The Jannah Dam project develops close to the Nahr Ibrahim River, about 30 km North-East of Beirut (Lebanon). The project will allow to store about 38 milion of m3 of water for Byblos, Beirut and its suburbs.
STM is involved is this project since 2018 and designed a conveyor belt system able to supply about 650 tons/h of concrete. The total conveyor lenght is about 650 meters and is designed to place concrete on the dam site. The conveyor line runs outside the Jannah dam body and its configuration is managed by a self-lifting device.
STM designed a 90mt tower which will manage the inclination of the conveyor line in order to follow every phase of the dam construction. At the end of the line, there is a swinger conveyor that allows the loading of trucks with RCC in the dam body.
On September 2019, the first part of the RCC Conveyor system has been assembled on site. This first section is 45 mt long and it will help to place concrete for the build of the 162 m tall dam.
The Jannah Dam is designed as a massive arch gravity dam to store 38 Million m3 of water to feed the areas of Byblos, Beirut and its suburbs. The maximum height of the dam above the foundation level is 162 m.
Reaching the dam foundation level at sound rock requires an excavation to some 65 m below the original ground level and river elevation. The hydraulic control is ascertained by two cofferdams, at the upstream (U/S) and downstream (D/S) side, both constructed on alluvial deposits.
Plastic concrete cut-off walls, ranging about 50 m below the foundation of the cofferdams, prevent the water to flow under the cofferdams into the excavation pit. The slope of the deep excavation to the dam foundation level is supported by an arch-shaped bulk head.
The installed plastic concrete cut-off walls provides the necessary vertical underground sealing below the cofferdams and extends over a length of 128 m (U/S) and 161 m (D/S).
Approximately 9,500 m² cut-off wall with a nominal thickness of 1,0 m (U/S) and 0,8 m (D/S) was completed in December 2017 which included a percentage (12%) of excavation through moderately weathered and slightly weathered Limestone (Dolostone/Dolomite) in order to reach the designed toe levels.
The total length of the conveyors is 650 mt and it has a slope range of +22° -20°. Its max capacity is 650 t/h and the volume of materials that will be carried is around 1.300.000 m3.
The conveyors line is designed for the concrete placing on the dam site. The conveyors line runs outside the dam body and the configuration is managed by a self-lifting device. A tower of 90m will manage the inclination of the conveyor line in order to follow the dam construction phases. At the end of the line a swinger conveyor loads trucks with RCC in the dam body.