Efficient construction of two sedimentation tanks in Chambéry

Chambéry (Savoy, France)

The municipal sewage treatment plant in the old ducal city in the French Alps will be expanded. The contract was awarded to Eiffage TP Rhone Alpes branch (Lyon). Initial construction work started in 2010; it is envisaged that the plant will start operation in the course of 2013.

Building Technology

Beneath the buildings to be constructed will also be the sedimentation tanks with a 9.96 metres internal diameter and a height of over 13 metres.
It was decided to use the TTS, a completely smooth steel circular formwork, which constructs the fair faced concrete surfaces in series. Four segments of 3.00 metres height each and an extension element of a height of 1.50 metres were used, meaning that in total a formwork height of 13.50 metres was achieved. The class S3 concrete was inserted with the concrete pump.
The multifunctional Multip working platform, which was already installed to the formwork during the assembly of the circular formwork, was used, in accordance with the French safety regulations.

All work was completed within the set schedule with great success and very smoothly.

TTS – the adjustable radii Trapezoidal Girder circular formwork with the steel formwork face

The adjustable radii Trapezoidal Girder circular formwork (TTS) was specifically used by the awarding authority for the construction of biogas plants.
The TTS has a 5 mm thick steel facing. The formwork is thereby solid, absolutely round and accurate to size and will maintain its exact radius even after being reused several times. The circumference can be formed to the centimetre and without any job-built fillers. The square metre forming surface will take up to 80 kN of concrete pressure. It’s exactly these advantages that are used in mainly sophisticated technical buildings but also in high-quality architecture and that were used to form these circular tanks. Due to the fast relocating processes, the particularly small number of openings for ties, the stability and/or stiffness of the formwork, all work progressed smoothly, securely and within the shortest time possible and therefore in the best possible way and efficiently. The low number of openings for ties also increased the quality of the concrete surface.

Overview: Chambéry, the ancient city in the Rhône Alps will expand its sewage plant to be completed by 2013. TTS steel circular formwork was used for the round tanks.

Multip – die multifunctional work platform

The multifunctional working platform Multip is a foldable working platform system, which is fixed to the formwork elements to achieve a high degree of safety at work. Once assembled, the side guards can be expanded. The board can then be spread easily. Element and scaffold are therefore transported as one unit per crane cycle to the next concreting section. The setting and removal of connection pieces, the assembly or removal of the crane lifting clamp or the removal of ties can be carried out quickly and safely. The ladders are an integrated part of this turnkey system that enable one to safely reach the individual working places at differing heights. All system parts are made of steel, warranting a long life.

• The continuous assembly of individual platform brackets, coverings and side guards will not be necessary
• After unfolding it provides immediate construction site safety, no delays or improvisations due to assemblies to be carried out
• Saves time due to folding mechanism
• Remains assembled during relocating, there are no loose parts that could fall off
• All regulations of the German Federal Building Code [BauBG (BGR 187)] are fulfilled
• All accessory parts like ties and openings for ties can be serviced much more quickly from a secure working place
• Considerably longer life than the usual wooden coverings
• Purchase or cutting of wood for coverings and side guards are not necessary