A new residential and commercial district is currently being built in Frankfurt, consisting of no less than four high-rise giants. A special material from Stahlwerk Annahütte was used here. The high-strength reinforcing steel with SAS 670 threaded ribs ensures a slender but stable structure.
In "Mainhattan," Germany's most impressive skyline will be further enhanced with Four Frankfurt, introducing not just one but four high-rise giants. The ensemble of towers of different heights creates a new quarter with ample residential and office space in the direct vicinity of Commerzbank Tower, OMNITURM, and MAIN TOWER. The high-rises are connected by a common multi-story base, which practically joins them together to form a huge building with around 213,000 square meters of floor space. As with its neighbors, the design comes from an internationally renowned architectural firm – in this case: UNStudio. The building also shares a decisive structural characteristic with the OMNITURM, currently the latest addition to the banking district.
© Groß & Partner
None smaller than 100 meters
A look at the key numbers of the project reveals that Four Frankfurt matches the scale of the largest developments in both the Main metropolis and Germany. The tallest tower (Tower 1) is expected to reach a height of 233 meters, making it Germany's new third tallest building from 2024. Towers 2, 3 and 4 follow with heights of 173, 120, and 100 meters respectively. Thus, none is smaller than 100 meters. The offices (which account for almost 50 percent of the building's use) are distributed between the largest and smallest towers. Tower 2 houses rental apartments and serviced apartments. Tower 3 houses condominiums and a hotel.
© Groß & Partner
Slim yet strong thanks to high-strength SAS 670 threaded steel
In total, Four Frankfurt is expected to provide accommodation for up to 1,000 people and employ around 4,000 people. So much size needs stability. As with the neighboring OMNITURM, this is ensured by high-strength SAS 670 reinforcing steel from the Annahütte steel mill. And for good reasons: since SAS 670 is up to 34 percent more efficient than conventional reinforcing steel (B500B), the reinforcement area can be significantly reduced. This makes the high-performance steel virtually predestined for particularly tall and simultaneously slender buildings in regions with scarce space and astronomical land prices such as Frankfurt. Further advantages arise in the handling of the steel on the construction site due to endlessly screwable coarse threads as well as good resistance to mechanical damage. In total, approx. 2,200 tons of SAS 670 were used in the precast columns and in various in-situ concrete components of the project.
Four Frankfurt is already the seventh major building construction project in Frankfurt to use SAS 670. However, next to prominent international examples that were also built with the high-performance steel, such as 432 Park Avenue in New York (432 meters) or the Lotte World Tower in Seoul (555 meters), the high-rise buildings in Hesse seem downright tiny.
By the way, Allplan users can easily design with SAS 670. Since version 2017, the SAH SAS 670/800 catalog for screw coupler systems has been integrated in Allplan.
© Marius Bertsch
