April 15th, 2013
After recently celebrating its century anniversary, Sopot’s Forest Opera in Poland is currently undergoing a huge renovation. The Opera rebuilding project will see the structure’s unique location brought together with 21st century facilities and one of the best sound and vision systems in Europe.
The £16.6 million (75 million zł) re-design contains the largest ever cold bent arches, curved by West Midlands based company, Barnshaw Section Benders. The modernized, open-air amphitheater, which sits in the picturesque Sopot forest, will be covered by a bowstring structure, shaped by two arches spanning 90m.
The project involved Barnshaws bending 16 steel tubes at 1300 cut diameter, which were bent to a radii of 49.785m. Supplied by Interfare Rohr Union, each tube was 70mm thick, with the largest section weighing 26 tonnes. The weight of all the tubes totaled 361 tonnes. Contractors acknowledge that previous options of producing structures such as these were limited to induction bending or producing the curve by a series of facets, which is not so appealing architecturally.
The tubes were the worlds largest ever to be cold bent, with a strength of 78,95cm³, the equivalent of bending five 914 x 419 x 388 kg/m at the same time. The jobs required a custom made bending machine and incredible forces to bend. In the end, the job supplied by Barnshaws added up to £322,000 worth of free issuing bending. Typical applications for the machine used by the company’s expert benders are for stadia, roof structures and bridges.
Working well ahead of schedule, Barnshaws originally estimated a 22-week delivery date for the curving of all 16 tubes, on behalf of German agency Stabikon. However the company finished the bends in merely 14 weeks. Architects and clients are encouraged to involve Barnshaws Section Benders at an early stage as limitations of previous bending capabilities are surpassed by the company’s acquired new technology.
Additionally, Barnshaws can curve the entire range of universal sections, cold bend tube up to 1500 dia x 60mm thick and induction bend up to 711 dia tube.
To find out more about tube bending please visit our Pipe Bending page.
