Львівський інститут Українського державного університету науки і технологій ( Раніше Львівський факультет)

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ENG: Lviv Institute of the Ukrainian State University of Science and Technology (Formerly Lviv Faculty)

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A Comprehensive Procedure for Estimating the Stressedstrained State of a Reinforced Concrete Bridge Under the Action of Variable Environmental Temperatures
(РС ТЕСHNOLOGY СЕNTЕR, Kharkiv, Ukraine, 2021) Kovalchuk, Vitalii V.; Onyshchenko, Artur; Fedorenko, Olexander; Habrel, Mykola; Parneta, Bogdan Z.; Voznyak, Oleh M.; Markul, Ruslan V.; Parneta, Mariana; Rybak, Roman
ENG: This paper reports the full-scale experimental measurements of temperature distribution over the surfaces of bridges’ steel-concrete beams under the influence of positive and negative ambient temperatures. It has been established that the temperature is distributed unevenly along the vertical direction of a bridge’s steel-concrete beam. It was found that the metal beam accepted higher temperature values. The maximum registered temperature difference between a metal beam and a reinforced concrete slab at positive ambient temperatures was +9.0 °C, and the minimum temperature difference was −2.1 °C. The mathematical models for calculating a temperature field and a thermally strained state of bridges’ steel-concrete beams under the influence of variable climatic temperature changes in the environment have been improved, taking into consideration the uneven temperature distribution across a bridge’s reinforced concrete beam. The possibility has been established to consider a one-dimensional problem or to apply the three-dimensional estimated problem schemes as the estimation schemes for determining the thermoelastic state of reinforced concrete bridges. The temperature field and the stressed state of bridges’ reinforced concrete beams were determined. It was found that the maximum stresses arise at the place where a metal beam meets a reinforced concrete slab. These stresses amount to 73.4 MPa at positive ambient temperatures, and 69.3 MPa at negative ambient temperatures. The amount of stresses is up to 35 % of the permissible stress values. The overall stressed-strained state of a bridge’s reinforced concrete beams should be assessed at the joint action of temperature-in- duced climatic influences and loads from moving vehicles.
Investigating the Temperature Field Distribution Over Transport Structures’ Metal Corrugated Construction Surface under Temperature Influences
(Széchenyi István University, Győr, Hungary, 2022) Kovalchuk, Vitalii V.; Kravets, Ivan B.; Nabochenko, Olga S.; Petrenko, Oleksiy V.; Milyanych, Andriy R.; Hermaniuk, Yuliia M.; Dzhus, Volodymyr S.
ENG: The experimental studies results of temperature distribution over metal corrugated sheet structure surface at positive and negative ambient temperatures are presented. It is established that the temperature is distributed unevenly over the sheet surface along its plane. An analytical method for calculating the temperature field from a fragment of a structure metal sheet in the case of setting the temperature at the sheet area boundaries is presented. The calculation of the temperature field distribution on the metal sheet of the structure with the setting of the temperature along the contour of the sheet is performed. As a result, it is established that at the metal sheet boundaries there is a temperature difference, which can cause the occurrence of temperature stresses and deformations.
Study of the Temperature Field and the Thermo-Elastic State of the Multilayer Soil-Steel Structure
(Institute of Roads and Bridges, Poland, 2020) Kovalchuk, Vitalii V.; Hnativ, Yuriy M.; Luchko, Joseph; Sysyn, Mykola P.
EN: The technology of renewal of metal corrugated structures allows efficient and economical reconstruction of existing reinforced concrete structures by the method of encapsulation. However, such structures can be exposed to adverse temperature effects that in combination with traffic loadings could influence the operational reliability of the structures. This article deals with the method of evaluation of the stress-strain state of a three-layer cylindrical structure. The technique is based on the thermo-elasticity theory. The study is performed in two steps: determining the temperature field of a structure, and then calculating the temperature stresses and deformations. As a result of calculations, it was established that the level of temperature field and stresses in a three-layer structure caused by the maximum and minimum ambient temperatures can reach a significant level.