Aarhus City Tower – A 100% Precast High-Rise

Tim Gudmand-Høyer
Senior Chief Specialist
Ramboll Group, Copenhagen

Precast and prefabrication in Denmark have become more and more viable in the last 60+ years as 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 become more congested, which further 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 93-meter mixed-use Aarhus City Tower contains 34,000 square meters 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 a double-tiered façade column 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, colored concrete and sustainable photovoltaic panels all in one unit.This design approach required a strong focus on connections and reinforcement detailing. Extensive use of 3D-modelling of the precast elements as well as of the reinforcement elements was key in implementing effective solutions for this project.