Investigation on Mechanical Properties and Suitability of Highland Bamboo ( Yushania Alpina ) for Use in Structural Truss Members

Abstract

In responding to the demand for construction materials that are sustainable, eco-friendly, safe and cost effective, several researches were conducted and came up with recommendations including the use of alternative construction materials. In this regard bamboo is taken as one of the alternatives. In Ethiopia there are two bamboo species that are commonly referred as high land bamboo or scientifically as ‘Yushania alpina’ and low land bamboo or scientifically as ‘Oxythenantera abyssinica’. Both of which cover nearly 1.4 million ha of land. Due to their attributes including fast growth, regeneration rate, low cost and strength, different countries are using bamboo for building of different structures and other products like furniture. In order to use the material for construction uses, it is of vital importance that properties of bamboo are determined to explore its potential uses. In this paper Experimental analysis was carried out on high land bamboo culms collected from selected regions of Ethiopia to investigate the compressive, tensile and bending strengths for their suitability as astructural member specifically for roof truss. The samples were collected from three regions in Ethiopia namely, Oromia Regional State (Tikur inchni), SNNPRS (Gurage), and Sidama Regional State. From the tests it was observed that air dried bamboo from the Gurage area (58.12 N/mm2) had the highest average compressive strength at ambient condition. On the other hand, an oven dried bamboo specimens from the three areas were tested and they showed similar average compressive strengths between 118 and 122 N/mm2 which were considerably different from the results of air dried bamboo samples. For bending strength Sidama area bamboo (58.53 N/mm2) showed highest value at ambient conditions. For the tensile strength the Gurage area bamboo (136.13 N/mm2) had a highest average tensile strength at ambient conditions. A truss using the Tikur inchini area bamboo was designed for G+0 building according to Ethiopian building code standard and built using Tikur inchini area bamboo and tested for stability by applying load of 110 kgs and it was found stable. The material strength of the tested samples for compression and tension were better than the design load of the truss. The research indicated that the highland bamboo can be used as a roof truss which saves cost and environment and provides better strength.