New building of the Cantonal Hospital Aarau “Dreiklang”

Short description

The Cantonal Hospital in Aarau is currently the largest new hospital building in Switzerland. The name "Dreiklang" (triad) is explained by the optimal interplay between functional areas and outpatient clinics in the base building and the ward block above.

The project

The "Dreiklang" project is not only a high-quality hospital building, it also has the potential to become a landmark in the city of Aarau. Its location in the middle of the newly designed hospital park is a guarantee for exchange between visitors and patients, employees and passers-by. The portico in front signals openness and at the same time provides orientation. The building demonstrates clarity not only on the outside, but also in its interior spaces. Divided into the three areas of use - outpatient clinics, functional areas and wards - independent, easy-to-find zones are created. Their combination results in a simple and easily comprehensible structure. This ensures what the Aarau Cantonal Hospital stands for today: medical care that is characterised by competence and efficiency and at the same time promises maximum flexibility.

One basic idea dominates the concept for the three building zones: The principle of short distances for staff and patients. The wards that are most frequented - such as the emergency room, radiology and the outpatient departments of internal medicine - are placed on the ground floor. On the first floor are the surgical disciplines, on the second the interventional and the conservative as well as the intensive care. The mother-child centre is located on the third floor. The ward block with its nursing wards and an exceptional view of the green surrounding countryside extends from the fourth to the ninth floor. Consistent care was taken to separate the outpatient and inpatient areas as well as their traffic flows. To make optimal use of synergies, a boulevard connecting all areas was inserted as the centrepiece of the building.

The new KSA building is being constructed in accordance with the highest current building standard, Minergie P-ECO, and thus meets the highest standards in terms of quality, comfort and energy.

Services in detail

The project is currently one of the largest new hospital buildings in Switzerland. It consists of two staggered basement floors, four base floors, six bed floors and an upper technical floor. The first bed floor (= 4th floor) will be left as it is and the concept will be designed in such a way that other uses are also possible on this floor. There are also possibilities for expansion in the basement floors to the north and east. This ensures maximum flexibility for future adaptations.

The entire planning is carried out according to the BIM method (BIM = Building Information Modelling) in 19 disciplines and with around 200 sub-models, which are merged into one overall model. Project-related quality management (PQM) ensures that the relevant standards and specifications are adhered to. In addition, this enables the systematic management and control of the relevant success factors and risks by the client, overall manager, planners and contractors. Each phase is subjected to a continuous risk analysis and seam analysis. The existing BIM execution plan regulates how model-based planning, collaborative execution and quality and schedule controlling are used integrally and ensures that no knowledge is lost between the individual construction phases. Thanks to planning according to the BIM method, all building data can be used for the future management of the building as part of the hospital's own facility management. The KSA is currently Implenia AG's largest project and is being realised on the construction site using the BIM2FIELD method without paper.

All possible adaptations are subject to the criteria of economic efficiency and functionality of future operations. The supporting structure of the new hospital with its uniform column grid, the centrally placed core zones as well as the ten systematically laid out riser zones of the building services result in a floor plan structure with maximum adaptability. This ensures that future structural modifications can be carried out efficiently and cost-effectively, with the least possible impact on operating costs.

Scheduling on the KSA is done with lean construction to ensure stable processes and a plannable and coordinated construction process. Forward-looking action along the process chain and collaborative teamwork also support this way of working.


User coordination, coordination of hospital construction incl. operating theatres, BIM planning (incl. BIM2FIELD), virtual reality


  • The project will be certified according to Minergie-P-Eco.

Further information

  • Civil engineer: WaltGalmarini AG, CH-8008 Zürich
  • Heating, Cooling, Air conditioning / Sanitary planner: Kalt & Halbeisen Ingenieurbüro AG, CH-8048 Zürich
  • Ventilation planner / Medical gases: Vadea AG, CH-8304 Wallisellen 
  • Electrical planner: IBG AG, CH-8409 Winterthur
  • Floor area (GF): 114713 m2
  • Number of nursing beds: 472
  • Number of places in day clinic: 130

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