Compressive Strength Characteristics of Ara and Apado Nigerian Timber Species
The paper examined the reliability of the Nigerian grown Ara and Apado timber species as column materials. The work centers on the compressive strength characteristics of Nigerian Ara (Pterocarpus erinaceus) and Apado (Berlinia spp) timber column of nominal lengths 200, 400, 600 and 800 mm and cross section of 50 by 50 mm. The steps involved collection and conditioning of Apa and Apado timber species, preparation of test specimens, determination of physical and compressive strength properties and derivation of continuous column design equations. Twenty (20) test samples were used for all the tests carried out. Apa and Apado have an average density of 652.74 and 472.60 kg/m3, respectively. Moisture content of both species less than the maximum recommended value of 20 % and the average strength at yield of Apa and Apado were 35.65 and 14.00 N/mm2. The derived continuous equations for design of Apa and Apado column are and respectively. Ara and Apado have the reliability index of 0.63 and 0.65 respectively for a service life of 50 years, assuming other serviceability conditions are met. The paper therefore recommends the adoption of these equations for the design of compression members from these timber species, in Nigeria.