In the practice of noise reduction in rooms, in addition to conventional flat sound-absorbing linings, rocker-type structures are also used, placed on the ceilings of rooms in the form of various systems. Currently, there are no simple methods for evaluating the acoustic efficiency of such systems, which significantly limits their use, and in particular, the use of rocker systems of the caisson type. The article proposes a numerical method for calculating the acoustic efficiency of a coffered curtain wall system based on a geometric ray tracing method with different types of sound reflection from fences. It is shown that the method can be used when choosing the dimensions of the coffered structure of the wings based on the sound-absorbing characteristics of the curtain elements and the sound absorption of the ceiling. The method at the early stages of object design will allow for a preliminary assessment of the impact of various parameters of the curtain wall systems on their acoustic and economic efficiency.

Ventilated Soundproofing Structures are widely used today to protect buildings and adjacent areas from noise generated by industrial equipment that requires air supply for normal operation. Designers pay considerable attention to the development of ventilated noise barriers, even though standardized or reference methods for calculating their acoustic performance are virtually nonexistent. In this context, research on louver-type screens, which provide both noise reduction and airflow, is highly relevant. A specific case of a louvered screen is a grille with parallel slits—this article focuses on the calculation of sound transmission through such a structure. The noise reduction provided by a screen consisting of thin plates spaced at equal intervals is calculated using the finite element method. This paper describes the numerical experiment setup, introduces a parameter characterizing the noise reduction efficiency of the screen, and presents the calculated results of this parameter depending on the grille’s geometric dimensions and sound frequency.

 It is shown that the screen’s efficiency is determined by the ratio between the plate width and the gap between them: the smaller this ratio, the higher the efficiency. The study identifies grille parameters that ensure noise reduction of at least 10 dB. The results can be directly applied to the design of soundproof ventilation grilles and ventilated noise barriers.

This article examines methodological approaches for experimental studies of loadbearing behavior in thick reinforced concrete slabs (without shear reinforcement) with varying tensile zone reinforcement characteristics. A critical analysis of regulatory standards (SP 63.13330, Eurocode 2, ACI 318, Model Code 2020) reveals their inconsistency with experimental data when the shear spanto-effective depth ratio is ≤2.0. Through comparative analysis of domestic and international research practices and numerical simulations, the study establishes justification for test specimen parameters to investigate strength, crack formation, and failure mechanisms under punching shear. The developed loading methodology ensures punching effect generation in the support zone, complemented by comprehensive stress-strain monitoring techniques during incremental loading stages.

Non-resonant and resonant sound transmission through the enclosing structure was investigated. The method of statistical energy analysis was used, non-resonant energy links were added to the system of energy balance equations. A well-known variant of representing non-resonant sound transmission directly from room to room, bypassing the enclosing structure, is considered. A scheme of energy connections between the elements is proposed, which shows non-resonant sound transmission from room to panel, formulas for calculating the coefficients of non-resonant energy connection from room to panel are proposed by calculating the impedance of transverse vibrations of the panel, taking into account the impedance of mass, bending stiffness and losses in the panel. The results of calculating and measuring sound levels in reverberation chambers and vibration acceleration on a glass plate between them are presented. A satisfactory convergence has been shown between the calculation and measurement results, which makes it possible to use the applied methodology for calculating sound and vibration parameters in more complex vibroacoustic systems.

This paper presents the results of experimental studies that provide strong confirmation for the proposed hypothesis on the fractal nature of concrete's structure. The authors established that traditional analysis methods fail to fully capture the complexity of this composite material's architecture. For an adequate and comprehensive assessment of its structural heterogeneity and inherent multi-scale nature, the application of fractal geometry's mathematical framework is strongly recommended. The experiments clearly demonstrated the critical influence of the identified structural heterogeneity on the failure mechanism of concrete specimens. It was found that the fracture process is not localized or single-scale; on the contrary, it is distinctly multi-scale. This means it develops and propagates simultaneously across different structural levels—from macroscopic cracks to micro-defects. As a theoretical basis for describing this complex process, the article proposes new methodological principles. These principles synthesize the fundamental tenets of fracture mechanics with modern approaches of fractal geometry, enabling the development of a completer and more adequate model for predicting the behavior of concrete under load.

This paper presents a method for assessing the actual load-bearing capacity and stress-strain state (SSS) of cross-laminated timber (CLT) floor structures with variable section parameters. The method is based on a functional relationship between the natural frequency of oscillations and the maximum deflection of plates, expressed through a proportionality coefficient K. This coefficient remains constant for a given type of support conditions and has been numerically validated for multi-layer orthotropic CLT plates with various geometric configurations. Five different CLT panel types were tested in the study, each with varying layer geometries: three-layer solid sections, thickened longitudinal layers, thickened transverse layers, panels with gaps in transverse layers, and five-layer solid panels. All samples were simply supported along two sides. Natural frequencies, maximum deflections at the center of the structure, and normal stresses along the span under uniformly distributed loads were recorded experimentally. The multi-layer CLT structures were converted into an equivalent single-layer orthotropic plate using effective cylindrical stiffness values.

 Calculations of maximum deflection and bending moments were performed using classical plate theory and verified against experimental data. Deflection deviations did not exceed 10%, while normal stress deviations remained within 13% for most cases, confirming high accuracy of the proposed method. A key feature of the method is its ability to assess structural performance without requiring precise knowledge of actual stiffness, relying solely on one dynamic parameter — the fundamental frequency of natural oscillations. This makes the method fast, safe, and cost-effective for field testing. It is particularly suitable for evaluating structures under the second group of limit states and, under certain conditions (e.g., neglecting shear stresses and stress concentrations), can be applied to the first group as well. Further research is recommended to expand the applicability of the method to different support conditions and aspect ratios of CLT panels.

This article outlines the planning and development of a program for conducting field studies to investigate the impact of vibration on buildings and structures caused by the combined dynamic loads from surface and underground urban transport systems. The existing regulatory framework concerning transportation-induced vibration is reviewed. The paper analyzes available practical data on the vibrational impact from individual sources (tram, bus, metro) as well as the combined effect of simultaneous vibration from all three transport types. An identified correlation from the analysis of the complex dynamic loads allows for predicting future events related to crack propagation in buildings located in immediate proximity to the sources of man-made impact. The sources of vibrational impact are metro trains, trams, and buses operating in close vicinity to the structures. Specialized equipment was selected for vibration measurements: a noise and vibration analyzer, a data recorder, and a vibration test system. To select the field site and conduct the experiment, an analysis of traffic load on surface and underground transport arteries in Moscow was performed. Three areas with the highest traffic load were chosen for simultaneous vibration measurements from the metro, trams, and road transport along Krasnoprudnaya, Paveletskaya, and Baumanskaya streets.

The article examines the effect of corrosion in prestressing strands on the fatigue endurance of reinforced concrete crane beams of type BK 12-7 K7T. The main corrosion mechanisms are discussed, including chloride-induced corrosion, carbonation of concrete, and galvanic corrosion, which are most relevant for industrial structures. A methodology is proposed for assessing the residual service life of beams, taking into account the loss of cross-sectional area in the prestressing strands, supplemented by a probabilistic model of corrosion current density, which improves prediction accuracy. Calculations of the number of cycles to failure were performed for different degrees of corrosion (5%, 10%, 20%), showing that at 20% corrosion, the beam's service life decreases by 2.5 times. The study results demonstrate a significant reduction in fatigue durability with increasing corrosion levels, highlighting the need to account for corrosion factors in the design and operation of crane beams. The proposed methodology can be useful for engineers and specialists involved in condition assessment and repair of industrial structures.

Risks associated with accidental actions on buildings and structures lead to the demand for design measures aimed at protection against progressive collapse. In this case, the actual task is to assess the sufficiency and effectiveness of structural measures to protect both newly designed and reconstructed buildings and structures to prevent their collapse in an accidental situation. The solution of this problem is possible with the usage of criteria and measures of robustness. A variant of the relative robustness index, which takes into account the degree of damage to the elements of the structural system of the building during long-term operation and the level of the current load, has been proposed.

 The relation between the relative measure of robustness and technical condition of structures is examined. The results of robustness check of reinforced concrete multistorey building frame with plane beamless floor slabs, in which perimetric, longitudinal and transverse internal ties, selected by the method of tie forces, are provided as a structural measure to protect against progressive collapse. The effectiveness of using a system of additional ties to provide protection against progressive collapse has been demonstrated. It is shown that at the design load level the lowest relative robustness index corresponds to the accidental situation caused by the loss of bearing capacity of the corner column of the building, and the highest - to the middle column. As a result of concrete and reinforcement strength reduction by 30% (or equivalent reduction of effective cross-sectional dimensions as a result of aggressive medium action), the relative robustness index decreased to RRI = 0.65 under the action of constant and long-term characteristic loads and accepted characteristic properties of construction materials.

The article deals with the urgent problem of ensuring accessibility of hotel real estate objects for low-mobility groups of population (further-MGP). The authors have developed a complex methodology of information support of barrier-free environment, including seven consecutive stages: from systematisation of hotel objects to formation of their accessibility rating and development of recommendations for adaptation. Special attention is paid to the following issues: standardisation of the procedure for assessing the accessibility of hotels; creation of a project using geographic information systems (further-GIS) for data visualisation; development of an objective system for ranking accommodation facilities. The developed methodology makes it possible to identify problem areas in providing MGN with accessibility of hotel real estate objects in a large city. In addition, the result of the implementation of the developed methodology is a rating of hotels on the provision of MGN. At the end of the presented research the first results of the survey of hotels in the city of Rostov-on-Don were obtained: a structured list of objects (80 hotels) with basic characteristics; diagrams based on the analysis of these objects, and an electronic map formed with the help of GIS-technologies. Realisation of the significance of accessible service in hotel real estate objects opens new horizons for attracting a diverse audience to the cities, strengthening the socio-economic potential.

Massive reinforced concrete structures – foundations, walls, floors, crossbars, bridge support bodies, dams – are subject to significant temperature deformations due to concrete exothermy and external thermal effects. Uneven temperature distribution over the structure leads to the occurrence of temperature stresses, which can cause cracking in concrete and lead to a decrease in the durability of the structure. Thermophysical modeling makes it possible to predict with a high degree of probability the temperature fields of structures under construction and stresses at the design stage, optimizing concreting technologies (the rate of turnover of the formwork, heat treatment, the composition of the concrete mixture, etc.).

 The methodological basis of the research consists of the theory of unsteady nonlinear heat and mass transfer, approaches of mechanics of deformable solids, which allow modeling the stress-strain state of massive structures, taking into account the associated thermal, phase and chemical processes. When concrete hardens, an exothermic reaction of cement hydration occurs, accompanied by the release of heat. In massive structures, due to the low thermal conductivity of concrete, heat accumulates, which leads to: uneven heating; temperature deformations (expansion during heating and compression during cooling); stress due to limited freedom of deformation. Modeling of heat transfer processes makes it possible to predict temperature fields and stresses, optimize concreting technologies, and prevent structural failure. Modern computational methods ensure high accuracy of calculations, which is especially important for critical structures (dams, bridges, foundations of nuclear power plants).