OPTIMAL UTILIZATION OF TIMBER POLES AS STRUCTURAL MEMBERS OF FORMWORK

Abstract

Timber poles of the type "Mirunda" are commonly usedin East Africa as formwork support structures for castingof reinforced concrete slabs, beams and canopies. It isalso widely known that the "Mirunda" poles as structuralmembers of formwork are massively used without anystructural consideration and guidance. This commonpractice has resulted into wastage of natural resourcesand escalated construction costs. This study hasattempted to establish the load bearing capacity ofrandomly selected "Mirunda" poles through laboratorytesting. Using an existing construction site as a casestudy, the results have been used to establish the actualnumber of timber poles required to support freshly castreinforced concrete slabs, beams and canopies. Theloading has been assumed for normal accessibility as perspecifications in BS 6399: Part1 (1984).with a dynamicfactor arising from the impact of dropping the concreteonto the formwork as well as the dynamic effect of theconcrete vibrating machine. A comparison has beenmade between the actual requirement and the quantity oftimber poles counted on site. On basis of the studyfindings appropriate recommendations have beenprovided on how "Mirunda" poles can be optimallyutilized as structural members of formwork.