Influence of growth rings position of wood on the determination of its shear strenght parallel to the fibers

Abstract

Shear strength parallel to the fibers (f _v0 ) is extremely important for the design of timber structures. Then, due to the lack of information related to a possible variation in the f _v0 of hardwood species according to the load application plane in relation to its growth rings/rays, this work performed tests for the determination of f _v0 according to NBR 7190-3 (ABNT, 2022b) varying load planes. Thereby, the load was applied on the longitudinal-tangential (LT) and longitudinal-radial (LR) planes of the species of caixeta (Simarouba amara) and roxinho (Peltogyne spp.). Through variance analysis (5% confidence), results did not point to statistical differences between f _v0 values when the load plane was changed. Therefore, the f _v0 of this species can be determined without significant risk of reduction according to ray/ring orientation. Furthermore, it was determined a ratio of f _v0,k /f _c0,k equal to 0.23 and 0.38 was determined for roxinho and caixeta, respectively. Thus, this result confirms the need for characterizing unfamiliar wood species when received on construction site, in order to save money and/or for safety reasons.

Keywords:
Shear strength; Longitudinal-tangential plane; Longitudinal-radial plane; Mechanical characterization; Unfamiliar species. Hardwoods