Luxury hotel with complex constraints

Optimised structural design gives terraced hotel solid foundation

Not only architecturally and structurally, but also structurally, Mövenpick Brussels Airport is a special realisation. COBE engineers were appointed to guarantee the stability of the open shell construction. A challenging job given the specific character of the new hotel complex.

Text Tim Janssens |    Image AB-Eiffage

Philippe Alders, project engineer at COBE engineers: "First of all, we went looking for the best structure for the superstructure in relation to the substructure, with an eye for the budgetary picture and the architectural design. We also helped to think about how the building pit could be constructed safely, since the intention was to provide three underground levels - quite a challenge in terms of structural design. We then elaborated 3D formwork plans in Revit Structure, including the drafting of the specifications and the measurement statement that served as the basis for appointing the contractor. Afterwards, we also drew up all reinforcement plans, and finally proceeded with the site follow-up. So we were closely involved both in the preliminary stage and during execution."

Design adjustments

The building's supporting structure was further optimised at the suggestion of COBE engineers. "The structure of the superstructure had to be redone on the ground floor on the one hand and above the basement on the other. Since the loads became so great because of the height of the building, we ensured that the structure continues as much as possible from the basement upwards, so that as few re-takes as possible were necessary. This was to save costs and avoid having to place unnecessary columns in open spaces," Philippe Alders explains. "The required design adjustments were done in close cooperation with the architect and the developer. The fact that we had already realised many other hotels with Fjord RED in the past certainly helped (including in providing the necessary recesses and technical shafts). With Buro Architectuur we had not worked together before, but that also went fine."

Lots of calculation and thinking

The heavy concrete façade finish also made Mövenpick Brussels Airport anything but ordinary. "It was not fitted until after the load-bearing structure was completed in order to minimise the risk of damage during construction work and to ensure perfect alignment between the façade elements. In consultation with precast concrete supplier Enjoy Concrete and structural contractor AB-Eiffage, we provided everything to make this possible. A lot of calculation and thinking went into this, just like into the realisation of the roof level. The fact that we absolutely could not exceed the imposed maximum height involved the necessary detailing in terms of accessibility, roof upstands and so on. All this made Mövenpick Brussels Airport a challenging project that we look back on with great satisfaction", Philippe Alders concludes.    

Orona - Lifts

Mövenpick Brussels Airport is a special hotel. Not only because of the fine appearance of the tall building, but certainly also because of its atypical layout. Since the reception and restaurant will not be on the ground floor, but on the panoramic upper floor, vertical circulation is a crucial concern. "It is quite a challenge to optimise the busy passenger and goods traffic between the lower levels and the eighth floor, both for hotel guests and external restaurant visitors," says Robbe Driessens, sales engineer at Orona. "Besides a service lift accessible only to staff, four lifts in Quadruplex design were opted for. This implies that their operation is coordinated with each other via a smart control system, which takes into account the proximity of the different lifts and the number of people already in the lift car. The finish is in line with the luxurious nature of the hotel. It had to be something special that would match the style wall with vertical wooden slats on the ground floor. Consequently, both the recessed lift doors and the inside of the lift car and control panel are finished in bronzo pallinato, a stainless steel variant with a matt bronze look. It was great to be able to carry out such a high-quality project for a client we often work with. Two more lifts will be installed in phase 3, so we are already looking forward to that!"

CS Window constructions - Aluminium exterior joinery and curtain walling

Together with precast concrete, glass is the common thread in the façade design of Mövenpick Brussels Airport. CS Raamconstructies was responsible for installing the aluminium exterior joinery and curtain walls. "A varied and challenging assignment," says project manager Tom Willemsen. "The ground floor involved standard curtain wall profiles, from floor 1 to 7 fixed windows and on the eighth floor curtain walls with vertical structural joints, accounting for 1700 m² of external joinery in total. The windows of the hotel rooms are fitted with heavy acoustic glass and acoustically finished all around to avoid noise pollution. The curtain walls on the panoramic upper floor hang outside the plane of the supporting structure and were installed - from inside and using small aerial platforms and the tower crane - before the underlying facades were clad with precast concrete panels. Moreover, to prevent overheating of the glass and thermal breakage, those curtain walls have an atypical composition: toughened glass on the inside and laminated glass on the outside. Because the client and architect wanted glued joints instead of vertical cover battens, we had to clamp the glass sections along the outside so that there would only be a cover battens at the bottom and top. Finally, part of the façade was fitted with a 5-metre-wide strip of green glass over almost the entire height, which was no sinecure in terms of thermal expansion and fire safety, among other things. During the study phase, attention was paid to the design so that the construction could fit into phase 3. So there were some peculiarities involved. Fortunately, the rapport with AB-Eiffage was excellent, especially since we were able to work with the same project manager as for the Nike site in Ham. A happy reunion that benefited the end result!"

Enjoy Concrete - Facade panels 

The concrete cladding at Mövenpick Brussels Airport is an eye-catcher in itself. Not only because of the subtle contrast provided by the combination of two different finishes (smooth and micro-washed) and shades (creamy white and beige), but mainly because of the integrated geometric patterns that symbolise flared curtains. "On the longitudinal facades, these 'gable curtains' are 1.4 metres high - just like the windows they flank - and fan out to the left or right depending on their specific position. On the end facades, they are two vertical strips 3.2 metres wide that continue over the full height of the building," says Maarten Durnez of precast concrete supplier Enjoy Concrete. "We manufactured the façade panels based on a parametric design, which we received digitally via the architect. This took a lot of work, as we immediately established that the curtain structures were not formworkable in their initial form. Fortunately, via our own 3D modelling and 3D-printed models, we came up with a valid alternative that met everyone's wishes and requirements. We then produced the full-size façade panels using special moulds in milled EPS, according to a sophisticated three-step plan. During our intensive search for the optimal solution, we had considered two other options - textile formwork and formwork with 3D printed concrete moulds - but judging by the highly successful end result, we can say that we made the right choice. In the meantime, we are saving the moulds for when phase 3 goes into execution."