Influência da resistência característica do concreto à compressão (fck) nas taxas de armadura de pilares e nos custos em edifícios de concreto armado

Abstract

In recent years, with the development of the construction industry, advancements in market competitiveness have occurred. The use of quality materials, along with the application of appropriate dimensions for structural elements, is essential to ensure a safe structure without risks to users. The Civil Engineering Final Project aimed to conduct a comparative analysis of different characteristic compressive strengths of concrete (fck) and their influence on reinforcement rates and the costs of columns in a reinforced concrete residential building. Four structural models were compared, with five, ten, fifteen, and twenty floors, using a multi-family residential floor plan. The design and determination of the steel areas were carried out using CYPECAD software and Excel spreadsheets. For the cost analysis of the columns, the material quantities provided by CYPECAD were used, and the material prices were based on the values from the city of Manaus, as of November 2024. It was found that an increase in fck led to greater reductions in reinforcement rates and costs starting from the 10-story building. Compared to concrete C25, the use of concrete C40 resulted in reductions in reinforcement rates and costs exceeding 40% and 20%, respectively. In the 5-story building, the reductions were smaller than those in the other buildings. However, when analyzing the most stressed column of the structure, a 40% decrease in reinforcement rate was observed when using concrete C40 compared to concrete C25. This value is considered significant, representing almost half of the steel area.