The article contains the methodology and results of theoretical and experimental studies of the stress-strain state of a conical radial-beam dome with triangular shell elements. The results obtained by various methods are analyzed and compared. The triangular membrane panel is part of the radial beam dome structure and consists of a support frame and a steel membrane in the shape of a triangle. The shape of the triangle forming the membrane panel can be different and depends on the number of ribs in the radial beam dome. The supporting contour is a compressed-bending element of the dome and is made, as a rule, from a rolled steel profile with a channel section. The membrane is made of thin steel sheet and attached to the upper flange of the channel with self-tapping screws or spot welding. To assess the strength and deformability of a steel membrane sheet, its operation under the action of a uniformly distributed snow load, an unevenly distributed snow load and a concentrated installation load was considered. Several options for nonlinear static calculations in various computer systems are shown.

Keywords: building structures, wooden structures, membrane panel, stress-strain state, radial beam dome, dome, membrane, design, experimental study

The results of a study of the influence of shrinkage deformations on the basic physical and mechanical properties of concrete are presented depending on various production and technological factors. The research methodology took into account the choice of the period of aging concrete in a dry, hot climate to study the influence of physical processes in concrete on its physical and mechanical properties. The influence of shrinkage deformations on the strength characteristics of concrete was studied. an increase in the intensity of mass transfer processes between concrete and the environment leads to an increase in destructive shrinkage deformations, mainly plastic shrinkage of concrete, which lead to changes in the structure and physical and mechanical properties of mature concrete. The consistency of the concrete mixture also influences the amount of strength reduction. with a greater value of plastic shrinkage of concrete, its compressive and tensile strength in bending decreases. the destructive effect of plastic shrinkage on concrete caused depends on a number of technological factors (consistency of the concrete mixture, w/c, temperature and humidity hardening conditions, etc.).

Keywords: curing period, mass transfer processes, plastic shrinkage, concrete structure, concrete strength, reconstruction, buildings and structures

The main properties of slag-alkaline binders were studied to determine their optimal composition. The possibility of controlling the properties of binders developed on the basis of phosphorus and blast furnace slag by introducing corrective additives into the aluminosilicate component of slag-alkaline binders, as well as by changing the type of alkaline component, has been experimentally proven. The conducted studies confirm the effectiveness of the use of sulfate-containing alkaline components for the production of slag-alkaline binders. As a result of the conducted experiments, slag-alkaline binders with an activity of 30 to 110 MPa were obtained. The possibility of regulating the properties of the developed slag-alkaline binders has been established. The required binding strength is achieved by adjusting the composition of the aluminosilicate component by introducing additives and the type of alkaline component.

Keywords: alkali-silk binders, slags, optimal composition, basicity, chromium peak, construction materials, reconstruction, work technology

Defensive structures of the Middle Ages were (and are) unique objects both in historical, architectural, and engineering terms. They intertwine the eras of many peoples and ethnic groups. Their development was influenced by a large number of factors. Their detailed analysis is the purpose of this work.

Keywords: defensive structures, architecture, fortress, construction, architectural appearance, stages of development, Kazan yurt

The relevance of the study lies in the fact that historical areas of cities and individual buildings that are objects of historical and architectural heritage were once built on pile foundations. Until the beginning of the 20th century, wooden elements, usually up to 9.0 m long, were laid as piles at the base of buildings and structures, which over a long period of operation received defects and damage in the form of damage by soft rot up to the complete destruction of the heads. The purpose of the work is to study the stress-strain state of the pile foundation at successive stages of development of defects and damage. The work systematizes the results of examinations of wooden piles and other elements located in the ground for a long time; laboratory studies of the actual operation of piles in water-saturated silt-clay soils were carried out. The results of field and laboratory studies are included in the calculation apparatus implemented by the finite element method in an elastoplastic formulation. The authors showed the actual operation of pile foundations of historical and architectural heritage objects at successive stages of pile damage and obtained a calculation model at the stage of complete destruction of the pile heads. Laboratory and theoretical studies have shown that in the modern practice of preserving objects of historical and architectural heritage, there is a vicious practice, which consists in the fact that they often strengthen the foundations in cases where there is no need for this, and sometimes it is even harmful.

Keywords: cultural heritage sites, artificial foundations, piles, wood, water-saturated soils, structures, technical expertise

The assumptions of mathematical models for calculating the crack resistance of reinforced concrete structures are considered. For each of them, an analysis was carried out to determine whether they correspond to reality throughout the entire life cycle of the structure: from the hardening of the concrete mix to destruction. Based on the results of the analysis, it was proposed to use only one single calculation at the level of standards to assess the crack resistance of structures - according to the crack opening width, acrc. So, for example, at a certain value of acrc, the structure will still remain airtight (the cracks will be non-through), and if this value is exceeded, it will not. At the same time, the calculations already available in the norms for limiting permeability and the safety of reinforcement will still remain in demand. At the junction of the theory of damage accumulation and nonlinear fracture mechanics, a compressed algorithm is proposed for possibly taking into account the influence of cracks at all scale levels of the concrete structure, the key for which is the normalization of the statistical parameters of the distribution of discontinuities by diameters, lengths, openings, depths, directions, distances between discontinuities, etc.

Keywords: reinforced concrete, crack resistance, cracking moment, crack width, plasticity coefficient, damageability, non-linear fracture mechanics

The Kazan Kremlin is a unique object in its historical heritage. It intertwined epochs of many peoples and ethnic groups. Arising as a parking lot, and then as a Finno-Ugric settlement, it developed as a Bulgarian, Tatar and Russian fortress. The last so-called Russian era is rich in its diversity. References have been preserved in the sources and a lot of literature has been written about it. This publication gives the main points of the development of the fortress in the second half of the 16th - 18th centuries.

Keywords: Kazan Kremlin, fortifications, architecture, fortress, construction, architectural appearance, stages of development

The defensive structures of the Kazan yurt are unique in both historical and architecturally objects. The era of many peoples and ethnic groups intertwined in them. Their development was influenced by a large number of factors. Their detailed analysis is the purpose of this work.

Keywords: defensive structures, architecture, fortress, construction, architectural appearance, stages of development, Kazan yurt

Issues of carrying out the identification of hazardous production facilities are discussed. On a real example of a survey of a warehouse of combustible substances, the implementation of a technical expertise with a conclusion drawn up on its results is illustrated. The article was written on the basis of the completed research work No. 22-78.

Keywords: hazardous production facility, identification, technical expertise, industrial safety, building structures

The issues of developing a project for strengthening the building structures of a cable overpass after an emergency (accident) are discussed. On a real example, a description of the accident is given, the performance of work on the ghost of structures to the standard state is illustrated. The article was written on the basis of the completed research work No. 18-26.

Keywords: building structures, safety, cable trestle, emergency response, technical expertise, buildings and structures, metal structures, reinforcement project

The technology of organizing the construction of decentralized energy systems based on wind power plants is given. New design solutions for the structural elements of wind turbines and overhead lines (tower, collapsible ballast-type foundation, protective element) are proposed, taking into account the specifics of the technology of construction and installation works. Data are given on reducing the cost of construction production by optimizing the machines and mechanisms used.

Keywords: wind turbine structures, overhead lines, tower, collapsible ballast-type foundation, protective element, in-line method, decentralized system

The assumptions of mathematical models for calculating the crack resistance of reinforced concrete structures are considered. For each of them, an analysis was carried out to determine whether they correspond to reality throughout the entire life cycle of the structure: from the hardening of the concrete mix to destruction. Based on the results of the analysis, it was proposed to use only one single calculation at the level of standards to assess the crack resistance of structures - according to the crack opening width, acrc. So, for example, at a certain value of acrc, the structure will still remain airtight (the cracks will be non-through), and if this value is exceeded, it will not. At the same time, the calculations already available in the norms for limiting permeability and the safety of reinforcement will still remain in demand. At the junction of the theory of damage accumulation and nonlinear fracture mechanics, a compressed algorithm is proposed for possibly taking into account the influence of cracks at all scale levels of the concrete structure, the key for which is the normalization of the statistical parameters of the distribution of discontinuities by diameters, lengths, openings, depths, directions, distances between discontinuities, etc.

Keywords: reinforced concrete, crack resistance, cracking moment, crack width, plasticity coefficient, damageability, non-linear fracture mechanics

An example of a technical examination of a cultural heritage object of federal significance is given in order to identify the fact of violation of the Federal legislation during its restoration. Recommendations are given on the preparation of a technical conclusion of this examination. The article was written on the basis of the research carried out (at the request of law enforcement agencies).

Keywords: technical expertise, object of cultural heritage, violation of the law, building structures, temple, dome, restoration

The optimization of the taxable base of capital construction objects is considered, this is the desire of customers and operating organizations to manage the cost of ownership of one or another technical solution, which is certainly reasonable in modern conditions, when when making a technical solution, its full cost is estimated, including the so-called cost of ownership for the entire period of the life cycle of the object, from the formation of an idea for the creation of a future object to its decommissioning.

Keywords: collapsible foundation, protective element, flow method, wind power plant, building structures

The procedure for carrying out a set of works to preserve the object of cultural heritage of regional significance "The mass grave of Soviet soldiers who died of wounds" is given. All stages of carrying out such types of work are considered, recommendations are given for solving issues that arise in the process of carrying out work.

Keywords: repair, object of cultural significance, work technology, inspection, building structures, mass grave