STRUCTURAL RELIABILITY OF A STEEL COLUMN UNDER FIRE CONDITIONS

Resumo

The structural projects are usually made in a deterministic way through normative codes that
do not consider directly the uncertainties associated to the problem. However, for exceptional cases such
as fire and earthquake conditions, the use of prescriptive methodologies may lead to projects with high
costs and indeterminate or unacceptable levels of safety. In this context, the application of the reliability
theory to structures under fire conditions arises as a better option than the deterministic methods
contained in the normative codes. The structural reliability analysis enables that the uncertainties
associated to each variable are considered, quantifying the safety level of the structure and giving the
engineer a better comprehension of the structural behavior under fire situation. The present study aims
to apply the structural reliability theory to a steel column under fire condition, analyzed by the ABNT
NBR 14323:2013. First, the basis of the application of this kind of analysis is stated. Then, the
methodology is applied through computer modules developed in Excel and MATLAB and the
probabilities of failure are determined as a function of time, temperature, and other variables involved
in the problem. Eventually, the results indicate that the deterministic design made according to the
Brazilian code does not lead to an acceptable safety level proving the importance of the reliability
analysis in the structural projects.