In December 2015, the improvements on the Cambambe hydroelectric power station, in the Kwanza River, nearly 111.8 mi. (180 km) southeast of Luanda, the capital of Angola, will be concluded. Work has been ongoing since 2009. The dam currently supplies power to the cities of Luanda, Ndalatando, Cacuaco, Malanje, Gabela, Porto Amboim and Sumbe, benefiting a population of approximately 8 million people.

Built in 1962, the station is being renovated and expanded to increase its energy production by 80 percent. From the current 180 mW per year, this infrastructure will then produce 960 mW, becoming the largest power production plant of the Kwanza basin. In 2014, Cambambe was certified with ISO 9001, 14001 and 18001 seals, being the first hydroelectric project in Africa to obtain such recognition.

Part of the project, which is being conducted by the Brazilian construction company Norberto Odebrecht, is raising the height of the dam by 65.6 ft. (20 m). This will increase the capacity of the reservoir, and allow the four existing generators to produce 65 megawatts each instead of the present 45.

In order to place more than 85,016 cu. yd. (65,000 cu m) of concrete that will be needed to raise the dam, Odebrecht counts on the help of three Linden Comansa tower cranes: two 21LC750 with maximum load capacity of 52 tons (48 t) acquired in 2012 and a 21LC400 with maximum capacity of 19.8 tons (18 t) leased by IBERGRU, the exclusive distributor of Linden Comansa in Angola.

The first 21LC750 was located on the left bank of the Kwanza River, erected with fixing angles on a special concrete foundation, which given its short width, was anchored to a rock on the river bank. It was mounted with a freestanding height of 258 ft. (78.8 m), the maximum possible height with 8.2 ft. (2.5 m) wide mast sections (fourteen D36 sections) and a jib length of 262.5 ft. (80 m).

On the right bank, a second 21LC750 was erected with a freestanding height of 286 ft. (87.2 m), achieved with 12 sections D36 — as her “sister” in the left margin — increased by three 16.4 ft. (5 m) wide D56 sections at its bottom. Another concrete foundation was anchored on the riverside to allow this crane’s assembly on fixing angles.

After a year and a half, the first 21LC750 (left bank) was relocated within the job site and substituted by a 21LC400 from IBERGRU’s rental fleet, which was erected with a freestanding height of 262.4 ft. (80 m) and a jib length of 229.6 ft. (70 m). This crane was assembled on the same fixing angles of the previous 21LC750, so it was necessary to have two transition sections in order to allow the progression from the 13.1 ft. (4 m) wide fixing angles to the 8.2 ft. (2.5 m) wide D33 mast section.

The relocated 21LC750 is currently working on the construction of the power house (or power generation center) where it was assigned to moving precast segments up to 20.9 tons (19 t) for the new water tunnels, as well as lifting and placing all the electromechanical gear that will allow the production of energy, such as turbines and generator sets.

The assembly of the first 21LC750 was performed by Linden Comansa’s technical assistance service team, while the remaining assemblies and technical service was entrusted to IBERGRU.

IBERGRU is the official distributor of Linden Comansa in Portugal since 2002. In 2008, the company opened offices in Angola, where it offers its tower crane rental services as well as technical planning and coordination for lifting projects.

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