233 Works

Scheduling workflows for scattered objects

Yuri Kalugin & Roman Romanov
As a rule, the task of optimal scheduling, including reducing the total duration of the project occurs when developing and adjusting schedules. The essence of flow shop scheduling problem on the scattered objects with the use methods and models calendar planning was presented. The branch and boundary method were proposed as an exact method for determining the optimal permutation including the scheme of branching and rules for determining the lower boundaries. Heuristic algorithms for determining...

Granulated foam-glass ceramics for ground protection against freezing

Konstantin Ivanov
The problem of seasonal freezing and frost heaving of soils of the engineering structures foundations is considered. For the purpose of thermal protection of soils, a granular inorganic closed-porous material, named granulated foam-glass ceramic is proposed. In the laboratory modeling of seasonal freezing, the dynamics of temperature and deformation, as well as the distribution of moisture over the depth of the soil, were studied in three cases: a soil without thermal insulation, a soil with...

Lifetime of earth dams

Tamila Titova, Rasul Akhtyamov, Elina Nasyrova & Antonia Longobardi
The level of safety of small earth dams, operating without staff and measurement and control equipment, are considered in this study. Approach enabling the possibility to define the finite lifetime (Tf) of a small earth dam here presented. The proposed approach does not require any variables monitoring. It is based on the definition of Tf by assessing the water impact on the small earth dams by quantitative methods of system analysis. To assess the earth...

Ultra-high rockfill dam with combination of the reinforced concrete face and clay-cement diaphragm

Mikhail Sainov & Vladislav Soroka
The article deals with design validation of a new type of an embankment dam structural design, i.e. rockfill dam with combination of two types of non-soil seepage-control elements – a reinforced concrete face (in the dam upper part) and a clay-cement diaphragm made of bored piles (in the dam lower part). The dam of the considered design has a number of advantages over classical structural design of concrete faced rockfill dam (CFRD). First of all,...

Thermal cracking resistance in massive foundation slabs in the building period

Aleksandra Bushmanova, Yuriy Barabanshchikov, Kirill Semenov, Ayyyna Struchkova & Sergey Manovitsky
The article deals with the research of the thermal cracking resistance of massive concrete and reinforced foundation slabs of buildings and structures in the building period. The article examines the results of the analysis of the thermal stress state of a massive foundation slab with a fixed thickness of thermal insulation as well as the results of changing the minimum thickness of the insulation on a surface, providing the cracking resistance of the structures on...

Fluid filtration in the clogged pressure pipelines

Elena Loktionova & Dinara Miftakhova
Reducing of the hydraulic characteristics of pressure pipelines in the course of their operation due to corrosion, clogging and other causes leads to an increasing of operating costs. The existing information on the change in the capacity of pipelines under the influence of certain factors is currently insufficient. The aim of the work is to determine the influence of the clogging degree of the pipeline on its throughput. This paper describes the results of hydraulic...

BIM технологии в оценке уровня охраны труда

Шарманов Владимир Владимирович, Симанкина Татьяна Леонидовна & Мамаев Антон Евгеньевич
В статье представлена методика мониторинга и контроля техники безопасности и охраны труда на основе современных инновационных технологий и цифровой модели строительной площадки. Мониторинг на основе BIM технологии позволяет качественно по-новому подойти к контролю техники безопасности и охраны труда на строительном объекте. Показано, что результат контроля предложенным методом в виде индекса безопасности отражает фактическую ситуацию на проверяемом объекте и даёт возможность оценить влияние опасных производственных факторов. Выявлено, что данный подход к оценке позволит оперативно реагировать на...

Organizational and technological reliability of the construction process

Vadim Kabanov
Construction projects of buildings and structures, as well as plans of construction and installation works are often subjected to fair criticism from the Pro-producers of the work. Such criticism is that the calculated cost value and long lasting-STI CMP does not take into account the specificity of real contractors. To address these criticisms and proposals were developed for the assessment of such intensity values of SMR production, which most realistically take into account the actual...

Влагоперенос в вентилируемом канале с нагревательным элементом

Елена Александровна Стаценко, Татьяна Александровна Мусорина, Анастасия Федоровна Островая, Вячеслав Янушевич Ольшевский & Антон Леонидович Антуськов
В данной статье изучается явление влагопереноса в вертикальном вентилируемом канале. Определяются параметры конструкции НВФ, оказывающие влияние на скорость влагопереноса. Необходимо иметь h ≤ L/25 ≈ 8 см. Наибольшее движение воздуха создается в конструкции с открытыми рустами. Выявлено оптимальное расположение источников тепла по высоте канала, а также их выгодные сочетания с точки зрения процесса высушивания наружной поверхности теплоизоляционного материала. В результате исследования скорости движения воздуха по высоте вентилируемого зазора, было установлено, что на максимальной высоте скорости...

Hysteresis of the soil water-retention capacity: estimating the scanning branches

Vitaly Terleev, Aleksandr Nikonorov, Roman Ginevsky, Viktor Lazarev, Issa Togo, Alex Topaj, Kirill Moiseev, Viktoriia Pavlova, Kasim Layshev, Mikhail Arkhipov, Aleksandr Melnichuk, Ielizaveta Dunaieva & Wilfried Mirschel
Designing of underground constructions, such as irrigation and drainage systems, requires engineering surveys. Such surveys include the study of the hydrological conditions of the territory, which are determined by the hydrophysical properties of soils, such as their water-retention capacity. The formation of a hysteresis loop for the soil water-retention capacity occurs because of the variability of meteorological conditions. It is almost impossible to measure all possible scanning branches that fill the gap between the main...

Efficiency of activation of mineral binders in vortex-layer devices

Ruslan Ibragimov, Evgeny Korolev, Rashit Kayumov, Timur Deberdeev, Vladimir Leksin & Andina Sprince
Improving the efficiency of construction composites is a relevant problem for modern-day material science. One of the ways to solve the problem consists in activating the binders by means of vortex-layer devices. Mathematical transformations produced a formula for calculating the dependency of the number of ferromagnetic-particle collision on the number and velocity of such particles, as well as on the device chamber fill factor. The results obtained by applying the proposed formula differ from D.D....

Express-techniques in study of polluted suburban streams

KHristina Il'ina, Nadezhda Gavrilova, Ekaterina Bondarenko, Maria Andrianova & Alexander Chusov
Water samples from streams in suburban region of new builds were analyzed in order to suggest methods and parameters for pollution monitoring. Concentrations of total nitrogen (TN) varied from 0.6 to 9.0 mg/L, ammonium – from 0 to 6.8 mg/L, total organic carbon (TOC) from 8.3 to 21.1 mg/L. Electric conductivity (EC) varied from 80 to 640 mkSm/cm, optical density at 254 nm – from 0.41 to 1.07. Increased concentrations of TN and ammonium at...

Water permeability of the polymer screen with a system of slits of hydraulic structures

Yuri Kosichenko & Oleg Baev
The calculation of water permeability through a system of defects (long narrow slits in the junctions) in the screen is considered based on the filtration model. Its structural layout and description of the model main elements are given. The solution is carried out for the plane formulation of the problem by the methods of the filtration theory using the method of conformal mappings and the velocity hodograph method. A distinctive feature is the study of...

Behaviour of concrete with a disperse reinforcement under dynamic loads

Sergey Nikolenko, Elena Sushko, Svetlana Sazonova, Andrey Odnolko & Vyacheslav Manokhin
Disperse reinforcement of concrete greatly contributes to the properties of the latter. Most research has dealt with the properties of disperse reinforced concrete and influence of disperse reinforcement on structures under a static load of one sign or for a regular dynamic load that is not highly intensive. In practice there might well be alternating dynamic impacts that are highly intensive and over the calculated ones, e.g., seismic ones. The paper presents the results of...

Performance characteristics of differentially quenched rails

Sergey Kosenko & Sergey Akimov
With the development of railway transport, the train speed, the traffic intensity, and the axle load all permanently increase in magnitude. This increase adversely affects the rail operation. The quantity of rail defects and, especially, the rate of rail-head surface wear both show an increase. Such service conditions require an enhanced mechanical strength of rails, their enhanced resistance to wear, and prolonged service life. In the present study, we analyze the operation performance of modern...

The behavior of concentric brace with bounded fuse

Mohammad Ali Kafi & Ali Kachooee
The concentrically braced system is one of the most common lateral load-bearing systems among the steel structures. This lateral loadbearing system has various apparent forms where the main characteristic of them all is their significant stiffness and lateral strength. The main weakness of the concentrically braced system is buckling in compression. This issue causes that concentric bracings have low compressive load-bearing capacity together with undesirable ductility and limited energy dissipation capacity. In this study to...

Reliability assessment of the construction schedule by the critical chain method

Marina Petrochenko, Viktor Velichkin, Yuryi Kazakov & Yevgeniya Zavodnova
Implementation of the construction projects is associated with significant current material, technical and financial costs. They increase significantly in case of the breaking deadlines the large stages of projects and putting buildings into operation. The main aim of the current research is development the new approach for reliability model of the construction schedule for increasing reliability of the calendar planning regarding the meeting the construction projects on time. The following task were solved: the model...

Workability of high rockfill dam with a polymer face

Mikhail Sainov & Andrey Zverev
The results of numerical study of stress-strain-state (SSS) of a rockfill dam with a face whose main watertight element is a polymer geomembrane. Analyses were conducted with consideration of non-linearity of contact interaction of structure elements and non-linearity of soil behavior. Bar finite elements were used for modelling of the thin geomembrane. The study was conducted on the example of Bovilla dam structural design which was built in 1996 in Albania. Initially Bovilla dam was...

Heat dissipation of cement and calculation of crack resistance of concrete massifs

Ayyyna Struchkova, Yuriy Barabanshchikov, Kirill Semenov & Albina Shaibakova
In this paper, the problems of thermal cracking resistance of massive concrete and reinforced concrete structures during the building period are considered. The calculation results of a research on the effect of hardening temperature on the process of heat dissipation process of concrete are given. The analysis of the thermal stressed state of a massive foundation plate with a fixed thickness of thermal insulation was carried out, the values of the minimum thicknesses of the...

The interaction between the kaolinite or bentonite clay and plasticizing surface-active agents

Pavel Bulanov, Lenar Mavliev, Yevgeniy Vdovin & Eduard Yagund
The influence of a number of superplasticizers of various chemical bases on the physical and technical properties of clay soils has been studied. Model soils are considered as clay soils: kaolin clay with kaolinite mineral content up to 95 %, bentonite clay with montmorillonite content up to 70%. The greatest increase in the physical and technical properties of clay soils is achieved when they are modified by a polycarboxylate superplasticizer, which is due to adsorption...

Composite binders for concrete of protective structures

Roman Fediuk, Valeriy Lesovik, Aleksandr Mochalov, Kamil Otsokov, Irina Lashina & Roman Timokhin
The composite binders, obtained as a result of joint mechanochemical activation of Portland cement, rice husk ash, quartz sand, screening of limestone crushing and plasticizing additive were considered. The type of binder influence to the rheological and mechanical characteristics of self-compacting concrete mixtures and fiber-reinforced concrete is established. By scanning electron microscopy, it was revealed that the application of the developed binder leads to the compacting of the microstructure, with lamellar and acicular neoplasms filling...

Method of calculating the optimal sand content in normal-weight concrete

Leonid Dvorkin
In the practice of proportioning concrete compositions, the optimum sand content in a mixture of aggregates is usually found empirically. The disadvantage of this approach is the considerable complexity and duration of the required tests. The aim of the work is to develop a calculation methodology for finding the content of sand in the normal-weight concrete, taking into account the optimality criteria given. Based on the well-known theoretical concepts, the design equations are substantiated for...

The seismic stability of facade system with facing by composite panels

Valentina Tusnina & Denis Emelianov
The hinged ventilated facades installing is a perspective technology of buildings decoration. Suspended facade systems are widely used for construction and reconstruction of residential, administrative, public and industrial buildings. Using suspended facade systems for decorating exterior walls is helping designers to solve the problems of thermal protection and architectural and artistic expressiveness of buildings by using modern heat-insulating and decoration materials. The finishing of facades with composite panels is especially effective for buildings erected in...

Probabilistic seismic assessment of concrete frame with mass irregularity

Elahesadat Hashemi, Ali Kheyroddin & Mohsen Gerami
As mass irregular structures are more influencing on the behavior of the structures, it is investigated the effect of these irregularities according to the probabilistic approach. Comparison of seismic performance of ten regular and irregular 6-story concrete special moment frame is done, based on the Mean Annual Frequency (MAF) method. The probability of collapse in all irregular models has exceeded the 1 % that is permissible value specified in the ASCE/SEI 7-16. The largest rate...

The nonlinear stress-strain state of the concrete-filled steel tube structures

Vera Snigireva & Gleb Gorynin
The article is devoted to the mathematical modeling of the nonlinear stress-strain state of the concrete core in the concrete-filled steel tube structures. The paper uses a nonlinear diagram of concrete deformation under compression, which consists of two straight sections. In addition, the increase in the Poisson's ratio with increasing longitudinal deformations is taken into account. The article discusses two types of concrete-filled steel tube structures: the traditional concrete-filled steel tube column and the concrete...

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