RESEARCH OF INTERNATIONAL EXPERIENCE IN PROVIDING A REGULATORY FRAMEWORK FOR CALCULATING RESISTANCE OF BUILDINGS TO THE PROGRESSIVE COLLAPSE

Minimizing the possibility of progressive collapse is one of the most important tasks in ensuring the reliability of buildings This paper analyzes the regulatory frameworks of the world experience in ensuring resilience to progressive collapse to the current state of the national one. The purpose of the work was to search for basic information on ensuring resistance to progressive collapse in relevant foreign regulatory documents, in particular: minimum required characteristics of buildings to take into account progressive collapse at the design stage, accepted approaches to reducing the probability of progressive collapse, basic criteria for determining progressive collapse, parameters of modeling progressive collapse by the method of the sudden removal of the load-bearing structure. Current editions of foreign regulatory documents on ensuring resistance to progressive collapse contain similar provisions. The article compares the key provisions of the norms, in particular, the main attention is paid to the main approaches to reducing the probability of progressive collapse, namely the alternative path method. The alternative path method can be implemented in three ways: linear statics, nonlinear statics, and nonlinear dynamics. The minimum characteristics of buildings to take into account progressive collapse in the design are based not only on the building category (risk level, risk category), but also on additional parameters such as number of storeys, building purpose, new construction or reconstruction. The criteria for determining progressive collapse are generally characterized by the acceptance criteria for the rest of the building structure as a result of explicit consideration of resistance to progressive collapse (modeling of the progressive collapse process). The criteria vary from one regulatory document to another, but in general, these criteria are not allowed to be exceeded - localized failure of load-bearing structures is not allowed, except for the removed structure.