Influência da resistência característica (fck) na taxa de armadura em lajes nervuradas de concreto armado sob diferentes configurações de apoio para os concretos do grupo I e II de resistência, segundo a NBR 6118 (ABNT, 2014).

Abstract

Ribbed slabs are being widely used in civil construction because they allow for large spans with low reinforcement rate, low concrete consumption and lower own weight, compared to massive type slabs, thus allowing execution of slender structures and consequently more economical. In addition to being easy to perform, it can be performed on site or through precast material and in various types of buildings, from homes to large hospitals and malls. Thus, the present work aims to verify influence of (fck) on the reinforcement rate in reinforced concrete ribbed slabs under different support configurations for strength groups I and II concretes, according to NBR 6118 (ABNT, 2014 ), through case study and elaboration of sizing routines based on the current literature. It can be observed that, for proposed case study, the increase of the (fck) had no great influence on reduction of the reinforcement rate, with only a 8.4% decrease in steel section, generating a cost reduction of 34% in its consumption, while the concrete had a significant increase of 190% in her cost. However, such an analysis was made only for ordinary residential buildings with small spans and small loads, so for spans and loading of special works such as bridges, nothing can be afirm.