Experimental analysis of nailed LBL-to-LBL connections loaded parallel to grain

Abstract

Laminated bamboo lumber (LBL) has become increasingly popular in recent years attributed to its superior mechanical properties compared to wood. The nailed LBL-to-LBL connection comprised of LBL main member sandwiched between two LBL plates is introduced, which plays an essential role in the safe and reliability design of modern bamboo structures. A comprehensive study was conducted in order to determine effect of the parameters on load-slip behavior and failure modes of specimens loaded parallel to grain, including end distance, edge distance, row spacing, center-to-center spacing, number of lines and rows of nails. Three main failure modes were investigated in the experiments, namely bearing failure, splitting failure and row shear failure. Minimum requirements of end distance, edge distance, row spacing and center-to-center spacing in nailed connections were suggested to avoid brittle failures. Results showed that the strength of a multi-nail connection equal the strength of a single nail connection multiplied by an effective number of nails, which is smaller than the actual number of nails. Furthermore, the Foschi formula used to model wood connections can also predict the full process failure of LBL nailed connections and were in good agreement with experimental results. The provided experimental results are motivation for development of design and analytical modes of LBL structures containing nailed LBL-to-LBL connections.