STRENGTH CHARACTERIZATION AND GRADING OF LESS-USED NIGERIAN GROWN TIMBER SPECIES FOR STRUCTURAL APPLICATIONS

The demand for timber is unlimited as it continues to increase rapidly in Nigeria. There is problem of undocumented properties of unpopular timber species used locally, especially in developing countries such as Nigeria. This research therefore aimed at characterizing and grading of three (3) less-used timber species in Nigeria for structural uses. Ayunre (Albizia zygia), Eku (Brachystegia eurycoma) and Ire (Funtunia elastica) timber species were obtained from different sawmills in Ilorin, Nigeria and preparation of various test specimens are in accordance with British Standards BS 373: 1957. A total of 300 specimens were used in determining the strength characteristics of the timber species a 300 kN capacity Testometric Universal Testing Machine (UTM) at Agricultural and Biosystems Engineering Laboratory, University of Ilorin. Twenty (20) specimens for each timber species were tested for structural/strength properties according to the British Standard. Results show that the timber species had average moisture contents of 12.47, 11.78 and 12.71% for Ayunre, Eku and Ire, respectively. For density classification, Ayunre and Eku were classified as heavy wood and Ire as light wood. The results obtained provided quantitative details of the strength properties of selected timber species which can be used in determining the application of these timber species for structural applications. The timber species were, therefore graded according to NCP 2 (1973), EN 338 (2009) and BS 5268 (2002).