Development of EN 338(2003) Strength Classes of Doka (Isoberlinia doka), Madaci (Khaya senegalensis) Gawo (Acacia albida) and Rimi (Ceiba pentandra) Timber Species of Nigerian Origin

Development of EN 338(2003) Strength Classes of Doka (Isoberlinia doka), Madaci (Khaya senegalensis) Gawo (Acacia albida) and Rimi (Ceiba pentandra) Timber Species of Nigerian Origin

Abstract:

In this research work, laboratory experiments were conducted to generate bending strengths, modulii of elasticity, moisture contents and densities of four common timber species: [Doka (Isoberlinia doka), Madaci (Khaya senegalensis) Gawo (Acacia albida) and Rimi (Ceiba pentandra)] . These timber species which are common from Northern Nigeria. Extensive review of relevant literature was undertaken to provide background information on the specie under investigation. The experiments conducted were in accordance with the EN 408 (2003). The generated properties include bending strength, density, modulus of elasticity, other properties such as tension and compression strength parallel and perpendicular to the grain, shear strength and shear modulus were also computed. Two-way analysis of variance (ANOVA) was undertaken using analysis-it software, with the view to examine the equality of mean values of material properties within and between each of the tested species. The results indicated that, all the samples of particular specie considered come from the same population. Likewise, the difference between the mean values of the tested species are significant .The species were assigned to appropriate strength classes defined in the EN 338 (2009). Doka (Isoberlinia doka), was assigned to strength class D30, Madaci (Khaya senegalensis) to strength class D35, Gawo (Acacia albida) to strength class C16, and Rimi (Ceiba pentandra) to strength class C14. The data was analyzed with the Easy fit (2010) statistical package in accordance with the EN 384 (2004) The stochastic models (mean, coefficient of variation and distribution models) of each species were generated.

Development of EN 338(2003) Strength Classes of Doka (Isoberlinia doka), Madaci (Khaya senegalensis) Gawo (Acacia albida) and Rimi (Ceiba pentandra) Timber Species of Nigerian Origin