Effects of moisture content and load orientation on dowel-bearing behavior of bamboo scrimber

Abstract

The influences of moisture content and load orientation on dowel-bearing behavior were investigated in order to understand the dowel-bearing behavior of dowel-typed fastener on bamboo scrimber. The half-hole embedment tests in compression were conducted with samples of equal characteristics with the same thickness, length and width, only with changes in the investigated factors. The result indicates that the effect of moisture content (MC) on initial stiffness is not significant. There is significant effect of MC on the dowel-bearing strength. The initial stiffness and dowel-bearing strength decreased first, then remained a constant value of 33.4 kN/mm for initial stiffness (with an average MC of 14.0%), 63.7 MPa for dowel-bearing strength (with an average MC of 21.2%), respectively. A linear regression for determining the relationship between the dowel-bearing strength and various MCs was proposed. The dowel-bearing behavior was affected by load orientation significantly. Hankinson’s formula could commendably predict the initial stiffness of arbitrary load orientations to the grain, but segmental Hankinson’s formula was satisfactory for estimation of dowel-bearing strength. The failure modes at various load orientations was complex because of the interaction between brittle and ductile failures. They changed from splitting to crushing when the load orientation changed from 0° to 90°. The study contributes to a safe and efficient design of dowel-typed joints in bamboo scrimber.