Disposable formwork for lightened one-way slabs in reinforced concrete cast on site.
U-Bahn Beton® is a modular framework in recycled polypropylene that was specifically designed to create one way slabs that are cast on site or semi-prefabricated.
The various modules, which overlap on the edges, make it possible to create beams of any length.
Thanks to its conic elevator feet, immersing the U-Bahn Beton® formworks in the concrete casting will obtain thick, parallel beams that are closed from the bottom and top by a flat plate made in sequence with a single casting; this results in reduced use of concrete and steel as well as considerable advantages in terms of fire risk in comparison to formworks in expanded polystyrene.
Light and stackable, it is easy to handle during positioning, functional in its use, can be exposed to bad weather and is easy to store in the yard with minimum dimensions.
Designed according to strict quality criteria, the U-Bahn Beton® framework is guaranteed to resist without concrete 150 kg concentrated on a load imprint of 8 x 8 cm, as foreseen by current regulations.
Unlike with the use of classical hollow brick blocks, the empty space left by U-Bahn Beton® can be used for the passage of cables and systems.
U-Bahn Beton® o alleggerimento in polistirene?
Even if polystyrene is widely used in the construction industry due to its low cost and workability, it has many disadvantages that are being addressed by the technical-scientific community.
With reference to lightened slabs, the Italian Ministerial Decree of 16.02.2007 to enclosure D.5.1 establishes that: “In the case of polystyrene formworks, or formworks in similar materials, there must be appropriate vents for the overpressures”. Even prior to this, the UNI 9502 standard – article 7.2.2 – established that: “In the case of elements incorporating materials that when subject to high temperatures turn to gas, there must be appropriate vents facing the side exposed to fire to ensure that the bearing capacity is not compromised by explosions”.
Therefore, using polystyrene slabs cast on site requires the extra expense of fitting vents in the cavity to counteract the excessive pressure of gas that is sublimated by the formwork. However, in the event of a fire there would still be the problem of toxic gas escaping into the environment (styrene).
As U-Bahn Beton® is made of polypropylene, it is not toxic even if burnt. Moreover, the slab will not explode due to the escaping of over pressurised gas from the feet (4 every 20 cm of the formwork) that act as safety valves.
Other advantages of U-Bahn Beton® compared to EPS are the dimensions, handling (just think of transferring it overhead on the slabs being built) and outdoor storage. Polystyrene is, in fact, bulky and cannot be stacked; it is particularly fragile on its edges and corners that crumble leaving those annoying balls that, statically charged, stick to everything (especially to the reinforcements) and are very hard to get rid of.