The Mont Saint-Michel rock off the northwest coast of France is one of the world's most famous landmarks. And not only cultural, but also natural: the stunning beauty of the landscape and the unique, highest and fastest tides in Europe attract tourists here no less than the medieval Benedictine abbey located on the island. But the construction of a dam connecting the island and the "mainland", as well as a dam at the mouth of the Couenon River, which flows into the sea nearby, endangered the existence of the monument. They trapped sand and silt, raising the level of the seabed, and as a result, the island was gradually connected to the continent, losing its status.
A tender for a delicate engineering solution that allows tourists to access the island and, at the same time, preserves its unique position, was held back in 2002, but construction began only in 2011. (More about the background of the project - in our material
"Mont Saint-Michel departs from the mainland"). Pedestrian traffic on the new bridge was opened in July 2014, and most recently, the final stage of this large-scale project, worth about 37 million euros, was finally completed.
Instead of a dam, built at the end of the 19th century, a thin, permeable pier with a length of 1841 m appeared. At first, it curves smoothly along the coast, allowing tourists to fully enjoy the views, and then crosses the strait between the Mont Saint-Michel island and the Normandy coast. The length of the bridge itself is 765 m. It is interesting that throughout its length the pier has the same height, which allows it to merge with the horizon without disturbing the spectacular views. Moreover, during high tides, it practically lies on the surface of the water. Only near the island itself there is a slight slope of only 1%, and when the tide becomes too high for several days a year, the rock is completely surrounded by water, again turning into a "real" island.
To facilitate the natural washing out of sand and silt (which will preserve the status of the island), it was necessary to minimize the thickness of the supports, for which a very complex structure was created. 67 pairs of concrete pylons with a diameter of 1.2 m were driven into a depth of about 30 m, on which 134 piles with a diameter of only 24.4 cm are supported. Each pair is 12 m apart from the other. the concrete foundation of the bridge itself is already at rest. This central part has a width of 6.5 m (at the very end - 8.5 m) and is occupied by an asphalt roadway for shuttle buses. Despite the fact that the structure is capable of withstanding a load of up to 38 tons, access to the island for private vehicles is now completely closed.
Like two endless "balconies", pedestrian and bicycle paths hang to the right and left of the roadbed. Their width is 4.5 and 1.5 meters (expanding to 5.5 and 2.5 meters near the transport terminal, 300 meters from the entrance to the monastery). The flooring of textured, untreated oak perfectly matches the spirit of the place and becomes an organic part of the landscape. The wider walkway along its entire length is separated from the carriageway by a curb, which also serves as the world's longest bench. Soft LED illumination hidden under it "leads" visitors to the brightly lit island in the evening.
Finally, the pier solves one more important problem: engineering communications are hidden under the concrete base, providing the island with water, electricity and communications. So engineers and architects managed to achieve a virtuoso combination of functionalism, technical perfection and harmonious, extremely tactful from an aesthetic point of view, coexistence of their buildings with a very characteristic natural and man-made landscape.
