Title: CO2 optimized flat plate slabs with spherical void formers

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Publication: CIA

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Date: 2/28/2011

Abstract:
Flat plate slabs are used in concrete construction when slender and beamless floors are required. When combined with columns and shear walls they provide a modern and economic way of concrete construction. However, flat slabs are limited in their range of application to smaller spans due to the fact that for larger spans their depth and thus dead load will significantly increase. This is mainly driven by the deflection criteria which governs the slab’s span/depth ratio. For these larger spans, flat plate slabs with integrated spherical void formers allow up to 35 percent lighter flat slabs compared to traditional solid flat plate slabs, but still providing the same load bearing capacity. This is achieved by placing roundly shaped void formers contained in positioning cages between the bottom and top reinforcement of the flat plate slab. The void formers are manufactured from recycled plastic. The slab will structurally still work as a flat plate slab and can therefore be designed in this way. The benefits of this technology are: Achievement of larger spans without beams, reduction of dead load and thus loads on vertical members and foundations, reduction in building materials, namely concrete and reinforcement steel. The reduction in concrete consumption allows to further optimize the CO2 generated by the production of cement.