In 1992 IPL developed a retractable roof for the open-air theatre in Tecklenburg. Once in place the roof protects the spectators during the annual summer festival.

The structure consists of six filigree cable girders from which five longitudinal rails are suspended. Six steel arches with a carriage to which the double-layered membranes are attached move along these rails. As soon as the roof is extended, the membranes are inflated into cushions, so making them windresistant, covering an area of 29 x 40 metres. When retracted, the membranes become parked in a type of garage which protects them from bad weather.

24 years later the roof was refurbished. An inspection carried out in 2010 revealed that only the membranes needed to be replaced.

Due to the extensive 3D-CAD documentation out of IPL’s inventory the roof was refurbished efficiently. This meant that all that was necessary was to carry out a comparison of the measurements of the disassembled membranes and fittings with the old plans. As there only a few discrepancies were found, formTL produced the cutting pattern which were adapted to the new membrane material within a month. During the course of the refurbishment, not only the service life was extended but also the process of opening and closing the roof was accelerated with more powerful suction and pressure blowers.

formTL
workshop design oft he exchanged cushions, patterning

construction and manufacture
CENO Membrane Technology

photos
Dr. R. Borgmann
Peter Wejdling
Schwarzenberger

covered area
ca. 1.100 m²

Membrane:
PVC/PES Polyplan Type II