Road upgrading operations, technical report

Based on inventories of existing road conditions, review of equipment and staff in the Government of Zaire"s Office of Routes (OR), and joint meetings between USAID/Z and OR project personnel, a detailed technical analysis was made of appropriate site-specific construction methods, road surfacing and widening operations, technical assistance and training, and proposed maintenance strategies. Present roads are characterized by sump holes, uncrowned roadsides, and trench-like alignments. The construction methodology devised to upgrade existing roads envisions a crowned 6 m wide platform with a 1 m shoulder on each side. In plateau areas, 10 m wide borrow ditches should be used to permit efficient water evaporation/absorption, while underbrush and tree roots should be left in place in forested areas to prevent erosion. Excess soil resulting from widening operations can be used to build up the roadbed; concrete drainage ditches installed on the uphill side of steep areas will help prevent erosion. An evaluation of the availability of unskilled labor, the wage structure, and of community and private contractor capabilities revealed the use of labor intensive construction/maintenance methods to be feasible only on very low-volume roads (l0-20 vehicles per week). The two technical advisors, an engineer/construction superintendent and a master mechanic, should have previous hands-on construction experience with LDC road organizations rather than having engineering degrees and living experience in a developing country, as is originally called for. Furthermore, decentralized, onsite training of local workers is preferred to formal, in-class training techniques. Construction of a shorter, alternate route to Idiofa from Kikwit was deemed unfeasible because of difficult terrain.