FIRE DESIGN OF REINFORCED CONCRETE BEAMS BY SIMPLIFIED METHOD

Abstract

Currently, when considering the effects of fire on reinforced concrete beams, the design software is generally limited to the ABNT NBR-15200:2012 tabular method-based verification since it is the only method detailed by the Brazilian standard. However, depending on the reinforcement arrangement, this design method could produce solutions excessively in favor or against safety. This paper's main objective is to propose a simplified method to verification reinforced concrete beams in fire situations, which allows easy implementation in commercial design software. Such a method combines structural safety, ease of application, and economical construction. The calculation model validation was accomplished through a comparative study with values found in literature and calculations by the 500 ºC isothermal method and results from the finite element method in the ANSYS software. It was verified that the proposed simplified method presents very similar results to those obtained by the 500ºC isothermal method, whose maximum variation of the resistant moment in fire situation was 5%, in favor of safety. When comparing the values ​​obtained by the simplified methods found in the bibliography, in general, the results are similar, however, in some cases, the values ​​differed a little more due to the different temperatures found. In summary, the proposed simplified method generally presents satisfactory values ​​in favor of safety.