NEKORA V. Improvement of the method of calculation assessment of fire resistance of enclosing structures with glass elements –

Relevance of the research topic. The most common building structures made of glass are translucent elements of enclosing structures, external and internal load-bearing structures for the implementation of special architectural solutions, massive decorative elements of the interior and exterior of buildings. At the same time, the destruction of glass structures in a fire is one of the fire hazard factors, as it increases the risk of fire spread, as well as the risk of death and injury to people. It is known that the modern regulatory framework, which is also in force in Ukraine, contains guidelines on methods for calculating the fire resistance of building structures. These regulatory documents comply with the second parts of European standards with guidelines for the design of building structures, i.e. Eurocodes. A significant danger in this case is posed by, among other things, glass elements of building enclosing structures, since they are often part of fire barriers. Their collapse is especially dangerous during the evacuation of people and the work of emergency and rescue units. Existing approaches to assessing the fire resistance of glass structures are quite effective and have a theoretical and practical basis, however, they are not systematized and generalized into a single hierarchical system that could be implemented when drawing up a relevant regulatory document on the guidelines for the design of fire-resistant enclosing structures with glazing. Revealing the patterns of changes in the parameters of thermal processes and the stress-strain state in glass elements of enclosing structures as a result of the thermal impact of a fire is a relevant scientific and technical task, the solution of which allows creating a scientific basis for improving the methods of calculating the fire resistance of glass elements of enclosing structures. The purpose of the work is to reveal the patterns of changes in the parameters of thermal processes and the stress-strain state in glass elements of enclosing structures under the conditions of the thermal impact of a fire as a scientific basis for improving standardized methods for calculating their fire resistance. The object of research is the processes of heat exchange, deformation and destruction of glass elements of building envelopes under the thermal influence of fire. The subject of research is the influence of the structural characteristics of glass elements of building envelopes on the predicted parameters of the time of fixation of the limit states of loss of fire resistance of glass elements under the thermal influence of fire. The scientific novelty of the dissertation is the disclosure of the patterns of dependences of the time of occurrence of the limit states of loss of fire resistance of glass elements of building envelopes due to stretching and destruction of glass under the influence of the standard temperature regime of fire. The established patterns are the scientific basis for improving the method of calculating the fire resistance of glass elements of building envelopes. Simplified standardized methods of calculating the fire resistance of glass elements of building envelopes have been further developed using the proposed reference tables. The scientific and methodological base has been improved to ensure that glass elements of building envelopes comply with the regulatory requirements for their fire resistance. The practical significance of the results obtained is the justification of an improved method for calculating the fire resistance of glass elements of enclosing structures under the thermal effects of fire with a standard temperature regime, which allows determining the compliance of glass elements of enclosing structures with the established fire resistance class. This method has high performance and can be part of the hierarchy of methods for assessing the fire resistance of these structures, which is proposed to be used as a basis for the relevant regulatory guidelines. The reference tables proposed in the work allow their use in 5 justifications of express methods for establishing the compliance of enclosing structures with glazing with the requirements for their fire safety. The proposed improved method for calculating the fire resistance of enclosing structures with glazing has been introduced into the draft state standard of Ukraine “Fire safety.