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Structural Glass for Unique All-Glass Constructions

By: Andreas Geyer, seele (S) Pte. Ltd

Minimalist, maximum transparency, large glass formats, amazing attention to detail – those are the attributes of the building envelopes designed by world-famous architects. Fixing elements are not to be found. It is the glass itself that carries heavy loads via shear-resistant interlayers and does not require any further mechanical connections by structural bonding. That opens up totally new possibilities for glass roofs and façades as well as glass balustrades, stairs and bridges in the interior.

In 2007, for example, an all-glass construction for a retail store in Sydney with panes measuring 13.5 x 3m was implemented. Most recently, 17 x 2.8m cold-bent insulating glass units were used, which clearly shows the advancement in all glass constructions – all realized by construction specialist Seele. A deep understanding of the materials used results in unique façade and roof solutions. Comprehensive expertise in structural glass designs, high-precision steel construction manufacturing and know-how in the field of digitalisation is the key for such exclusive façades. From engineering, design, production, and logistics to assembly, the façade construction specialist takes over the entire process of creating unique building envelopes. In this way, numerous architectural icons have been created in recent years.

17M High, Curved Insulating Glass Units For The Trade Fair Tower In Frankfurt

For the redesign of the lobby façade of the trade fair tower “Messeturm” in Frankfurt, Germany, the largest curved insulating glass units are used. The special feature of this design is that the façade essentially consists of only a few parts: just nine panes and ten posts on each side of the tower. There are no horizontal members interrupting the glass, which helps to create lightness and transparency despite the dimensions. Owing to the huge size, each pane requires special bearings and must be held in place with glazing bars.

The cold-bent insulating glass units measure approx. 17 x 2.8m, is approx. 71mm thick overall and are supported by stainless steel posts weighing approx. 3.5t each. With its solar-control coating on level 4 to reduce solar heat gains, the insulating glass, therefore, combines aesthetic and functional criteria.

Super-Sized Glass Formats – Iconsiam

In 2018 the skyline of Bangkok along the riverfront of the Chao Phraya got a new 750,000sqm landmark, the luxury mall ICONSIAM. The design by Urban Architects incorporated a giant 5,300sqm “shop window” into the riverside façade of the building. A 3-story high, 3-dimensionally shaped all-glass façade, aiming for maximum of transparency by minimising the fixing details.

The glass panels are sloped in 2 directions, are arranged in a jagged pattern and follow the curved plan of the podium of the building – A 3-dimensional structural challenge with zero repetition. The total height is up to 24m. For the suspended construction, glass fins are used as a main structural element. Those fins were assembled from up to 16m long and multi-laminated glass elements to achieve the total length of 24m.

The steel elements connecting the fins are executed as bolted connections to avoid the tolerances that would be occurring when welding such construction. The front glass consists of single glass panels of up to 16m x 3.1m. The weight of such a panel is up to 3.5t.

For the successful execution of the project, it was essential to master all challenges – from engineering, fabrication and transportation of the super-sized façade elements, to their installation in Bangkok, against the background of an extremely tight schedule. Since the opening in 2018, the “luxury façades” of this project became an icon, that stands for Thailand’s fast-paced urban modernisation process.

Unique Testing Expertise

Load and performance tests are done in-house at Seele. Innovative solutions are tested at the testing centre in Gersthofen, Germany. Engineering services and façade structures are tested according to international guidelines as well as test scenarios developed in-house using true-to-scale mock-up buildings. Individual approval is required for almost all building envelopes. Extensive tests are usually necessary for the realisation of complex building envelopes. In the case of all-glass constructions. Primarily, tests are done by checking fittings and adhesive joints and their load-bearing capacity.

ICONSIAM – a 3-story high, 3-dimensionally shaped all-glass façade. ©seele/ Andreas Keller

Handling Of Large Glass Formats Worldwide

The handling of large glasses can be realised with specially developed suction systems and assembly equipment. The experienced assembly team carries out the fitting of the large glass panes with millimetre precision. Often the biggest difficulty is the assembly in the middle of a big city, which is challenging, especially with regard to space and time management. Roads, for example, have to be specially closed or installation can only be carried out at night. To successfully execute such complex projects one must master all aspects of the business, and the logistic part must not be underestimated.