A hot summer for the offshore extension project

"This will certainly be a busy summer." For the director of Bouygues TP Monaco, Christophe Hirsinger, there is no doubt about it: the work in the coming months will be relentless. Some 50 to 60 workshops will be operating simultaneously. This, however, can only be viewed as a natural progression of the highly intense activities conducted at the site for the past several months. 

"The installation of the boxes is conducted at a sustained pace,” the director was happy to tell us at the end of June. 

“The belt, made of 18 concrete boxes, is just about finished. As scheduled, we will have completed the installation of the boxes before the end of July, including the installation of the box featuring large underwater windows that will serve as the foundation for the swimming pool. 

“We will be installing no less than four boxes in the course of July alone, which is exceptional in terms of efficiency." 

The installation of the various outcrops was marred by numerous unforeseen events, especially for the one located at the level of the Fairmont, the completion of which was no easy task. 

Removal of rock fills before closing the belt 

For the past months, the Filippo has been removing the outer layer of the rock fills located along the ancient coastline of the Anse du Portier. In total, 40,000 tons of rock are to be removed and transported out to sea to create eco-reefs. Obviously, once the belt of boxes is complete, and therefore sealed off, no ship will be able to access the ancient coastline. It is therefore important to finalise this operation before the installation of the last boxes. Christophe Hirsinger: "By the end of June, we removed 80% of these rock fills, and we should be able to complete the operation before mid-July, which will enable us to finish the eco-reefs and install the final boxes."

New scheduling constraints 

At the request of the client of Bouygues TP Monaco, the part of the project supporting the building designed by Renzo Piano had to be sped up. Thus, the platform, which is located on the Fairmont side, was constructed, and its related vibro-compaction operations, which are currently ongoing, should come to an end by mid-July. 

"This will allow us to proceed with the installation of numerous stakes - about a thousand in total - which will support the platform on this section by mid-November, Christophe Hirsinger tells us. 

“For this specific workshop, we will have completed the work nearly one year ahead of schedule!" This achievement also comes with gains in terms of quality; according to the original project, the platform was to be made 100% out of sand, but the section currently under works is being made with 20/180, i.e. a quarry material that is slightly more advantageous structurally, according to the director. 

The arrival of the world's largest ocean rig 

Once the belt of boxes is sealed off, the Leiv Eiriksson will visit Monaco's waters in August, according to the current provisional timetable. The mission of the world's largest trailing suction hopper dredger will then be to fill the platform with sand from Sicily, thereby completing the terrace of Monaco's offshore extension. To overcome turbidity issues, pumps will be operating to evacuate the water still present in the boxed enclosure, into which the Leiv Eiriksson will pour more than half a million tons of sand. 


This article was originally published in July-September 2019 edition of the Gazette de Monaco.