Cobiax precast panels offer a huge range of advantages in construction projects where large spans, without beams and with a reduced number and size of vertical bearing elements, are the preferred solution. Cobiax technology was developed in Switzerland, and Hanson designs and manufactures the precast concrete product under licence in the UK at our factory in Washington Tyne and Wear.
Slab thicknesses range from 240mm up to more than 600mm depending on application.
Cobiax has been designed to remove the non-working, dead load in concrete slabs whilst maintaining biaxial strength. This is achieved by placing hollow plastic spheres between the upper and lower static reinforcement of the concrete slab, displacing concrete where it has no structural benefit. The effect is to decrease the overall weight by up to 35% when compared to a solid slab of the same bearing capacity.
The reduced weight allows the quantity and dimensions of vertical bearing elements, such as columns, to be reduced. Reduced dead weight means a smaller deflection of the slab, and also provides scope for savings in foundation design, including fewer piles and/or reduced length of piles.
While the design reduces overall weight, the Cobiax slabs offer very high load carrying capacity and flexibility. However, in contrast to more conventional hollowcore slabs which have load transfer in only one direction, the Cobiax slabs allow load transfer in any direction.
Because the Cobiax flat slab does not require beams, flat unobstructed soffits are produced and the costs of installing services in a building are also substantially reduced.
With up to 40% less columns supporting the slabs, Cobiax offers great design flexibility to architects. It also enhances the potential to easily change the use of a building in either the horizontal or vertical direction.
From the developer's and contractor's viewpoint the technology offers other benefits including direct and indirect cost savings in building materials (reduced volume, lower transport costs and easier, more cost-effective, lifting). Cobiax also means improved build-speed through reduced bracing and formwork (no beams) and because there is less concrete volume to place on site.
Hanson is already the UK's leading supplier of precast Omnia wide slab panels, and the Omnia panel, with its integrated lattice girder panel, forms the basis of the Cobiax system. Rebar cages containing the plastic spheres, manufactured from recycled polyethylene, are also cast into the panel and the system is completed with upper reinforcement and in-situ concrete.