Structural Properties of Some Indigenous Timber Species in Nigeria.

Abstract

Indigenous timber has been in use for centuries now, but the absence of data on their structural properties has made their application technically inconclusive. In this study, samples were taken for field and laboratory tests and experiments conducted by NCP 2 (1973), BS 373 (1957), and BS 5268 (2002). The field experiments result of the ten species obtained were observed to fall within the range of 28 to 35m for height, 0.8 to 1.5m for diameter, brown and yellow for colour, 32.78N/mm2 to 68.67N/mm2 for compressive strength, 68.64N/mm2 to 98.95N/mm2 for flexural strength, 61.34N/mm2 to 166.08N/mm2 for tensile strength and 3022N to 12805N for hardness. Some species taste pleasant, unpleasant, bitter and unspecific taste. Some species were fine to coarse for texture with straight and interlocked grains. Other include moisture content of compressive strength was 10.27% to 12.77%, moisture content for tensile strength was 10.13% to 12.67%, and moisture content for flexural strength was 11.41% to 16.09%. Density for the ten species ranges from 640kg/m3 to 1060kg/m3. The study identified Lophira alata, Nauclea diderrichii, Cylicodiscus gabunesis, afzelia bipindensis, Entandrophragma cylindricum, Brachystegia nigerica, Holotelea grandis, Khaya ivorensis, Mitragyna cilliata and Terminalia superba to be structurally adequate for civil engineering construction and Furniture, and are sufficiently available in commercial quantities for required applications. In this research, engineering data of these indigenous timber have been generated for practical applications in the design and construction of structures as well as furniture fabrication.