SAFIR is a computer program that models the behavior of building structures subjected to fire. The structure can be made of a 3D skeleton of linear elements such as beams and columns, in conjunction with planar elements such as slabs and walls. Volumetric elements can be used for analysis of details in the structure such as connections. Different materials such as steel, concrete, timber, aluminum, gypsum or thermally insulating products can be used separately or in combination in the model.
The thermal exposure conditions from the fire must be entered as input data in the program. SAFIR allows interfacing with a range of fire models, including Computational Fluid Dynamics (CFD) outputs. Simple time-temperature curves recommended in international standards are also readily available for use as boundary conditions.
From these thermal exposure conditions, 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).
SAFIR is a GMNIA software, i.e., it completes geometrically and materially nonlinear analysis with imperfections. Failure is automatically checked by the software through evaluation of the equilibrium in large displacements, with consideration of the stress-strain behavior in each integration point of the structure based on current and past temperature conditions.
Reference
The software SAFIR is developed by Jean-Marc Franssen at University of Liege and Thomas Gernay at Johns Hopkins University.
If you use SAFIR please cite the following reference in your work (articles, presentations, books, reports, etc.):
- Franssen, J.M., Gernay, T. (2017), Modeling structures in fire with SAFIR®: Theoretical background and capabilities, Journal of Structural Fire Engineering, 8(3):300-323. https://doi.org/10.1108/JSFE-07-2016-0010