Patte d"Oie housing project, Dakar, Senegal : reports on shifting sands stabilization and housing rehabilitation

The report is one of three studies contracted by A.I.D. (cf. DOCID"s: B6850226004101 and B6850226004103) for a proposed project to rehabilitate the POHP. A 1968 A.I.D. Housing Guaranty helped the Government of Senegal (GOS) build 669 middle-income housing units in Patte d"Oie outside Dakar. Due to poor design and construction, many units deteriorated in the face of the strong area winds and shifting sands. Four elements of the damaged structures are analyzed. (1) Due to insufficient design depth, the footings of 80 foundations, mostly in POHP"s western section, have been exposed, although without great danger of settlement. (2) The exterior building walls of POHP"s western section were built with non-galvanized expanded metal lath. Rusting has caused the lath to separate from the cement plaster, causing serious cracks. Moreover, the use of thin, rust-prone wires instead of welding to attach the metal lath to the open web steel studs caused the plaster to fail. Studs are also rusted, posing the danger of a partial collapse of roof and walls. Protection of the non-galvanized studs is a necessity. Waterproofing the concrete exterior walls which have hairline cracks is suggested. (3) Flatness of the roofs, combined with the deflection of the open web steel joints, has enabled water puddles to form on roofs, causing marked deterioration. Failure of the roofing expansion joint connecting adjoining roofs is widespread -- there was no provision for expansion. Most importantly, the lack of a basic flashing detail at the roof edge exposes the roofing to windborne sand. (4) Although garden walls have generally fared well, several have had to be replaced; one has failed. To avoid further failure, many more walls should be protected in the same manner as the exterior building walls. Suggestions for correcting the above problems are provided throughout. Also included are illustrative diagrams, a recommended implementation plan, cost estimates, and a list of suggested building materials.