Статьи журнала - Строительство уникальных зданий и сооружений
Все статьи: 774
Статья научная
Данная статья содержит обзор мирового опыта в области применения аддитивных технологий в строительной сфере. Использование 3D-печати позволяет воплотить в жизнь архитектурные проекты любой сложности, уменьшить количество производственных отходов, сократить дефицит жилого фонда, снизить материальные, энергетические и трудовые затраты на строительство. В статье рассмотрены основные технологии, которые используются для печати зданий и сооружений, их отличительные особенности. Также изучен вопрос о материалах, применяемых для изготовления строительной смеси. Особое внимание уделено оценке современного состояния 3D-печати в мире. Проведён обзор строительных компаний, производителей оборудования и исследовательских центров, которые являются основными участниками рынка. Основными задачами исследования являются: популяризация аддитивных технологий в России, способствование внедрению инновационных методов строительства, а также созданию нормативных документов, регламентирующих производственную деятельность
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3D-проекты первокурсников по курсу «Инженерная графика»
Отчет
В представленной публикации, являющейся продолжением [1], приведены примеры проекта по дисциплине «Инженерная графика», выполненного в осеннем семестре 2011 г. студентами первого курса кафедры «Технология, организация и экономика строительства» Инженерно-строительного факультета СПбГПУ. Данная дисциплина поддерживается дистанционно с помощью обучения на платформе Moodle.
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Algorithm for selecting a concrete pump in the construction of high-rise buildings
Статья научная
The use of concrete pumps allows you to mechanize and automate the main processes of laying concrete in construction, use additive technologies. To choose the right pump, you need to know the hydraulic characteristics of the network, the rheological properties of the mixture. This article is devoted to developing an algorithm for calculating the pump characteristics for specific construction conditions. Method. The algorithm is based on the empirical dependencies previously proposed by the authors for pump characteristics, mixture rheology, and hydraulic network characteristics. Results. For stationary piston concrete pumps, an example of calculations using the proposed algorithm is given. It is shown that when choosing a piston pump, information is needed about the value of the filling factor, the dependence of the total efficiency of the pump (or the power consumed) on the pressure drop.
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Analysis of the existing technology of wood impregnation by different polymeric compositions
Статья обзорная
The problem of efficiency of application of special means of improving the quality of impregnation, modification and preservation of wood is extremely important in Russian economy. Economic and environmental efficiency of wood treatment with the aim of increasing its structural and finishing properties is quite obvious, but at the moment there is no single methodology for determining it for different types of impregnating polymeric composite materials and for the method of impregnation. The aim of this study is a detailed analysis of traditional and perspective methods of impregnation, preservation and modification of wood using different types of polymer composite materials, and identifying the most effective methods. The study gives a list of the main methods and means of wood protection, all groups of pests harmful to wood, and forms a list of technologies for the impregnation of wood using different physical peculiarities of the process and equipment according to the critical analysis of the technological equipment of the impregnation plants. One of the important results of the study is identifying criteria for the quality of impregnation of wood and recommendations on labor protection in enterprises, with consideration of environmental aspect. According to the results of the study the following conclusions are given: 1. It is extremely advisable to optimize parameters of deep impregnation of the wood with the use of basic available technologies. 2. At this time the most promising methods of wood treatment are autoclave method using a vacuum and high pressure, and the method of exposure to wood ultrasonic electromagnetic waves. 3. Technology ultrasonic industrial impregnations is still not developed, there is no technological scheme and necessary equipment.
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Статья научная
The object of research is a flat statically determinate trapezoidal truss with a rectilinear lower chord and four supports, one of which is a pinned, and three are roller. The purpose of this work is to analyze the dependence of the deflection of the truss and the shift of the movable support on the size, load, and number of panels. The load concentrated in the middle of the span, the load uniformly distributed over the nodes of the upper or lower belt are considered. Method. The initial forces in the elements are determined in analytical form by method of joints in the Maple computer mathematics system. The dependence of the truss performance characteristics on the number of panels is derived by induction based on analytical calculations of the sequence of trusses with different numbers of panels. External static uncertainty is revealed by adding five reactions of supports to the number of unknown components of the equilibrium system of the structure. The deflection of the truss and the displacement of the support are based on the Maxwell-Mohr formula. Results. By solving a number of problems for trusses with a different number of panels, it is found that for trusses whose number of panels is a multiple of three, the determinant of the system of equilibrium equations of nodes turns to zero, which corresponds to the instantaneous kinematic variability of the truss. The corresponding scheme of possible node speeds was found. For kinematically unchangeable trusses, formulas for deflection depending on the number of panels are obtained. The coefficients in the formula are polynomial type. The solution graphs show an abrupt increase in deflection as the number of panels increases.
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Approbation of alternative polymeric coagulants to eliminate turbidity of model surface water
Статья научная
Performance to remove turbidity was studied in model waters for five coagulants: ferric chloride, alum, polyaluminum chloride, polyferric sulfate and polyaluminum chloride ferrous. In waters with high turbidity (100-300 NTU) performance of coagulants are similar (over 90%). Polymer coagulants showed better performance and low optimal dosages in waters with low turbidity (10 NTU). In general, polyferric sulfate showed better performance in removal of turbidity.
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Assessment of efficiency of the vibration damping material «Teroson WT 129»
Статья научная
The application of vibration damping material is considered to be the most effective way of vibration absorbing of the steel shells of wagons and locomotives. The study showed dissipative characteristics of material by the example of the "Teroson WT 129", which were obtained experimentally: the elastic modulus E=0,096; 0,103 MPa, the dissipation factor ŋ=0,628; ŋ=0,454 for appropriate coating thickness 3.6 mm and 6.1 mm. Based on the findings comparative analysis was made with existing vibration-absorbing mastics: characteristics of the new coating "Teroson WT 129" higher than dissipative properties of other materials. In addition, our task was to estimate the effectiveness of the new material: a reduction of the vibration level ∆N is equal to 29dB. The final result of this study was the good prospects of practical application of studied material in thin sheet metal constructions in the manufacture of vehicles, railway wagons.
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Assessment of straw construction technologies in terms of thermal efficiency
Статья научная
Sustainable construction nowadays requires the use of environmental friendly materials with high rate of insulation. Straw construction presents some advantages such as renewability with low energy input, recyclability, CO2 storage, and local availability that implies short distribution cycle. However, before the introduction in the construction industry, attention needs to be paid to the construction technology using such natural materials. In this paper there were developed elements of enclosing structures for two technologies of straw frame building; was done thermal modeling of potentially weak assembles of building envelope; were calculated R-values and then compared with normative indexes; was evaluated efficiency of usability two technologies of low-raise building in cold and wet conditions of St. Petersburg.
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Automated masonry method with evaluation of its productivity and quality characteristics
Статья научная
The article presents the way of using articulated robotic manipulator with building a 3D printer for automation of brick masonry using traditional water-cement solution. The article describes in stages all the steps that need to be done with a robot manipulator in order to build a brick column, similar to the real one, without the use of hands. The column, according to preliminary data, must withstand a maximum load approximately equal to that which would withstand a column of the same material, but made by man. Later, the properties of 6 built brick columns are compared, half of which is built by a robot, and the other part - by a man. All advantages and disadvantages of the automated method of construction of stone structures are also considered. In the course of the work, such indicators as masonry time, structural strength, as well as their comparison with the indicators of structures erected by physical effort were revealed.
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Autonomous power installation with complex power effective electroproviding
Статья научная
Application of natural gas for ensuring heat and electricity is actively applied in many settlements of the Russian Federation and is the most favorable resource. Networks of distribution of natural gas don't cover all volume of consumers and the question of accession to networks to become more and more sharp in view of a constant gain of again formed complexes of the housing estate remote from the cities and megalopolises, and consequently and from network communications.Alternative of leading of network gas is the device of the autonomous (personal) gasification, capacities resumed by liquefied gas. This method involves big financial expenses which have a big payback period, occupy part of elevated and underground space of the expensive earth, and also demands attention regarding maintenance and that periodic replenishment of the tank by the liquefied gas, as private use is important, attracts the raised expenses on transportation.The technology of application of the liquefied gas for the centralized providing with energy resources of a complex of building remote from network energy resources is considered in this work, the economic-mathematicalmodel of the first approach of the concept of the device of the settlement, allowing to determine the cost of received energy and equipment payback periods is offered.
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AВК-система автономной вентиляции и кондиционирования
Статья научная
Проблема обеспечения требуемых параметров влажностного и воздушного режимов помещений актуальна как для производственных и общественных, так и для жилых зданий. Было проанализировано, что на данный момент большинство систем регулируют только температуру, концентрацию углекислого газа и влажность, а давление либо вовсе не регулируется, либо поддерживается повышенное или пониженное по сравнению со смежными помещениями. В данной статье рассмотрена новая система с автоматическим поддержанием параметров микроклимата в обслуживаемом помещении - система Автономной вентиляции и кондиционирования (AВК). Особенностью данной системы является способность поддерживать постоянное давление, в зависимости от колебаний атмосферного давления.Произведен обзор существующих систем аналогичного действия и оценка их возможностей. Выявлено, что AВК система в отличие от других существующих систем способна обеспечить повышенную комфортность внутри помещения за счет управления воздушным давлением относительно колебаний атмосферного. Вследствие чего были сделаны выводы об уникальности и новизне системы AВК.
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BIM-технологии в мостовом проектировании
Статья обзорная
В настоящее время строительные проекты приобретают все больший масштаб. Все шире становится спектр конструктивных и архитектурных форм мостовых сооружений, осваиваются новейшие строительные технологии и материалы. Контролировать и управлять крупными технологическими процессами невозможно без использования компьютерных технологий. Вследствие этого, широкое применение в области строительства находят BIM-технологии (Building Information Modeling - информационное моделирование здания). Главной целью данной статьи является определение и изучение инновационной BIM-технологии в отрасли проектирования мостов, а также раскрытие проблемы внедрения BIM-технологий в мостовое проектирование. В статье показано, что благодаря технологии BIM можно собрать и систематизировать все данные об объекте, а управление этой информацией сделать эффективным. На примере строительства моста через реку Янцзы выявлено, что в результате применения BIM, время реализации проекта сокращается в два раза, а также значительно проще и удобней осуществляется обслуживание готового объекта. В рамках поставленной цели решаются такие задачи, как выявление преимуществ и недостатков использования BIM-технологий в мостовом проектировании, а также изучение факторов, влияющих на переход к использованию данных технологий в проектных организациях. Для этого были изучены статьи, в полной мере раскрывающие возможности BIM-проектирования, и статьи, отражающие уровень распространенности BIM-технологий в гражданском строительстве и конкретно строительстве мостов на данный момент.
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Bearing capacity of reinforced concrete T-beams with a steel profile
Статья научная
The object of research is a reinforced concrete T-beam element of prefabricated monolithic slabs with a thin-walled steel profile. Previously, the steel profile was used in the beams as a stay-in-place formwork, while the authors proposed to include it in the structural behaviour by anchoring. Four variants of T-beam elements have been tested to assess the influence of a thin-walled steel profile on the load-bearing capacity over normal sections. As a result, the strength capacity of reinforced concrete beams with anchored steel profile is 55% higher than the strength capacity of similar samples without steel profile.
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Building energy model detail level
Статья научная
Three energy models of the apartment building with different level of detail were studied. The study was carried out to assess the possibility of simplifying the model of the late design stage or using the model of the early design stage to perform energy calculations. The maximum divergence of the calculation results of the simplified and detailed models did not exceed 10%. On average, the divergence of the results was equal to 8% in the case of the calculations of the concept and detailed models, and the divergence of the results was equal to 5% in the case of the calculations of the moderately simplified and detailed models respectively. In the case of energy calculations at the early design stage it can be considered a rather small value. The use of the simplified building model for energy calculations can be recommended. The use of the detailed model was considered to be irrational and can be recommended only in the case of the existence of compelling reasons.
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Статья научная
The research object was a spatial cantilever statically determinate truss composed of three planar trusses with a triangular lattice. The spectrum of natural frequencies of the structure was analyzed. The same concentrated masses model the inertial properties of the truss at the nodes. The task was to obtain an analytical dependence of the lowest vibration frequency of a truss on the number of panels, mass, linear dimensions of the structure, and material properties. Method. The induction method and the Maple computer mathematics system operators were used to determine the forces in the rods and generalize the result to an arbitrary number of panels. The problem was solved using the Dunkerley approach, which gives a lower frequency estimate. Maxwell-Mohr's formula determines the rigidity of the structure. Homogeneous linear recurrent equations were compiled and solved to find the common members of the sequences of coefficients in the formula for the frequency. Results. The accuracy of the formula obtained by the Dunkerley method was estimated from comparison with a numerical calculation of the entire spectrum of natural frequencies. The comparison shows the good accuracy of the derived formula. As the number of panels increases, the accuracy of the lower estimate increases too. The same frequency for all trusses was found in the spectra of trusses with a different number of panels. This frequency is the spectral constant and depends only on the size of the system, the stiffness of the members, and the mass. The existence of spectral isolines with the property of asymptotically tending to a certain constant value was shown.
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Статья научная
This article is devoted to fireproof processing of steel structures. The main task is to consider different types of sections of rod elements and to choose the most effective section for a steel column from the point of view of fire protection. For the solution of this task the steel columns with various cross sections working in identical entry conditions were considered. All neces-sary calculations for all types of sections were carried out. Results of calculations were pre-sented in the summary table according to which the comparative analysis was made. At the end of work the conclusion that the compound section from four equal corners is the most effective from the point of view of fire protection.
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Calibration and validation of the Menetrey-Willam constitutive model for concrete
Статья научная
Flow plasticity theory has been widely used for nonlinear simulation of reinforced concrete (RC) structures. Constitutive relations of flow plasticity theory in CAE software are referred to as material models. One of the most popular concrete models is the Menetrey-Willam model realized in ANSYS software. The Menetrey-Willam constitutive model can well capture many important mechanical behaviors of concrete such as different tensile and compression strength, nonlinear hardening, softening, and dilatancy. However, there is no published calibration methodology with a clear foundation based on structural design standards. This study suggests an effective calibration procedure to identify the input parameters for the Menetrey-Willam model, mainly according to the CEB-FIP Model Code. Firstly, the identified parameters were verified on basic material tests by a single element simulation. Verification revealed full compliance simulation results with the standards for uniaxial compression, uniaxial tension, and biaxial compression stress states. To validate the ability of the material model to objectively reproduce structural behavior we validated it on six structural tests: confined uniaxial compression of a cube specimen, four-point bending test of a RC beam, three-point bending test of a notched concrete beam, eccentric compression of a RC column, shear rupture test and push-off test of an S-shaped specimen. For all structural tests, a mesh sensitivity analysis was also carried out. The use of the proposed model parameters allows to achieve a good match with the experimental data for all the considered problems almost independently of the mesh size. The obtained parameters can be conveniently used for occasional users without special knowledge in the field of concrete mechanics.
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Climate change and the thermal island effect in the million-plus city
Статья научная
A qualitative and quantitative analysis of changes in the outdoor temperature in St. Petersburg (Russian Federation) for the period from 1743 to 2018 was performed. (276 years old). Used data from open sources. It is shown how the annual average outdoor temperature in St. Petersburg, the average monthly air temperatures, as well as the air temperature during the warm and cold periods of the year, changed. Climate change is divided into stages lasting 50, 25, 10 and 5 years. The main sources of thermal pollution of the urban environment, including man-made. A quantitative assessment of the contribution of anthropogenic sources to the thermal pollution of the urban environment, which amounted to about 586 PJ per year. The main contribution to thermal pollution is provided by consumers of thermal energy (220 PJ per year), transport (220 PJ per year), consumers of electric energy (120 PJ per year), population (26 PJ per year).
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Composite binders with superabsorbent polymers
Статья научная
The object of research is a composite binder with superabsorbent polymers. The work aims to research the combined action of composite binders and superabsorbent polymers. Methods. The particle sizes distribution of the composite binder was studied by laser granulometry. The fresh properties of the mix were determined by examining the slump flow. The average density was calculated by dividing the mass of the sample by its volume. The compressive strength was studied under a static load on the press on samples with a rib of 70 mm at 3, 7, and 28 days of age. Results. Obtaining polymineral composite binders was carried out by joint grinding of Portland cement CEM I 42.5 N and wet magnetic separation (WMS) waste to a specific surface area of ≈ 550 m2/kg in a vibration mill, followed by the introduction of pre-ground Opoka-like marl (Ssp ≈ 700 m2/kg) used as a mineral modifier. Joint grinding of cement and WMS waste in different percentages and introducing the optimal amount of a mineral modifier made it possible to identify the effect of the composition on the compressive strength. When tested on the 28th day of hardening of the compositions CB-3 and CB-2, an increase in the compressive strength by 82.2 and 60.3%, respectively, was found, while in the composition of CB-1, there was a decrease in the compressive strength by 14.5%. As a result of joint grinding to an equal specific surface, despite the different ratios of components and their hardness, an almost equal grain composition of polymineral composite binders was achieved. Taking into account the increase in the strength of the developed compositions of polymineral composite binders, optimized by the chemical modifier, and the losses caused by the introduction of SAP into the cement system, the effectiveness of the use of CB-2 and CB-3, due to strength compensation, in combination with SAP modification B3 (
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