Installation of a sheet pile scour protection system for the foundations of a transmission tower installed on a sandbar island of the Zambezi River.
The project
Tete, a city located on the Zambezi province and crossed by the Zambezi River, is mostly well-known due to its huge reserves of coal. In 2011 due to the necessity of the power line, that supplies some of the mines, crossing this large river, 4 transmission towers where installed on a sandbar 11km downstream of Tete.
In 2012, due to the worrying undermining of one of the towers foundations, located at the island‘s edge, a protection system had to be designed and installed.
The challenge
The establishment commenced in the beginning of 2013, during the rainy season, which represented heavy rains and high temperatures. The equipment and material were transported using a barge and faced strong river currents and fluctuation. The crew had to travel to site by boat every day and the presence of a professional wild life hunter on the island, during the works, was mandatory due to the presence of hippos and crocodiles.
The solution
The solution consisted of a sheet pile cofferdam with reinforced concrete capping and tie beams.
This project comprised the installation of 136 No. PU18 steel sheet piles to 18m (supplied in lengths of 6 & 12 meters), coated on the top 6m only and equated to a total weight of 177 tons and a structural area of 1 512m², using a Liebherr HS845 crane and an ICE 815 Vibrator machine and power pack.