The Rhein-Galerie, located directly on the bank of the river Rhine in Ludwigshafen, provides an attractive place to shop and have fun. Around 130 specialist retailers provide a modern variety of products and services over 30,000m² of sales space spread out over two floors. The adjacent Rhein-promenade directly connects the Rhein-Galerie with the Rhine.

Imposing roof architecture

Particularly memorable is the membrane roof designed to create an architectural link between the river and the rhythmic oscillations of the building’s lateral arches. The translucent roof covers the entire shopping centre and lends the architecture a distinctive character.

High-quality materials for optimum interior conditions

The decision was taken to use PTFE (Teflon®) coated glass fabric. This material’s long life is not its only impressive trait. The Teflon surface coating also makes it easy to clean, because ordinary dirt and dust is simply washed away by rain. The high level of sunlight reflected off the surface as a result of the white colour ensures that the area under the membrane roof is heated less, but also ensures that a high level of light from outside can penetrate the roof, as was desired.

Elegant structure with unique details

The supporting structure of this extraordinary building is an elegant, three-dimensional, curved structure supported by a welded steel tube girder framework consisting of column supports upon which arches and frames were built. There are a total of 68 discrete surfaces, which are cladded with mechanically pre-stressed membrane sheets. The roof surface is left open above the interlocking elliptical courtyards of the interior in order to ensure optimum lighting from outside.

The membrane sheets were fixed into place using steel fixture strips for each sheet, following the curved form of the steel structure. The membranes were joined using aluminium sections that were produced specially for this project, and these were also pre-cast. The joints between the sections were sealed by mounting them on modified extruded neoprene strip seals. The aluminium sections allow each of the membrane sheets to be subjected to linear pre-stressing and fixed in place in a straight line without having screws penetrate the surface of the membranes.

Produced precisely to order

One of the core tasks was to produce the 68 membrane sheets with sizes of between 70 and 380m² in the Greven factory in a way that enabled them to be fitted directly at the shopping centre without any further modifications. This advance production process used the 3D model provided by the steelworker as the basis, together with jointly agreed production tolerances.

In order to ensure that the membranes were sufficiently pre-stressed, thereby providing them with sufficient long-term stability against snow and wind, the tensile properties of the coated fabric were determined using biaxial testing. This process enabled each of the sheets to be produced precisely in advance while the construction of the steel structure was ongoing.

Planning the fitting process – down to the last detail

The panels were fitted by a team of experienced industrial climbers. Because the coated glass sheets were so susceptible to kinking, a refined and precise plan for fitting them had to be developed. Firstly, the sheets were spread out on a pre-mounted support net and protected from exposure to the wind. They then had the special aluminium sections attached to all sides. The linear pre-stressing of around 4KN/m had to be applied in steps to ensure that the material was not damaged. It was only at the end that the aluminium section could be attached to the supporting steelwork with the sealant strips and corresponding screw joints.

The three-dimensional nature of the structure and the necessity of doubling over and reinforcing the edges meant that around 33,000m² of material were processed in order to cover around 24,000m² of surface area. The fitting took a total of eight months.