Germany’s future fifth-tallest building

As Germany’s financial capital and home to the European Central Bank, Frankfurt has one of Europe’s most distinctive high-rise skylines. Now, another landmark is taking shape: the Central Business Tower (CBT), which will become Germany’s fifth-tallest building upon completion. Designed by KSP Engel for Helaba, the tower integrates the listed façade of a historic bank building dating from 1889–1892. The project is being delivered by ZÜBLIN in a joint venture with Dobler Metallbau GmbH, with Doka providing the engineering and formwork expertise to support the demanding construction cycle.

Neo Renaissance meets Corporate Modernism
The striking glass high-rise incorporates the listed, more than 130-year-old historic building at its base. As part of the redevelopment, its concrete core was renewed after the historic sandstone façade and former banking hall (rotunda) had been carefully dismantled and restored.

The tower itself comprises three high-rise cores. The north and south cores climb ahead, allowing the walls and slabs of the central core to follow between them. For the formwork, Doka’s Platform SCP is combined with loading platforms that supply the site team with materials that cannot be stored on the slabs. Powerful hydraulic cylinders lift the platform, formwork and material containers to the next casting section in a single operation. By keeping materials closer to where they are needed, the solution reduces crane demand and contributed to maintaining the planned one-floor-per-week cycle.

The east and west façades each feature three vertical setbacks. At levels 16, 29 and 41, the tower narrows by several metres, gradually revealing more of the light-filled central core. To ensure safe working conditions while constructing the slab edges, the Protection screen Xclimb 60 units in these areas are supported by a bracing structure. The layout of the protection screen elements was planned from the outset so they can step back precisely with the façade at each setback.

Limited space calls for close coordination
Another challenge was the extremely limited space available on site. “As you can imagine, in the middle of Frankfurt’s city centre, there is very little space for storage and assembly,” says Tillmann Walz, Site Manager at ZÜBLIN. “That’s why we coordinated closely with Doka to ensure that formwork materials were delivered just in time and could be put to use quickly. This significantly eased our on-site material logistics.”

Precision by design with Revit
With three high-rise cores being constructed in parallel, formwork planning for the Central Business Tower was particularly demanding. Due to the complex beam and folding mechanisms, Doka engineers modelled the wall formwork in Revit. The precise sequence of the folding mechanisms was critical to avoid obstructions, while custom steel components were modelled to ensure that the formwork elements could be connected precisely and stripped without collisions. The Revit model also provided the basis for planning formwork operations and the climbing sequence on site.

Sustainability is another key consideration for the project, which is targeting LEED Platinum certification, the highest rating under the international LEED standard. Planned measures include integrating photovoltaic panels into the glass-and-metal façade – a first for Frankfurt’s financial district.

The Central Business Tower is scheduled to be ready for occupancy in 2028.