download: 887-6167-4-PB.pdf .The Brazilian standard ABNT NBR 15200: 2012 details a procedure for decreasing the required time of fire resistance in buildings with good fire safety characteristics. It called equivalent time method. This name can confuse the less habituated to the fire safety area, because the Brazilian procedure is not equal to the original equivalent time method, European. The purpose of this paper is to discuss the equivalent time method, to detail the origins of the Brazilian method and present their limitations no explicit in the Brazilian standard. Some unknown aspects of most researchers or technical means are presented. It should be highlighted the abundant bibliography presented to aid the understanding of a seemingly simple issue, but it incorporates many concepts of fire safety, not always understood by the users.
O dimensionamento de barras de aço sob compressão centrada conforme a NBR 8800
de 1986 tinha por base as múltiplas curvas europeias. A base escolhida para a ABNT
NBR 8800:2008, no entanto, foi o AISC, norte-americano. Apesar de ambas levarem a
resultados similares, a formulação é diferente. Neste trabalho apresenta-se uma
detalhada e didática introdução sobre o comportamento dessas barras de aço. São
abordados tópicos relacionados à teoria clássica de flambagem, que é válida somente
para barras ideais, e o efeito de imperfeições geométricas e do material. Apresenta-se,
também, um estudo simplificado da estabilidade do equilíbrio de barras com rigidez
concentrada. Inclui-se uma dedução da curva para dimensionamento de barras
constituídas por materiais elástico-lineares e a comparação entre resultados obtidos
de várias curvas.
The structural materials, as reinforced concrete, steel, wood and aluminum, when heated have their mechanical proprieties degraded. In fire, the structures are subject to elevated temperatures and consequently the load capacity of the structural elements is reduced. The Brazilian and European
standards show the minimal dimensions for the structural elements had an adequate bearing capacity in fire. However, several structural checks are not contemplated in methods provided by the standards. In these situations, the knowledge of the temperature distributions inside of structural elements as function of time of exposition is required. The aim of this paper is present software developed by the authors called ATERM. The software performs the thermal transient analysis of two-dimensional structures. The structure may be formed of any material and heating is provided by means of a curve of temperature versus time. The data input and the visualization of the results is performed thought the GiD software. Several examples are compared with software Super TempCalc and ANSYS. Some conclusions and recommendations about the thermal analysis are presented.