No 3 (2019)
THEORY OF ENGINEERING STRUCTURES. BUILDING UNITS
3-10 70
Abstract
Taking into account features of climate of the Far East and the capitals of the Khabarovsk and Seaside regions - the cities of Khabarovsk and of Vladivostok the technique of the complex accelerated assessment of a durability of elements of the translucent protecting designs (TPD), such as, aluminum shapes, double-glazed windows of structural appointment, sealants and sealing laying for structural glazing of the modern front systems is offered. Two new modes of integrated accelerated tests under the influence of climatic factors for double-glazed windows, sealants and sealing laying (mode 1) and aluminum shapes (mode 2) allowing to carry out at the same time tests of elements of TPD with use of a unique test equipments are developed. The short state-of-the-art review of high-rise construction in Khabarovsk and Vladivostok is given. As artificial climatic factors at the accelerated laboratory tests cyclic influences of positive and negative temperatures, humidities, transitions through "0 ° C", ultra-violet radiation, the slaboagressivnykh of chemical environments (solutions), the salt fog are accepted (for aluminum shapes). Requirements to assessment of test data on each characteristic indicator of elements of TPD are provided. On the basis of the developed technique NIISF RAASN standard is developed.
11-21 108
Abstract
The unique properties of high-strength steel fiber concrete, such as reduced fragility, high crack resistance, increased tensile strength, and others, make this material quite attractive for using in various areas of construction. However, at present, our knowledge of the properties of this material is not yet supported by a sufficient amount of experimental data. The article aims to eliminate this gap. In our work is compared the behavior of the steel fiber concrete with rational fiber content and its matrix, fine-grained high-strength concrete under compression. The method used in the described experiments with the inclusion of a metal pipe acting as a force sensor and receiving a part of the load at stresses close to the design resistance of concrete allows to obtain the relative deformation values corresponding to prism strength. So, we get the opportunity to construct full strain diagrams of steel fiber concrete. As a result of the tests, the effect of a “clip” was confirmed: introduction of steel fiber into the concrete matrix causes a decrease in transverse deformations, increases crack resistance. The nature of the destruction also changes and becomes smoother. As a result of theoretical data processing, the dependences were corrected for calculating the characteristics of high-strength steel fiber concrete under the short-term action of a compressive load.
BUILDING AND STRUCTURE SAFETY
22-33 83
Abstract
At modern industrial enterprises, equipment emitting impulse noise is widespread. Impulse noise has a more adverse effect on the body of working people. Therefore, more stringent requirements are imposed on its limitation. Performing them requires the use of constructive measures to limit the power of radiation of pulses of sound energy by equipment and building-acoustic measures to reduce noise in the ways of its propagation. In both cases, it is necessary to evaluate the acoustic efficiency of the proposed measures. This is possible if there is a calculation method that objectively evaluates the propagation of impulse noise in rooms taking into account their space-planning and acoustic characteristics. The article proposes a statistical energy method for calculating impulse noise, allowing to evaluate its spatial-temporal characteristics when solving a wide range of tasks to reduce the impact of noise on the body of workers. The possibilities of the method are shown in solving these problems.
34-40 69
Abstract
The proposed engineering method of calculation of sound insulation of multilayer intercommunication pen-indoor. The calculation takes into account the effect on the sound insulation of cylindrical stiffness and surface density of inertial elements, as well as the stiffness of sound-proof gasket materials, which allows for rational design of the overlap. The calculation is reduced to the calculation of the frequency response of the impact noise reduction due to the multilayer structure of the floor and to the comparison of the calculated value of the index of the reduced level of impact noise with the standard. The list of necessary initial data and the validity of the calculation are given. Formulas are given to determine the boundaries of the natural oscillation frequencies within which the value of the reduced level of shock noise is calculated. The sequence of constructing the dependence of the natural oscillation frequencies of the system and reducing the level of shock noise by multi-layer inter-floor overlap is described. It is shown that above the second resonance frequency of the eigenfrequencies of the multilayer floor, the improvement of the shock noise isolation (relative to the single-layer overlap) is 24 dB per octave in the low frequency region and 12 dB per octave in the medium and high frequency region. Comparison of the calculated and measured frequency characteristics of the impact noise reduction showed a good agreement of the results obtained by the engineering calculation method with experimental studies.
41-46 197
Abstract
The article assesses the impact of traffic noise on the facades of high-rise buildings in order to identify the floors most affected by traffic noise using the example of two objects in Moscow. The sources of noise are considered streams of road and rail transport. Noise characteristics of noise sources were determined using field measurements and calculations based on data on the intensity of ytaffic flows. The forecast of sound levels at 2 m from the facades of buildings was made using approved software that implements the provisions of GOST 31295.2-2005. It is shown that without the use of noise protection screens on the objects in question, significant exceedances of permissible sound levels occur, especially on facades that go directly to noise sources. A computer simulation of noise protection screens has been carried out in order to assess the possibility of their effective use to reduce noise levels on different floors of the buildings under consideration. It is illustrated that the use of noise protection screens has a limited effect of protection against noise for high-rise buildings, depending on the proximity of the location of the screen to the source of noise. To protect the upper floors of the buildings in question, the use of noise screens is inefficient.
47-53 91
Abstract
The analysis of the influence of digital advertising structures on the adjacent residential buildings on the example of billboards 3x6 and 5x15 meters with digital image change. The main parameters of led screens of separate billboards, which have an impact on the adjacent residential buildings, are considered. Based on the carried out NIISF RAACS lighting studies obtained maximum allowable distance from the installation of billboards to the window openings of residential buildings, in which billboards can be operated in the dark in dynamic mode, depending on the angle of the location of billboards in relation to the window openings of nearby residential buildings, presented in the form of graphs. The importance of the obtained results is noted, which allows to assess the impact of digital advertising structures on the adjacent buildings before their installation and to determine their optimal "landing" in order to eliminate or minimize their negative impact on residential development in the dark during dynamic operation.
ARCHITECTURE AND TOWN-PLANNING
54-62 91
Abstract
Questions of overheating of premises at the expense of solar radiation in various regions of the country are considered. The assessment of the existing normative documents on design of solar control and shading devices is carried out. Are shown absence in them effective methods of calculation of optimum carrying out of the shading elements of solar control and shading devices. Methods of calculation of parameters of the main types of solar control and shading devices (SCSD) in the form of awnings, vertical and horizontal lamellae established before fenestrationareoffered. Methods consider orientation of windows, a trajectory of apparent motion of the sun on the heavenly sphere, the latitude of the area, a power component of solar radiation. Are brought numerical an example of calculation of parameters of solar control and shading devices and the recommendation about effective use of solar control and shading devices in the form of awnings, vertical and horizontal lamellae. Calculations and the analysis of protective characteristics of SCSD are carried out that allows to create preliminary recommendations about efficiency of the SCSD various types. Solar control and shading devices in the form of stationary awnings both continuous, and trellised will be effective only at high values of heights of standing of the sun. With average heights of the sun and furthermore with low heights stationary awnings become not expedient because of disproportionately big carrying out. SCSD in the form of blinds with horizontal and vertical arrangement of the lamellae located are more effective as it is perpendicular to a wall surface, and under some corner to it. Recommendations about effective use of different types of blinds depending on orientation of fenestrationare provided in article.
CONSTRUCTION MATERIALS AND TECHNOLOGIES
63-71 91
Abstract
In connection with the 90th anniversary of the city of Magnitogorsk reviewed best practices of builders in the development of large-panel housing construction. The work of Magnitostroi always been innovation and best practices. In the 30 years of the twentieth century in the construction of Magnitogorsk was first applied electric warming up of concrete under winter concreting, established mechanisms for the development of frozen soil, organized the production of large blocks of concrete based on blast furnace slag, built one of the first in the USSR large-block high-rise residential buildings. The paper contains a description of structural precast elements and characteristics of the nodes, their pairing in the first large-panel residential building of the USSR, built in Magnitogorsk in 1951.The basis of planning decisions of the first panel of the building was based on the project ordinary block section of frame-panel houses a series of M-1. The marked ad-vantages of frameless large-panel residential buildings.The use of prefabricated building systems compared with traditional reduced labor costs two and a half times, to reduce the construction time by 1.5 - 2 times, reduce estimated cost by 12 - 15%. Discussed the development of panel construction in the city, starting with a series of large-panel residential buildings, developed in Magnitogorsk since 1958 after the commissioning of the factory panel construction. The article presents the characteristics of houses designed for mass construction in different time periods
72-82 86
Abstract
The experimental studies of thermal characteristics of PVC windows at negative temperatures of the outside air are performed. The experimental studies results are compared with the requirements of regulatory documents and existing calculation methods of infiltration heat loss through the windows. The laboratory tests show, that under the influence of the temperature difference of the external and internal air (in winter) window profiles get large deformation. The temperature deformation of PVC profiles and window gaskets elasticity degradation lead to a violation of the window thermal characteristics. The effect is to increase the windows air permeability and reduce the temperature on the inner surfaces of their profile elements. This leads to an increase in infiltration heat loss through the windows and violation of the normal microclimate parameters in the room. The established effect of reducing the PVC windows thermal characteristics at negative outside air temperatures is not taken into account by the existing calculation methods.
83-93 80
Abstract
In low-rise construction, heat losses to soil foundations are of great importance in the heat balance. For a number of technical reasons, this subject is not well understood. The paper proposes a physical-mathematical and numerical method for calculating unsteady heat transfer, which takes into account outside temperature year changing. A model for calculating heat losses in groundwater is proposed. The numerical model is based on the use of an explicit two-step-in-time, highly stable finite difference computational method. The objects of the study are unheated and heated building with a foundation like a slab on the ground. The effect of insulated blind area on the temperature field under the building and heat loss to the ground is considered. The role of thermal resistance of the blind area and its geometric size is shown.
94-99 54
Abstract
To simulate the operating conditions of the main types of heat-insulating materials as part of various facade systems, an experimental stand was designed and installed. Sampling of heat-insulating materials was carried out to establish the operating humidity after the summer period and in the late autumn period of the year at the beginning of the heating period. It is shown that the modeling of flooding in the zone of the wall joint with the ground, significantly affects the values and nature of the distribution of operating humidity inside the insulation layers. By monitoring the parameters that determine the heat-shielding properties of the enclosing structures, it was concluded that the soil in the interface zone with the wall as a result of freezing in the cold period of the year does not improve the thermal protection characteristics of the building barrier, therefore this design zone requires insulation. Confirmed the correctness of the changes in the regulatory documents relating to the studied issues.
100-111 78
Abstract
Considered relevant the problem of quality regulatory documentation for thermal protection of buildings, not only depends on the quality of the thermal protection designed buildings but also ensuring favourable hygienic conditions in the premises, as well as reliability and cost of enclosing structures. Provides a critical analysis of existing regulations on heat-shielding of buildings for compliance with the requirements of "technical regulations on safety of buildings and constructions (FZ 384)-creation of thermal comfort indoors and ensure constructive reliability of external walling during the cold period of the year. It is noted that the existing regulations on heat shielding buildings incorrectly defined the main objective of the thermal insulation of buildings. How to ensure a given level of heat energy consumption. Critically analyzed the main sections of the existing regulations and proposed methods of Thermo-physical parameters of rationing of exterior fencing of buildings in which priority is energy conservation and ensuring thermal comfort in rooms, the main criterion which is established by specialists the difference between the room temperature and the temperature of the inner surface of the outer fence. Offered a simple and reliable technique for regulation of water resistance design that provides no moisture accumulation in constructions during the cold period of the year. The technique of integrated calculation of heat and vapor barrier layers of multilayer enclosing structures, Thermo-physical properties which meet regulatory requirements
112-119 68
Abstract
The process of changing the state of moist air in the equipment of mechanical ventilation or air conditioning systems using a plate cross-flow heat exchanger for the purpose of indirect evaporative cooling of the inflow in the cooling period of the year under the conditions of evaporation of water carried away from the humidification section is considered. The features of heat transfer in the heat exchanger in the presence of evaporation are studied and the results of calculation of the increasing coefficient to the temperature efficiency of the heat exchanger for the flow of heated exhaust air depending on the number of units of heat and moisture transfer are presented. The refinement of the construction of the process of changing the state of moist air on the I-d diagram for the scheme under consideration, taking into account evaporation, is shown and the effect of increasing the efficiency of the heat exchanger on the required air exchange in the serviced room is revealed. The presentation is illustrated by numerical and graphical examples.
120-128 87
Abstract
Accidents on sewers accompanied by the destruction of building structures have been a most serious problem not only for the water industry but also for the entire city. In the world the damage from the deterioration of reinforced concrete sewer tunnels and in-line structures due to corrosion is estimated at billions of euros per year. A way out of the current situation with corrosion in sewers can be timely and prompt repair and rehabilitation using protective coatings applied by trenchless methods. One of the methods of sewer rehabilitation is lining the internal walls of the sewers with plate composite materials (blocks) or continuous protective coatings where polymer concrete can be used. Polymer concrete comprises a thermosetting organic binder (usually epoxy resin) and a large amount of dispersed filler (talc, aerosil, crushed quartz, basalt, granite chips, etc.). The special composition of filler materials and advanced production technologies ensures the high qualities of polymer concrete. An assessment of the technical and economic indicators of the reconstruction of existing sewers and canals using polymer concrete blocks is given. Through a realistic example it is shown that the most effective option of the reconstruction of a sewer canal while ensuring environmental safety is lining with polymer concrete blocks (segments).
ISSN 2073-7416 (Print)