Eficácia da ABNT NBR 6118 (2014) na previsão da carga última de pilares curtos/esbeltos em concreto armado sujeito à flexão composta normal.

Abstract

Once the short/slender reinforced concrete columns theory has been slightly presented in the national technical/scientific literature, it could be considered as a research goal working up this kind of publication. However, bringing about the accuracy judgment of the ABNT NBR 6118 (2014) design guidelines to predict the load-carrying capacity for short/slender reinforced concrete columns under combined axial load and bending has been the outstanding inquiry target. Wherefore, both the simplest proposals as well as the accurate one have been introduced and taken stock herein. It is worth underscore that two concepts have marked the simplest proposals, namely, standard-column methods with approximate curvature (AC method) and approximate stiffness (AS method). Thus, the interaction diagram concepts together with load-moment curves (P-M), which were addressed in a linear (L) and nonlinear (NL, geometrical issue) way, had accounted for the accurate method. To vouch for the scrutiny undertook before, 17 experimental investigations, which had added up to 320 reinforced concrete columns, composed the database (DB) handled currently. From then on, the performance index ξ has been embraced and assessed by means of descriptive statistic thought, where ξ = Pexp/Ptheo (Pexp = experimental failure load recorded in the DB and Ptheo = theoretical/predicted failure load). Ended up the quest, the effectiveness of whole design guidelines to predict the failure load for short/slender reinforced concrete columns from DB was bearing out by the results had brought forth herein. Notwithstanding the previous positive outcome, it was also pointed out that predicting the failure load of slender columns with slenderness ratio high than 35 the P-M (L) proposal had been in an unsafe condition.