The Estrel Tower is currently under construction in Berlin, which will rise 176 metres above the rooftops of the city once it is completed. The 45-storey tower will be part of the Estrel Hotel complex. Anchor plates together with fischer FAZ II Plus bolt anchors and the fischer InnoLock FES cast-in channels are used to anchor the façade elements permanently and securely to the façade.
The Estrel Tower in Berlin-Neukölln, designed by the German-American architecture firm Barkow Leibinger, will be the tallest high-rise building in Berlin at 176 metres when completed. There will be 522 hotel rooms, suites, lofts and long-term flats as well as a fitness and spa area spread over 45 floors. The Estrel Tower will also house office and co-working spaces, a gallery, a restaurant, a sky bar and a flexible event space. Civil engineering work began in July 2021. The building - a ferro-concrete structure with a single-leaf glass façade - is expected to be completed by the end of 2025. From green roofs including photovoltaic systems to wildflower meadows, a newly created park along the Neukölln shipping canal and a bicycle parking garage to CO2-neutral district heating, high environmental and sustainability standards are being implemented. The Estrel Tower is aiming for an LEED certification (Leadership in Energy and Environmental Design) with the highest "Platinum" award.
The glass façade offers a spectacular view of the city. Aluminium fins were specially adapted to the local solar radiation to prevent the rooms from heating up in summer. The solar control glazing and closed façade sections also contribute to this effect. In terms of design, they lend depth to the building's appearance, supported by their diagonal alignment and their various distances from the building envelope. The façade elements are delivered to the construction site prefabricated at the factory. The classic structure consists of an aluminium supporting structure and a continuous glass pane as infill, in some cases also vertical opening wings, as well as integrated air inlets and outlets, the sealing system and connecting elements. Joint and saddle seals guarantee air and water tightness - thus ensuring energy efficiency and protection from the weather. The joints are properly bonded. This ensures that the building envelope is installed in a closed, tight and energy-efficient manner. Movements in the façade due to thermal expansion or wind loads are compensated for.
The façade builders commissioned by FKN FASSADEN install the elements storey by storey from bottom to top. The decisive factor here is to secure people and the heavy parts against falling. On average, the building envelope of one floor is completed with 64 elements per week. A total of 2,881 elements are installed.
In addition to intermittent winds, transport is one of the challenges faced by the façade builders during installation. The cladding elements are 2.5 metres wide and weigh approximately 800 and sometimes 1,000 kilograms, depending on their size. They are pulled upwards in a basket using electric cable winches. A second system is used to pull the elements out of the basket and transport them horizontally around the building to the installation site.
Secure fixing is crucial for the heavyweight façade elements. Each element is anchored in concrete to a depth of at least 85 mm using two anchor plates together with two 173 mm long fischer FAZ II Plus 16/50 R bolt anchors. The "power bolts" absorb very high tensile and transverse forces. The anchors also score points with advantages such as quick and easy installation without cleaning the drill hole and high security. With a service life of up to 120 years (confirmed by an independent external expert report), the FAZ II Plus guarantees a firm hold even after more than a century.
Another fixing method uses the fully hot-dip galvanised fischer InnoLock FES RS-S cast-in channels. Here, the substructure brackets are fastened on the front side in front of the column with M16 x 80 mm channel bolt FBC-S-225. The InnoLock rails are already embedded in the concrete flush with the concrete support. The façade installers use the corresponding channel bolts and nuts to attach the add-on parts. To do this, they turn the channel bolt clockwise by approximately 90 degrees and then apply the specified torque. The façade elements are then positively hooked into a recess in the anchor plates.
The wide, robust toothing of the fischer InnoLock channel and channel bolt creates connections that can withstand the highest loads, even in the longitudinal direction of the channel, thanks to proven positive locking. At the same time, the toothed connection and the low tightening torque facilitate and accelerate secure installation. The patented lip geometry (stepped rail lip) also enables high retention values for tensile, transverse and longitudinal loads. Thanks to a sophisticated functional concept, the channel bolt remains securely connected to the anchor channel even under the highest loads.
The right fastening technology guarantees a permanently secure hold for the Estrel Tower skyscraper, Berlin's new landmark that radiates beyond the city's borders.
