In the article, the authors analyze main issues of protecting buildings and structures against vibroseismic effects with the help of system of elastomeric blocks, which are characterized by high vertical stiffness, low shear stiffness, high energy dissipation and ability to center vertical load; besides, they feature high reliability with no risk of sudden failure. Results of static and dynamic tests of parametric series of elastomeric blocks used for protection of residential buildings against vibrations are presented. Design of pile with anti-vibration rubber supports is described. Calculation of elastomeric blocks under static compression is presented. Components of the stress-strain state of the thin-layer elements were investigated, and rate of the thin rubber layer compression under the action of vertically applied force was calculated. In numerical calculation, weak compressibility of rubber was simulated by moment force of the finite element for weakly compressible materials, which assumes triple approximation of displacement fields, deformation components, and volume change function. The numerical solution was obtained by the finite element method for different radius-thickness ratios in case of geometrically nonlinear elastic and viscoelastic deformation.

Using probabilistic methods, the reliability and seismic resistance of a large-panel building on kinematic foundations (KF) at the seismic isolation site in Almaty is analyzed. The building is modeled by a nonlinear single-mass system with an experimental deformation diagram. Seismic impact is modeled by a random process with a given correlation function. To calculate probabilistic characteristics, the method of statistical tests is used (Monte-Carlo method). The seismic impact parameters are set in accordance with the “Map of the seismic zoning of the Republic of Kazakhstan” by the median values of peak accelerations. 2 accelerograms of the 1990 Baysorun earthquake were chosen as the impact model. Therefore, these accelerograms were taken as the basis for modeling the seismic effects of a random process. Generation of realizations of a stationary random process is performed by recursive filtering. The influence of the number of statistical tests (artificial accelerograms) on the accuracy of calculating the moments of the distribution function of displacements was investigated. According to the results of a Monte Carlo calculation using 5000 realizations, the reliability of the building is determined (probability of failure-free operation). Conclusions about system effectiveness of seismoisolation of kinematic type for the influence specified like buildings at regional parameters are drawn.

In 2017-2018 and 2023-2024, a full passportization of the housing stock of apartment buildings in the city of Almaty (Republic of Kazakhstan) was carried out for the first time. The database includes 2666 multi-story large-panel buildings of different numbers of stories, from 2 to 9 floors. The aim of this study is to assess the reliability of standard-series large-panel buildings based on previous experimental research and passportization results, as well as to evaluate their seismic resistance and reliability using passportization data. The latest earthquakes in Almaty have allowed for refinements in seismic impact models. Therefore, the reliability assessment has been conducted considering this information using the Monte Carlo method. The technical condition of large-panel buildings has been assessed. The earthquake recurrence is taken into account according to the current "Map of seismic zoning of the Republic of Kazakhstan". Reliability value for the whole group of large-panel buildings has been obtained. It is revealed that large-panel buildings with the first flexible or brick floor are not earthquake-resistant. For the first time, the theoretical analysis of reliability and failure values for 2 types of large-panel buildings with the use of experimental data is performed. Regional peculiarities of seismic impact for Almaty City are taken into account. The results of reliability and failure values estimations are used for practical recommendations on risk reduction and expected losses in case of possible earthquakes. The novelty lies in the reliability and failure assessment based on the large-scale passportization of the housing stock in Almaty. It is established that the main types of large-panel buildings are earthquake-resistant. Estimates of earthquake resistance according to the results of passportization and the results of reliability calculations coincided. It is proposed to reinforce large-panel buildings with the first flexible or brick floor (33 buildings). The method of reinforcement should be determined by special studies. Doi: 10.28991/CEJ-2025-011-05-019 Full Text: PDF

In this article, the authors analyze results of their long-term researches on protection of buildings and structures against dynamic loads caused by the nature and/or human activities. They also give the grounds for necessity to provide vibration insulation of buildings, and show how to choose and calculate proper parameters for rubber vibroseismic insulators. Specifics of finite element method applied for static calculating the vibroseismic insulators is also described. In order to take into account weak compressibility of rubber, a moment finite element scheme was used, which assumes a triple approximation of the displacement vector components consisting of strain tensor and volume change function. Stress-strain state of the shock absorbers was determined for different standard sizes and diameters. The authors also describe two variants of calculation depending on the method of fixing the insulator’s ends. In the first case, the ends are vulcanized to the metal plates. In the second variant, the ends are free and can move in a horizontal plane. Influence of ratio of the shock absorber height and radius to the strain state of a structure was also analyzed. In order to determine factual levels of the soil and pile vibration (in two horizontal and one vertical directions), vibrodynamic studies were carried out. The obtained vibration signals were registered by the one-component vibration transducers 731A (vibration sensors) produced by the Wilcoxon Research company (the USA). Then, the vibration records were processed by the specialized program “Seismic Monitoring”. Based on the results of these studies, numerical calculations were performed in order to determine whether the predicted levels of the residential building vibrations are in compliance with the existing sanitary standards when exposed to real technogeneous loads. Vibrodynamic tests on vibration acceleration levels of the vibration-insulated reinforced concrete slabs and floors in residential building confirmed high effectiveness of the used vibroseismic insulation system with the rubber elements: the registered vibration acceleration levels in the residential building on all floors did not exceed acceptable levels set by the sanitary standards, and ensured comfortable living conditions under different dynamic impacts. The results of this work make it possible to design buildings with anti-seismic protection by using the designed rubber elements in accordance with the local conditions of the city of Almaty.

The aim of this study is to experimentally and theoretically investigate the behavior of a three-story fragment of a frame building constructed using the PGF-SIKF system—Prefabricated girderless frame with seismic-isolating kinematic foundations. Magnetic dampers are employed at the support level. The novelty of the research lies in the combination of a girderless frame with kinematic foundations and innovative magnetic dampers. The experimental research method involved loading the system with horizontal static force using a stationary winch, followed by the release of the load. Vibration measurements were recorded using a digital measurement system. The normative live load was simulated by applying additional static load. It was determined that the oscillation period varies between 1.8 and 2.1 seconds, depending on the amplitude of the impact. The dissipative characteristics of the seismic isolation system were obtained, with acceleration values during the testing phases ranging from 95 to 177 cm/s². The experimental results confirmed that the building fragment showed no visible damage. The logarithmic decrement of oscillations was found to range between 0.08 and 0.16. Theoretical studies involved calculations based on a sample of 14 real accelerograms, with parameters corresponding to the magnitudes of local earthquakes (M=6), the maximum magnitude expected in Shymkent. The main result is the reduction of seismic loads achieved by using kinematic foundations in the girderless frame system. It was established that, under 7-8 intensity seismic events, the average displacements at the foundation level will not exceed the experimental values. Doi: 10.28991/CEJ-2024-010-11-018 Full Text: PDF

The aim of this study is to determine the possibility of producing non-autoclaved foam concrete of grade M35 with a density of 900 kg/m³. A distinctive feature of this development is the testing of twin samples from the same batch: some were steamed in a chamber at 90 °C under normal atmospheric pressure, while others were autoclaved at a pressure of 8 bar and a temperature of 170 °C. It was established that ordinary natural feldspar sands with a fineness modulus ranging from 1.43 to 2.45, containing quartz below the standard-regulated levels, can be used in the production of non-autoclaved foam concrete. It is not possible to obtain non-autoclaved D900 foam concrete of grade M35 strength using only cement, sand, and foaming agent. To achieve the specified strength, it is necessary to use coarse sand with a fineness modulus (FM) greater than 3, subjected to short-term grinding to reduce the FM to recommended values, and to additionally introduce sol-gel liquid glass. The novelty lies in the experimental confirmation of the features of strength formation in cellular concrete under both non-autoclaved and autoclaved curing conditions. Comparative tests showed that high strength in cellular concrete is achieved only when a chemical bond forms between the products of cement hydrolysis and hydration with quartz sand grains—conditions made possible through autoclaving.