The cause of failure of the Massingir Dam Bottom Outlet Works: lessons to be learned for designers of reinforced concrete pressure conduits or penstocks

摘要

Massingir Dam in Mozambique has a maximum height of 48 m and a gross storage capacity of 2 900 million m~3. Completed in 1977, the dam is owned by the Government of Mozambique and administered by Administracao Regional De Aguas Do Sul (ARA-Sul).rnOn 22 May 2008 there was a massive bursting failure of the two 8 m x 8 m horseshoe-shaped reinforced concrete conduits that comprise the outlet structure of the Bottom Outlet Works. Prior to the failure, the two downstream radialrngates were closed and the reservoir water level was at 122,4 m, which is 7,4 m above the level of the gated spillway sill. Because the spillway gates had only been installed a few years earlier, the hydrostatic pressure in the conduits was then the highest that it had ever been in the life of the dam.