Tower C1 in the “Les Vergers” ­eco-neighbourhood

One storey higher every 12 days with MevaDec and Mammut 350

Data & Facts

  • Project
    • 17-storey high-rise building including a health centre and 82 flats in the “Les Vergers” environmentally friendly neighbourhood in Meyrin, Geneva
  • Architects
    • Group8
  • Principal
    • Coopérative Immobilière Le Niton
  • Contractor
    • Marti Construction SA
  • MEVA systems
  • Engineering and support
    • MEVA Formwork Systems, Seon, Switzerland


Mammut 350 for shafts

In Meyrin, a municipality located on the periphery of Geneva on the border to France, a new environmentally friendly neighbourhood known as “Les Vergers” (The Orchard) is being developed to house 3,000 new residents. 30 residential complexes with 1,350 flats, along with schools, day nurseries and parking spaces and bike racks are under construction. All buildings are being built to the Minergie A standard.

Tower C1 is a 17-storey high-rise residential building with a health centre and 82 flats with a total area of 9,960 m² from the third floor upwards. More than 450 precast concrete components are being used for the façades, balcony parapets, stairways, and the roof. 8,000 cubic metres of in-situ concrete are being used to pour the slabs, walls and shafts, as well as 800 m² of MevaDec formwork for the slabs and 350 m² of Mammut 350 large-area formwork for the shafts.

Asymmetrical floor plan
The building has an obtuse angle in the middle of both long sides. The two end faces also have an obtuse angle as well as a wall offset. A total of 12 corners give the building a dynamic appearance; however, pouring the slabs demands a formwork system that permits speedy work without complicated compensation for any assymetry in the floor plans. That is where ­MevaDec can prove particularly useful.

MevaDec: advantage 1
Arbitrary grid pattern minimises need for compensations

In addition to the asymmetrical floor plan, there are also stairways and lift shafts of various sizes inside the building, meaning that the slab formwork is often interrupted. The arbitrary grid pattern allowed by MevaDec is a huge advantage here. The orientation of the main beams can be changed as desired and the panels can be placed longitudinally or transversely in the beams and moved as required – and can even project beyond the beam or drop head. This flexibility allows the slab to be poured using standard formwork to the greatest extent possible, while the number of filler areas can be ­minimised, even when there are numerous interruptions and angles. This saves considerable time and effort.

MevaDec: advantage 2
Craneless construction work

The props are installed by hand and the lightweight aluminium beams and panels are inserted from the ground, or using a lifting platform or similar equipment for high slabs. This saves expensive crane time and interruptions to work while waiting for the crane.

MevaDec: advantage 3
Early stripping

The MevaDec system allows various working methods. Panels, beams and props with drop heads are used on this construction site, making early stripping possible. When the poured slab has set to the point where it can no longer deform, the drop head is actuated using a hammer. The drop head, the beams and the panels lower by 19 cm. The beams and panels are now removed by hand and used in the next cycle. A number of props remain in place to provide continued support. Early stripping saves time and up to 40% of materials. Arbitrary grid pattern, crane-free working, and early stripping: with  work is being carried out on a number of slabs, sometimes at the same time and other times in succession, these combined advantages offer maximumflexibility, reduced workloads, and time savings.

Mammut 350 for shafts
The Mammut 350 wall formwork can bring its strengths to bear in different-sized shafts, thus saving time and effort. In partly polygonal shafts, the wide range of panels and the ability to combine them freely mean the number of job-dependent compensations can be kept to a minimum. The high fresh-concrete pressure load of 100 kN/ m² allows concrete to be poured up to a height of 4 metres without restricting the rate of placing, allowing the shafts of one storey to be poured in one go. The stripping corners on the inside formwork of the shafts make stripping easier and they can also be extended in height. The entire shaft formwork can be moved by crane in one lift, even when extended – without time-consuming disassembly and reassembly work.

The work on the building shell is proceeding rapidly and will be completed in December 2017.