Vestnik of Polotsk State University. Part F. Constructions. Applied Sciences

PRACTICAL MODELING OF THE STRESS-STRAIN STATE OF REINFORCED CONCRETE ELEMENTS UNDER FORCE AND TEMPERATURE INFLUENCES

D. LAZOUSKI — 2025-06-26

The results of the practical application of a nonlinear deformation calculation model for determining the parameters of the stress-strain state, calculating the strength and crack formation force of normal separation using the example of centrally stretched reinforced concrete elements under force and temperature influences are presented. The analysis of studies of the influence of negative temperatures on the parameters of the base points of the diagrams of deformation of concrete and reinforcement of reinforced concrete elements is carried out. Modeling of the stress-strain state using the example of centrally stretched reinforced concrete elements was performed taking into account forced temperature deformations due to the difference in the coefficients of temperature deformations of concrete and reinforcement. The distribution of relative deformations and stresses in the cross section of centrally stretched reinforced concrete elements during the formation of cracks of normal separation under the influence of negative temperatures in the range from (+15°C) to (–165°C) is given. The verification of the proposed methodology for calculating the strength and cracking force of centrally stretched reinforced concrete elements under force and temperature influences has been carried out.

STRENGTH ASSESSMENT OF STEEL-REINFORCED CONCRETE STRUCTURES OF THE BOOK DEPOSIT OF THE NATIONAL LIBRARY OF THE REPUBLIC OF BELARUS

D. LAZOUSKI — 2025-06-26

The unique building of the National Library of the Republic of Belarus includes not only urban planning, architectural, technological modern solutions, but also structural ones. One of such modern structural solutions is the use of steel-reinforced concrete structures that combine the advantages of metal and reinforced concrete structures. The article presents the results of applying a nonlinear calculation based on the diagrammatic method of stress-strain state parameters at any stage of work under load, including the construction stage, paying attention to the effects of the dead weight of steel structures and freshly laid concrete, accounting for forced deformations of concrete shrinkage, as well as the strength, deformability of complexly loaded steel-reinforced concrete elements of the building of the National Library of the Republic of Belarus, subject to the joint operation of rigid steel sections and reinforced concrete. A criterion for calculating the internal force corresponding to the strength of a composite element is proposed in the form of the maximum force at which the conditions of force equilibrium in the cross-section under consideration are met, which does not require standardization of the ultimate compressibility of the composite element components and allows taking into account the high degree of force redistribution between them in the cross-section.

HYDROCHEMICAL MODELS OF IRON AND MANGANESE REMOVAL ON QUARTZ SAND AND SORBENT AC

E. VELYUGO — 2025-06-26

The article describes a comparative analysis of the structural and energy parameters of fresh and used sand and AC grade sorbent by the water vapor adsorption method using a BELSORP MAX porometer. The processing of adsorption-desorption isotherms was performed in the BELMaster MicrotracBEL Corp software package with the calculation of the specific surface area, total volume, average pore size and adsorption energy of water vapor using the BET, Langmuir and Dubinin-Astakhov (DA) methods. An increase in the specific surface area and porosity of the used sand and sorbent of the AC brand is observed, which indicates structural changes during their operation: an increase in the specific surface area and porosity. The obtained results allow us to draw a conclusion about the possibility of reusing spent sand and AC grade sorbent after regeneration, as well as the need to take into account changes in their properties when designing treatment systems.

TRAINING AND WORKER TRAINING AS AN ELEMENT OF SAFETY DURING THE CONSTRUCTION OF A NUCLEAR POWER PLANT IN THE ARAB REPUBLIC OF EGYPT

S. KOZHARSKIY — 2025-06-26

This article analyzes the level of fatal industrial injuries of workers in the construction industries of a number of countries, and identifies unacceptable levels of risk of death in construction. It substantiates the need to improve the process of training and education of workers in the safe performance of work at height. Using the example of the procedure for selecting and training personnel to perform work at the El Dabaa NPP construction site in the Arab Republic of Egypt, options for improving the process of training and education of workers in the safe performance of work at height in order to reduce the level of industrial injuries are shown.

LIME BASED ON TPP WATER TREATMENT SLUDGE

A. MEZHENTSEV — 2025-06-26

A derivatographic analysis of water treatment sludge was carried out in the temperature range of 25–1000°C. Based on the data obtained, the kinetics of the formation of free CaO during calcination of samples of dry highly dis-persed sludge at temperatures of 800–1000°C and sludge pressed in the form of tablets was studied. To determine the temperature of interaction of CaO with various additives, the corresponding mixtures with AlOOH and SiO₂ additives were modified. It was shown that the decomposition of fine particles of sludge (CaCO₃) and their interaction with oxides that impart the hydraulic properties of lime (AlOOH and SiO₂) can be carried out at a temperature of 1000°C. Samples of beams were made and their strength properties were determined. X-ray diffraction analysis of the samples showed the presence of CaO∙Al₂O₃, CaO∙2Al₂O₃ and 2CaO∙SiO₂. As a result of the research, weakly hydraulic lime was obtained using chemical waste sludge, which makes it possible to dispose of waste and at the same time improve the environmental situation in the Republic of Belarus.

HEAT GENERATION IN ENERGY ABSORBERS OF SHEAR TYPE

E. MOISEYCHIK — 2025-06-26

Based on the analysis of literature sources, it is shown that steel energy absorbers using the active elements in the elastic-plastic and plastic stages of work can be used to protect massive bridge structures. The article proposes locations of elastic-plastic steel energy absorbers in span bridge structures and shows their energy efficiency. Experimentally, using laboratory samples made of low-carbon plastic steel, it has been proven that in the vicinity of structural and technological defects (holes, cutouts) in stretched and sheared elements of EA structures, localization of deformations occurres, especially at the elastic-plastic and plastic stages of steel work, with an increase in the average temperature of the steel surface during deformation by several tens of degrees (up to 90°С), which allows in the mode monitoring by the temperature field of the active element to control the performance of elements of steel span structures of bridges and energy absorbers.