Since 2008, Energias de Portugal (EDP), the largest electric utility company in Portugal, has been building the Baixo Sabor hydroelectric plant in the municipality of Torre de Moncorvo. Registered within the National Plan of High Potential Hydroelectric dams, this facility will enter into service in August 2014, with an installed capacity of 170 MW and generating up to 444 GWh per year. Comprised by two dams, the main one is located upstream of the Sabor River and set 9.5 kilometers apart from the downstream one, that will flood an area over 50 km, thus creating the third largest lake in Portugal.
The temporary consortium Baixo Sabor ACE, formed by Odebrecht / Bento Pedroso Construções and Lena Construções is the company responsible for the construction of the dams, with a budget of over 480 million euros (around $643 million USD). The jobsite will employ up to 1,675 people, with an excavation volume of around 3,000,000 m3, where a volume of 1,100,000 m3 concrete shall be used.
The magnitude of the project also requires a large amount of machinery. Therefore, Linden Comansa’s official distributor in Portugal, IBERGRU, has supplied to the jobsite with 15 flat-top tower cranes from the Spanish manufacturer, with maximum load in a range between 5 and 48 tons.
The main plant, located upstream, is a double-curvature dam and will have a height of 123 meters and a width of 505 meters. Four tower cranes are being employed in its construction, all Linden Comansa, model 10LC140, with maximum load capacity of 8 tons.
The assembling of two of these 10LC140 cranes was a challenge due to the difficult accessibility. However, Ibergru found a solution that allowed to efficiently use the available resources on site, saving other costs. To pour large amounts of concrete, many dams, including Baixo Sabor, use an air transport system with cables, very similar to the cable car, called blondin in honor of Charles Blondin, a famous French tightrope walker of the 19th century. IBERGRU proposed to the site managers the utilization of these blondins in the assembling of the two 10LC140 cranes, a very unusual solution that was not only successful but also cost-effective.
Next to the upstream station, a 5-ton LC5211 tower crane is constructing a building that will be part of the administrative facilities of the dam, and two 5LC5010 with maximum load of 5 tons work as service cranes in the yards that serve as warehouse and workshop of the jobsite materials.
The secondary plant, of gravity type, is located downstream closer to the river’s mouth, will feature a height of 45 meters and a width of 315 meters. The five largest tower cranes working in this project are the following: two 21LC750, with up to 48 tons capacity, and three 21LC550 with maximum load capacity of 18 tons. Another 5LC5010 with maximum load of 5 tons is working as service crane, helping to manage the machinery and materials required on the site.
In addition, two Linden Comansa 21LC290 cranes, with maximum load capacity of 18 tons, are working in the construction of a new bridge with 268 meters of length and 40 meters of height. Located near the downstream plant, this bridge will allow the EN102 road to cross the river, since the current Portela Bridge will be submerged by the waters.
Ibergru is supplying the rental cranes and advising the jobsite management in choosing the right equipment for each task. Ibergru has planned, coordinated, and executed all logistics entailed by the erection of the cranes, in conditions of difficult accessibility given the complex topography of the jobsite.