Evaluation of the shear effect to determine the longitudinal modulus of elasticity in Corymbia citriodora round timber beams

Abstract

This study aimed to investigate, based on three points static bending tests, the influence of ratio between length (L) and diameter (d) in structural round timber of Corymbia citriodora to determine the modulus of elasticity (MOE) using equations that do not consider shear influence in beam displacements. Non-destructive tests were carried out in 24 round pieces, medium length 750cm and average diameter 30 cm, moisture content around 12%. Modulus of elasticity for six different ratios (L/d) between length and diameter (9, 12, 15, 18, 21, 24) were determined, providing obtains six distinct values of MOE for each structural elements. Hypothesis tests results indicated equivalence of modulus of elasticity only to ratios (L/d) 24, 21 and 18. This implies that for proper use of the simplified equation to obtain MOE, based on static bending tests over structural round timber, it is necessary to respect L/h≥18 ratio.