Engineering: issues, challenges and opportunities for development ...

ENGINEERING FOR DEVELOPMENT: APPLICATIONS AND INFRASTRUCTUREWhat is an Appropriate Building Technology■■■■■■■■Maximizes the use of locally-available materials.Requires locally-available equipment that does not depend onimported supplies of electricity or fuel to operate.Draws on skills that are easy to learn and adopt at a communitylevel.Are environmental-friendly overall and will not damage the localenvironment.Is used and maintained without external assistance.Is safe and affordable.Is not necessarily ‘low technology’ or ‘high technology’, butprovides a capability.Skills are easy to learn and adopt at village and community levelThe COMAC construction programme has primarily focusedon immediate public buildings needs such as schools and hospitals,working with NGOs and other development mindedorganizations in introducing Appropriate Building Technology(ABT) for the reconstruction of Sudan. In so doing, COMACbelieves ordinary people will gradually pick up and adopt theuse of these technologies in their private projects.By using this approach, COMAC has been able to achieve anddemonstrate the following:■■Introduced ABT such as Stabilized Soil Blocks (SSB) that aremade from soil mixed with a small percentage of cement.The SSB technology is on average 50 per cent cheaper thanburnt bricks.Provided employment to the unemployed. An SSB productionplant employs six unskilled workers. Further employmentis created for the unskilled Sudanese who are trainedin construction, instead of importing a skilled labour forcefrom neighboring Kenya or Uganda. Black Cotton soil strata.© S. Mwangi■■Improvized special foundations for construction in BlackCotton areas.Helped conserve the environment by using environmentallyfriendly technologies. This has been achieved by replacingburnt bricks with cement used to stabilize soils and bindsand to make building blocks. Burnt bricks also create landdegradation as massive pits are left open after making brickswhile SSB are made on site using soils dug from trenchesdug for foundations of the intended building.Some of the Appropriate Building Technologies usedin SudanCOMAC has been promoting the use of three constructiontechnologies in Sudan. These are:Stabilized soil blocksThis building material was developed in Colombia in the early1940s and introduced into East Africa in the 1970s. The technologyhas benefited from developments that include:■Robust, manually operated equipment that requires littlemaintenance.■ A common performance standard that conforms to internationalbuilding standards for materials approved for permanentconstruction (such as concrete blocks).■■■Wide application and adoption in Kenya, Malawi andUganda.Use of interlocking blocks to further reduce costs by reducingthe need for mortar.The blocks are made on site using soils dug from thetrenches made for foundations.Poles and Rammed Earth TechnologyPoles and Rammed Earth Technology is an improvement onthe traditional African construction comprising of poles andmud. In this modern technology, treated poles that protectthem from termites and other insects are used as the structuralframework of the building. The poles are spaced atmaximum intervals of 1.5 metres, and then concreted to theground. Barbed wire or hoop iron is then nailed horizontallybetween the poles at a spacing of 300 mm, helping anchor therammed earth to the poles.Form work support is then used, temporarily fixed on thepoles both internally and externally, to support the wet mix ofsoil and cement used to stabilize it. On average, only 5 per centof cement is used to stabilize and bond the stable soil type.© S. Mwangi © S. Mwangi The wasted bricks duringproduction. Typical conditions of roads inSouth Sudan during the rains.281