Design of a base isolated timber building in the historical center of a high seismic hazard area of Italy

This paper deals with the design of an innovative school building under construction in the historical center of Ariano Irpino (Italy). The building has been designed to be integrated into the historical Town, with very peculiar and innovative structural aspects. The very characteristic heritage location, with small access roads and typical historical buildings, and the site topography, at the top of the hill characterized by sloping sides and high retaining structures, with high seismic hazard, strongly influenced the structural and architectonical solution. In order to deal with the site complexity, and realize a sustainable building, the designers developed an innovative solution: the substructure is a reinforced concrete (r.c.) volume on three sides underground, the superstructure is composed by a couple of timber buildings. Between the base and the timber buildings a base isolation system is placed (which results above the third floor of the complex). The use of cast onsite concrete offer an optimal solution for the basement, with the multiple function of soil retaining system, foundation and location for several fundamental functions (gym, conference hall and restaurants), whereas the use of timber frames and Cross-Laminated Timber (CLT) elements, for the buildings in elevations, allows to obtain a low energy consumption and eco-sustainability, not requiring big construction machines, notwithstanding the use of prefabrication. In this paper the architectural and structural solutions are presented discussing functionality, safety and sustainability issues.