Aarhus City Tower – 100% Precast High-Rise

Tim Gudmand-Høyer
Senior Chief Specialist
Ramboll Group, Copenhagen

Precast and prefabrication in Denmark has in the last 60+ years become more and more viable and the preferred solution for buildings. Today almost all residential and commercial buildings incorporate a very high percentage of precast technology. With the increasing densification of our cities, building sites becomes more and more congested, which again drives the need for offsite construction. The Aarhus City Tower is a good example of precast construction where effective use of precast and offsite construction has generated a viable solution.

The 93m mixed-use Aarhus City Tower contains 34.000m2 of commercial and hotel space combined with a penthouse apartment at the top of the building.
Aarhus City Tower is one of the highest fully precast structures in Denmark and challenges the height limit for precast structures using limited vertical connections across floors.

The structural concept is a shear wall system utilizing the central core for stability combined with double-tiered façade columns for the vertical load. The hollow core deck slabs were designed for diaphragm action without the use of structural topping.
One of the key challenges in precast construction is the shear strength of the wall-to-wall connection. This is solved by an intelligent use of a combination of post-tension cables and non-tensioned reinforcement in corrugated pipes.
The innovative precast sandwich façade solution combines precast concrete, beam action, insulation, coloured concrete and sustainable photovoltaic panels all in one unit.
This design approach required strong focus on connections and reinforcement detailing. Extensive use of 3D modelling of the precast elements as well as of the reinforcement was key in solving this complex and ground-breaking project.