Introduction. In seismically active areas, structures made of various materials are widespread, each of which has its own advantages and disadvantages.

Materials and methods. Among the existing materials, metal and wood stand out, which are used for the manufacture of various structures in both civil and industrial buildings.

Results. The active use of these structures in seismic areas makes it possible to create structural solutions that can resist seismic effects of various frequency composition and intensity. At the same time, when choosing a material, special attention should be paid to the influence of the prevailing frequency or period of an earthquake on the behavior of the construction site. The article presents the results of research on this influence and some examples of the implementation of structural solutions made of metal and wood.

Currently, seismic isolation technologies are becoming increasingly widespread in earthquake engineering. The technology, known since ancient times, has been developed in the modern world. The effectiveness of various seismic protection technologies used has been repeatedly confirmed after strong earthquakes in many countries of the world, including Russia. That is why scientific engineering does not stop working to improve the seismic protection of buildings and structures. The article presents the main conceptual seismic protection systems, examines existing design solutions for the implementation of seismic isolating devices, taking into account the peculiarities of their operation during earthquakes, since the reliability of the operation of seismic protection systems largely depends on the characteristics of the seismic impact, its frequency component, direction, intensity, etc. The systems developed and used in Russia currently have economic and social efficiency, making it possible to achieve, in comparison with traditional structures, an increase in the seismic reliability of structures, a reduction in the cost of anti-seismic measures, a reduction in damage from earthquakes, and more accurate assessments of investment and insurance risks.

The widespread use of high-rise buildings was caused by the growing population of cities and the lack of land. As practice shows, the structural system of high-rise buildings with a load-bearing core is one of the most reliable. A variety of such buildings are buildings with suspended structures. This structural system has found application in many high-rise buildings around the world, including in seismically active areas. At the same time, such a constructive solution is rarely found in Russia. We have no recommendations on the use of this structural system, and there is also no information about the behavior of suspended structures with high seismic activity. The greatest interest in the study of buildings with a load-bearing core occurred in the 80s – 90s of the 20th century. It is worth mentioning a number of important advantages of the considered constructive system. First of all, these structures have significant flexibility, which leads to an increase in the natural period of oscillations and a decrease in the seismic load on the load-bearing elements. In some cases, suspended structures of buildings with a load-bearing core act as dynamic absorbers. This makes it possible to ensure the stability and reliability of the entire building without the use of special devices. This article presents the results of some studies conducted to use a structural system with a load-bearing core and suspended floors in seismic construction areas.

Buildings of rigid structural systems with the inclusion of "flexible floors" in their designs are a well-known solution that has become widespread in many southern regions for the organization of summer rooms, recreation, sports, etc. At the same time, the "flexible floor" was located at the level of the first floor. This approach allowed not only to create comfortable living conditions, but also with its help it was possible to reduce seismic loads on buildings by increasing the flexibility of the entire building and improving its dynamic characteristics. In another constructive solution, the earthquake resistance of the building increases due to the location of the "flexible floor" in the uppermost part, while the "flexible floor" performs the role of dynamic vibration dampener. However, according to architectural and planning requirements, there is a need to use free spaces in the middle part of rigid buildings, which can also be implemented through a "flexible floor". Assessment of the seismic resistance of these buildings in seismic areas under impacts different frequency composition is of great importance for the safe operation of these facilities. Some of the results of this study are presented in this article.

Introduction. The relevance of the chosen topic is shown. The calculation of a short-wave radio transmitting antenna installed on a communication structure in the form of a mast on guy wires is considered. The construction site is characterized by high values of wind pressure, seismicity of 9 points and soils of category III.

Goal. The purpose of the calculation is to check the rack and guy ropes of a typical mast provided by the plant, taking into account the characteristics of the construction site and to assess its seismic resistance.

Materials and methods. The calculation was performed in the computer-aided design program SCAD. The seismic impact is set automatically using the capabilities of the software. Graphs of the dynamism coefficient were adopted according to SP 14.13330.2018 Construction in seismic areas.

Results. The mast stand and the guy ropes have the necessary margin of strength and stability and are allowed to be installed on a site with existing climatic conditions. The seismic load had less impact than the combination of wind and ice load.

Conclusions. Wind load and the combination of wind and ice loads are more likely to determine the design of communication structures than seismic effects. The masts are relatively light (the calculated wind forces will be greater than the gravitational forces) and since their mass is more or less linearly distributed over their height, the lateral inertia forces generated by seismic excitations of this distributed mass will not be as significant as the wind forces.

The active development of the Arctic zone, Siberia and the Far East in Russia in the last decade has prompted the authors to return to the problem of construction of structures in areas that may be affected by a number of natural phenomena during construction and operation. In the article, the authors narrow down the identified problems and analyze only options for the construction of earthquake-resistant buildings on permafrost soils, the situation most common in the territories of the so-called permafrost. The review and analysis of the existing and most frequently used construction options on permafrost soils according to the I and II principles are presented and the possibility of using special seismic protection systems at such facilities is assessed. The requirements for the characteristics of backfills in the case of construction according to principle I, variants of structural solutions of pile foundations during construction using principle II are given. The analysis of constructive solutions applied more than 40 years ago in the construction of residential blocks of buildings of the 122 series in Severobaikalsk, well-proven during the past earthquakes. The authors give examples of various variants of seismic protection devices when implementing the principle of seismic isolation, the implementation of which is carried out in the usual way by introducing various malleable support elements into the foundation part of the building. In the conclusions based on the results of the study, recommendations are given for the construction of earthquake-resistant buildings for the conditions of the Arctic zone.

This article analyzes the existing solutions for applying special seismic protection to building complexes. The PSTU developed at the “Buildings” department designed model for a number of buildings in a seismic region in the North Caucasus with seismic isolation, made in the form of rubber-metal supports. Preliminary structural calculations have been performed showing that the use of such a seismic protection system helps to reduce the load on the building while saving money on seismic strengthening.

This article discusses the analysis of damage received, architectural monuments on the territory of Syria: Castle of Krak des Chevaliers; the Great Umayyad Mosque in Aleppo; the Great Mosque in Maarat al-Numan; Triumphal Arch in Palmyra, Colonnade street in Palmyra; Mosque Omar in Bosra as a result of past earthquakes and the fighting that began in 2011. 

The article presents the results of studies the buildings suspended type in seismic areas. The study contains a comparative analysis of various constructive schemes. Then it was revealed the best option and made a trial design of a suspended type of building. Calculations were performed in software and computing complex SOFiSTiK, based on the finite element method. The study showed that the use of suspension systems can significantly reduce the load on the building structure of the seismic action. Suspended buildings have both advantages and some of the features that complicate its construction. 

Article is devoted to the 150 anniversary of  «Buildings» chair and the 120 anniversary of «Theoretical Mechanics chair» of FGBOU VPO PGUPS Imperator of Alexander I. The main scientific achievements in the field of aseismic construction executed at university are presented.

Results of researches are analyzed in a chronological order. The assessment of settlement and theoretical researches in the field of seismic stability of buildings and various transport constructions, including bridges is given. It is featured questions of studying of seismoisolation. The contribution of scientists of university to development of aseismic construction is shown.

Practical value of the presented analysis consists in possibility of its use by the beginning young scientists, engineers dealing with issues of construction of buildings and constructions in regions of high seismic activity.

Research of buildings in permanent frost area shown that using of the I principle of building is an acceptable way to secure constructions. The high pilework is common and an acceptable way of realization of the I principle. Besides, high pilework make functions of seismic isolation. Researchings of buildings with high pilework in 7, 8, 9 point seismic areas show that increasing of «free» length of pile increase period of oscillations. This decrease seismic load, but increase square of reinforcement. Acceptable section for 7-point area is 40x40 cm for reinforced piles. In higher than 7-point areas using other different constructions of piles or dampers is required.      

Pools for the long term storage of spent nuclear fuel are extremely dangerous buildings. Their seismic resistance is very important and topical theme. Design feature of such structures is the presence of a rigid bottom and flexible frame top, which is most vulnerable to earthquakes.

The article considers the influence of various factors on the intensity of the vibrations of flexible frame top оf VVER-1000 spent nuclear fuel repository during earthquake. These factors are: soil stiffness, frequency composition of the initial impact and functioning capacity of repository.

The I principle of building in permanent frozen and seismic zones is viewed. The I principle is realized by using of high pilework. The special frictional damper is installed between foundation piles. Different constructive solutions of frictional dampers are presented. Behavior resolution of buildings with accepted antiseismic system is given too.

Pools for the long term storage of spent nuclear fuel are extremely dangerous buildings. Their seismic resistance is very important and topical theme. Design feature of such structures is the presence of a rigid bottom and flexible frame top, which is most vulnerable to earthquakes.

This article presents the results of a study of the effect of damages of building structures of the existing "wet" storage of spent nuclear fuel at its earthquake resistance

Earthquakes cause huge damage to civil and industrial infrastructure construction facilities. Earthquake engineering continues to be extremely relevant, as it is not only able to prevent material losses, but also to save human lives. Currently, the basic principles of designing aseismic buildings and structures on the territory of the Russian Federation have been formed, presented in various regulatory documents and recommendations, the task of which is to reduce the seismic load by increasing the strength of structural elements, the use of high-strength materials, the choice of rational planning and design solutions, as well as other recommendations. Along with traditional approaches, special methods of seismic protection, which include seismic isolation, are becoming more widespread.

The change in the level of seismicity of buildings and structures occurs as a result of updating the maps of general seismic zoning. Ensuring the seismic resistance of buildings and structures is a factor that must be taken into account, especially during construction in seismically active regions. Nowadays, one of the main approaches to increasing seismic resistance is the use of various seismic isolation systems. It is not always profitable and rational to increase the seismic resistance of building structures or foundations for equipment by simply increasing the strength. A classification of seismic reinforcement systems is given, among which the most sparing are special methods of seismic protection in the form of seismic isolation. Practical examples of the use of seismic isolation systems to improve the seismic resistance of existing buildings are given. A computational study was carried out, the result of which showed the effectiveness of using rubber-metal supports for hanging the seismic resistance of buildings.

 

There are many approaches to ensuring the stability of high-rise buildings to seismic impacts. Among them, it is worth noting the use of suspended structures. This approach makes it possible to reduce the loads in load-bearing structures caused by dynamic influences. The effectiveness of the use of suspended structures in earthquake-resistant construction was confirmed by studies of the behavior of such objects in earthquake conditions. The development of computer systems allowed us to unlock the potential of using suspended structures in seismically dangerous areas. However, the engineering community has not yet come to an unambiguous solution to the problem of significant displacements of suspended ceilings during low-frequency seismic impacts. The question of ensuring the stability of the core structures of the building also remains open. Proposals for solving these problems, as well as the supporting structures of suspended high-rise buildings themselves, are diverse. This article discusses the main existing and promising design solutions that provide earthquake resistance of high-rise buildings with suspended structures. The results of computational studies of these design solutions are given in the article

Today, in the world practice of earthquake-resistant construction, there is a fairly large amount of information about the destruction of reservoirs for storing oil and gas products. To protect such structures abroad, it is proposed to use special means of seismic protection, which make it possible to reduce the destruction of tank structures and preserve the fuel stored in them. However, on the territory of Russia, these methods of seismic protection have not yet become widespread. This report presents research on the application of seismic isolation of reservoirs for oil and gas products in seismically active regions.

Wood is one of the most popular building materials, widely used in various forest-rich regions of the country. The article discusses the possibility of using small-scale wooden elements in the earthquake-resistant construction of low-rise buildings. To improve the seismic resistance of buildings made of small-scale elements, it is recommended to use additional damping pads, reinforcing bars, and energy-absorbing elements. Proposals for their implementation are given. The calculation evaluation of the proposed measures showed the possibility of their use in earthquake-resistant construction.