Experimental study of withdrawal behavior of self-tapping screws in laminated bamboo

Abstract

The results of an experimental study of self-tapping screw withdrawal behavior in laminated bamboo are presented. Seventy-two specimens were prepared and tested under monotonic withdrawal loading conditions. Test variables considered were screw diameter, screw penetration length and the orientation of screw insertion relative to the laminate. The screw diameter and penetration length were the key parameters affecting screw withdrawal behavior. Both the slip stiffness and withdrawal capacity increased with an increase in screw diameter. Withdrawal capacity increased with increased penetration length. At a penetration of 12 times the screw diameter, the tensile capacity of the screw was achieved. Direction of insertion relative to the laminate orientation – flatwise or edgewise – had no apparent effect on withdrawal performance. An empirical linear model of screw withdrawal capacity is recommended and calibrated to the presented results.