# Risk and Resilience Assessment of Lisbon's School Buildings Based on Seismic Scenarios
## 6 Resilience Assessment  
### Current Situation  
In addition to calculating the estimated losses, recovery times of each school due to seismic damage were also computed, which enables the assessment of their post-earthquake functionality. In particular, it allows for the estimation of which schools would be closed after an earthquake and, consequently, the need to relocate students for a significant period of time after the earthquake.  
This section presents the results in terms of the estimated number of days each school would be closed due to seismic damage, either annually or over a 50-year period, as well as the corresponding resilience indicator \"relocated students x month\" (SMD). From the sum of the product of the annual probabilities of exceeding each limit state by the corresponding interdiction days, the Annual Expected Interdiction days (AEI) for each school is obtained. The calculation of the interdiction days over 50 years (TEI) is done similarly to the calculation of expected losses over a similar time frame. These values are shown in Figure 13. To facilitate the reading of the results, Figure 14 presents the number of interdiction days in 50 years, in decreasing order.  
Figures 13 and 14 show that four schools are expected to register a number of interdiction days in 50 years above 3 months, while three other schools will be closed for more than 2 months in 50 years. Regarding the SMD indicator, three schools have a value greater than 2400. The values presented here can serve as a basis for developing a response plan for seismic events at the municipal level.  
Figure 13: Expected number of interdiction days and “relocated students x month” indicator (SMD).  
A post-earthquake resilience assessment is performed by calculating the recovery times associated with each school given the occurrence of seven different seismic scenarios. For each scenario, the performance level achieved by each main building allows for the computation of the number of interdiction days and, consequently, the recovery time. Consequently, it is possible to determine the number of schools closed as a function of the time after the earthquake.  
Figure 15 shows the resilience curves of the schools analyzed for seven different seismic scenarios, as well as the median curve (weighted by the probability of each seismic scenario) and median minus one standard deviation. These curves relate the number of operational schools as a function of time after the seismic event. For instance, for Scenario 1, the lowest intensity of the seven scenarios considered, only 7% of the analyzed schools are expected to be closed the day after the earthquake (for inspection, planning and execution of the cleaning, rehabilitation, or reinforcement intervention). The remaining schools did not exceed the first limit state (completely operational); therefore, no inspection is required and they may continue to function immediately after the earthquake. On the other hand, for Scenarios 6 and 7, the most intense that are considered, all 28 schools will be closed for at least 1 day. However, after 240 days, only about 25% of the schools will remain closed. Over time, schools will be incrementally reopened, by meeting the proper conditions or due to rehabilitation actions, until all schools are operational again, which is anticipated to take place in a maximum period of two years (730 days).  
Figure 14: School ranking according to the number of interdiction days over 50 years.  
Figure 15: Resilience curves of the school buildings portfolio (28 schools) for seven seismic scenarios.  
This data may assist in the development of individual emergency plans and of an integrated emergency response plan that addresses the need to relocate students after an earthquake event. The analysis of the remaining CML schools (under development), as well as complementary systems, namely accessibility, will provide additional data for future analyses of the resilience of the CML school network.