Concrete pouring operations by the largest pair of Potain tower cranes ever built are averaging 450,000m3 a month on the Three Gorges Dam construction project in Hubei Province, China.
The two specially-built MD 2200 Topbelt cranes support a concrete conveyor system designed by Nippon Conveyors. They will help to place a total 5.4 million m3 of concrete during the course of this year.
As previously reported in Cranes Today, the towers can lift 22.8t at a radius of 80m and have a maximum lifting capacity of 60t. As the dam wall rises, the cranes will climb to an underhook height of 185m. Concrete can be poured at rates up to 400m3/hour at a distance of 105m.
The cranes were built from components manufactured in France and by Potain’s Chinese subsidiary Zhangjiagang Potain. They are the first Potain cranes to feature an LCC 373kW hoist winch. The winch, controlled by direct current, raises and lowers the hook at infinitely variable speeds up to 80m/min.
The $25bn dam will stretch 2.3km across the Yangtze river and have a storage capacity of 39.3billion m3. The base thickness of the dam wall is 126m.
The project also includes the largest hydropower station in the world, with 26 turbines providing a total installed capacity of 18,200MW. The first 14 generators are scheduled to come on stream in 2006, with the other 12 following in 2009.
(See also Mass movement Aug99, pp12-17 and China bound May98, pp18-21)
