Análise estrutural de uma edificação em concreto armado sob ação de incêndio utilizando o software CAD/TQS: a influência da resistência do concreto

Abstract

In Brazil, during the 70s, the discussion about the risks of fires in buildings gained emphasis in response to the incidents that occurred in São Paulo, which resulted in property, cultural, and environmental damages for the country. These events led to revisions and developments of regulations focused on safety in this context. However, this sector lacks practical studies that discuss the influence and impact of these regulations on the structural safety of buildings, as well as the construction characteristics, especially considering the characteristic strength of concrete. Considering this, this study presents the design of a reinforced concrete structure of a 14-story building, simulated under fire conditions computationally, based on Brazilian technical standards, using CAD/TQS software. The structural analysis of the building was first based on NBR 6118 (ABNT, 2014) and reference studies, followed by verification of the structure under fire conditions according to criteria from NBR 15200 (ABNT, 2012). In this study, the influence of the characteristic compressive strength of concrete is analyzed by comparing the results of structural design for strengths of 30 MPa and 50 MPa. Specifically, the impact on verification equations regarding fire action is evaluated, especially in terms of fire resistance time. The analysis indicated that with an increase in the value of the characteristic compressive strength of concrete, a more stable building capable of supporting higher loads under normal temperature situations is obtained, generating more efficiency in load support when the building was subjected to fire and increasing its fire resistance time. Thus, throughout the study, parameters and formulations were identified that vary in different scenarios, contributing to improving existing research and better understanding the influence of concrete strength in structures subjected to fires, a field that has been little explored until now.