European Central Bank
The striking twin tower shapes the skyline of Frankfurt’s Ostend.
The design of the Viennese architectural studio Coop Himmelb(l)au for the new premises of the European Central Bank in Frankfurt combines the horizontal structure of the landmarked Grossmarkthalle with a twisted double tower, which rises to 185 meters. United by an entrance building, these two elements form an ensemble of special architectural significance. Featuring bridges, pathways and platforms, the glass atrium between the two highrises creates a vertical city. The semi-public and communicative functions are located in the former Grossmarkthalle. The exceptional atrium and visible steel support structure show that the ECB building belongs to an entirely new typology of skyscrapers.
The hyperboloid cut
From the beginning it was an explicit request of the ECB to create a unique, iconic building as a symbol for the European Union. A distinctive and unique building can only be achieved by a completely different kind of Geometry.
The design concept of the ECB is to vertically divide a monolithic block through a hyperboloid cut, wedge it apart, twist it and fill the newly created intermediary space with a glass atrium. The result is a very complex geometry and a multifaceted building offering a completely different appearance from each angle: massive and powerful from the South-East, slender and dynamic from the West.
The principle of the “Vertical City”
The architectural concept of the ECB is to vertically divide a monolithic block through a hyperboloid cut, wedge it apart, twist it and fill the newly created intermediary space with several glass atriums. The connecting and transitioning platforms divide the atrium horizontally into three sections with heights from 45 to 60 meters. This is where all vertical entry points are joined – and just like public squares, they invite visitors to communicate. The planned “hanging gardens” ensure a pleasant room climate while elevators and stairs connect these places with the offices and communication areas of the Grossmarkthalle.
The Grossmarkthalle – the communicative forum
The existing landmarked Grossmarkthalle, a former wholesale market from the 1920s, is used as an “urban foyer”. The conference and visitor’s center, library and employee cafeteria are placed diagonally in the spacious interior of the hall as independent building structures (with a “house within a house” concept). A floating entrance building penetrates the hall structure from the outside. With its asymmetrical contours, slanted facades and generous windows it marks the representative access to the ECB. The lobby, two-story press conference room and a lecture room are located here. The so-called “loop” – a glass walkway between the highrise and the market hall – completes the ensemble.
The sustainable energy concept
Energy efficiency and sustainability were key factors in the competition. The energy concept includes the following measures: utilization of rain water, heat recovery, efficient insulation, sun protection and illumination as well as a natural ventilation for the offices. Some areas, such as the atrium and open zones of the Grossmarkthalle, are not equipped with an air conditioning system; instead they serve as a buffer zone between the interior and exterior climates. The "shield hybrid facade" of the office towers consists of three layers and offers a direct and natural ventilation of the offices via vertical, room-high ventilation elements.
Urban construction and architecture
The ECB’s architecture was carefully attuned to its location in Frankfurt’s Ostend district. With its clear orientation towards the urban perspectives, the ensemble enters a dialogue with Frankfurt’s most important reference points: the Alte Oper, the Museum Embankment and the skyline of the financial district. The distinctive double tower can be seen from all of the important places in Frankfurt’s city center and from the Main river, creating an initial point for a second center in the East of Frankfurt.
“This corresponds to the principle of a polycentric city, which is much more dynamic than a monocentric city,” explains Wolf D. Prix, Design Principal and CEO of Coop Himmelb(l)au. “Tension areas begin to emerge between the centers, in which new developments are being provoked.”
