Investigation of the tensile and compressive strength of Ugandan Borassus Aethiopum (African Fan Palm)

Abstract

Uganda has over forty-five (45) timber species on market. The most common timber species include eucalyptus, mvule and mahogany that are used in making furniture and for construction works among other uses. There is increasing scarcity of the traditionally valuable timber species and advocacy for use of locally available materials like Borassus aethiopum (African fan palm) in construction works. Borassus aethiopum has inadequate information on its mechanical properties like tensile strength which is required in design. Users of Borassus aethiopum timber rely on experience in determining dimensions of the timber to uses in construction. This leads to either wastage of timber in case of over design or the integrity of the structure is undermined in case of under design. This research was focused on investigation of both compressive and tensile strength of Borassus aethiopum parallel to the grain. Samples of this timber were obtained from Gulu district in northern Uganda. Small clear specimens were prepared from these samples. Testing was done using the universal testing Machine and results were analysed using statistical analysis. It was noted that at 12% moisture content, Borassus aethiopum had an average peak compressive strength of 39.763 N/mm2. Of the specimens tested, 99% of the compressive test results were greater than 32.85 N/mm2. When a factor of safety of 2.25 was subjected to this value, the basic compressive stress obtained was 14.6 N/mm2. For the tensile tests done, it was found that the average peak tensile strength at 12% moisture content was 76.794 N/mm2. On statistical analysis 99% of the test results were greater than 60.926 N/mm2. On application of a factor of safety of 2.25, the basic tensile stress was 27.078 N/mm2. The specific gravity of the timber from Borassus aethiopum was 0.724.