Structural vulnerability of old precast building stock: case studies from the period 1940s-1970s

This work aims at evaluating the structural performance indexes of different typologies of reinforced concrete precast industrial buildings built in the 40-70s of last century. Precast industrial buildings belonging to the pioneer era of this technology are quite common all over Italy and were mostly devoted to house industrial activities. As a matter of fact, they were designed according to criteria which are now obsolete, mainly for lower static actions as compared to current codes and without any concept for seismic or fire resistance. As such, they potentially feature strong vulnerability. With reference to two industrial complexes located in Brianza (Northern Italy), both built with successive expansions from the ‘40s to the ‘70s, the structural performances of 10 different typologies representative of the Italian precast building stock of this period are evaluated under static, seismic and fire actions. These typologies include vault roofs with truss systems, restrained arches, tapered beams, and moment-resisting portal frames. A preliminary assessment of the vulnerability associated to these types of structures is performed based on their geometry and reinforcement details. Tentative ranges of cost associated to their retrofit are calculated based on the experience of past interventions gained by the technical partner of the paper