Evaluation of end bearing capacity of drilled shafts in sand by numerical and SPT-based methods

Drilled shafts are a common type of pile foundations which are often used as foundations for buildings, bridges and other structures. The end bearing capacity of drilled shafts, which plays an important role in their design particularly in sandy soils, has traditionally been estimated using empirical or semi-empirical methods. With advances in computing power, it is now possible to conduct more realistic analyses. In this paper, at first, the end bearing capacity of drilled shafts in sandy soils is analyzed numerically and validated with the results of pile load test. Then, the numerical results are compared with the results of Standard Penetration Test (SPT)-based methods. The comparison indicated that there is a satisfactory agreement between the results of numerical method proposed in this paper and the results achieved by SPT-based methods

Forecasting the condition of petroleum impregnated load bearing concrete and reinforced concrete structures

Petroleum products (PP) used in industrial processes systematically fall on the load-bearing CRC structures and gradually impregnate therein. Currently, available guidelines for the assessment of technical condition and reliability of load-bearing CRC structures do not fully take into account the effect of viscosity of PP that impregnated therein. Our study was performed on the basis of analyzing, generalizing and evaluations of experimental data on the effect of PP of different viscosities on the physical and mechanical properties (PMP) of concrete using the methods of probability theory and mathematical statistics. The obtained results allow to constitute a scientifically substantiated forecast of changes in PMP of PP impregnated load-bearing CRC structures and to provide a quantitative characterization of their technical condition.Keywords: viscosity, strain, endurance, fatigue

Effect of modifier mb10-50c on the physical and mechanical properties of high-strength fine-aggregate "powdery" concrete

In this study we used concrete modifier MB10-50C, an admixture on an organic-mineral basiscontained of micro-silica, fly ash, hardening regulator, superplasticizer, to produce thehigh-strength fine-aggregate "powdery" concrete (HSFPC). We produced samples of HSFPCwith dimensions of 100x100x100 mm and 100x100x400 mm. The physical and mechanicalcharacteristics of HSFPC, such as: compressive strength, tensile strength at bending, strengthat axial tension, cracking moment, HSFPC grade, and elastic modulus, at the curing periods of7, 14, 28, 60 days, have been determined. The research results have been implemented in theconstruction of high-rise buildings of the Moscow International Business Center "MoscowCity", and in reconstruction of the Engineering Faculty building of the RUDN University.Keywords: compressive strength, tensile strength at bending, strength at axial tension,cracking moment, elastic modulus

Influence of Formwork Structure on Heat Treatment of Precast Concrete Elements by Solar Energy

The present paper aims to study the influence of the formwork structure on the efficiency of heat treatment (HT) of precast concrete elements (PCE) by solar energy in various climatic conditions. The objects of the study were different types of formworks composed of solar energy equipment for HT of PCE. In total, six types of formworks, made of steel sheet, laminated plywood and timber, with and without insulation were studied. Calculation and experimental study were carried out for humid continental, and subtropical climates. Experimental study was carried out in the laboratory and in the open air. According to the obtained results, the heat insulation material in the formwork structure contributes to increase the strength of concrete. Formwork with heat insulation layer of 40 mm gave the best results. However, the level of the contribution depends on climatic conditions. Heat insulation material in the formwork structure is necessary in humid continental climate. Even the thickness of the insulation layer of 20 mm gives good results and the difference between the concrete strength with thickness of 20 mm and 40 mm is insignificant. On the contrary, in humid subtropical climate, the heat insulation material in the formwork structure is favorable, but not compulsory, since the difference between the concrete strengths is not significant and the strength values, obtained in all six types of formwork, allow it to be removed after 24 hours of curing

Прогнозирование состояния железобетонных трубопроводов, находящихся под автомобильными дорогами

In this paper offered a new method for forecasting the condition of reinforced concrete pipelines, which are located under the roads. It has a practical value in the absence of special diagnostic equipments and robotics.Предложена новая методика прогнозирования состояния железобетонных трубопроводов, находящихся под автомобильными дорогами. Это имеет практическое значение при отсутствии специального диагностического оборудования и робототехники

ВЛИЯНИЕ КОНСТРУКЦИИ ПРОЗРАЧНОГО ПОКРЫТИЯ НА ЭФФЕКТИВНОСТЬ ТЕРМООБРАБОТКИ БЕТОНА В ОПАЛУБОЧНЫХ ФОРМАХ С ИСПОЛЬЗОВАНИЕМ СОЛНЕЧНОЙ ЭНЕРГИИ

The shuttering forms, equipped by inventory frames with transparent cover, are the simple solar energy equipment for heat treatment of reinforced concrete elements during their manufacturing at the plants. They are similar with solar collectors by their design and thermal-physical processes, taking place in them, with difference that the heat sink is hardening concrete. The research results of influence of transparent cover construction on efficiency of concrete heat treatment in shuttering forms with employment of solar energy in different climatic conditions are given in the article. The volume of energy, consumed and lost by concrete during its direct heating by solar energy in the simple solar energy equipment like solar collector, depends on the transparent cover construction. Under other same conditions, the increase of cover layers affects its transparency, which is characterized by the solar energy transmittance, but in this case, it reduces heat losses in environment, which are characterized by the coefficient of heat losses through transparent cover. One-layer and two-layer transparent covers are chosen for assessment of efficiency of heat treatment of concrete elements, because the increase of cover layers more than two reduces intensity of the heat sink warming in the daytime and it is accepted by scientists in solar energy field as pointless. Optimal number of transparent material layers in cover construction is determined based on energy assessment in result of thermal- physical calculation and experimental research. The economic losses for production of transparent cover due to the increase of its layers are taken into account in addition with energy assessmentОпалубочные формы, оснащенные инвентарными рамами с прозрачным покрытием, являются простейшими гелиотехническими устройствами для тепловой обработки железобетонных изделий при производстве их на полигонах при заводах ЖБИ. По своему конструктивному решению и теплофизическим процессам, протекающим в них, они схожи с солнечными коллекторами, с разницей в том, что теплоприемником является твердеющий бетон. В статье приведены результаты исследований влияния конструкции прозрачного покрытия на эффективность термообработки бетона в опалубочных формах при использовании солнечной энергии в различных климатических условиях. Количество теплоты, поглощенное и потерянное бетоном при прямом нагреве его солнечной энергией в простейших гелиотехнических устройствах типа плоского коллектора, зависит от конструкции прозрачного покрытия. При прочих равных условиях, увеличение количества слоев покрытия негативно влияет на его прозрачность, характеризующуюся коэффициентом пропускания солнечной энергии, но при этом снижает тепловые потери в окружающую среду, характеризующиеся коэффициентом тепловых потерь через прозрачное ограждение. Для оценки эффективности тепловой обработки железобетонных изделий выбраны однослойное и двухслойное прозрачные покрытия, так как увеличение слоев больше двух снижает интенсивность нагрева теплоприемника в дневное время суток и признано учеными в области гелиотехники нецелесообразным. На основе энергетической оценки в результате теплофизических расчетов и экспериментальных исследований выявлено оптимальное количество слоев прозрачного материала в конструкции покрытия. Помимо энергетической оценки, учтены экономические затраты на изготовление конструкции прозрачного покрытия при увеличении его слоев

COMPARATIVE ANALYSIS OF THE CUSTOMS REGULATION OF VEHICLE IMPORT IN THE G20 COUNTRIES

The purpose of this article is to conduct a comparative analysis of customs regulation procedures for the import of vehicles operating in the G20 countries, to determine the possibility of adapting and using their experience in order to improve the customs procedure in force in Ukraine. Since most researches of Ukrainian scientists mainly concern the adaptation of existing customs procedures to the requirements of the Ukraine– EU Association Agreement and the search for ways to solve the problem of shadow schemes of vehicle import, the selected research purpose is relevant. The subject-matter of the study is the procedures for customs regulation of the import of vehicles of the G20 countries. Methodology. To achieve this purpose, a set of general scientific methods was used that ensure the objectivity and validity of the results obtained, namely, methods of abstraction, comparison, analysis and synthesis, generalization. Results. The research results showed that Ukraine is far behind the leading countries in terms of implementing the standards of environmental and technical safety of imported vehicles. If compliance with the requirements of environmental safety, namely compliance with European standards, is still taken into account when importing, then the issues of technical safety are not regulated by the current customs procedure. Secondly, the system of taxes and payments that are paid in Ukraine upon importation, namely duty, excise duty, and VAT, does not provide for compensation for the negative impact of imported vehicles on the environment. Thirdly, comparing the practice of temporary importation of vehicles operating in the G20 countries and Ukraine has allowed highlighting a number of inconsistencies. So, in the G20 countries, only non-residents can use this regime in the vast majority. Citizens of the country are entitled to temporary admission only if strictly defined requirements are met. However, unlike Ukrainian practice, the very procedure for temporary admission implies the absence of requirements for payment of customs duties and other payments, regardless of whether the person who uses it is a resident or non-resident of the country. Practical significance. The conclusions made allow proposing the necessity to amend the current procedure by introducing the practice of confirming the conformity of imported vehicles with the technical requirements for their operation, increasing the tax burden on vehicles with low environmental efficiency, settling the issue of the availability of the regime of temporary admission of vehicles and strengthening control over compliance with this regime. Relevance/originality. Proposals for the adaptation and use of the experience of the leading countries in the field of customs regulation of import of vehicles are a way to prevent the negative phenomena in Ukraine in this area

Совершенствование технологии возведения фундаментов в вытрамбованных котлованах и устройство для ее реализации

Uniform and periodic covering of a surface rammer a layer of a lubricity liquid for reduction of friction of the soil and prevent soil from adhering to surface rammer produced by the spongy plate established in a cavity of the guide trunk and impregnated with lubricity liquid.Равномерное и периодическое покрытие поверхности трамбовки слоем смазывающей жидкости для снижения трения о грунт и предотвращения налипания грунта к поверхности трамбовки производят посредством губчатой пластины, установленной в полости направляющего ствола и пропитанной смазывающей жидкостью (вода, отработанное машинное масло, дизельное топливо и пр.)

Техническое состояние инфраструктурных систем жизнеобеспечения городов Ирака и показатели их надежности

Maintenance, inspection and repair of drainage pipes are characterised by increased responsibility for their technical condition and quality of work. This allows more efficient use of economic, logistical and human resources in the maintenance of pipelines.Эксплуатация, обследование и ремонт трубопроводов водоотведения характеризуются повышением ответственности за их техническое состояние и качество выполняемых работ. Это дает возможность более эффективно использовать экономические, материально-технические и трудовые ресурсы при эксплуатации трубопроводов

Editorial Preface

The present proceedings include a selection of papers submitted to the International Conference on Engineering Systems 2020 (ICES 2020), which was held during 14-16 October 2020 in the RUDN University, Moscow, Russia.ICES 2020 was dedicated to the 60th anniversary of RUDN University. International Conference on Engineering Systems (ICES), held annually at the Peoples’ Friendship University of Russia (RUDN University), has created a platform for summarizing research in various areas of engineering. The aim of the conference is to foster and conduct collaborative interdisciplinary research amongst the researchers, professionals and industrialists to share their research experiences and indulge in interactive discussions and special sessions at the event.In light of travel restrictions around the world to control COVID-19 pademic, ICES 2020 adopted the format of virtual conference through Google Meet network to provide a forum for experts and scholars to share real-time information and discuss the latest findings on various engineering fields. The conference included keynote speech and online discussion, and each presenter has 20–25 minutes (including Q&A).With the full support from the International Scientific Committee, all submissions have been through rigorous review and process to meet the requirements of international publication standard. Accepted papers were presented in five sessions of the conference: 1) Fundamental Engineering, 2) Civil and Structural Engineering, 3) Mechanical Engineering, 4) Composite Materials, 5) Hydraulic and Geological Engineering. We hope that this collection will be useful for many specialists and researchers from various engineering fields.List of Conference Chair, Conference secretary, International Scientific Committee and Guest Editors are available in this pdf