and very promising trenchless pipeline crossing technology. On the basis of the related literature research at home and abroad and our pipeline construction site investigation, focuses on several common soil properties are introduced, and then the formation adaptability of directional drilling is analyzed. The drilling selection methods are made when drilling in the specific geological conditions, and the possible risks of the construction process have been classified in the directional drilling.


2018 ◽  
Vol 222 ◽  
pp. 01013 ◽  
Author(s):  
Katarzyna Pacewicz ◽  
Anna Sobotka ◽  
Łukasz Gołek

Three dimensional printing is a promising new technology to erect construction objects. Around the world in every moment a new prototypes constructions are made by using this method. Three dimensional printing is taken into account as technology which can be used to print constructions in automated way on the Moon or Mars. The raw materials, which can be used with three dimensional printing have to fulfil basic requirements for those which are used in construction. That means that components of printing mortars are made from ingredients easily accessible in area nearby construction site and can be reusable. The cost of printing building objects due to that requirements is comparable to costs of traditional building, which are currently available. However additive techniques of printing needs a dedicated mortars for printer supplying. Characteristic for such mortars is: setting time, compressive strength, followability in the printing system, shape stability of every printed layer, controlling the hydration rate to ensure bonding with the subsequent layer, reusable capabilities, easily accessible raw materials, cost of such mixtures shouldn’t be too high in order to keep 3D printing competitive for traditional ways of building, mortar components should be recyclable and printing process should not influence negatively on an environment and people. All properties of printing mortars are determined by the device for additive application method. In this paper review of available materials used for three dimensional printing technology at construction site is presented. Presented materials were analysed in terms of requirements for building materials technology. Due to the lack of detailed information’s in available literature, regarding to the properties of raw materials, the results of this analysis may be used in the designing of new concrete mixtures for the use in three-dimensional printing technology for construction.


Author(s):  
A.V. Golenishev ◽  
A.V. Nadezkin ◽  
M.E. Starchenko

Рассматриваются подходы по определению пороговых значений концентрации продуктов износа в отработанном цилиндровом масле, характеризующие переход объекта диагностирования судового крейцкопфного дизеля из одного технического состояния в другое. Показано, что существующие методики не учитывают индивидуальные особенности и техническое состояние деталей цилиндропоршневой группы. Предложено для решения задачи их трибодиагностики использовать разработанную имитационную модель, позволяющую провести моделирование процесса изнашивания цилиндровой втулки и поршневых колец судового дизеля и на основании полученных расчетов определить концентрацию продуктов износа поступивших в отработанное цилиндровое масло при различной скорости изнашивания трущихся деталей. Данные о фактической концентрации продуктов износа в отработанном цилиндровом масле в дальнейшем соотносятся с результатами моделирования, что позволяет оценить техническое состояние деталей цилиндропоршневой группы двигателя. Представлены результаты моделирования по определению пороговых значений концентрации продуктов износа в отработанном цилиндровом масле, характеризующее переход судового дизеля из исправного в несправное техническое состояние. Даны практические рекомендации по выбору пороговых значений содержания продуктов износа в отработанном цилиндровом масле для различных типов судовых крейцкопфных дизелей и условий их эксплуатации.The article examines approaches to determine the threshold values of the concentration of wear debris in used cylinder oil that characterize the transition of a ship crosshead diesel engine unit under test from one technical condition to another. It is shown that the existing methods do not take into account the individual characteristics and technical condition of the parts of the cylinder-piston group. To solve the problem of tribodiagnostics, it is proposed to use the developed simulation model, which allows modeling the wear process of the cylinder bushing and piston rings of a marine diesel engine and, based on the obtained results, determining the concentration of wear products issued in the used cylinder oil at different wear rates of the moving parts. The data on the actual concentration of wear products in the used cylinder oil are subsequently correlated with the simulation model results, which makes it possible to evaluate the technical condition of the parts of the engine cylinder-piston group. The article presents the results of modeling of threshold values determination of the concentration of wear products in used cylinder oil, that measure the transition of a marine diesel engine from a working condition to a malfunctioning technical condition. Practical recommendations are given on choosing threshold values for the concentration of wear products in used cylinder oil for various types of marine crosshead diesel engines and their operating conditions.


Author(s):  
Г. Смоляго ◽  
G. Smolyago ◽  
С. Дрокин ◽  
S. Drokin ◽  
А. Дронов ◽  
...  

The use of expanded lightweight concrete for the production of building structures can significantly reduce the weight, which is important in the manufacture of hollow-core slabs; the weight is a significant proportion of the total load. In the current regulatory documents, the physical and mechanical properties of expanded lightweight concrete differ significantly, and sometimes contradict each other. The defects and damages of expanded lightweight concrete hollow-core slabs are described in the case of the kindergarten built near 50 years ago. They appeared during the manufacture of the slabs - uncompacted concrete and uncovered ribs, or in the course of exploitation of the building - normal cracking, holes for pipes and corrosion of reinforcement. Two slabs in emergency condition have numerous longitudinal and shear cracks and chips of concrete caused by overloading. The differences in normative documents and methods of calculations used at the time of designing the kindergarten building and at the present time are shown. The assessment of the technical condition of the expanded lightweight concrete hollow-core slabs considering defects and damages are carried out


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