Дослідження методик розрахунку прогресуючого обвалення

Abstract

Modeling of the progressive collapse of buildings under fire conditions was carried out using the LIRA-CAD software environment in order to increase the level of fire safety. Scientific works and standardization of requirements for the progressive collapse of buildings in fire conditions are analyzed, the causes of progressive collapse in fire conditions, modern methods and approaches to calculating progressive collapse in fire conditions in the USA and Ukraine are considered. It has been established that currently there is no single methodology for calculating "progressive collapse". Ensuring (development of calculation methodology) the necessary resistance of objects to progressive collapse under various combined special effects of fire and explosion is an urgent scientific and practical task. A numerical model of the progressive collapse of the building under fire conditions, which can lead to the progressive collapse of the building, has been developed. For this, the LIRA-SAPR software complex was used. A finite-element model of a three-story parking lot was created. The applied differential equation of thermal conductivity takes into account radiation-convective heat transfer from the gas medium to the heating surfaces of the column, heat transfer by thermal conductivity in the column. Stiffness types and corresponding characteristics were determined for the model. As a result of the numerical modeling, the place of the fire was established, the consequences of which will lead to the loss of the load-bearing capacity of the structures, and, as a result, to the loss of the overall stability of the parking building. It has been established that approaches to increase the area of reinforcement take place in the design of buildings and structures, but are generally not acceptable in the operation of already constructed buildings and in the case of the need to increase the fire resistance limits of reinforced concrete structures to standardized values.