In the absence of daylight, subway stations quickly become dark and eerie places. The planners of the new Karlsruhe Metro countered this effect with appropriate materials: façades and floors are executed in light architectural concrete based on Dyckerhoff Weiss.
Both the façades and the platforms in all seven newly erected stations are executed in large cast-stone panels, manufactured by the company Schwab-Stein from Horb, Germany. The panels for the façades were manufactured with Dyckerhoff Flowstone white. The aggregate used was quartz 2/8 mm, in addition to white limestone granules as filler and the white pigment titanium dioxide. The basis for the manufacture of the floor panels and the platform edges was Dyckerhoff Weiss; the remaining formulation was nearly identical to that of the wall panels.
The dimensions of the panels were individually determined for each of the stations in order to avoid the use of visible shims. Most panels have a width of approx. 100 cm and a height of approx. 50 cm. In addition, there is a large number of individually dimensioned panels. All of the transverse joints run in one line down the wall, across the platform on the ground, virtually across the tracks, and from there over the second platform and up again on the other wall. The panels for the walls were sanded with a 120 mm grit, and, those used for the floor were sanded with a grit of 60 mm to comply with the specified skid resistance SRT value of > 55. The objective here is to achieve a mat surface.
6,700 façade panels for 6 subway stations
The conceptual design for all stations was developed by the Munich office of Allmann Sattler Wappner Architekten. The seven stops of the subway station will be transformed into a single piece of art made of clay.
The Karlsruhe subway is already the second underground system whose stations are provided with façades of cast stone. In Düsseldorf, the Wehrhahn line was opened already in 2016. Here, all six stations were designed with a total of 6,700 façade panels made of Dyckerhoff Flowstone. For planning, the office of netzwerkarchitekten from Darmstadt, Germany, was responsible. Here, too, a challenging design concept was implemented; each station was designed by a different artist. The developer of the Karlsruhe subway system is the city of Karlsruhe, and the opening is planned for 2021.