Shkarabura I. Evaluation of Fire Resistance of Steel Structures at the Stage of Operation of Buildings and Structures

Summarizes the current state of the issue and sets research objectives, indicates the main prerequisites for the protection of steel structures from high temperatures. The review of theoretical and experimental researches of various aspects of protection of designs, definition of a technical condition in the course of operation after various influences and its adjustment by repair, strengthening or replacement is resulted. The works of well-known scientists in this field are analyzed, in which the provisions of the theory of calculation of building structures taking into account hightemperature influences are stated. The analysis of literature sources and normative documents allowed to establish that the existing methods of assessing the technical condition and fire resistance of steel structures of buildings and structures at the stage of their operation need to be improved. Based on the review, conclusions were drawn and research objectives were set. Presents the results of studies of the influence of indicators of the ability to adhere fire-retardant materials of different types on the results of assessing the fire resistance of steel structures by a specified experimental method. Appropriate calculations were performed and the convergence of the results of fire resistance assessment, which was obtained taking into account and without taking into account the indicators of adhesion. The components and procedures of the simplified method of estimating the fire resistance of steel structures are determined. Substantiation of parameters is performed, the form and number of samples for tests by this method are determined. The range of critical temperature of steel, which is from 350 ºС to 500 ºС, has been established, for which the minimum thickness of the fire protection system should be calculated by a simplified method. The choice of such a range is justified by the acceptable difference between the results of the fire resistance assessment of protected steel structures, taking into account the indicators of the fire protection system's adhesion and (or) its ability to remain undamaged during fire and without taking them into account. The procedure for assessing the fire resistance of steel structures during operation is proposed. A model for predicting the parameters of an explosive environment based on the use of expert opinions in the absence or inaccuracy of input data is proposed. The presented technology can be used to design buildings and structures with a steel frame to take into account the impact factors due to the explosion.