In-plane capacity of existing post-WWII beam-and-clay block floor systems

Abstract A growing attention has been paid to the deep renovation of RC buildings, particularly focusing on their structural vulnerability and development retrofit strategies; however, issue in-plane diaphragm action capacity existing floors rarely addressed. Although floor does not seem critical for seismic structures, commonly affected by greater vulnerabilities, it may become when an additional lateral force resisting system is introduced. This paper investigates beam hollow-clay-block system, typical European post-WWII buildings. Considering as associated with tied-arch mechanism developing within thickness, main failure mechanisms are discussed, some simplified equations provided preliminary estimate maximum floors. Experimental numerical analyses than carried out validate analytical model. The relevant influence possible staircase openings load paths flexibility also considered. Finally, assessment in conceptual design a intervention discussed. study shows that only beam-and-block systems have reliable capacity, while other typologies cannot serve diaphragms. When can be relied upon, diaphragms often exhibit fairly stiff behaviour up brittle failure, which ultimate at supports.