Análise da competitividade econômica entre vigas de concreto protendido e vigas de concreto armado submetidas a vãos definidos

Abstract

In view of the growing use of prestressed concrete elements in Brazil, the recurring architectural requirements that subject structural elements to free spans, challenging loads and the need for technological innovations that seek to generate savings, there is a certain level of uncertainty among the members of the civil construction as the real economy provided by the use of prestressed concrete structures to the detriment of the conventional concrete structures. Thus, this study seeks to analyze the economic competitiveness between prestressed concrete beams and reinforced concrete beams by submitting them to free spans, with increasing distances at each meter, from 5 to 10 meters, and loads typical of commercial buildings. For this, a calculation model was elaborated for the dimensioning of the reinforced concrete and prestressed concrete parts through spreadsheets in the Microsoft Excel software and, subsequently, the extraction and quotation of the inputs involved was carried out, according to the databases SINAPI and ORSE. Assessing the overall cost of making the beams, with all the materials involved, prestressed concrete beams were more attractive than conventional reinforced concrete beams from 6 meters of span, ranging from 5% in 6 meters, at 15%, in 10 meters. Specifically, for the cost of concrete volume and form area, savings of up to 35% and 30%, respectively, were observed for the 10-meter span. In addition to being economical, prestressed concrete beams presented advantages related to durability, as they had arrows ranging from 0.01 to 0.44 centimeters, while reinforced concrete beams ranged from 1.83 to 3.61 centimeters. Notably, it was possible to conclude that, the increasing increase in the free span of the pieces indicated for prestressed concrete more economical and useful life advantages than those of conventional reinforced concrete.