Performance-Based Urban Planning: Framework and L'Aquila Historic City Center Case Study

A performance-based methodology for urban seismic risk evaluation is presented. It stems from the performance-based framework used in seismic design of structures. Different performance, or acceptable damage, levels are introduced for increasing earthquake intensities. The number and definition of urban performance levels is not unique. Due to the inherent seismic vulnerability of historical centers, it is advisable to start from very basic performance requirements. One performance level, the Minimum Urban STructure, shows the concept of the minimum amount of elements that must remain functional in the aftermath of a major earthquake in order to keep the town open. The proposed methodology is applied to a subarea of the L’Aquila historical center severely damaged by the 2009 earthquake. The application considers buildings, roads and open spaces only, but the example illustrates how the overall methodology works and points to possible applications of seismic risk assessment.