The article discusses the energy efficiency of walls with louvered sun shading devices. It has been noted that louvered façade systems with a ventilated layer are an effective means of protection from solar radiation in summer. As a result of the experimental studies carried out on building models, a number of significant thermophysical regularities were noted that determine heat and wind processes in the near-wall layer of facade systems, which can rightfully be applied in the actual design, construction and operation of objects. Prerequisites and conditions have been created for the development of a universal methodology for assessing heat and wind processes, determined by geometric and physical similarity when modeling processes in the near-wall air environment in solving architectural and structural problems of various compositions. It has been established that the effectiveness of ventilation of the wall layer of air and the first unbuilt column floor is achieved by using façade louvered sun-protection devices with an angle of inclination of their lamellas of 45° - 60° to the plane of the facade during their insolation. The energy efficiency of building walls was revealed through the use of sun-protection louver devices. Prerequisites for the architectural and construction design of external walls with louvered sun-protection devices have been determined that contribute to the formation of convective flows in the wall layer of air, which can subsequently be used for heating premises, as well as for extracting exhaust air from premises by determining the location of natural supply and exhaust openings and the operating mode of windows sashes, transoms, vents.

The article discusses various aspects of the problem of assessing crack opening in reinforced concrete based on experimental data obtained in recent studies. The author proposed a classification of crack types, introduced a number of new hypotheses, established experimentally the effects of deformation of reinforced concrete in the crack zone. The principles formulated on their basis include schemes for the distribution of force flows between cracks, the concept of progressing main cracks and the deformation effect in reinforced concrete - a special two-console element in the local region near the crack banks, new generalized hypotheses, theorems and functionals about linear and angular deformations of the compressed and tensile zones of reinforced concrete element sections at all levels of elastic-plastic deformation. The proposed model of composite rods in the form of single strips for determining the stiffness of a section of reinforced concrete with intersecting cracks has made it possible to reduce the differential equations of the theory of composite rods by an order of magnitude when solving such problems. The connection is established and analytical dependences for displacements in the crack with opening and shear of the crack banks are given. The main vector of displacements and the angle of equidirectional forces in the reinforcement crossing the crack are determined. Calculated dependences for determining the level distances between cracks and crack opening widths are constructed. Within the framework of the general methodology of the considered problem of crack opening in reinforced concrete, using the formulated principles, a general combined numerical-analytical model of the structural mechanics of reinforced concrete is constructed, which takes into account the deformation effect in the crack modeled by a double cantilever element, the types of cracks, the spatial surface of strain distribution in the cross section with the crack and other experimentally determined features of the mechanics of reinforced concrete, cracks types, spatial surface of strain distribution in the cross-section with a crack and other experimentally determined features of reinforced concrete mechanics.

The purpose of this research is to develop the method of shape factor interpolation for calculating the maximum deflection of thin plates on an elastic Winkler base, which are widely used in modeling the operation of elements of building constructions of buildings and structures. The above calculation method allows to obtain solutions based on direct analytical dependences, the argument of which is an integral characteristic of a flat convex one-connected area - the shape factor. This characteristic has applications in a number of problems of mathematical physics and is known from the works of scientists G. Polia and G. Szegö. The shape factor was first applied to the calculation of plates by Professor V.I. Korobko. The method of interpolation by shape factor was developed by Professor A.V. Korobko. When determining the maximum deflection of thin plates on an elastic base, some parameters of the problem are considered as functions of the shape factor of the plate in consideration and are determined by the type of boundary conditions on its contour. The present study is devoted to the construction of approximating functions for continuous sets of plates of characteristic outlines and boundary conditions. The paper presents functions for calculating the maximum deflection of elastic plates in the form of isosceles triangles, rhombuses and rectangles. The plates with various combinations of hinged support and rigid pinch along their individual sides, loaded with a continuous uniformly distributed load, are considered. The established functional dependences are intended for direct use in the calculation of plates of the specified outlines, as well as for obtaining reference solutions during interpolation of the values of maximum deflections of plates of more complex outlines.

In Russia, the volume of sawn products produced by cutting large-sized logs on band saws is increasingly expanding. The blades of band saws work from 20 to 500 hours and the technology of their secondary use is currently not provided. The creation of an effective method of reinforcing wooden structures with spent band saw blades will increase their load-bearing capacity, rigidity and operational reliability. It is assumed that in terms of the combination of strength indicators and manufacturability, the new reinforced wooden structures will correspond to existing analogues, and in terms of economic indicators they will surpass them. The conceptual novelty consists in the secondary use of man-made waste from woodworking industries in the construction of buildings and structures, which for the first time will allow to justify the effectiveness of the method of reinforcing wooden structures with treated band saw blades at a high theoretical level. The article examines beams made of solid wood with a length of 6 meters with a cross section of 100 × 200 mm, bending tests are performed. Numerical simulation of the plane stress state by the finite element method is performed. The load-bearing capacity of a beam reinforced with spent band saw blades increased by 1.5 times in comparison with an unreinforced beam.

The paper presents the results of investigation of creep and shrinkage of steelreinforced concrete specimens. For this purpose, parallel tests of specimens made of the same class of concrete but with different reinforcement were carried out. Concrete specimens, specimens reinforced with bar reinforcement frames and steel reinforced concrete specimens with external sheet reinforcement were investigated. The tests were carried out in climatic rooms using spring setups to maintain a constant load acting on the specimens over time. The load on the specimens was selected based on the equality of stresses in the concrete in all series of specimens. The specimens were tested both waterproofed and non-waterproofed, and the effect of waterproofing coating on shrinkage and creep strains was evaluated for different series of specimens. A system was developed to capture information. which allows, in addition to longitudinal shrinkage and creep deformations, to determine transverse deformations, longitudinal deformations along the faces of the specimen to determine the influence of reinforcement and steel of the outer plate, to evaluate the change in longitudinal deformations from the center of the specimen to its edges, to evaluate separately the deformations of concrete and steel plate in steel-reinforced concrete specimens.

The analysis of the results allowed a comparative assessment of the influence of conventional bar reinforcement as well as steel sheet of steel-reinforced concrete specimens on creep and shrinkage deformations; the influence of waterproofing coating on the test results in different series was also assessed. Based on the results of this work, extended requirements for experimental and theoretical studies of steel-reinforced concrete specimens with external sheet reinforcement to determine their design stiffnesses were formulated.

The theory of damage accumulation in concrete as a heterogeneous-brittle material, as applied to conditions of high-temperature, abrupt heating, is supplemented by the premise of the invariance of ultimate structural stresses, which makes it possible to imagine the development of a nonlinear component of deformation and a decrease in strength as a single process. A characteristic of this process is the elasticity coefficient (secant modulus coefficient) of concrete, which in the formulation under consideration acquires the character of an entropy parameter of material damage. The consequences of this premise are formulated in the form of basic thermomechanical relationships, thanks to which it becomes possible to consider the reaction of concrete to the action of temperature and load as a result of the action of two degradation mechanisms: evaporation of moisture from the gel of cement stone and destruction of structural bonds with increasing temperature, which are realized respectively in the form of linear and nonlinear components of force deformation.

A method of normalization (representation in a form relative to the initial value) of the development curves of force deformations of concrete is proposed, which allows us to reasonably separate these components when analyzing the deformation curves and find the temperature parameters necessary for their description under heating conditions in a loaded state. It was revealed that at the same load and temperature, an increase in deformability when heating concrete in a loaded state compared to loading after heating occurs due to an increase in the linear component while maintaining its share in the total deformation, characterized by the elasticity coefficient, constant. It is shown that the assumptions made in existing models of deformation of loaded concrete during unsteady heating are partial solutions, and the conditions under which their use becomes possible are determined.

A conceptual approach is presented to predicting the durability of concrete under conditions of frost exposure and strong saturation based on the actual work of concrete in the structures of port facilities on the sea coast of the south of the island. Sakhalin. It is shown that the lack of methods for predicting concrete corrosion under frost exposure, despite the large amount of theoretical and experimental work on this topic, is due to the diversity and synergistic effect of factors that determine durability. It has been established that the multicyclic effect of sign-variable temperatures due to sea tides is not always the determining critical indicator of severity for the zone of variable level. Non-freezing water in the port waters and severe hydrometeorological conditions in the form of strong waves predetermine the icing of structures throughout the winter period. This factor in certain cases can be critical for concrete. Based on the results of the study of the state, properties and temperature-humidity regime of concrete in the structures of the zone of variable water level and the generally accepted theoretical principles of frost destruction of concrete, it is proposed to predict its service life in the zone of variable level of port facilities based on the concept of a two-stage process of frost corrosion. The possibility of predicting the durability of concrete based on scenario modeling of the process of development of the system of pore structure of the cement matrix, depending on its parameters by the beginning of frost exposure and the mechanism of freezing of concrete in structures, is shown.

On the energy basis, using the diagrammatic method, the solution of the problem of determining the survivability parameter of the reinforced concrete frame structure of a multistory building with complex-stressed elements under static-dynamic deformation caused by a special impact is obtained. Determination of the parametric load value, at which in the most stressed spatial section at the considered loading mode one of the criteria of the special limit state comes from the system of canonical equations of the extraordinary version of the mixed method. Comparison of the experimental and design survivability parameters gives an assessment of the efficiency and reliability of the proposed design dependencies. It has been shown that with the adopted initial hypotheses, the proposed method for calculating the survivability of frames with complex stressed elements satisfactorily describes the process of their deformation and destruction under the considered impacts.

The technology of reinforcing structures by the shotcrete method has been known for more than a hundred years. The first experiments using this method refer to approximately 1910-1912. At the same time, at this moment there are questions both with the calculation methodology of reinforced structures, and taking into account the new properties of shotcrete, which appear in this material as a result of improving equipment and material for shotcrete directly. This article examines the experience of calculating, projecting and applying shotcrete to strengthen load-bearing masonry structures accumulated over the past two years. The current methods of work are presented, as well as the corresponding methods of calculation justification (taking into account the stage of work on strengthening structures) for objects that are difficult from an engineering point of view: arches, brick walls with a large percentage of damage, including as a result of mine-explosive impacts. The results of the implementation of reinforcement of stone masonry by the method of one-sided applications of shotcrete are shown.

In the presented work, the process of thermodegradation of unmodified and borazote-modified crushed stems of Sosnovsky's Heracleum by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) was investigated. The general purpose of the study is to determine the decomposition temperature of the main chemical components and the values of mass loss of unmodified and modified crushed stems of Sosnovsky's heracleum to establish the conditions for the production of thermal insulation materials based on modified crushed stems. The concentration of the used modifier was 10%, 30% and 50% of monoethanolamine (N→B) trihydroxyborate (MEATHB). The data obtained allowed us to conclude that the use of 30% and 50% MEATHB modifier reduced the magnitude of mass loss compared to the control samples. Thus, the optimal concentration of the modifier different 30% was established for the manufacture of composites from modified crushed stems of Sosnovsky's heracleum with the possibility of processing and/or drying at temperatures less than 100°C.

The article considers the technologies for the construction of mainly civil buildings in different periods of construction in St. Petersburg. The subject of the study is building systems and building construction technologies, which are considered in order to study the development of industrial construction methods in St. Petersburg and predict trends in technical progress in the field of industrial construction methods. The prerequisites for technological progress in the construction complex of St. Petersburg is the development of the industry of material and technical resources of construction, namely the production of new building materials, structures, construction equipment, fixtures and construction machines, as well as small-scale mechanization and tools. This inevitably becomes the reason for the appearance in construction of more advanced building systems erected by industrial methods. In the course of the study, building systems were evaluated by the methods of an expert survey of specialists according to a previously developed questionnaire, in which there were mutually incomparable criteria reflecting the architectural, strength and economic characteristics of building systems of industrial production. The results of an expert assessment of building systems became the basis for determining the rational scope of prefabricated and precast-monolithic construction and identifying trends and promising directions for the development of industrial construction methods and scientific research in this area.

The article discusses the provisions on the choice of vehicles for the transportation of prefabricated reinforced concrete structures. The need for the use of railway transport in the delivery of structures may be caused by construction in remote areas of Siberia, as well as the existing location of supplier enterprises.

General-purpose gondola cars, as well as four-axle platforms, are mainly used for transporting structures. The methods of fixing and placing reinforced concrete structures are given.

The main causes of damage to reinforced concrete structures are considered and recommendations for their elimination during transportation are developed. In most cases, structural damage during rail transportation occurs at the moment of collision of wagons when they are improperly lowered from the sorting slides due to displacement or fracture of fasteners under the action of shifting cargo, when the speeds of the platforms exceed the standard ones. The amount of damage is also affected by poor-quality fastening.

The possibilities of loading mass-produced structures into gondola cars and onto platforms are investigated, assuming that they are loaded with reinforced concrete structures of the same weight and size.

The proposals for improving the efficiency of rail transport are presented, including a recommended technical solution with the installation of a frame on a platform for transporting slabs.