Abordagem probabilística para estimativa das propriedades de resistência e rigidez visando o dimensionamento de estruturas de madeira

Abstract

The ABNT Standard (1997), referring to standards for wooden structures projects, is the main national reference for professionals and researchers who use wood for structural purposes. According to this document, a given mechanical strength property must be calculated based on its characteristic value, which corresponds to the 5th percentile of a given probability distribution model, to ensure structural performance within safety requirements. Thus, the Brazilian Standard establishes relationships to estimate characteristic values of wood strength, but the results obtained may differ significantly from the different probabilistic models. This fact indicates the need for research to evaluate the equations proposed in the Standard, with special emphasis on the reliability of relationships for strength and stiffness properties, which are highly relevant in structural analysis. Considering the results of compressive and tensile strength (fc0; ft0) and stiffness (Ec0; Et0) in the direction parallel to the grain of 60 tropical woods, analysis of variance (ANOVA) was used along with regression models, distribution functions of probability and discriminant analysis of observations to evaluate the statistical equivalence and establish new probabilistic models and allocation classes to the characteristic strength values. These new statistically reliable parameters will contribute to the structural design of wood.