European Central Bank in Frankfurt am Main: unitised façade

34,200sqm

glass façade

2,636sqm

roof

6,081

elements

european central bank – a solitary figure in germany’s banking capital

The new headquarters for the European Central Bank (ECB), designed by architectural practice COOP HIMMELB(L)AU, has been built on the site of a former covered market in the east of the city. The new building consists of three main elements: twin office towers, an entrance structure and the former covered market. Frankfurt’s skyline has now been augmented by a pair of twisted high-rise blocks.

The entrance structure connects the two glass towers to the refurbished covered market, a listed building which was built in the 1920s. seele designed, fabricated and installed the external envelope to the pair of 185m high skyscrapers. This is a type of hybrid double glass façade – a three-leaf unitised aluminium façade which includes electrically operated, storey-high, parallel-opening window elements on every second façade grid-line so the offices get direct, natural ventilation.

Shading against sunlight and glare is incorporated in the cavity. This energy-efficient façade is part of the overall energy concept. One of the outcomes of the arrangement of the twin office towers was sloping, hyperbolic façade surfaces requiring many different elements. A total of 6,081 individual elements were needed for the total area of about 34,000sqm. Despite the individual symmetry of the façade elements, seele developed a system that enabled serial production and reduced the complexity. It was then possible, for example, to use data from the 3D design directly to programme and control the machining centres used to fabricate the elements.

Reference overview: © Robert Metsch, Header image: © Ulrich Wozniak

The new building of the European Central Bank in Frankfurt is 201 meters high. seele was responsible for the 34.200sqm unitised façade and the 2.636sqm roof area.

The high-rise building of the European Central Bank consists of two towers. The oblique roof shape and the glass façade of seele cater for light-flooded office spaces.

A façade area of approx. 34,200sqm made up of 6,081 elements. Their scale-like arrangement led to a significant reduction in the number of different formats.

Thanks to seele’s concept for the economic subdivision of the façade surfaces, asymmetric elements were only needed along the curving edges of the building.

Electrically operated, storey-high, parallel-opening window elements on every second façade grid-line ensure direct, natural ventilation for the offices.

Aesthetic yet economic façade

seele managed to achieve an economic and practicable solution for the façade design. The technical concept reduced the number of different element formats required from 4,000 to about 1,000 and at the same time enabled economical serial production plus simpler logistics. seele was therefore able to assemble the highly aesthetic, curving façade surface without using any asymmetric panels. Instead, the exclusively straight elements were installed turned through an angle of 2° about the vertical axis. This scale-like arrangement has resulted in a perfectly homogeneous appearance. As turning the elements resulted in small overlaps along the horizontal edges, seele devised a new sealing detail: seals were first fitted in the sides during installation so that they join the elements reliably over the full length.

Despite the use of exclusively straight panels, positioning the elements next to each other like scales achieved a homogeneous, curving surface without corners, projections or returns.

Turning the elements led to skewed sealing details at the junctions between elements staggered by up to 4°. Using an adaptable solution developed by seele itself, it was possible to achieve reliable weatherproofing.

Every element is connected to the supporting construction at four points, but only in the middle of its vertical axis is an element parallel with the building. The turning of the element edges with respect to each other resulted in staggered sealing details.

Credits

Client	European Central Bank
Main contractor	Drees & Sommer
Architect	COOP HIMMELB(L)AU
Engineer	Ingenieurbüro Lange
Date of completion	2014
Scope of work by seele	34,200sqm unitised façade 2,636sqm roof area
Awards	Hessian Culture Prize 2013