Short Term Lateral Shear Loading of Nailed Spruce-Steel-Spruce Flitch Joints and the Modification of Eurocode 5 Predictions for Design Resistance

Parvez Alam,Martin P Ansell

doi:10.4172/2165-784x.1000107

Abstract

In this paper, spruce-steel-spruce flitch joints connected by shot fired nails are subjected to short term loads. The failure modes and design resistance equations are compared with those detailed in Eurocode 5. The formation of a plastic hinge is observed in the nails at the steel-timber interface and Mode I (tensile opening) occurs longitudinally along the grain following the row of nails. The predictive equations of force in Eurocode 5 for dowel-type joints are modified with respect to yield moment and unequal fastener penetration depths to produce a significantly improved predictive equation for force.

Highlights

Flitch joints are ubiquitous in timber constructions
The embedment strength was defined as p/dt where d is the diameter of the fastener, t is either the thickness of the timber member or the length of the fastener in the timber and p is the maximum load exerted upon the fastener
Equations 10–13 can be considered as general equations representative of any given nail penetration depth for both pointside and headside penetration within a timber-steel-timber flitch joint given any value for embedment strength in each timber member

Summary

Introduction

Flitch joints are ubiquitous in timber constructions. The overall performance of such joints relies on the applicability and durability of mechanical fastenings. According to Hilson [3], the embedment strength of nailed joints remains unaffected by loading at any angle relative to the timber grain This is a possible consequence of the nail slenderness as compared with bolts and dowels. At the load bearing limits rigid fasteners give rise to shear failure in the timber along the row of fasteners [17] They reported on the importance of spacing distances between rows of fasteners. Edge distances influence the failure mode and the load bearing capabilities and fasteners farther from the loaded edge carry higher loads [22] The aim of this communication is to assess the performance and behavior of high strength steel nails in a timber-steel-timber joint where the nails are subjected to lateral double shear. The predictive force equations for dowel type joints in Eurocode 5 will be assessed as regards validity of application to these shot fired nailed flitch systems

Procedure

Findings

Conclusions