Determinação da espessura ótima da proteção contra incêndio para elementos estruturais metálicos submetido a flexão e flexo-compressão

Abstract

With the development of studies related to fire safety, there is a growing concern to know not only the causes, but also the effects of fire action. Civil engineering seeks to design buildings that guarantee the good use, comfort and safety for the user, so it is relevant to study the sizing of structural elements capable of supporting the fire performance on them resulting from an accident, reducing risk of ruins and ensuring that they withstand the time required for evacuation of people present in the fire local. The use of steel structures in construction has advantages such as ease of construction and consequent speed of execution, and are often associated with lightweight structures, however, steel proves to be a sensitive material when exposed to high temperatures. In order to avoid damage to metal parts in a fire situation, construction methods are employed that rely on the application of passive protection materials in order to protect and alleviate the effects of fire on the parts, thus ensuring proper protection of the element. The present work aims to develop a worksheet of sizing of metallic structural elements subject to fire situation, in search of the optimum thickness of the material layer used in the protection of parts subjected to flexion-compression and flexion actions, using Excel software thus saving costs with the application of protective material avoiding its waste. It was observed the influence of the rigidity of the profiles in the determination of the necessity of the use of passive protection, and in more rigid profiles this protection was dispensed, it was also analyzed that parts that present critical temperature near the steel temperature, have low values for reducing coefficient of yield strength of the steel, thus reducing its resistance, and it was also possible to verify that the choice of the protective material to be used had influence on the choice of the profile, because during the same simulation the profile was rejected for the choice of projected mortar, and approved when the protection has been replaced for plasterboard.