2- The method of designing the foundations of the various buildings erected on this land filled area reinforced our scepticism. Effectively, the foundations were designed to reach solid grounds, on average 25 meters deep, through the various back filled materials.
As an example, we can mention the Louis II stadium for which the below-ground foundation structures represented some 50 per cent of the total above-ground civil work.
3- When seismic design standards were introduced later in Monaco, the question was raised of the dike ability to substain seismic induced loads. Fortunately, a group of experts, formed of three independent teams respectively French, American and Italian, concluded that in the event of seismic tremors, there was no risk of soil liquefaction underneath the dike.
4- Finally the economic aspect, resulting from the previous considerations is overwhelmingly in favour of our artificial island concept, based on offshore construction methods.
Professor Frankel(1), of the Boston MIT, stated that the cost of offshore platform, per in has been halved over the last 10years and that today's investment in offshore facilities is in the order of US$ 200,000 per man(for 50 m2) This is comparable to the cost of land acquisition per in floor in Monaco today.
The Fontvieille's development has demonstrated that, beside the significant inconvenience imposed upon the local residents, the overall cost of the dike and buildind foundations were higher than the above estimate.
We admire the major offshore projects undertaken worldwide and we endorse the studies performed by the Ministry of Public Work of Monaco under the management of Mr. Rene Bouchet (2) for a new dike and the Fontvieille II scheme.
However, we believe that our project "La Tour de Ia Mer"(The Sea Tower) provides a feasible and realistic alternative to "Fontvieille II" for expanding Monaco toward the sea(Fig. 4).
GENERAL CONCEPT
"La Tour de la Mer" is a buildind rising 390 m above the sea. It will be built on three artificial islands, each consisting of a circular concrete caisson with a diameter in the order of 100in.The three caissons will rest on the seabed at respectively-90 m, -85 m and -60 m. Arranged in a three point star shape, the caissons will receive the loads of the Tower legs and will tranfer them to the cretaceous seabed (Fig. 5).
At sea level piers of reinforced concrete, supported by the caissons at one end and tripods at the other end, will support concrete slabs. The pre-stressed concrete slabs will provide for atifical beaches, harbours and other leisure facilities.
The three legs of the tower, also arranged as a three point star, will be supported by the caissons and will converge in a single platform at elevation 66 m. From this level, still in a star shape, the tower will rise to respectively elevations 336 m, 360 m and 390 m for the tallest section.
Every fifth floor above the level +66 m, a "garden slab" will provide a green environment for the residents and the necessary stiffening of the structure to resist the torsional stresses induced by wind or seismic loads.
The floors above 66 m will provide accomodation while the floors below will be dedicated to office space and leisure facilities.
Within the caissons parking facilities as well as utilities for the day to day running of the tower will be accommodated.
A suspension bridge anchored to the tower structure and some 9 meters above sea level, will link the tower to the Fontvieille dike.
The road bridge will allow vehicles to reach the Tower parking facilities and importantly it will also provide, through its structure, for all the necessary technical links with the mainland.
