Módulo de elasticidade aparente em vigas roliças estruturais de madeira Pinus elliottii

Abstract

This study investigates the influence of the measurements between the length (L) and diameter (d) of Pinus elliottii round timber structures to determine the modulus of elasticity (MOE), using the Brazilian standard ABNT NBR 7190:1997 (Design of Wood Structures) and the three-point static bending test. 24 pieces of green wood with an average length of 750 cm and average diameter of 30 cm were tested nondestructively. In order to do that, the values of the modulus of elasticity for six different ratios (L/d) between length and diameter (9, 12, 15, 18, 21, 24) were determined, producing six different values of MOE for each structural element. The ANOVA results indicated equivalence of the modulus of elasticity only between the L/d relations equal to 24, 21, 18 and 15, where 15 proved to be the smallest value able to alleviate the shear effect. This implies that for the proper use of the equation to obtain the elastic modulus by the Brazilian standard for Pinus elliiottii structural round timber, it is necessary to respect the L/d≥15 relation.