The Initial Assessment of Fire Safety of a Plane Steel Frame According to System Reliability Analysis

The purpose of this research was to indicate the importance of an efficient design of steel frame structures, taking into account the fire design situation. In the case of steel frame structures, the typical mechanisms of failure (sway, beam, and mixed) are well known. Using this knowledge, combined with a reliability assessment of single nodes, may let designers reduce both the amount of material used for a structure and the total cost of the structure. In this article, one-story, single-nave frames with different loads were analyzed. Two types of loads were analyzed: symmetrical and unsymmetrical. Both cases resulted in different failure paths. The static analysis of the structure in the following minutes of the fire duration was carried out in the Robot Structural Analysis programme. The temperature load was computed according to the Eurocode recommendation with the assumption that the temperature of fire gases is described by the standard fire curve. Afterward, the system reliability analysis for the selected failure paths was conducted. Additionally, the displacement analysis was performed in the following minutes of the fire. The biggest challenge in the proposed method is that there are many potential failure paths, and checking all of them is very time-consuming, even when using advanced computers. Therefore, only selected collapse modes were analyzed.