Proposição de parâmetros para dimensionamento de estruturas de concreto armado com vida útil de projeto entre 50 e 100 anos

Abstract

The durability of structures is essential to the performance of the building, since its replacement may not be viable due to its high direct costs and executive risks, in addition to its indirect costs and the disturbance generated for users. Despite many advances made in recent years, such as the implementation of the Brazilian Performance Standard Code, Brazilian Standards for dimensioning loads and reinforced concrete structures recommend parameters for structures with up to 50 years of service life. However, more and more efforts are being made to increase the service life of structures. This paper had as main objective to propose design parameters for projects with service life between 50 and 100 years, such as concrete compressive strength, water/cement ratio, minimum cement content and minimum reinforcement cover, following the premises of NBR 6118 (ABNT, 2014). Furthermore, an analysis was also carried out to verify whether the design parameters related to time, such as accidental loading, creep, shrinkage and variation in the concrete compressive strength, are relevant to the performance of reinforced concrete structures designed for the same time interval. The durability parameters were proposed based on a bibliographic review and the choice of models for predicting service life, which were calibrated by Brazilian Standards and allowed obtaining the parameters for the studied time interval. The design parameters related to time were analysed according to the corresponding Brazilian and foreign standards. At the end of the work, a table with durability parameters was proposed for the design of reinforced concrete structures, as well as it was concluded that the design parameters related to time do not suffer significant variations for the period of time studied that justify their change in design of a structure in normal conditions.