Resource and Energy Center

18 Meters of Concrete – with Nothing Below

One of the many engineering challenges on this major construction site: erecting an 18 m high “bottomless” wall above an open space – meaning there is nothing underneath to carry the load. That alone makes the transfer of forces highly complex. Added to this, the ambitious schedule requires the wall to be constructed using slipform technology, which increases the demands on the shoring structure. With every meter poured, the loads increase and shift continuously. Against this backdrop of “unpredictability,” a particularly reliable, flexible, and safe load-bearing solution is required – a task that Doka’s heavy-load experts handle with engineering precision and a keen eye on cost efficiency.

Stable Beyond the Perimeter

To develop a statically optimized shoring solution, the team turned to Doka’s universal engineering kit, Doka UniKit. The chosen solution: UniKit towers 480 – economical, adaptable to the site conditions, and, above all, easy to handle. Special features such as a substructure of cantilevered HEB 400 primary beams ensure the towers can be stably positioned beyond the structure’s perimeter, transferring vertical loads safely back into the building. Distribution beams direct the enormous forces precisely and evenly into load-bearing sections of the existing slab. Where the existing structure is insufficient, additional supporting measures are implemented.

Equally important to safe load transfer is ensuring the safety of the site crew throughout construction. For this reason, the areas below the new wall are extensively shored and temporary protection decks are installed at tower height. This measure serves purely as occupational safety, reliably preventing falling hazards and ensuring secure working conditions.

Load-Bearing Capacity on a Countdown

True to the principle “Think about dismantling while still assembling!”, the entire shoring phase was meticulously planned in advance. To guarantee the timely release of the next construction stage, the assembly of the towers, concreting of the wall, and subsequent dismantling all had to be completed within a clearly defined time frame. For dismantling, just one month was available – a very tight window. The UniKit solution was therefore designed not only to deliver maximum load-bearing capacity, but also to allow for rapid, safe assembly and disassembly. In this regard too, the UniKit towers 480 proved ideal: lighter and more flexible to handle than other systems, they can be erected and dismantled significantly faster. Together with Doka’s pre-assembly specialists (SVM), the shoring experts also developed a detailed installation and dismantling concept that streamlined processes and optimized material logistics. Doka supervisors were on site to oversee every step – ensuring that every crane lift was executed flawlessly. This made it possible to complete the towers on schedule and free up the site in time for subsequent trades.

Edgar Feist, Project Engineer in charge for the project at Doka, sums it up: “On large-scale projects, it’s crucial that all building blocks interlock perfectly. With Doka UniKit, we had exactly such a building block – one that made even the unpredictable calculable and kept the tight schedule achievable.”