Description

The gas temperatures produced by fire must be entered as input data in the program (some time-temperature curves recommended in international standards are proposed).

From these gas temperatures, SAFIR will first calculate the evolution of the temperatures in the structure. The structure can be made of different materials such as steel, concrete, timber, aluminum, gypsum or thermally insulating products, used separately or in combinations. These temperatures are stored in different files.

As an example, the video below shows the temperature evolution in a steel section HEB300 filled with concrete (courtesy eca-vaud).

The mechanical behavior of the structure is then calculated on the basis of its geometry, its support conditions, the loads that it must withstand and the strength of the materials, taking into account the progressive increase of temperature. The elevation of temperature in the materials produces thermal elongations together with a reduction of strength and stiffness. As a consequence, the displacements of the structure increase continuously during the course of the fire until collapse.

As an example, the video below shows the behavior of a composite steel concrete structure subjected to fire until collapse of one of the column (courtesy eca-vaud).