The vibration displacements of the center of mass of the conditional foundation from a seismic impact lasting 5 seconds have been determined, taking into account the attachment of a reinforced concrete slab to the foundation and the formation of local plastic deformations in the system under consideration. Graphs have been constructed showing the changing numerical value of the logarithmic decrement of oscillation damping over a time interval of 0 to 1.5 seconds. The amount of energy required to generate local plastic deformations in the foundation-attached slab system under a single force application has been determined.

Introduction. The construction of civil buildings in permafrost areas is accompanied by risks associated with the formation of a thawing bowl at the base.

Materials and methods. Numerical modeling of the "building – foundation – base" system under seismic impacts of various frequency compositions has been performed.

Aim. Assessment of the impact of the thawing bowl on the earthquake resistance of civil buildings with various structural systems, taking into account seismic impacts of various frequency compositions.

Results. It has been established that the presence of a thawing bowl changes the dynamic behavior of a building depending on its structural system and the frequency characteristics of an earthquake. The most pronounced increase in horizontal displacements is observed for medium–rigid and flexible structural systems in the low- and medium-frequency range, while rigid frameless systems maintain a more stable behavior.

Conclusions. The results show that when calculating seismic impacts in permafrost conditions, it is necessary to consider the integral system "building–foundation–base". Taking into account the joint work of the structure and the thawing ground allows for a more accurate assessment of the seismic response of buildings with various structural systems.

Introduction. Ensuring the seismic resistance of reservoirs for the oil and gas industry is an important task in ensuring the safe operation of enterprises where they are used. The main difficulty in performing calculations to determine the seismic resistance of such structures is to take into account the joint work of fuel and tank structures. There are various calculation methods to determine the seismic resistance of reservoirs. This article discusses the methods outlined in STO-SA-03-002-2009 and NP-031-01.

Aim. Comparison of the results of calculating the seismic resistance of reservoirs, taking into account hydrodynamic loads using various methods.

Materials and methods. Numerical modeling of the RVS-10000 reservoir for the oil and gas industry by the finite element method has been performed. The study was carried out taking into account the different reservoir occupancy rates, namely 100 % and 50 %, the influence of ground conditions was taken into account – thawing of the frozen base, the seismic load was determined using a linear spectral method and the multi-frequency nature of earthquakes.

Results and conclusions. The difference in the values of internal stresses has been established when calculating using different methods. During medium- and low-frequency seismic impacts, a significant increase in internal stresses in reservoir structures is observed. It is revealed that during thawing of the soil base, the values of internal stresses increase, especially during vertical seismic impacts. It has been found that with a lower filling capacity of the tank, internal stresses in the structures of the walls and roof are significantly reduced.

Introduction. The series of recent earthquakes that have taken place on the territory of Russia has once again clearly shown that this natural disaster is characterized not only by its unpredictability, nature, and direction, but even by a significant duration, as was the case, for example, in Kamchatka in 2025. It is possible to resist the elements only with the use of reliable and proven earthquake-resistant construction constructive solutions, to these include multicommunicated systems made of precast reinforced concrete structures, among which bulk-block structures form a special group. The effectiveness of their operation significantly depends on the presence of additional damping elements in the system. The article presents an analysis of some of these solutions, which is necessary to understand how structures work during earthquakes.

Aim. To show the features of structural solutions of three-dimensional block buildings in the presence of damping elements in them in the form of friction bonds that ensure continuous energy dissipation during the entire exposure period.

Materials and methods. The analysis of existing structural solutions of three-dimensional block buildings with the inclusion of damping elements in the form of friction bonds is carried out.

Conclusions. Additional computational and experimental studies are needed to substantiate the possibilities of the considered solutions for three-dimensional block buildings with friction elements.

Introduction. Due to global climate change, which has been particularly noticeable in recent years, emergency situations in the form of earthquakes, hurricanes, tornadoes, as well as manmade impacts, such as drone strikes, are increasingly occurring. In this case, the most negative impact is absorbed by the building's roofing, its upper part, including the cornice and parapet. All this is accompanied by serious destruction and material damage. In addition, a situation is possible when one destructive impact follows another. Scenarios for such situations are mainly considered for large energy facilities, including nuclear power plants. There are currently no specific recommendations for mass civil construction projects. In this regard, there is a need to search for solutions of complex protection that could be used these types of impacts.

Aim. Investigating the use of a "flexible upper floor" to protect building roofs from earthquakes, hurricanes, tornadoes, and drone strikes.

Materials and methods. To evaluate options for protecting the building's roof from natural and manmade impacts, technical literature, recommendations, and design standards were studied and analyzed.

Results. The proposed solution for the comprehensive protection of the building's roof involves a known design: a flexible upper floor that functions as a dynamic damper during earthquakes. This article examines known design solutions of dynamic dampers, highlighting their potential use in protecting buildings from extreme loads.

Discussion. Further research is required to justify the possibility of using a modified dynamic vibration damper in the form of a flexible upper floor as a comprehensive protection for the building roof.

Introduction. Frame buildings can be constructed from various building materials, the most common being steel, reinforced concrete, and wood. Frames made of these building materials will be considered in this study.

Aim. To assess the influence of structural features of frame civil buildings on their seismic resistance under seismic impacts of various frequency compositions and in the presence of permafrost in the foundation.

Materials and Methods. Numerical modeling was used to analyze the seismic resistance of a frame building. The study was conducted taking into account varying parameters: type of column-beam connections, arrangement of beams in the building plan, type of foundation (including frozen and thawed soils), and the predominant frequency of seismic impact.

Results and Conclusions. Numerical analysis of the behavior of a frame building under the influence of seismic impacts of different frequencies, material, type of joints, and soil foundation revealed that high-frequency impacts (<0.3 sec) ensure the seismic resistance of all types of frames, while longer periods (>0.4 sec) increase the stress-strain state (SSS) parameters. The most seismically resistant frames were those with longitudinal beams. Under medium-frequency impact, frames with transverse beams on permafrost show a decrease in SSS parameters, but with thawed soil, the effect of hinged joints is noticeable only in frames with longitudinal beams. In conditions of medium-frequency impact and thawed soil, reinforced concrete proved to be the most preferred material.

Introduction. Modular buildings currently have a wide geography of application. Due to their advantages, one of the areas of their application in the Russian Federation is the construction of modular buildings in hard-to-reach regions, which are often seismic. Modular buildings are in high demand for industrial facilities, for example, for gas and oil refineries: control and operator buildings, complete transformer substations and switchgear buildings, gas boiler houses, pumping and sewage stations. Such structures require justification of their reliability and compliance with design standards, including seismic ones. At the same time, the standards both in general for modular buildings and in particular for their seismic resistance is poorly developed. Therefore, studying the issue of using modular buildings in seismic regions is a relevant topic. Aim. The purpose of this paper is to study and analyze existing experimental studies of modular buildings and joints for seismic impacts. Materials and methods. Tests of full-size modules and buildings are carried out in Russia and abroad. Accelerogram tests and tests of impacts corresponding to earthquake standards show a fairly high level of seismic resistance of modular buildings, up to the estimated seismicity of 9 points. Studies of joints for cyclic loads demonstrate a fairly high ability of nodes to dissipate energy, which leads to a decrease in the reaction under seismic impact. damping coefficients in the considered studies lie within 0.2 ÷ 0.3, which is close to reinforced concrete structures. At the same time, various dampers in nodes can be used to increase the seismic resistance of a modular building. Discussion. Modular buildings have a wide geography of construction, including seismic regions. Certification and laboratory tests of full-size modules and buildings show their high level of earthquake resistance, up to an estimated seismicity of 9 points. Intramodule assemblies also have high dissipative properties, while various dampers can be used to increase earthquake resistance.

Introduction. The northern climate zone occupies significant territories of the Russian Federation, which today are very promising, as they have a high potential for development, due to the rich reserves of minerals, rare metals and precious stones. With the extensive development of the extractive industry in these remote territories, the question arises in parallel of the construction of civilian facilities, which include public and residential buildings for various purposes, the main task of which is to ensure reliable, safe and comfortable operating conditions. Part of this zone, which affects the regions of the Far East, Western and Eastern Siberia, is in difficult conditions, such as the combined combination of permafrost and high seismic activity, the score of which varies from 6 to 10 points. That is why these territories dictate special requirements and conditions for design and construction, as well as pose complex tasks for engineers that require non-trivial approaches and solutions.

Materials and methods. To assess the behavior of civil buildings of various design solutions in conditions of the combined propagation of permafrost soils and seismic impacts of various frequency compositions, a numerical study was conducted using the method of direct integration of the equation of motion over time.

Results. The article presents the results of computational studies of civil buildings of various design solutions in conditions of the combined spread of permafrost soils and seismic impacts. It is shown that the earthquake resistance of civil buildings with various structural solutions in conditions of permafrost soils and high seismicity differ significantly from each other. This indicates the need for a detailed justification of the design decisions of civil buildings for the conditions under consideration, taking into account the properties of permafrost soils.

 

Introduction. The Necessity of constructing high-rise buildings in dense urban development in the 1960s led to the introduction of a new structural system of high–rise buildings with rigid core. One of its varieties is the suspended structural system, which has been implemented in many buildings around the world. In addition to the architectural advantages of the suspended buildings, the system has design features associated with significant flexibility of the load-bearing elements. This feature of high-rise buildings makes allows reducing the seismic load on structures. The technical implementation of the suspended floors has some difficulties. The calculation methods did not allow us to show the behavior of suspended structures under dynamic influences. This was an obstacle to the use of a suspended system in the construction of high-rise buildings in seismically active areas in the past. Another approach to providing seismic protection for high-rise buildings is the installation of dynamic vibration dampers. This requires the insertion of additional massive elements into the structure of the building, occupying its internal space. Suspended structures in buildings with a load-bearing core can potentially act as elements of dynamic vibration dampers. Modern methods of calculating mathematical models and computing complexes allow us to verify this assumption. These methods are capable of performing complex tasks in the field of dynamic linear and nonlinear vibrations, in particular vibrations of suspended structures of buildings. This article presents a new design solution for a suspended building with rigid core. An assessment of the influence of the engineering parameters of the suspended part of the building on its seismic resistance is given.

Materials and methods. For evaluation of the effectiveness of the proposed building structural solution in the conditions of seismic impact, numerical modeling of the building in the LIRA software package in a stepwise nonlinear setting was performed.

Results. Movements and accelerations of a suspended building during an earthquake depend on the magnitude of the longitudinal stiffness of the elastic links and the mass of the upper suspended floor block. The rational parameters of suspended structures have been determined to reduce the oscillations of the building.

Conclusions. A change in the mass of suspended floors and the rigidity of the connections between the elements of suspended building can lead to a decrease in displacements and accelerations of structures and damping system vibrations. Further research can be devoted to the analytical determination of the optimal parameters of suspended structures that ensure the dispersion of seismic action energy.

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.