Condamine port extension

The Hercules Port or Condamine Port extension project was devised in 1999 with the goal of positioning Monaco as an important port for cruise liners and luxury yachts. It consisted of the construction of a one-hectare backfilled platform at the foot of Fort Antoine to which a breakwater was attached by a metal ball-and-socket joint; a prefabricated jetty (145 metres long) and six concrete caissons for protection; a transition structure between the breakwater and the coast; and an abutment caisson supporting the articulated joint forming the fixed point of the breakwater. This port is one of the rare deep-water ports on the Côte d’Azur. This feature makes it a natural choice for receiving large yachts. That is why the construction drew on specific techniques which took the marine environment into consideration and which were developed and patented in the principality.

BACKGROUND

In 1901, Prince Albert I instituted a commission for the construction of a port for the many leisure yachts wintering on the Côte d’Azur. When the Hercules Port was constructed, the depth of the water did not allow the construction of a jetty and counter-jetty using traditional techniques to provide adequate protection to the harbour. So, two 170 metre-long breakwaters were built in alignment from either side of the shore to create a 100 metre-wide passage. But extending the port proved to be necessary for several reasons. One was to protect the harbour from eastern winds. The second was to double the capacity to receive pleasure boats and create an outer harbour specifically for cruise ships. The goal was to make this a true port of call for luxury cruise ships.

TECHNICAL OVERVIEW

The Condamine Port extension involved three parts. This infrastructure consists of a one-hectare platform at the foot of Fort Antoine. This platform was built from backfill and then fitted with six caissons. These concrete caissons, with a height of 10, 20 and 30 metres and weighing between 15,000 and 35,000 tonnes, were built using steel-reinforced panels and formwork. This was followed by the construction of a semi-floating 30 metre-wide and 352 metre-long breakwater attached to the embankment through a metal ball joint.
In addition to its primary function of protecting the waters of the outer port and port itself, it was intended to provide docking facilities for cruise ships on both the port and sea sides. It is connected to the platform through the abutment caisson to which it is attached by a large metal wheel. The sea side end is fastened by two sets of anchors fixed at a depth of more than 55 metres. The breakwater has at its base two 8 metre-wide wings for stabilisation to support a total underwater 44 metre-long mooring. Their role is to counter rolling and pitching. The structure is 3 metres above water level on the port side and 6.6 metres above on the sea side. The large submerged volume allowed for the installation of 360 parking spots on four levels and a dry harbour for 25,000 m² of storage on two levels. The outer harbour is protected through the “fixed seawall” technique, for which a patent application was filed by the Principality of Monaco. The “fixed seawall” principle consists of mobilising the inertia of the mass of water between the interior of a caisson and the bottom of the sea, which behaves like a wall to bounce back swelling waves. Finally, the structure has a 145-metre counter-jetty supporting its ends. The land side is on an abutment and the sea side is on a supporting caisson. This shelters the outer port better and creates an additional basin for large pleasure boats. It is a fixed structure with a prestressed concrete caisson 2 metres above water level.

To meet our client’s requirement for a structure that would last at least 100 years, we had to use steel bars with a diameter of 40 mm for the iron framework and high-performance, very fine and compact concrete.

IMPACT

Faced with the shortage of land on which to build, the Principality of Monaco has always turned to the sea to fulfil its economic development needs and the expansion of its activities. Monaco was until now unable to receive luxury “floating cities” sailing around the world. This gap was filled through an ambitious upgrade of the Condamine Port. In addition to the pursuit of this tourist and commercial goal, the project also enhanced the protection of the port against high tides and reclaimed land from the sea for real estate development. The Condamine Port extension project helped develop leisure and enhance the policy of receiving prestigious cruise ships (700 instead of 300 berths, of which 110 are reserved for vessels measuring between 20 and 100 metres), develop the urban landscape and economy of the Condamine neighbourhood, and remodel the coast. Finally, the decision to prefabricate various structures before towing them to Monaco resulted in fewer nuisances being caused by a worksite on an urban seafront and greater respect for the marine environment.

Project participants

Client
Principality of Monaco – Public Works Department

Contractor
Doris Engineering

Key figures

Implementation dates
October 1999 to April 2003

Hydraulic backfill
400,000 m³

Dredging
130,000 m³

Reinforced concrete
41,000 m³

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