White architectural concrete walls in heights of up to 32 m, cast at the construction site, designed with formliners and executed in architectural concrete quality 4 – that is, in summary, the challenges that the staff of ARGE ZSC Arena are currently facing. They were awarded the contract by the total services company HRS with the construction of the new ice-hockey stadium for the ZSC/GCK Lions organization. In order to be able to carry out this task in high quality, the decision-makers decided to use formliners from the company NOE-Schaltechnik.
The ZSC/GCK Lions organization, with more than 70 teams and 1,400 players is, according to its own statement, one of the largest ice-hockey organizations in Europe and will now have its own arena in Zurich-Altstetten. It will comprise two ice rinks and one car park on the roof, on which a spectators’ terrace will be installed. The main arena is designed for approx. 12,000 fans. The parties involved in the construction like to refer to it as “the witches’ cauldron,” referring both to the expected atmosphere and the height of the building with its steeply inclined spectators’ seating arrangement. An additional ice rink is installed as training hall and playing field for juniors and other leagues and offers room for up to 300 guests. The joint venture ARGE ZSC Arena (Marti AG Zürich, Barizzi AG Bertschikon) was awarded the contract for construction of the building ensemble.
Curtain made of concrete
The ARGE’s challenges include erection of the complex architectural concrete façade, which is a special highlight of the building complex. Whereas the longitudinal sides are designed in the form of concave waves, the shape of the north and the south façade calls to mind a curtain, including glass portholes with a diameter of approx. 2 m that gives the object a festive appearance.
The surface texture of the concrete façades is created by formliners from the company NOE-Schaltechnik.
Formliners glued onto supporting boards
The company has been marketing this product for many years under the name of NOEplast and offers both a broad spectrum of standard structures as well as the possibility to realize desired personal motifs. For manufacture of individual formliners, NOE-Schaltechnik requires detailed information on how the finished relief should appear. In the case of the Zurich arena, this took place on the basis of 3D vector data. Based on these data, the NOE team manufactured the model in advance with a CNC-controlled, 5-axis milling machine. The final formliner was then cast in several intermediate steps that involved a great deal of manual work.
Unlike formliners used in precast plants, here – as they are used onsite – they must be fixed to the formwork to prevent them from slipping during casting. In this process, the formliners are glued over their entire surface onto a supporting board. NOE Service, by gluing the formliners onto supporting boards at the production site, guarantees temperature-resistant and weather-protected production and is readily accepted by building contractors. At the construction site, it is then only necessary to screw the glued-on formliners onto the reverse side of the formwork, and they are ready for use (up to 100 uses possible).
NOEplast reusable up to 100 times
The requirements placed on the architectural concrete façades of the ice-sports arena are very high and all participants in the project place the greatest importance on a perfect result. The more than 200 casting sections (cycles/steps) should be executed as smoothly as possible, as well as without visible transitions of formliners and joints between the casting sections. For this reason, it is the aim of site management to cast large continuous areas in one step. The largest casting sections are 21.70 m long and 11.59 m high. For this result, more than 50 formliners of different shapes and sizes of up to 1.76 x 3.42 m and a weight of 590 kg are used. To prevent visible formliner transitions to the greatest extent possible, any abutting ends occurring between formliners are padded with prefabricated filler formliners over widths of 5 mm and 7 mm and are closed with NOEplast filler material. Prior to casting, a release agent must be applied to the formwork and/or formliners to enable subsequent demolding. ARGE Baumeister had tested release agents of various manufacturers ahead of the required time. It was found that the best results can be achieved with NOE formwork wax, and it was decided to use this product. “Demolding at the right time is important,” says Marcel Lappert, Project Manager of ARGE ZSC Arena. “In the beginning we had some problems with this since, when a concrete has largely hardened, a vacuum is created. We prevent this by loosening the formwork after only one day. For separating the concrete from the formliner we use special pads that we attach between concrete and formliner and fill them slowly with air.” A great advantage of NOEplast textured formliners is that they can be reused up to 100 times. We are also taking advantage of this benefit for the ZSC-Lions project. Owing to the special façade geometry, some of the formliners will probably be used up to 30 times.
By now, NOE has produced around 45 models, and more than 200 formliners have been delivered on a total of around 40 trucks to the Zurich construction site. This is the largest individual contract for formliners that NOE has received and executed so far. It is a totally new experience also for the executing company ARGE Baumeister.
With regard to this, Marcel Lappert says: “To prepare for this task we had looked for similar projects. We wanted to know in advance the difficulties we would be facing and how to solve them. But we found no comparable project worldwide. That is why we are really proud that we are making such good progress with the work and that everybody at the construction site works with such commitment to achieve the required high quality.” The opening of the Swiss Life Arena is planned for August 2022. It will become a significant magnet for sports fans, event enthusiasts and lovers of architecture.