ПОРІВНЯННЯ РОБОТИ БАГАТОПОВЕРХОВИХ СТАЛЕВИХ КАРКАСІВ ПРИ ПОЖЕЖІ ЗА РІЗНИХ ПОЧАТКОВИХ УМОВ ТА ЇХ ВПЛИВ НА ЖИВУЧІСТЬ

Abstract

The researches devoted multi-storey buildings steel frames fire vitality was analyzed. It was found that the existing measures to increase the viability significantly increase the frames metal content. No detailed analysis of potential destruction mechanisms depending on different initial conditions has been identified. The need to research the frame elements stress state during a fire before the first destruction and subsequent potential mechanisms of destruction for a better vitality understanding. This publication analyzes the stress state of 2d multi-storey steel frames during a fire. Various frame elements load capacity factor dependence graphs on time are done. The frames operation in case of fire with different beam-to-column connections and different fire source locations are compared. It was found that during a fire in the beam frame elements, the stress state changes from bending to compressed-bent. It has been established that the frame elements should be designed in such a way that plastic deformations appear before local buckling occurs. It is necessary to design sections according to the Eurocode classification, where there is a classification depending on the geometry. The frames operation in case of fire with different initial load capacity factor is compared. It was found that in no the frame element temperature before the first onset of the limit state does not reach 400oC, at which the steel yield strength begins to decrease. It is established that the frames fire resistance of is more influenced not by the steel characteristics reduction, but by the forces distribution. The frames with rigid and hinged beam-to-column connections are compared in terms of vitality and fire resistance. It is established that frames with hinged connections are more fire-resistant, and with rigid connections ‒ more vitally to fire. The method of increasing the time to steel frame vitality loss is determined.