К ПРЕДЕЛЬНОМУ РАВНОВЕСИЮ МОНОЛИТНЫХ ЖЕЛЕЗОБЕТОННЫХ ПЛИТ ПЕРЕКРЫТИЙ КАРКАСНЫХ ЗДАНИЙ В АВАРИЙНЫХ СИТУАЦИЯХ, ПРИВОДЯЩИХ К ПРОГРЕССИРУЮЩЕМУ ОБРУШЕНИЮ КОНСТРУКЦИЙ

Abstract

A brief analysis of current standards concerning calculations of the resistance to progressive structural collapse of frame buildings in case of an accidental destruction is presented. Two analysis methods concern the resistance to progressive collapse of the slabs of monolithic frame buildings in case of accidental failure of one column are considered: direct method in which the entire building is calculated with a modified analysis scheme followed by checking the strength of structures with increased efforts, and calculating the slab located over the destroyed column by the ultimate equilibrium method with determination the slab destroying load. It is shown that the slab destroying load greatly depends on the model of its destruction. General equation of the ultimate equilibrium of the slab is written down. It includes not only the formation of plastic hinges in the slab, but also taking in account pushing through the slab by the column located on it. There are three possible options for an emergency destruction of the slab: from the formation of plastic hinges in the plate only, the slab pushing through by a column and formation of plastic hinges at the same time and situation when the slab is pushed through by the column. A criterion of the destruction option determination is offered. An example of calculation is given.