Vol 9, No 4 (2019)

The determination of the actual class of concrete in monolithic reinforced concrete structures is the most important factor determining the quality and strength of structures. In practice, the actual grade of concrete may differ from the design value. If this difference occurs in the direction of decreasing the actual concrete class, then the normative and design characteristics of concrete, the bearing capacity and rigidity of the structures, respectively, decrease and there is a need to strengthen the structures. Current regulatory documents allow you to determine the actual class of concrete in both continuous and spot inspection of structures. The article discusses specific examples to determine the actual class of concrete and draws conclusions about the rational use of a continuous or selective examination of structures of various types with specific examples.

The article describes the essence of the technological method of testing a reinforced concrete beam with central prop for fire resistance without destruction, based on a set of individual indicators of the quality of concrete and reinforcement. The influence of the geometrical dimensions of a reinforced concrete beam with central prop, the heating pattern of the calculated cross section under fire conditions, the placement of the reinforcement in the calculated cross section, the depth and degree of fire protection of the concrete, the coefficient of thermal diffusion of concrete, the magnitude of the test load on the beam and the stress intensity in the bars of the longitudinal working reinforcement were investigated. The fire resistance limit of a beam with central prop is determined by the sign of loss of bearing capacity using the analytical equation (1). The use of the new proposed technological method allows to determine the actual fire resistance of a two-span reinforced concrete beam without full-scale fire impact, simplifies engineering calculations, increases the reliability of static material quality control and non-destructive testing, reduces economic costs.

The analysis of the values of the concentrations of the formed nitrogen oxides and the temperatures of the jet plume under various conditions of mixture formation is carried out. The plots of the distribution of torch temperatures and concentrations of nitric oxide in the calculated area for oxidizer temperatures of 20, 60, 100, 150, and 200 ° C were obtained and analyzed. Mathematical modeling of the gaseous fuel combustion process was carried out using the FlowVision software package. An analysis of the results showed that a decrease in the temperature of the air supplied as an oxidizing agent leads to a significant decrease in the concentration of nitrogen oxides in flue gases, while not significantly affecting the change in the flame temperature. The research results can be used to solve the problems of optimizing boiler plants, in order to reduce harmful flue gas emissions. Further modeling is planned to determine the dependence of the influence of various factors on the degree of formation of nitrogen oxides in the flue gases of boiler plants.

A comparative analysis of explicit solutions of the Colebrook-White equation is carried out. The median values of relative deviations, coefficients of determination and computational complexities for each approximation were obtained. The results of the iterative solution of the Colebrook-White equation by successive substitution method were used as the intrinsic solution. Approximations by B. Eck and A.R. Vatankhah were identified as the most effective in terms of computational complexity. It was shown that widely used approximations by P.R.H. Blasius, A.D. Altshul and J. Nikuradze although simple, provide acceptable accuracy only within restricted ranges of Reynolds and relative roughness.

The calculations of the rain drainage system, which provides the collection of surface runoff from the interscholastic stadium, including a football field with artificial turf, running tracks, tribune, were performed. The optimal tracing of the system is designed, the best materials and storage capacity are selected. The assessment of the qualitative composition of collected effluents and the direction of their further utilization was carried out. Options of detailing of nodes of a shower drainage system according to different engineering and geological conditions of the territory of the Astrakhan region are considered: subsidence of soils, fl ooding by underground waters. The developed model, based on the principles of optimization and import substitution, allows to apply it as a model on the territory of the arid regions of the South of the country.

The article studied modern cleaning methods and technological schemes of enterprises of the fat-and-oil industry. Based on literary sources, the effi ciency of wastewater treatment by physicochemical treatment methods has been investigated. Reagent pretreatment of wastewater is widely used, and research focuses on the selection of optimal reagents and doses. A modern method for the treatment of fat and oil containing wastewater is biomembrane technology. Classic treatment schemes are often unable to achieve regulatory requirements for the quality of treated wastewater; therefore, the use of membrane bioreactor technology may be in demand for treating food wastewater. The problems of using various methods of purifi cation of fat-and- oilt wastewater are identifi ed. The economic effi ciency of the proposed cleaning methods is determined.

A version of the project for the installation of the spatial structure of the coating of an industrial building was developed. The technological feature of the project was the presence of cramped working conditions. The feasibility study of the methods of assembly and installation of the coating, taking into account the peculiarities of the construction of the coating, the features of the construction site and the needs for lifting machines, showed the eff ectiveness of the installation of the coating with enlarged blocks assembled on the ground. Mounting the unit using a traverse allowed to reduce the estimated height of the hook and select a crane that does not diff er in the high cost of rent. It became possible to apply the adopted installation scheme provided that an individual design of the beam was developed. The calculation and design of the traverse itself was performed, as well as the calculation of the enlarged unit for the installation situation.

The great interest of modern scientifi c society in architectural bionics is due to the signifi cant practical orientation of this science, which studies the principles of construction and functioning of biological systems, primarily with the aim of creating new bionic objects whose characteristics would be as perfect and highly effective as in living systems. Architectural-bionic practice gave rise to unusual forms, suitable in a functional and utilitarian sense. The architectural bionics family can off er a lot of cereals, which have the property of elasticity and resistance to bending and fracture with a few materials. In wheat, as in a number of other grain crops, the strength of the stem is determined by a set of features of the anatomical structure. The structure of the article reveals the concept of sustainable architecture, referring to antiquity. The basis of the study is a bionic object displayed in the form of a stalk of wheat, the properties of which allow wheat to undergo atmospheric infl uences under the existing load of ears, which greatly exceeds the own weight of the straw. The properties of the elasticity of the stem of the wheat are examined through the Young’s modulus (E), which provides resistance to lodging. In the experimental part, an explanation is given of the mechanical strength of the wheat stalk, characteristic of most cereals, due to: height, diameter of the stem, their ratio, the thickness of the walls of the straw, the development of mechanical tissues. For an illustrative example, the predominant properties of the stalk of wheat, the calculations of the relative volume using standard materials in the construction industry of uplifting buildings and structures are given.

In the research the morphology of the geological structure, the genesis of a natural object, embedded in such a “construction” as time, are studied. As a result of the loss of historical and informative artifacts of the environment, the territory loses its identity. In order to maintain the structural basis, a scientifi c study of the genesis of the object is carried out. The existing problems of modeling objects in conditions of disturbed landscapes are considered. The concept of historical genetic reconstruction method is introduced. A paradigm of research and modeling of the territory and objects that have lost their natural, aesthetic and cultural essence, based on formal features and is an imperative of design, is proposed. For this purpose, elements of the operating base are being developed.

Green construction is a new fundamental environmental direction in the design, construction, operation and dismantling of buildings. Currently, there are two international systems for assessing the eco-efficiency of construction: BREEAM (British system) and LEED (American system). BREEM is a scientific standard focused on a large number of environmental issues. LEED is a commercial standard for energy consumption. The above assessment systems have different levels of minimum requirements; buildings that meet these requirements receive respectively a BREEM certificate or a LEED certificate. The article discusses buildings certified according to different systems for assessing eco-efficiency, located both in the Russian Federation and in the world. The leading place in the number of “green” buildings in Russia belongs to the city of Sochi, thanks to the 2014 Olympics. Then, there are the capital cities of Moscow and St. Petersburg, on the territory of which are located not only shopping, entertainment and office “green” buildings, but also residential eco quarters. Sports arenas were built for the 2018 FIFA World Cup in host cities. In particular, the Samara 45-thousandth sports arena became the first Russian facility for the 2018 football championship, which won international recognition, having received a certificate according to the standard of the BREEM system.

The choice of the type of natural lighting in architectural and construction practice depends on a number of constructive, technological and engineering measures. The authors’ analysis of Russian and foreign experience in the design and construction of buildings allows us to ascertain the fact of a stereotypical approach to providing premises with sunlight and the lack of interest in actively developing technical means that can improve lighting. The article is devoted to the organization and improvement of the quality of lighting in buildings for various purposes. The paper generalizes the types of natural lighting used in modern buildings. The positive and negative sides of all types of lighting are analyzed and recommendations are given on the possibility of their use for buildings with “diffi cult to light” spaces. The parameters that infl uence the choice of options for lighting with sunlight are highlighted depending on the functional purpose of the building and its planning structure.

The article presents a comparative analysis of the main characteristics of planning elements “quarter” and “microdistrict”, identifies their significant differences; provides an analysis of the development of approaches to the construction of residential areas in Russia in terms of creating a comfortable urban environment for human life; reveals the advantages of modern quarter as a planning element of residential development.

In order to optimize energy consumption at the design stage and fine-tuning the main components of the gas distribution mechanism, calculations were performed. The method of calculating annular gaps was used to select the rational dimensions of the pusher assembly design, as well as the gas distribution mechanism of the engine of construction machines. A pusher model is considered in the design scheme of the engine lubrication system for construction vehicles, which helps to refine the calculated data on the oil consumption of the main consumers. The data obtained accelerate the development of the engine design at the design, development and operation stages of machines and mechanisms. The main task was to calculate the pusher of the indicated type to obtain data on oil consumption through the annular gap formed by the sleeve and the pusher body.

The object of study in this article is presented in the form of an inertial-vacuum dust collector (IVDC). There are two types of IVDC: first generation and second generation. The first experiment was conducted in 2009, and the second in 2018. The plants consider similar principles of dust collection. The purpose of this article is to compare the results of a full-scale experiment conducted on a second-generation inertia-vacuum dust collector at the Omsk TPP-4 station and the data of a numerical experiment calculated in ANSYS CFX. After the initial calculations, adjustments were made to the boundary conditions. The data obtained in the course of a numerical experiment with specified boundary conditions are in good agreement with the full-scale experiment. Measurement schemes and graphical dependences of the degree of capture efficiency on the geometric characteristics of the ash collector are presented.