Introduction. This paper addresses the problem of aerodynamic stability of bridge structures, specifically the phenomenon of buffeting. The relevance of the study is driven by regular accidents and failures of bridges, among the causes of which are insufficient consideration of wind effects and aerodynamic instability of structures. The aim of this work is to experimentally assess the aerodynamic stability of a two-span road bridge (with a central span length of 130m) considering the possible occurrence of buffeting. Methods. The research methodology includes manufacturing a physical model of the superstructures with geometric and dynamic similarity, conducting static tests to determine aerodynamic coefficients, and dynamic tests of the aerodynamic stability of the model. Key results. Experimental studies on section models have shown that buffeting can occur in a superstructure located in the aerodynamic wake behind another — with the inclination of the structure relative to the oncoming flow and the difference in the overall dimensions of the fairings playing a critical role. Experimental modelling in wind tunnels remains the key method for assessing the possibility of aerodynamic instability phenomena in long-span bridges. Refinement of computational models will reduce the risks of bridge structure failures caused by wind effects.
Introduction.This study assesses the landslide and proposes appropriate measures to safeguard the lake system along the Bau Trang shoreline, a well-known ecotourism destination in Binh Thuan province (now part of Lam Dong province), Vietnam. The area is threatened by shoreline landslips caused by both natural hazards and human activity. Methods. The methodology employed topographic and geomorphological geotechnical techniques, remote sensing, and Geographic Information Systems (GIS), using Geo-studio models. Results. The findings indicate that sections of the lakeshore with low safety factors are particularly vulnerable due to the reservoir’s fluctuating water level, vibrations, and the movement of cruise ships. To improve lakeshore stability, various technical solutions were proposed, including live load reduction plates, geotechnical textiles, reinforced concrete (RC) sheet piles, Melaleuca (Cajuput) timber piles, and sandbag revetments. These measures are expected to not only ensure the safety of the lakeshore but also protect the ecosystem and environment, supporting the need to preserve this outstanding natural and scenic location.
Introduction. This critical review underscores the importance of examining key factors such as particle morphology and porosity in the extensive body of literature on soil studies. A deeper understanding of how these elements influence soil thermal conductivity is essential for advancing knowledge in geotechnical and environmental research. Methods.Bysynthesising findings from a wide range of studies, this review highlights the complex nature of soil thermal conductivity and stresses the need to thoroughly investigate these parameters. Each factor plays a crucial role in determining heat transfer behaviour in soils. Through an in-depth analysis of existing research, this paper emphasises the necessity of systematically studying these variables to resolve inconsistencies, fill knowledge gaps, and enhance predictive models for geotechnical and environmental applications. Conclusions. Recently developed multi-variable functions offer a robust framework for predicting soil thermal conductivity by integrating these influential parameters. By providing a comprehensive perspective that connects theory with practical application, this review serves as a vital resource, supporting both scientific exploration and engineering practice.
Introduction. To ensure the safety of buildings and structures in seismically active regions, special protection measures against destruction are applied. One of the most universal, effective, and economical methods of active vibration suppression is the method of reactive damping. An important form of natural vibrations of buildings is torsional motion. Certain segments of seismic accelerograms can provoke the development of such vibrations. There is a relationship between torsional and bending modes of vibration: bending vibrations can cause torsional deformations, and vice versa. This occurs because the centres of mass and the centres of stiffness of structural sections do not generally coincide, which leads to the occurrence of coupled bending-torsional vibrations. The aim of this work is to investigate the response of finite element (FE) models of high-rise buildings to seismic effects represented as harmonic functions with variable frequencies, varying the direction of the effect and the position of the centre of mass, as well as a comprehensive study of the results of experiments on damping torsional vibrations of high-rise buildings using a pair of reactive dampers capable of generating variable moments counteracting torsional vibrations. Methods. To evaluate the behaviour of high-rise buildings with reactive dampers under harmonic loads, an appropriate mathematical model was investigated. The calculations were performed using a software package based on the finite element method (FEM), and the dynamic response of the structure was determined numerically using the Newmark method. Results. The developed software tool allowed for frequency-vector analysis considering the displacement of the centre of mass from the centre of stiffness, and provided data on the torsional angles of the building at various positions of its centre of mass and variations in the parameters of the harmonic effect (frequency and direction) considering internal friction. A comprehensive study of the results of experiments on damping torsional vibrations of high-rise buildings using a pair of reactive dampers capable of generating variable moments counteracting torsional vibrations was conducted. It is shown that the use of reactive dampers with optimally selected parameters reduces the amplitude range of torsional vibrations by 50–80 %.
The purpose of the study. This study investigates the impact of varying room heights on the heat transfer efficiency of heating systems, specifically comparing conventional radiator-based heating with underfloor heating. Methods. Using Computational Fluid Dynamics (CFD) simulations, we analysed temperature distributions at three ceiling heights (2.7 m, 3 m, and 3.3 m). The numerical model was used to examine airflow behaviour, thermal stratification, and temperature variation within the occupied space under different heating conditions. Results. The results indicate that lower room heights tend to reduce vertical temperature stratification, thereby increasing the overall perceived temperature, while taller rooms exhibit greater temperature gradients between the floor and ceiling. The simulations also show that the location and mode of heat delivery have a substantial influence on indoor temperature distribution. Furthermore, underfloor heating systems demonstrated superior thermal uniformity and energy efficiency compared to radiator-based systems by distributing heat more evenly across the lower occupied zone. Conclusions. These findings contribute to optimizing energy efficiency and occupant comfort in building design by tailoring heating strategies to specific room dimensions. The study also highlights the importance of considering room geometry alongside heating-system selection when evaluating indoor thermal performance and developing energy-conscious design solutions for enclosed indoor spaces.
