Cold-formed structures are used in buildings of various functional purposes: industrial, agricultural, sports. Interest in this kind of construction is growing, and this is due to the high speed of setting-up, low material consumption and, accordingly, the low cost of construction. Improvement and development of cold-formed structures in most cases is associated with the expansion of the range of profiles used in these structures, as well as with the development of new structural systems that provide an opportunity to increase the efficiency parameters of the structures. The introduction of the new code СП 260.1325800.2016 ‘Cold-formed thin-walled steel profile and galvanized corrugated plate constructions. Design rules’ became the basis for the development of such structures. But as long as this code does not fully cover all possible design forms and options for calculating the elements, that is why this article was prepared for the calculation of cold formed steel panels with double corrugations for combined bending and axial compression. During the work, an experiment was prepared and conducted with the aim of a combining a developed method of calculating existing panels, to methods of calculating according to СП 16.13330.2017. The article details the methodology of the experiment with a description of the assumptions that allow comparing the results of research with the actual work of the structure. The foundation was also laid for further scientific research on this topic.

The need to calculate structures on the progressive collapse is reflected in a number of codes and standards of the Russian Federation and often plays a crucial role in the design. Analysis of the existing design experience showed that this problem cannot be solved by general methods, its formulation and solution should be reflected in the sets of standards for designing specific buildings and structures. The analysis of the foreign experience shows that the most similar to Russian standards is EN 1991-1-7: 2006, which proposed a developed and integral system of approaches to ensure the reliability of the structures with different responsibility levels for special impacts (accidental actions), including the strategies to protect structures from progressive collapse. The problem is that the modern standards discussed in this article have a number of mistakes. Of course the new SP 385.1325800.2018 has positive innovations, for example, more detailed approaches to the reinforced concrete design, panel buildings, etc. At the same time, it does not fully take into account the requirements of SP 296.1325800.2017 and GOST 27751-2014. The introduction of a new standard not only does not resolve the existing shortcomings and contradictions in the progressive collapse regulatory framework, but only further confuses the situation.

Various types of the roofs hybrid metal structures are presented. The Russian engineer V.C. Shukhov was a first author of such designs. The roofs hybrid metal structures include structurally integrated tension elements and elements working for compression and bend. Flexible guys and rigid elements work in common. There is a lot types of the hybrid systems. Archguy systems contain a rigid curvilinear top chord and the tension lower chord. They are united by flexible elements such as guys, suspension brackets or compressed struts. The combined truss bar systems include the top and lower chords united by two couple V-figurative racks. The suspended combined systems include the rigid girder structure suspended to the external guys fixed on columns or pillars. The new progressive direction of development the hybrid structures are tensegrity-systems. The general concept and the theory of this system were offered and developed by B. Fuller. The tensegrity-system is a set of the elements working only for tension or compression. Stability and rigidity of system is provided with prestressing and a self- balancing of elements, at optimum redistribution between them external loadings. The description of a structure, optimal solutions, and examples of the constructed building are given.

The assessment of reliability parameters for design of construction structures, allowing to obtain the values of indexes of reliability, safety factors, value of reliability, the coefficients of variation in the distribution of loads and bearing capacity for log-normal law is given.

Preservation of authenticity increases the value of cultural heritage sites (monuments) and the national heritage of Russia. In the northern areas of low population density. People are not enough to maintain wooden objects, rotting and fires cause great damage. The Venice Charter provides for the adaptation of buildings for the benefit of society, provided that the architectural integrity and decor are preserved. The absence of the mention of the 'integrity of structures’ should not allow double interpretation for radical actions to the detriment of the supporting structures. Identified a number of violations caused by low legal literacy of the population and the actions of officials without regard to situations in the municipalities. Expert assessment by the method of analyzing hierarchies showed the importance of erroneous management decisions: violation of the periodicity of detailed surveys and monitoring of the state of structures - 25%; the use of workers with low qualifications - 55%; the use of cheap materials and products with low maintenance resource - 10%; strengthening structures without calculations reduces the periods between repairs and the operational life of the object - 10%.

The results of numerical studies of the strength and deformations of three-layer external walls with a face layer of masonry with flexible ties under temperature effects, taking into account the formation and development of cracks, are presented. The calculations were carried out according to the specialized program for calculating stone constructions KAMKON, which implements the finite element method. The verification of the KAMKON program was carried out by comparing the results of calculations and experiment on a large-scale model, taking into account the formation and development of cracks, as well as at the time before the formation of cracks by comparing with the results of calculations using the LIRA-SAPR software package. The results of field observations of buildings with masonry defects of the facial layer were also taken as a criterion for the validity of the chosen computational models. In the course of research, the technology of calculation by the finite element method for temperature effects was developed taking into account the formation and growth of cracks, features of the laying of the front layer, such as the heterogeneity of the masonry, the concentration of horizontal tensile stresses in the unfilled vertical joints of the masonry and cracks, tensile strength criteria for stretching over the vertical section, on inclined sections from the action of tensile stresses and forces to cut along horizontal mortar joints.

Features of development and consequences of fires in high-rise buildings and on objects of special purpose are analyzed. The results of theoretical and experimental investigations to substantiate the optimal compound for structural fire-retardant coatings of steel structures in the “cellulose” and “hydrocarbon” types of fire are outlined. The developed flame retardants series ‘Monokote’ on gypsum and cement binders are presented to provide the required fire resistance rating of bearing steel structures, taking into consideration the operating conditions of coatings based on them.

To study the effect of fiber on the strength of normal sections, we produced and tested polymer concrete (rubcon) beams of rectangular section with different heights of the dispersed reinforcement zone. As a result of the research, it was found that the height of the zone of dispersed reinforcement affects the strength of normal sections, but this effect is less than the percentage of longitudinal reinforcement. Also, due to the fact that the layered fibrorubcon bending elements do not exceed the fibrorubcon bending elements with dispersed reinforcement over the all height of the section, and only allow reducing the consumption of fibers for the product, at the same time the process of their manufacture is much more complicated, they are not recommended for use in production.

The operating experience of facades of buildings with brick cladding over the past 20 years is analyzed. Exterior walls of solid brickwork have ceased to meet energy efficiency requirements since 1997, and non-load-bearing, multi-layered brick structures with energy-efficient insulation began to be introduced into construction practice. SP 15.13330 ‘Stone armo-stone structures’ do not apply to such structures. The main problem addressed in this article is how to avoid problems in the design and further operation of brick cladding on the facades of buildings and what regulatory documents for these structures should be developed.

The paper deals with the ways of a software implementation of certain requirements of the Russian building code SP 14.13330.2018 on the dynamic analysis of structures under seismic actions, which in the building code are not fully covered and, therefore, may be different. The ways of accounting for these requirements used in the implementation of the software STARK ES are given. These are used in a numerical physically nonlinear analysis of structures under seismic actions, in methods to ensure the completeness of the normal mode basis in the mode superposition method and in methods of finding the dangerous direction of seismic action.

The chronology of changes in the assignment in the domestic standards of strength characteristics for the calculation of wooden structures from the method of permissible stresses to the method of limit states is presented. The prerequisites for changing the order of determining the design resistance of wood are given. The changes in the procedure for determining the design resistances of wooden structures in SP 64.13330.2017 for wood selected by grades are described, with the definition of the basic design resistances obtained from the results of standard tests and strength classes through standard wood resistances.

Results of the pilot research of the fire resistance of ceramic large-format masonry unit on heavy mortars and masonry glues are given. It is noted that the limit of fire resistance of a laying depends both on design features of stones, thickness of walls, and on a type of solutions and glue structure. According to the research results, recommendations were given on the need to test the fire resistance of masonry walls with a thickness of less than 120 mm by fire tests, as well as calculations. At the same time, it is recommended to supplement the Code of Practice for the Design of Fencing Constructions of Large-Format Ceramic Stones with a special section defining the requirements for the fire resistance of masonry.

The article gives the summary of C.A. Geniev’s theory ‘The failure criteria of masonry under plane stress’ developed in 1979 and elaborated in several works of his employees. At that time, there were few experiments to confirm the theory. Then the development of new wall materials, in particular large-format ceramic cellular concrete and silicate used for the manufacture of enlarged blocks, was started. Such blocks were characterized by high accuracy of geometric dimensions. Also it became possible to have thin-seamless and glued laying. Reduced wall thickness and increased stresses require taking into account biaxial stress state. Experimental studies are to be carried out for testing design solutions. Application of the calculation theory under plane stress state needs experimental verification. The article should contribute to the refinement of test methods and further development of the theory. The calculation example for the wall sample at biaxial compression is given.

The article deals with disclosure of characteristics of science, philosophy and technology in the epoch of Renaissance. The backgrounds of changes in the ideological orientation in the epoch Renaissance, science development of this period on the new natural-science bases in the works of scientists are being examined. The discoveries of great inventors, who left a mark in the development of science and technology, are represented.