Optimizing Local Plant Products in Building Construction:Effects of Truss Configuration, and Bamboo Reinforcement

Abstract

Recent statistics indicate that over 10 million Kenyans are in need of proper housing mainly due to high prices of conventional building materials, outdated building codes that discourage use of readily available local materials, lack of finance, increased population and high rate of urbanization. This situation has given rise to mushrooming of informal settlements (slums) in urban centres in Nairobi, where it is reported that over 60% of town dwellers actually live in slums. This work focussed on seeking means of optimising the use of local timber in truss construction for roofing, as well as use of readily available bamboo stems as alternative reinforcement in concrete beams. Experimental studies on structural behaviour of different timber truss configurations, and on bamboo reinforced concrete beams reveal that indeed truss configuration has marked effect on the stiffness and ultimate strength of trusses, where vertically aligned members as found in queen-post and Howe trusses are seen to be more effective than inclined members in load transfer and ultimate resistance. Results also indicate that local bamboo species had strength which was about half that of steel, and is able to reinforce concrete beams effectively in place of steel for simple housing constructions or moderate scale concrete works. However, bamboo has much lower elastic modulus that results in excessive member deformations but promote ductile behaviour.