The design, construction and operation of buildings in Ukraine is associated with the need to take into account additional special loads and impacts, namely: seismic, in complex en-gineering and geological conditions, on weak soils, artificial territories and subsidence soils, and in the conditions of the war with Russia during missile and artillery shelling and bom-bardment of populated areas – effects from explosions, blast waves, spread of fires, etc. [3]. The territory of Ukraine is located on the outskirts of the powerful Azores-Mediterranean-Alpine-Trans-Asian seismogenic belt of the planet. In general, Ukraine does not belong to particularly seismically dangerous regions of the planet. Low- and medium-magnitude (magnitude 3...6) earthquakes were recorded only within three of its regions: the Ukrainian Carpathians and the Crimean Moun-tains, the Azov region. But observations of the consequences of numerous earthquakes have shown that in different parts of the same seis-mic area they differ significantly in intensity. Thus, the intensity of the earthquake on the surface of the earth in areas with loose soils is 15 times greater than in areas with rocky ones. Therefore, during the design of buildings and structures, one should take into account the peculiarities of construction in the complex engineering and geological conditions of the territory of Ukraine, which are associated with research, design and arrangement of bases and foundations on weak water-saturated, clayey and peaty soils, peat and silt, subsidence, swell-ing, saline, swelling and unevenly compacted soils, loose sands and floating karst and forged territories, taking into account seismic and dy-namic action in compliance with the require-ments of DBN B.1.1-12:2014 "Construction in seismic regions of Ukraine" [5] and DBN V.1.1-45:2017 "Buildings and structures in difficult engineering and geological conditions. General Provisions" [6]. The design of modern buildings in seismic areas is developing in two directions that corre-spond to the main principles of seismic protec-tion - traditional (passive) and special (active). Complex systems of seismic protection of buildings combine passive and active systems. With traditional seismic protection, the load-bearing capacity of the main load-bearing structures of buildings is increased (the dimen-sions of cross-sections, their reinforcement, strengthening of joints, etc.) to absorb addition-al forces caused by seismic influences. At the same time, the nature of the buildings does not change. Special (active) measures to improve the seismic resistance of buildings consist in reducing loads due to modifications of their dynamic work schemes. Active seismic protec-tion of buildings is a new direction, which con-sists in the implementation of additional con-structive measures to prevent dangerous reso-nant oscillations and thereby reduce seismic impacts. It is achieved by changing the dynam-ic stiffness or periods of natural oscillations of buildings during earthquakes as a result of the use of special structural devices: sliding belts, connections that can be turned on or off, instal-lation of dynamic vibration dampers, kinematic or pile foundations, which have dissipative characteristics of self-organization, frame-linking systems with complex stiffness dia-phragms, rubber-steel cylindrical supports, etc.The article analyzes the features of design-ing earthquake-resistant steel structures of high-rise buildings. The schemes of earthquake-resistant high-rise buildings with steel frames were studied. The feasibility of using steel en-ergy-absorbing elements is substantiated and schemes for their installation in earthquake-resistant buildings with steel frames are pre-sented.

The problem of choosing a project for a developing engineering network is considered. A mathematical model of a developing engineering network, which even at the design stage allows us to take into account the possibility of expanding or reconstructing the system in case new customers are added to the target product, which is a two-criteria block programming problem with separable criterion functions. In the proposed mathematical model, the first criterion reflects the need to minimize financial costs construction and operation of the network, in order to ensure portability of the target product delivered at the time of designing. The second criterion expresses the requirement of minimizing financial costs for the future development of the system in the future from the achieved level, provided that the vector of the system’s development is known before the engineering network design starts. Taking into account the criteria preference vector, which allows you to take into account the inequality of both cost criteria in the constructed mathematical model and makes it possible comparing criteria of different orders makes it possible to replace the two-criterion optimization problem of choosing a project of a developing engineering network with a single-criterion mathematical programming problem without changing the set of solutions to the problem. The properties of the set of effective vectors of criteria values, which arise when solving a single-criteria optimization problem of choosing an engineering network project variant with a variation of all possible values of the criteria preference vector, have been formulated and investigated, which will make it possible to build dialogue procedures, during the execution of which the approximation of the set of values of the problem criteria will be carried out.

The emergence of new types of structures and construction technologies related to them became the impetus for the search for new forms of buildings and structures and the development of a new understanding of space. Technical and economic calculations show that the area of coverings in buildings with large hall rooms, as a rule, exceeds the total area of other enclosing structures, and therefore the cost of coverings, taking into account installation work, is of predominant importance in construction estimates. Spatial forms of coverings of hall rooms significantly affect the architectural expressiveness of buildings, and therefore the issue of choosing forms, materials and rational constructive solutions of coverings is extremely relevant. The most important components of the covering systems of buildings and structures are supporting structures, which have unlimited possibilities of interpretation of forms and materials, can be hidden or open and turn into architectural elements. It is obvious that in the process of designing the coverings of buildings and structures, it is necessary to consider and analyze various options for their constructive solutions. The article analyzes the types of arches, their classification, the conditions of use as load-bearing structures of building coatings, as well as some problems of their static operation, which are related to the choice of form and conditions of their support and division into structural elements. The authors considered the problems of calculating and designing arches, choosing rational forms of arches that ensure the prevention of loss of their stability from the bending plane and a high aesthetic level. The main principles and methods of construction and static calculation of arches are presented.

This days the use of concrete and reinforced concrete structures in construction is common. Their widespread use has been made possibleby the achievements of engineers and architects ofpast centuries. The authors consider the main defining stages of development of concrete and reinforced concrete structures and their widespread popularization in the world. A consistent historicaloverview of the development of structural forms of reinforced concrete in residential and non-residential buildings was made. Numerous examples illustrate the path of development of reinforced concrete structures - from strut-beam systems to curvilinear spatial forms.The works of prominent civil engineers and architects are considered: F. Gennebique, M. Kenneth, O. Perre, R. Mayar, D. Mate Trucco, V. Bonade Bottino, R. Piano, E. Fressine, M. Berg, G. Trauer, E. Torroha, P. Luigi Nervi and others [2,13, 15].The article analyzes the development of architecture, building structures and construction technologies in the crucial phases of historical development based on the use of architectural research,which is based on the analysis of objective features of buildings and structures, namely their functional purpose and design capabilities. The experience of designing and construction of unique constructionswith large-span coverings, the search for rationalconstructive decisions are traced, recommendations for the further perspective development of reinforced concrete designs are given.

The article considers and systematizes the load-bearing structural systems of buildings with complex space-planning configurations, taking into account design solutions, structural loading and stress states. The features of the perception of loads and their rational distribution between the structural elements of frame buildings with complex space-planning solutions are analyzed. The main structural schemes of complex frames, schemes of their deformations and plots of moments under the influence of vertical and horizontal loads are introduced. The paper reflects the modern practice of preliminary approximate calculations of the approximate dimensions of the sections of frame structures of frame buildings for the possibility of further collecting loads and performing refined calculations using modern calculation software systems. The proposed method for modeling the nature of the work of complex frames of frame buildings and coordinating their space-planning, design and calculation systems will be useful for researchers, architects and design engineers during the design of new types of buildings, taking into account their operation under emergency conditions.