The urban vulnerability assessment computed as the sum of the structural vulnerability of the individual elements is not sufficient to represent the response of a city during an earthquake. The expected damages on the components of the built environment and the overall response of a settlement should be evaluated considering the changes that the earthquake brings to relationships between the elements of the urban environment and the overall functioning of the city, considering structural, economical, societal issues. A method is proposed that assesses the city performance with respect to increasing levels of seismic intensity. Different performance levels are defined and are compared to corresponding expected earthquakes. The method serves on the one hand to access the actual overall performance of a town, on the other it helps guide limited financial resources to optimize investments that can maximize the performance enhancement. The proposed method borrows from the PBEE (Performace Based Earthquake Engineering) concept used to develop modern seismic design codes and translates it to the much more complex problem of the seismic vulnerability of cities. The proposed methodology is applied and verified to a portion of the historic city center of L’Aquila, severely hit by the April 6, 2009 Abruzzo earthquake (Mw=6.3). The outcomes of this applications are fragility curves of the urban subsystem corresponding to four performance objectives, and show the expected levels of damage to be expected (partly a posteriori verified) for increasing earthquake magnitudes. The results also point to optimal ways to increase the city center safety.
Performace Based Earthquake Urban Planning: definition and assessment of urban performance levels for mitigation of seismic risk
SPACONE, ENRICO;FABIETTI, Valter
2014-01-01
Abstract
The urban vulnerability assessment computed as the sum of the structural vulnerability of the individual elements is not sufficient to represent the response of a city during an earthquake. The expected damages on the components of the built environment and the overall response of a settlement should be evaluated considering the changes that the earthquake brings to relationships between the elements of the urban environment and the overall functioning of the city, considering structural, economical, societal issues. A method is proposed that assesses the city performance with respect to increasing levels of seismic intensity. Different performance levels are defined and are compared to corresponding expected earthquakes. The method serves on the one hand to access the actual overall performance of a town, on the other it helps guide limited financial resources to optimize investments that can maximize the performance enhancement. The proposed method borrows from the PBEE (Performace Based Earthquake Engineering) concept used to develop modern seismic design codes and translates it to the much more complex problem of the seismic vulnerability of cities. The proposed methodology is applied and verified to a portion of the historic city center of L’Aquila, severely hit by the April 6, 2009 Abruzzo earthquake (Mw=6.3). The outcomes of this applications are fragility curves of the urban subsystem corresponding to four performance objectives, and show the expected levels of damage to be expected (partly a posteriori verified) for increasing earthquake magnitudes. The results also point to optimal ways to increase the city center safety.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
