Aluminium Bridges under Fire Conditions: Structural Behaviour

Due to a number of advantages, aluminium is used in the attachment units of mullion and transom systems for decorative panels and translucent fillings, as well as for bridge structures. Despite its advantages, aluminium has a low melting point and does not have fire resistance performances required by regulatory documents under fire conditions. Therefore, this article is aimed at studying the behaviour of aluminium structures under high temperatures. To achieve this objective, we have analysed the aluminium structures most commonly used in construction-the attachment units of mullion and transom systems, with different protections against fire, columns and orthotropic decks used in bridge construction. In order to assess the behaviour of selected structures under fire conditions, we have developed methods for studying temperature distributions in structures in detail. Using the developed methods, tests have been carried out. Based on the received experimental data, we analysed the behaviour of aluminium structures in fire conditions and developed measures to increase the fire resistance of aluminium structures. Such measures include using hollow profiles to ensure air exchange with the cold sections of the structure, applying dedicated cooling agents to cool the structure and removing heat to the atmosphere and thermal barriers so as to protect aluminium structures. We found that fire resistance measures enhance the fire resistance of aluminium attachment units of mullion and transom systems by 1.5 times. The use of hollow air-permeable profiles and cooling agents in orthotropic decks increases fire resistance by 3 times by removing heat from the structures. The fire resistance rating of hollow profile aluminium columns is 1.5 times higher than that of structures without air-permeable profiles. The obtained results can be used as the most effective basis for the design of aluminium structures. The principles of increasing fire resistance given in this article are applicable to other types of structures, and can also be used with other methods of fire protection. Increasing the fire resistance of aluminium structures enables the expansion of the scope of their applications.

Automated summary

This article aims to study the behavior of aluminium structures under high temperatures. The most commonly used aluminium structures in construction and bridge construction were analyzed, and methods to increase their fire resistance were developed. Experimental results showed that these measures significantly improved the fire resistance of aluminium structures and could serve as a basis for their design.