FEATURES OF THE DESIGN OF STEEL EARTHQUAKE-RESISTANT STRUCTURES OF HIGH-RISE BUILDINGS

Abstract

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.