UNDERGROUND TEXTURES

In metro terms, Copenhagen is a young city. The first line on the London Underground opened in 1863 and Budapest followed about 30 years later. In the Danish capital, underground transport started in 2002 when the first Metro lines with 22 stations came into operation. After 10 years of intense work, the latest stage, Cityringen (M3), with 17 new stations, was inaugurated in September last year. Cityringen, with its driverless trains and revolutionary transit times, ferries passengers between Copenhagen Central Station, the city centre and the surrounding inner-city districts in just a few minutes. The people of the city have welcomed the new line, which, in addition to its obvious and appealing functionality, combines advanced technology and excellent design, in a result best described as state-of-the-art.

The first Metro lines, M1 and M2, were the result of a collaboration between the developer, Metroselskabet (Copenhagen Metro) and KHR Architects – under chief architect Nille Juul-Sørensen with COWI as the consulting engineers. Since then, Juul-Sørensen has moved to Arup, where he was chief architect when the studio won the tender for Cityringen.

The new line is also the result of close collaboration between the client, architects and engineers (COWI, Arup Systra JV). This time, they were all gathered under one roof, which was a huge advantage. The combined team worked together on all aspects of the process – engineering, design, safety, sustainability, operations and finances. The smooth, dynamic nature of the process was a significant contributing factor to the outstanding end result.

The fact that the new line was designed by the same group of people – within a relatively few years – meant they were able to refine the 2002 concept, while retaining the clear design identity. The main recurring feature was stations deep under the ground and built using the “cut and cover” construction technique. Instead of digging deep holes only to cover them again, the shafts of up to 20-metres are used to create impressively beautiful spaces through which passengers reach either the platform or the street. Ingenious, origami-style ceilings allowed the architects to filter daylight all the way down to the platforms – a unique effect not seen anywhere else in the world.

Like M1 and M2, Cityringen has a consistent and recognisable design language, both above and below ground. At street level, the stations are easily identifiable by their glass lift towers – and some by their daylightchannelling prisms – and the distinctive red Metro logo. Below ground, each station has a distinct look due to the wall cladding, which varies in the different parts of the city. Nille Juul-Sørensen explains: “The Metro stations play a dual role. They have to stand out and blend in at the same time. A station is not just a station, it is a space in the city. You have an emotional relationship with the station nearest to your home. We spent a long time visiting and assessing the neighbourhoods where the stations were to be built.”

For example, the wall panels in the Marble Church (Marmorkirken) station are clad in Gotland limestone, referencing the architecture of the Frederiksstaden area, where the buildings are predominantly clad in  natural stone. Once it had been decided that four stations should have brick decorations, the architects approached Petersen Tegl.

“Brick is an instantly recognisable and very Danish material – so if we didn’t use it here, where would we use it! Few materials are as tactile as brick,” Juul-Sørensen points out.” We went to Petersen brickworks, because we know that they don’t consider challenges a barrier, but are happy to develop new products. And we weren’t disappointed. It was an eye-opener, meeting artisans willing to tirelessly experiment throughout the development process with minor variations during the firing process, until the bricks had exactly the look we wanted.”

The architects knew early on that traditional brickwork was out of the question. “We chose a modified version of Kolumba, which was mounted in a lightweight steel construction, supplied by the German company Fischer, behind which there was room for cable. Because Kolumba is handmade, there is a certain amount of variation in terms of dimensions. All the bricks were therefore calibrated within a few millimetres on the one short side, so that they could be laid almost touching each other. The surface of the bricks faces outwards, creating a uniform but clearly rustic idiom. We see the panel wall as an indoor, suspended façade that expresses a quite simple idea,” says architect Anders Nøhr.

The stations clad in Petersen bricks are Noerrebro's Runddel, Nuuk's Plads, Aksel Moeller's Have and Enghave Plads.