The Prince of Monaco’s car collection gets a new home

Vintage veterans of Formula 1, the Monte Carlo and Paris-Dakar rallies, plus classics by Porsche, Maserati and Ferrari – these motorized beauties and many more are now ready to be admired in a new 3,500 m2 exhibition space at Monaco’s Port Hercule. Tractebel’s Urban experts from France and Monaco designed, managed and supervised the works to house the Prince of Monaco’s car collection.

Tractebel in high gear since 2014

To realize this challenging project, our experts’ mandate for client Cabinet Notari – NMI / Department of Public Works in Monaco included pre-feasibility, engineering and design studies, assistance in the tendering phase, assistance to the Owner’s Engineer, and work supervision including demolition, foundations, grading and structural work. Tractebel was also responsible for the management of all construction teams. Works began in 2014 and the new underground exhibition space was inaugurated by Prince Albert II and Princess Stéphanie in July 2022.

The challenges of building below sea level

The structure, almost all of which is below sea level, is 200 m long by 25 m wide. Its elevation ranges from 4 m above sea level (level of the roof) to 15 m below sea level (BSL). The entrance is at the surface, with the exhibition space one floor below. Under the exhibition level are three more floors of underground parking consisting of 276 parking spaces, including 10 for electric cars.

The watertightness of the structure is ensured by an 80-cm thick molded wall, with a perimeter of 420 m and a watertight bottom 3 m thick injected at about 30 m BSL. Roughly 300 m3 per hour of seepage water is collected by a drainage mat and two drainage galleries, then brought to the surface by a system of lifting pumps. The retaining wall is buttressed by the floor slabs as the excavation continues. Due to the site’s highly unfavorable geological context, construction of an underground dam to a depth pf 7 – 15 m BSL was required during the construction phase.

Drainage water provides low-carbon energy to the Principality

The site hosts Monaco's public seawater loop, SeaWergie, which provides energy to the buildings of the Condamine district. The structure thus doubles as a source of low-carbon energy for the Principality of Monaco, by recovering the drainage water to feed the water loop.

Remaining excavation to take place underground

Monaco wishes to regain the use of the quay as soon as possible to organize its major annual events such as the Formula 1 race, Yacht Show and the Jumping International. Therefore, ongoing excavation will be carried out underground, below a cover slab which will rest on the peripheral molded wall and 75 prefabricated supports of 25 m in length. The slab is capable of withstanding a load of three tons per m² at all points.

“The immense challenges of this project stem from the concentration of highly complex techniques in a single site and within a tightly constrained environment. Our teams had to combine various techniques already tested in the Principality and elsewhere in the world in order to meet the constraints imposed by this bold initiative. Construction in a dense urban environment and at the centre of Monaco’s events and economic activities required a complex construction schedule, innovative technical solutions and strict work schedules. We are proud of the result: not only is the museum a technical marvel in its own right, but also one that provides the Principality with a source of low-carbon energy.” Ludovic Giuge, Tractebel Infrastructures - Director of Operations in Monaco

2017		2018		2020

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