MECHANICAL CHARACTERIZATION AND GRADING OF Irvingia gabonensis TIMBER SPECIE ACCORDING TO BRITISH AND NIGERIAN STANDARDS FROM KWARA STATE NIGERIA

Abstract

This study was conducted to investigate the physical and mechanical properties of Bush mango (Irvingia gabonensis) timber specie using BS 5268 (2002) and NCP 2 (1973). Specimens used in the experiment were obtained from sawmills in Kwara State, North-central Nigeria in green condition. Samples were seasoned naturally for six months and prepared according to BS 373 (1957) Methods of Testing Small Clear Specimen of Timber. Mechanical properties (three point bending parallel, compression parallel and perpendicular, shear parallel, and tension parallel to grain) and physical properties (moisture content and density) were conducted. The properties determined were then adjusted to the values at 12% and 18% moisture content in conformity with BS 5268 (2002) and NCP 2 (1973) for application in the Northern part of Nigeria. Statistical analysis was carried out using the strength/structural properties obtained. Bush mango has an average moisture content of 13.95% and the mean air-dried density was 714.50kg/m3. The result of grade bending stress, density and mean modulus of elasticity showed that, Irvingia gabonensis can be graded and assigned to strength class D70 and N1 according to BS 5268 and NCP 2 respectively. The timber is suitable for load bearing structures like bridge beams, columns and railway sleepers.