Page 20 - Reinforced concrete voided slabs subjected to gravity and seismic actions

20Reinforced concrete voided slabs subjected to gravity and seismic actionsLightening techniques of the Roman vaults and the domes were further perfected with methodologies and practices that are almost identical to the Renaissance period, and even later, as will be demonstrated, in the early 19th century, at the dawn of the diffusion of modern reinforced concrete.Coinciding with the increase of spans of the vaults and domes, soon veritable lightening devices were devised that were a precursor to the modern idea of stationary formwork. This is essentially actual containers with lid (called olle) or terracotta amphorae (also called pignatte) that were inserted empty into the structure of the opus caementicium for the purpose of creating, in fact, lightening voids inside the wall fabric.This construction technique was fairly widespread and evidence of this is found in se- veral buildings, including one of the most famous, namely the mausoleum of Helena erected in Rome by the emperor Constantine I between 326 and 330 A.D. The olle now visible in the remains of the mausoleum have given rise to the name of Torpignattara (i.e. pignatte tower) by which the mausoleum is known.Figure 1.9. (a) Section of the dome of the Pantheon – Taken from Andrea Palladio, The four books of architecture, (1570). (b) Plan and section of the dome of San Vitale at Ravenna (525 - 547 A.D.) with suitable arrangement of “clay pipes” in the dome [image taken from (Di Pasquale, 1996)]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