The recent renovation of a submarine bunker in Saint- Nazaire, France by German office LIN Finn Geipel + Giulia Andi has transformed an eerie, imposing relic of war into a serene public art space. Completed in April 2007, Alveole 14 is now a flexible art space for performances of theatre, dance, film and music.
Alveole 14, literally 'Cell 14', was a project that was as always going to be controversial. The huge tomb-like U-boat pens were built between 1941 and 1942 during the German occupation of France by the Todt Organistion, a Nazi civil and military engineering group using slave labour.
St Nazaire was the only submarine base in France located in the centre of the city. The pens were designed to be indestructible and have been an eyesore along the St Nazaire docks for over 60 years, disconnecting the city from the waterfront.
Demolishing the 300m x 130m (985ft x 425ft) building was unfeasible. It was unlikely that French engineers would succeed where thousands of tons of Allied bombs had failed. "The Germans destroyed the city centre first," explains Finn Geipel of Berlin-based LIN Finn Geipel + Giulia Andi, who were awarded the project in March 2003. "Then the Allies tried to destroy the base but they couldn't do it, so they decided to destroy the whole city, and succeeded in levelling 85% of it. The only structure which remained in the centre was the submarine base."
As a result, the submarine pens are the only surviving link to St Nazaire's past if you want to understand the development of the city. La Mairie de Saint-Nazaire decided to reintegrate the city to the waterfront. Geipel says the city wanted the base to become a new link to rediscover the harbour. "It should not be a barrier," he says, explaining that the design was heavily informed by the continuing, and often highly divisive, debate over how France's World War II experience should be memorialised.
Geipel and Andi with project manager Hans-Michael Földeak envisioned a design in four parts incorporating an international centre for new art forms (LIFE), a contemporary music venue (VIP), an internal street, and a rooftop cupola. Alveole 14 is an intriguing example of how cities can reinvigorate their industrial waterfronts, making them a part of the city as opposed to voids in the urban fabric. The impact of the design was to be kept to a minimum, allowing for the retention of the enigmatic quality of the structure.
In total three cells were transformed and restructured into two event halls: one for contemporary music and second as a centre for emerging art forms. The street cutting the entire base links all the bunker cells
LIFE is a minimalist monospace, located in what was once the submarine basin and can be opened up towards the harbour through a large, retractable gate. VIP occupies one of the volumes inside the bunker and is an auditorium for 600 people enclosed by a steel frame, which also has a bar, a balcony, and an archive in cell 14 in addition to recording studios and an office in cell 13.
A concrete history
LIN is known for the highly integrative approach of both its architecture and designs – Geipel himself is currently head of the Laboratory for Integrative Architecture LIA at the Technische Universität Berlin.Teams of consultants from different fields have participated in their projects, which have ranged from urban programming to information design. LIN's previous projects include the Syn Chron installation in Berlin, Berne and Yamaguchi-city and the De Cornouaille Theatre in Quimper, France. Currently under construction is the Cité du Design in Saint-Etienne, which ironically built on the site of an old munitions factory in the Loire Valley.
The St Nazaire U-boat pens remain a potent lesson of history. During World War II, more than 4,600 workers were involved in the construction of the 14 pens, requiring more than 313,000m³ of concrete. When completed the pens were home to part of the Kriegsmarine's U-boat fleet that wreaked havoc on Allied shipping during the Battle of Atlantic. Consequently St Nazaire was a major target for Allied bombers and was one of the bases from where 28,000 German sailors departed never to return. It retains strong historical significance both for the French and the Germans.
Rather than try to hide or alter the structure, LIN decided to retain the rough exterior. The area of 3,300m² (Alveole 14) and 2,270m² (public space) presented formidable challenges to LIN's design process. "Alveole 14 was not built for people," says Geipel. "It was built for engines and war. People were just integrated into a mechanical process and were secondary." LIN's difficult objective was both to reinvent the space to make it people-friendly yet not deny the pen's original condition.
One of the biggest challenges was working with concrete. "It was not like an existing building, more like inside in a quarry," says Geipel.
An added problem was working with 60-year-old concrete that can crack after periods of erosion. "If you cut a hole, you never know where the cut will go on," he says. "So we had a lot of surprises. It's not perfect concrete but very uneven. As the pens got bombed, new layers were added so you end up with 8m-thick areas."
Despite the difficulties, Geipel did not find the conditions restrictive. "This was the basis of our work, and not a restriction," he says. "The challenge was how to transform the existing material into something that could be used and transformed by others later on. The elements were there and we had to deal with them."
Bomb traps and bunkers
Each pen has a roof made up of seven levels, up to 25ft thick – "A terrible surface," says Geipel. The Germans designed the roof to catch bombs and direct the blast to an explosion chamber beneath. They designed a fangrosten or bomb trap, an inverted U-shaped concrete beams positioned on parallel slabs.
Beneath the explosion chamber was an enclosed concrete layer that reached down to another solid area, and then into a void created from tilting the U-shaped beams against each other. Underneath there was further concrete reinforcement encased by a steel-trussed framework that spanned the 8ft-thick walls that divided each pen. The final layer was the steel roof above where the U-boats were moored in their pens.
The roof was the area where LIN could have the most visual impact in achieving one of their objectives of connecting Alveole 14 to the city. A radome and outside platform are positioned on the roof. An opening in the bunker ceiling connects them to the inside of the bunker via a large stairway. A striking design element was to incorporate an old radar dome from Berlin's Tempelhof airport onto the 3.5ha roof. The radome was reconstructed on-site after being dismantled at Tempelhof and transported to Saint-Nazaire. On 27 January 2007, it was lifted onto the bunker roof using a large crane.
The radar dome's aluminium frame is made up of 298 triangles, each covered with a transparent membrane. It's an unusual example of how to recycle architecture but, according to Geipel, not intended to be a historically loaded design statement. "What we were looking for was to put on the roof a kind of pioneer which should not be defined by its function, but to think about the future of the roof and its situation in the city," says Geipel. The dome's function is aesthetic. "A kind of think tank," says Geipel on a roof that now acts an experimental area – "A fantastic concrete terrace looking over the industrial harbour where they constructed the Queen Mary."
The huge structure provided more than protection. It was an integrated submarine base with repair and overhaul facilities, oil depots, mess halls, dormitories for over 1,000 sailors, a hospital all protected by 11ft-thick reinforced concrete external walls and 3ft-deep armoured double blast doors. "One quality of the bunker is to hide what is inside so our approach was to work on this relationship between inside and outside," explains Geipel. "This building is unlike any other in the city where you have a room and another room and another, where one area is a cultural centre and the other is a restaurant. You have to work from inside."
Alveole 14 design
In Alveole 14, LIN created an internal street along what was a large railed passageway used to transport goods and weapons. It connects the public spaces created by the project 'Ville-Port I' in cells 8-11 with Alveole 14, opening up new possibilities for use.
LIN suspended nearly 400 LED lamps from the ceiling in a regular grid and created a 'light carpet'. While obviously helping in navigation, these pinpoints of light exhibit the subtlety of the intervention, adding a sense of fragility to the structure. "This is an element on which the evolution of the bunker can be linked together," Geipel says. As the street cuts through the bunker, it approaches VIP, a three-storey steel construction and the central focus of the bunker.
Alveole 14 was never going to be normal. The design resurrected many of the additions from World War II including new pontoons linking different sections of the bunker. LIN created a very flexible space and incorporated acoustic panels that create an impressive sound. On completion of the project, St Nazaire's enlightened mayor gave LIN the space for one day. "We invited a friend of ours, German artist and composer Carsten Nicolai, to put on a performance," Geipel explains. Music at the midnight gig went up to 120db and tested, not just the acoustics, but the goodwill of the people of St Nazaire. "The good point was that the mayor was with us so no one could complain," laughs Geipel.
Alveole is an impressive renovation project and the scale of it might have overshadowed any attempt to bring a second reincarnation of a structure built during the darkest period of recent European history. LIN has succeeded in transforming Alveole 14 into a 21st century cultural centre of St Nazaire. "We want the bunker to become an active part of St Nazaire," says Geipel. "I think part of the city's history has been given back."