Bearing properties of engineered wood products I: Effects of dowel diameter and loading direction

Abstract

The embedment tests of laminated veneer lumber (LVL) with two moduli of elasticity (MOE; 7.8GPa and 9.8GPa), parallel strand lumber (PSL), and laminated strand lumber (LSL) were conducted in accordance with ASTM-D 5764. The load-embedment relation for each of these engineered wood products (EWPs) was established. The directional characteristics of bearing strength (σe), initial stiffness (ke), and effective elastic foundation depth were obtained from the tested results. The effective elastic foundation depth (α = E/ke, E = MOE), based on the theory of a beam on elastic foundation, was obtained from the ke and MOE. An α of 90° (perpendicular to the grain) was calculated by dividing E90 [MOE of 90° from the compression test, but MOE of 0° (E0), parallel to the grain, obtained from the bending test] by ke90, the initial stiffness of 90°. This study aimed to obtain the bearing characteristics of each EWP, taking into consideration their anisotropic structures, for estimating the fastening strength of a dowel-type fastener. The relations between the bearing coefficients (σe, ke, α) on the loading direction and dowel diameter were established from the load-embedment curves. Based on the results of the embedment test, tested EWPs showed different tendencies in all directions from wood and glued laminated timber.