Page 22 - Reinforced concrete voided slabs subjected to gravity and seismic actions

22Reinforced concrete voided slabs subjected to gravity and seismic actionsbegan to be studied, perhaps mindful of the ancient Roman lesson, but this time with the support of a now advanced knowledge of the static behaviour of reinforced concrete and slabs.On the other hand, the introduction of voided stationary formworks in the concrete ensu- red not only lightness and therefore fewer loads due to the self weight and the possibility of greater spans for the same service load but also, not least, a considerable saving of material.In a 1968 article published in the February issue of ACI Journal. Edgar H. Hendler wro- te: «This brief article will introduce to American engineers a relativevely new method of concrete flat plate construction using a cellular, or hollow design»1. The relatively new method that Hendler was referring to was the so-called Stahlbeton-Zellenplatte designed by the German engineer Leopold Müller of Heidelberg in 1967.He provides photographs of a typical floor with plastic filler blocks voids, before the casting phase and a plan and a typical section to describe this so-called alveolar slab system (cel- lular flat plate system). See theimages of 1.10 and figure 1.11.Hendler immediately highlights the advantages of this design compared to other systems that at the time were already fairly wide- spread, such as the so-called waf- fle slab, i.e. a slab with formwork intrados. These consist of the fact that the lower continuous slab enables taking full advantage of the benefits of the bi-dimensiona- lity: the floor does not behave like a grid of beams but is statically equivalent to a solid slab. Compared to a waffle slab then, continues Hendler, this new structural type can be used on spans that are almost double, with equal thickness of floor and accidental loads.1 «This short article presents American engineers with a relatively new method for construction of concrete slabs that uses a cellular or voided system».up © Dalifoform Group © Daliform Grouup © Daliform Group © Daliform Group © Dalifoform Group © Daliform Group © Daliform Group © Daliform Grouup © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Dalifoform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Grouup © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Dalifoform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Grouup © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Dalifo form Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Grou© Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Dalifo iform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Grouup © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Daliform Group © Dalifo form Group © Daliform Group © Daliform Group © Daliform Group © Daliform Grouup © Daliform Group © Daliform Group © Daliform Group © Dalifoform Group © Daliform Group © Daliform Grouup © Daliform Group © Dalif form Grou