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Administration building in Aachen
Understatement in precasting
Openness, forward-looking and communication, are all attributes property developers are looking for in architecture. The more common designs for constructions using steel and glass are being disfavored for lacking timelessness. The solution called for here is precasting.
The building concerned is the European headquarters for Emerson Climate Technologies, one the world’s leading companies in the field of air conditioning. With its language of architecture and shapes, the new domicile for the company shall promote corporate philosophy in a manner that is self-manifesting: forward-looking, open and communicative – inwards and well as outwards.
The otherwise so commonly found solution for such assignments realized in the form of a curtain wall for the steel panels was considered as lacking in timelessness. There was also the desire for a look of sustainability to be conveyed by the structure.
The answer here is more a hybrid construction of precast parts and site-placed concrete, execution of which shall be awarded the designation “innovative“. The building façade is made up of structural fair-faced concrete precast panels. For the office sectors these have been realized as a sandwich type construction. The panels include 16 cm of polystyrene insulation fitted at the factory. The construction of the unheated and thermally isolated emergency-exit stairwell has, for structural reasons, been realized using solid concrete units.
The side of the building facing the road is characterized by a framework of continuous stucco-type balcony. This imparts the impression of the floor slabs penetrating the façade at each storey and in actual fact this is intentional though, understandably for thermal reasons, has not been realized. It is more the case that the overhang elements are made from precast parts. These have been fastened to the structural components using Schöck Iso-cages. The cage construction itself has been elegantly concealed by a glass façade lying in the horizontal plane of this.
The floors of in-situ concrete have been placed on these structural façade units. Used here was the Sky Deck system from Peri as this makes quick stripping of the floor surfaces possible while retaining at the same time the supportive elements of a formwork construction underneath. The appearance of the fair-faced concrete created in this way fits in very well with the look given by the precast parts.
Apart from the floors and some of the round columns that could not be cost-effectively produced beforehand because of the high structural requirements, all of the other concrete parts have been produced at the precasting plant of the Aachen-based company of Nessler- Grünzig. Included here are elevator shaft, both utility shafts for the digital domestic engineering services, the cross wall bearing the company’s name and the stair elements. Whereas one major requirement to be observed with the stairs was to produce a surface as homogenous and free of pores as possible, a further demand on the horizontal structural beams was that these shall also contribute to the load-bearing structure of the stairwell. The structural beams were produced at the plant initially having a U-shaped cross-section and were installed as such in the building. L-shaped steel bars were then placed in the continuous recess to act as reinforcement. The recess was then completely filled with in-situ concrete. The metal now bonds the beam construction with the walling elements in a flexurally rigid manner. The placed concrete does however remain concealed because the lead-bearing beams have been subsequently covered using precast concrete tiles.
The building has been erected on the outskirts of a technology park on the city limits of Aachen at the gateway to the agricultural foothills of the Eifel. The stairwell in particular enables an impressive view of the gentle ascents in the distance and the greenness of the surrounding countryside. Besides by the fair-faced concrete, the design of the interior is characterized by the predominant simplicity for the building. Materials such as metal, glass and timber have been used with discretion in the background, and thus ample room is left for the more important aspects to be appreciated: Nature as the perspective and people in the office.
Robert Mehl, Aachen