The new railway bridge Weiherfeldstraße in Karlsruhe offers a unique opportunity for a public art installation at street level below the overpass. The existing railway bridge is made of riveted steel and was erected in 1908 immediately south of the main station in Karlsruhe. Eight sets of tracks cross Weiherfeldstraße and the Alb River via the bridge. We have chosen artist Heike Klussmann and a format similar to the Schwarzwaldstraße art installation to create an experience for the passersby which changes with distance and with the time of day and seasonally changing natural light. Although the wall surface is inaccessible to passersby, it provides a constantly changing atmosphere and spatial experience mainly due to the causal link of traffic flow, architecture, wall graphics and light!
The largely prefabricated wall structure, suspended and ventilated prior to construction of the abutments, is made of fiber concrete elements with integrated retroreflective glass beads. The wall is folded into vertical pleats which create a coherent image of the graphics that changes form when viewed from different angles. The image graphics receive a radiant effect through the use of the retroreflective surface and incidental solar or artificial light precisely reflected back in the direction of the light source. The installation changes from a passive to an active state, and varies, depending on the light source and the position of the observer.
The impact of the immaterial light and the reflection and transmission properties of the illuminated surface are key to the experience, although the light source itself is not visible: it requires an object with which to interact to be visible! The illuminated wall is also reflected in the Alb River, running parallel to the installation, and the light reflecting off the moving water further sets the mood in the overpass.