Motors and a special drive mechanism allow these two gigantic glass “doors” to be opened or closed in 12 minutes – and particularly quietly as well. The façade elements run on rails following the 232m radius of the building with a noise level of less than 40dB. There are two drives per element, and the electric motors and transmission mechanisms are installed in the basement. Besides meeting the specification for moving these façade elements, seele also had to comply with California’s stringent earthquake requirements. Being able to secure the elements in any position at any time called for ingenious drive and locking systems.
The design team at seele developed the façade elements as giant sliding door leaves. Each element consists of two steel posts and 11 stainless steel ties joining the steel beams top and bottom. A pretension of 30t was applied to each tie. The steel members form a framework for the panes of glass measuring 2.7 x 14.1m, which are only fixed with structural silicone along their sides. Fixing the panes (laminated safety glass made from two plies of 12 mm heat-strengthened glass) with adhesive only had never been used on this scale before. That called for numerous tests beforehand. The unique features of this project and the high demands placed on design and construction show that seele has once again accomplished pioneering R&D and engineering work on an exceptional level.