In order to negate the loss of strength, that can lead to collapse of constructions, we should take measures to prevent cracking. Every crack emersion in reinforced concrete indicates that the accumulated stress has been released in this area of the structure. The cause of cracks are internal tensile stresses that can occur due to internal processes in the element and from external loads on the structure. It is possible to eliminate cracks that have already appeared with the help of repair compounds that fill the volume of cracks in various ways. Injection, as one of the solutions, will help to maintain the strength and durability of the structure.

Keywords: cracking, concrete, reinforced concrete slab, crack, defect, deformation, strength, soil, repair compound, foundation, foundation slab, injection

This article is devoted to the analysis of factors influencing the energy efficiency of high-rise buildings. Using the example of the Aquamarine residential complex in the city of Vladivostok, an analysis of high-rise buildings was carried out, calculations were performed, and the results were presented in the form of graphs that reflect the dynamics of the speed of wind flows and temperature changes in the outside air along the height of the building. Changes in these parameters increase the intensity of heat loss, which must be taken into account when developing a space-planning solution and thermal protection of the facades of high-rise buildings.

Keywords: energy efficiency, aerodynamics, air exchange, heat resistance, high-rise building, microclimate, urban development, energy consumption

The article analyzes the heat-shielding properties of typical curtain-type ventilated façade (hereinafter referred to as CVF) systems used on multi-storey residential buildings in Moscow. We conducted analytical and visual studies, evaluated the technical condition by external features, including photographing the detected defects, thermographic scanning of facades, and took selective measurements of external geometric parameters, distortions, and structural properties for 18 objects in the city of Moscow. The level of defects in the thermal insulation layer at Moscow facilities was at least 50%. A gap of 10 mm at the joint of insulation slabs reduces the heat-shielding properties of the CVF fragment of the outer wall by 14.5–15%. The conclusions were drawn on the basis of the results of calculations of the reduced heat transfer resistance of a total of 18 CVF options from two manufacturers of the Kaptekhnostroy (aluminum CVFS subsystem) and Alfa-Prof (galvanized CVF subsystem) systems. When comparing these solutions, it is obvious that they are all inferior in value reduced resistance to heat transfer of the composite facade thermal insulation system. If the foundation is made of monolithic reinforced concrete or brickwork, the choice of finishing material does not matter. Moreover, the indicators of the reduced heat transfer resistance do not differ significantly. In the case of a base made of expanded clay concrete blocks, the galvanized steel subsystem is 2.9% (ceramic granite), 4.3% (fiber cement) and 4.6% (composite) more efficient.

Keywords: curtain-type facade system, ventilated, facing slabs, fasteners, defects, inspection, heat transfer resistance

Cryptography is the science of privacy methods. Encryption is a special case of encryption. The article discusses the issues of encryption, the use of two different methods of encrypting text phrases: the Caesar cipher and the Vigener cipher, the definitions of the alphabet and the key are given. An example of using these ciphers on two phrases of the Cyrillic and Latin alphabet is given. A program has been designed in the Java language that allows encryption and decryption. The description of the program is given. The program form includes two radio buttons for selecting the algorithm and two buttons for encryption and decryption.

Keywords: cryptography, encryption, decryption, vigener cipher, caesar cipher, java

The choice of a method for transporting hydrocarbons from the shelf of the northern seas is an urgent task, necessary for the economic justification of a project for the development of an offshore field. A comparative analysis of existing transportation schemes allows us to take into account both the advantages and disadvantages of possible options, namely, the natural and climatic features of the region, the technical capabilities of contractor organizations, the cost of field development facilities and vehicle rental.

Keywords: hydrocarbons, continental shelf, transport scheme, analysis, tanker, gas and oil pipeline, onshore infrastructure, offshore infrastructure

The aim of the work was to analyze the advantages and disadvantages of a typical 2-room apartment and find the optimal solution for redevelopment. As an example, we selected a typical planning solution from the developer of a two-room apartment in a multi-storey residential building. The article considers a variant of apartment remodeling in order to improve the housing characteristics of the premises. It is concluded that the typical rational solution for reconstruction is the reorganization of auxiliary premises in favor of residential premises, changing their configurations. The logic of applying the principles of free planning is reduced to creating conditions for comfortable spatial interaction of functional zones.

Keywords: Planning solution, apartment, functional areas, ergonomics, remodeling, living area, wet area, interior, visualization, furniture arrangement, redevelopment, area, insolation, installation, dismantling, building codes

The article discusses the issues of increasing the efficiency and reliability of the water supply system on the example of gravity water treatment plants. In this study, some of the measures for the reconstruction of structures on the daily regulation pools and introduced new technologies for water purification are considered. The use of a new technology has been studied, which involves the use of local coagulants in the form of aluminum sulfate together with a high-molecular synthetic anionic flocculant of the «POLY SEPAR AN 34 TW» type and clarification of water in sedimentation tanks equipped with horizontal thin-layer modules. As a result of the study, it was identified that the use of anionic flocculant of the «POLY SEPAR AN 34 TW» type, which has a flocculating and disinfecting ability in water treatment processes, is highly effective. Moreover, the use of a flocculant of the «Poly Separ» type for surface water purification at a dose of 0.5 - 1.0 mg/l, along with a decrease in turbidity and color, it ensures the removal of such impurities as iron, heavy metals, a decrease in the total microbial number from 10000 - 1000000 to 100 cells/ml at the filtration stage, since «Poly Separ» has a prolonged bactericidal effect.

Keywords: water supply, pool, regulation, technology, coagulant, aluminum sulfate, anion, flocculant, disinfection, turbidity, color, clarification, kinetics of the process

In recent years, studies have begun on the possibility of using anhydrite binders. However, the slow hardening makes it difficult to use this binder for residential and civil construction. The elimination of these difficulties is possible as a result of a deep and comprehensive study of the hardening process of anhydrite binder and the properties of the resulting stone, will make it possible to develop a technology for the manufacture of various building structures based on this binder.

Keywords: Investigation of the properties of a material based on a modified anhydrite binder

The article presents a comparison of architectural and planning solutions of social housing in the USSR, modern Russia and abroad. The socio-economic prerequisites of mass development in our country in different years are briefly considered. General disadvantages of design solutions of old and modern houses are analyzed, such as lack of unique architecture, small variety of layouts and insufficient area of apartments. The purpose of the article is to identify the shortcomings of typical development in domestic construction and to search for redevelopment directions to increase the comfort of small-sized housing, taking into account the individual preferences of residents. The article presents the main possibilities of improving the comfort of inexpensive residential premises. Several areas of redevelopment of small-sized apartments are offered, such as expanding the useful area by changing the purpose of small-used passage zones, redistributing the area by highlighting various functional zones, applying a circular layout and the effects of visual volume increase.Possibilities to increase comfort of small area housing are described: expansion of useful area by transformation of underutilized zones, redistribution of area with allocation of separate functional zones, use of circular layout. In the future, it is proposed to expand the range of unique architectural and planning solutions in modern construction.

Keywords: apartment, small area, redevelopment, housing improvement, planning solution, functional zone, comfort, social housing, affordable housing

The article deals with current methods of evaluating the organization and management in construction under conditions of uncertainty. The typology of the failure process is given, which determines the scenario of the crisis development at the enterprise. A model of forecasting and management in a crisis is proposed, and the conceptual aspects of building this model are considered. It is proposed to improve the enterprise management system based on the analysis of the economic component as a temporary function. Recommendations are given for improving the existing organizational forms of enterprise management.

Keywords: construction organization, organizational and technological solutions, reliability assessment, construction quality assessment

Questions of accounting of actors of influence on the investment and construction cycle are raised. An example of the use of BIM-technologies in construction is considered. It describes the solution of some specific problems that arise when maintaining the quality of construction of complex buildings, taking into account the possibility of introducing modern information systems, attention is paid to the peculiarities of improving the quality of work performed.

Keywords: organization of construction; quality of design, quality of construction and installation works, BIM-technology

The quality of construction affects the reliability and safety of the object as a whole, and its provision is an important and urgent task. This article discusses the issues of quality control at the stage of organizational and technological preparation of construction. The authors analyzed the current legal acts of the Russian Federation and regulatory and technical documentation in the field of construction organization, identified the main factors that affect the final quality of construction products. According to the report, the authors suggest that at the stage of development of POS and PPR to take into account the factors affecting the quality of the constructed facility, and to reduce the negative effects of organization control at all stages of building production.

Keywords: quality of construction, quality of construction products, organization of quality control, organizational and technological preparation, project of construction organization, project of work production

An algorithm for determining the lower confidence limit (NDH) for the minimum value of the hardness of a set of machine parts by calculation is developed. For processing of statistical data of the hardness measurements used a three-parameter Weibull distribution is offered. The transition from sample data to population data is carried out by the graphical method. According to the algorithm, NDH was found for the minimum hardness value with confidence probabilities p=0.9; 0.92;0.93;0.94.

Keywords: hardness, machine parts, sampling, aggregate, lower confidence limit, graphic method, calculation method

When forming in the process of centrifugation an annular section by the method of ""separate"" concreting with the formation of a section of the product at the first stage from the original, including fine-grained concrete mixture, and with the introduction of a coarse aggregate at the second stage into the formed circular section, followed by the final formation of the section and compaction of the concrete mixture by centrifugation, the speed, calculated for the compaction stage, increases, depending on the section zone, the concrete compressive strength from 20% up to 47%, the initial modulus of elasticity from 6 to 19% relative to single-stage centrifugation. The ratio vint / vext of ultrasonic pulse velocities for surface sounding along the inner (vint) and outer (vext) faces of a centrifuged annular section can be considered as a conditional indicator of the uniformity of the concrete structure over the cross section of a centrifuged product. Key words: centrifugation, separate concreting, structure homogeneity, strength and deformation properties, porosity.

Keywords: centrifugation, separate concreting, uniformity of structure, strength and deformation properties, porosity

Within approaching the plane-stress state the problem of a high-speed rotating disk being under side pressure is considered. Within the model of a perfect rigid-plastic body and the Mises yield criterion the values of external parameters for which the plastic zones appear have been defined. The stresses in plastic zones are obtained from the solution of the Cauchy problem, which includes two differential equations to define the stress tensor nonzero component. In order to estimate the stress state in the elastic zone the equivalent stress is introduced. The maximum allowable values of external parameters are obtained from the solution of the problem when the disk is in the limit state. The numerical results are represented as the stress vector hodograph.

Keywords: the plane-stress state, Mises yield criterion, the equivalent stress, an elasto-plastic solid, a rotating disk, a stress vector hodograph