Research of the stress-strain state of cylindrical elements of engineering constructions of special purpose under the effect of temperature load

Abstract

Active development of monolithic-frame construction in the recent period of time requires a new approach to the calculation of elements of building structures. Concrete columns are one of the most important elements of such buildings, the failure of which is of great durability. Loss of strength characteristics of the column may occur as a result of the loads caused by the effect of temperature fields. Therefore, research related to the influence of temperature on the supporting elements of structures of military objects, is relevant and of great importance. The non-stationary temperature field in a cylindrical concrete column, which changes over time under high temperatures, is investigated. When modeling the heating process of a column, the boundary conditions of the third kind are taken into account. Using the Laplace transform, we obtained analytical expressions for the research of a temperature field. The stress-strain state of the column with pinched and free ends is determined, which is caused by a non-stationary temperature field, where various values of the heat transfer coefficient between column and the environment were taken into account. One of the most significant causes of increased danger for such structures is uneven heating and changes in the characteristics of strength and deformability of concrete during and after the fire. At the same time it is necessary to solve the issues connected with ensuring sustainable and reliable operation of building structures, including the influence of high temperatures, due to the adoption of appropriate materials or protective coatings. Thus, mathematical modeling of the processes of temperature fields in a stress-strain state of cylindrical structures can significantly increase accuracy of calculations, which contributes to the strength and reliability of engineering structures. The graphic dependences of radial, ring, and axial stresses from the radius are researched as a result of the temperature fields of different intensity on the rod elements are obtained and we have found radial displacement at different temperature.