Embedding and withdrawal resistance of screws on thermal treated wood

Abstract

Tests were conducted at LNEC to assess withdrawal resistance and embedding strength of commercial heat treated wood (ThermoWood®) Thermo-D pine with various types of screws, to predict the short-term performance of screwed joints. These had in mind a suitable design and detailing of screwed joints in ThermoWood®, even in non-structural applications, where the wood components have to fulfil certain strength requirements and their assembly and fixings have to be strong enough to assure long-term performance and durability. Test results were analysed as a function of the material density, and compared to non-modified wood, in the light of common joint design principles. This work contributes to debate the suitability of using the equations given by Eurocode 5 (EN 1995-1-1:2004/A1, 2008) to the design of screwed joints in nonstructural ThermoWood®.