The Analysis of Bending Stiffness and Strength of Glue Laminated Nigerian Timber

Abstract

An analysis into the flexural strength of solid and laminated timber specimens under working conditions was conducted. Five hardwoods and five softwoods were investigated, namely: Mansonia, Mahogany, Orji, Ukpi, Ufi mmanu, White Afara, Owen, Melina, Akpu and Ubia. The dimensions of the wood specimens are 100mm×50mm×20mm. The wood samples were tested for flexural strength using a Universal Testing Tensile Machine. The results obtained shows that Owen has the highest ultimate wood strength of 46.806N/mm² for the softwood glulam. Ukpi has the highest wood strength of 73.375N/mm² for the hardwood glulam, and highest MOE at 2412.93N/mm². Akpu recorded the weakest sample with bending strength values for glulam at 11.929 N/mm². Comparisons of strength were made to their respective solid timbers. Failure modes were analyzed. The study therefore demonstrates that the timber species used can be engineered to load bearing glulam structural elements using polyurethane adhesive glue without severe loss of strength.