PRESENTAZIONE

L'impatto dei rischi naturali sull'ambiente costruito non si limita ai danni diretti ma comporta danni indiretti, legati alle interruzioni delle attività produttive e sociali. Le moderne analisi di rischio devono considerare questi aspetti e valutare la resilienza della comunità, ovvero: 1) capacità di limitare i danni prodotti dall'evento (robustezza delle costruzioni); 2) gestire al meglio le fasi dell'emergenza; 3) reagire prontamente, favorendo un rapido ritorno alla normalità (limitare il "down time"). 

Dopo un inquadramento del problema nei riguardi dei diversi rischi naturali (sisma, alluvioni, incendi, ecc.), il corso si concentrerà operativamente sulla resilienza sismica.

OBIETTIVI E CONTENUTI

OBIETTIVI FORMATIVI

Analisi del rischio sismico dell'ambiente costruito in relazione agli eventi naturali: pericolosità, esposizione e vulnerabilità. Valutazione probabilistica della pericolosità sismica: occorrenza dei terremoti, normative di mitigazione. Tassonomia e classificazione dei beni esposti. Modelli di vulnerabilità: osservazionali (metodo macrosismico), meccanici (analitici o numerici) e ibridi. Valutazione delle curve di fragilità da analisi dinamiche non lineari (IDA, MSA e cloud method). Framework probabilistico per il calcolo del rischio. Analisi delle conseguenze e delle perdite economiche (danni diretti e indiretti). La resilienza dell'ambiente costruito e della società: robustezza e tempi di recupero. Valutazione del rischio, prevenzione e gestione dell'emergenza sismica nel caso di edifici monumentali: modelli LV1, schede di rilevamento della vulnerabilità e del danno.

OBIETTIVI FORMATIVI (DETTAGLIO) E RISULTATI DI APPRENDIMENTO

Il corso sarà svolto con un forte coinvolgimento degli allievi. 
Nelle lezioni frontali, essendo la materia in continua evoluzione, saranno visitati i siti delle principali istituzioni mondiali (ad esempio UNESCO) che hanno elaborato manifesti programmatici sulla resilienza (Sendai Framework for Disaster Risk Reduction).
Inoltre sarà svolta una esercitazione attraverso la piattaforma IRMA (Italian Risk Maps), sviluppata da EUCENTRE per la Protezione Civile, nell'ambito della quale gli allievi potranno eseguire una analisi di rischio su diversi ambiti territoriali (comuni, province, regioni): 1) implementare le curve di fragilità delle diverse tipologie di edifici; 2) stimare i danni attesi agli edifici (numero di crolli e di edifici inagibili), le conseguenze alla popolazione (morti e feriti gravi, senzatetto) ed i costi necessari alla ricostruzione; 3) confrontare diverse strategie di intervent di prevenzione, attraverso analisi costi-benefici.   

MODALITA' DIDATTICHE

Le lezioni si svolgeranno in presenza, con l'utilizzo di slide e l'utilizzo diretto di piattaforme web. Alcune attività di laboratorio si svolgeranno nell'aula INFAL2 (area Villa Cambiaso), utilizzando una piattaforma web-gis per l'analisi del rischio sismico.

Gli studenti che abbiano in corso di validità certificazione di disabilità fisica o di apprendimento in archivio presso l'Università e che desiderino discutere eventuali sistemazioni o altre circostanze relative a lezioni, corsi ed esami, dovranno parlare sia con il docente che con il Prof. Federico Scarpa (federico.scarpa@unige.it), referente per la disabilità della Scuola Politecnica.

PROGRAMMA/CONTENUTO

Topic 1 – Resilience and built environment

• The natural disasters on the rise around the globe and the role of developing countries particularly vulnerable to natural disasters
• Definition of key terms for disaster risk assessment and introduction to resilience concept with its interdisciplinary applications
• Hyogo framework, Sendai framework and sustainable development goals
• Quantifying the concept of resilience and the dimensions of the resilience (Bruneau et al. 2003)

Topic 2 – Resilience and its components

• The three phases of resilience: 1) pre-event (Mitigation efforts and Preparedness – education, emergency management planning); 2) response (Emergency state); 3) post-event (Recovery)
  1. Pre-event mitigation efforts and preparedness (education, emergency response planning, exercise, …)

§  Risk assessment and review of the emergency management plan promoted by Institution (Department of Civil Protection), in the case of earthquake for example: IOPACLE e SMAV

§  Risk mitigation solution: insurance, incentives, …

§  Strengthening interventions which favor the localization of the damage and repairability in the case of earthquake

1. Response to the event: Emergency management

§  Definition of provisional works

§  Post-event damage survey aimed to the administration of state funding and project control

3.     Post-event: Recovery

• Post-disaster temporary dwelling (in Italy and in the case of earthquake: CASE Project and MAP - Moduli Abitativi Provvisori), hotel accommodation and alternative contributions
• Historical centre: the role of the aggregate and the whole project

Topic 3 – Resilience: A risk management approach

• Risk is a combination of three components:
  1. Hazard: Intensity measure (MMI, PGA etc.) at a given coordinate for a given earthquake (magnitude, location), for example
  2. Exposure: Locations, characteristics and value/count/area of the assets (population and buildings)

3.     Vulnerability: Damage and losses conditional on a given level of intensity for assets with certain characteristics

·       From damage to losses: direct and indirect losses

·       Probabilistic risk assessment independent of the peril considered, only the details are different

• Parallelism between earthquake and flood
• Aleatory Uncertainty (hazard, vulnerability, network, and financial computations) and Epistemic Uncertainty (multiple models) – Sensitivity analyses
• The different scale of analysis as elements:
  • Single building damage and loss assessment for risk mitigation and insurances purposes;
  • Portfolio of buildings damage and loss assessment for risk mitigation and insurance purposes;
  • Utility systems (potable water, waste-water, gas system, telecommunication, electric power) and transportation infrastructures (port, airport, road and railway system)
• The different scale of analysis as scope: social, economic, political
• Multi-hazard analysis

Topic 4 – Hazard (occurence and intensity)

• What Are the Events Considered? Natural and man-made Events
• Earthquake:
  1. Physical phenomenon, faults types, wave propagation, amplified ground shaking, …
  2. The measure of the earthquake: Magnitude, macroseismic intensity, instrumental intensity, …
  3. Earthquake Catalog Data (Instrumental and Historical) and the geophysical evidence
  4. Response spectrum, Ground motion prediction equations (GMPEs)
  5. Probabilistic seismic hazard analysis – hazard curve
  6. The secondary effects
• Other hazards

Topic 5 – Exposure information

• Single building VS Portfolio of buildings
• Portfolio of assets:
  1. Population, Buildings (residential, commercial, public), Infrastructure (bridges, dams, ports, etc.), …
  2. Building inventory: for example, through the ISTAT 2001 census, the database extracted from the CARTIS Form, more detailed databases at the Municipal Scale, on-site survey; use of satellite data
  3. The classification of the exposure through the introduction of suitable taxonomy that allow to group structure with a homogeneous seismic behavior à What are the Main Characteristics of a Construction Class?
  4. Building replacement value

Topic 6 – Vulnerability to the earthquake I: the post-earthquake damage survey

• Survey form to evaluate post-earthquake damage and vulnerability at national and international level for residential buildings:
  1. AEDES survey form (Baggio et al. 2007)
  2. ATC 20 Building Safety Evaluation Forms and Placards (Rapid and Detailed evaluation)
  3. Building Safety Evaluation During a State of Emergency, prepared by the New Zealand Society for Earthquake Engineering
  4. Monumental assets (church): Italian damage Survey Form (Lagomarsino et al. 2018)

Topic 7 – Vulnerability to the earthquake II: The seismic response of the structure

• Issues on damage of different types of structures: Masonry buildings, Reinforced Concrete Buildings, Pre-Cast Buildings, Monumental Buildings as Churches and Palaces, …
• Detailed structural evaluation

Topic 8 – Vulnerability to the earthquake III: The fragility curves

• Definition of the suitable intensity measures (IMs)
• Choice of the metric of damage: relation to specific Engineering Demand Parameters, Limit States, Damage States, ….

·       Different approach for the derivation of fragility curves: mechanical (analytical and numerical ATC 58), observational, empirical, macroseismic, hybrid, expert opinon (ATC 13) à Advantages and disadvantages

• The lognormal fragility curve parameters (median value and dispersion)
  1. creation of sub-types or or grouping macro-types
  2. need to have homogeneous types
• Fragility curves and corresponding damage levels distributions:
  1. Distance between damage levels (brittle and ductile)  

Topic 9 – Seismic risk analysys

• Conditional damage assessments: where the condition is the occurrence of an earthquake with a selected return period (with attenuation from source to site).
  1. Damage probability matrix using Macroseismic Intensity as input
  2. Damage scenario using shake map as input (derived from physical source models or attenuation laws)
• Unconditional damage assessments: where the condition is removed by considering the probability of a ground shaking severity in a selected time observation window. Probabilistic risk assessment approach (the integral convolution)
  1. Recalling the hazard curve and the fragility curves;
  2. The consequences functions and the vulnerability curves for the evaluation of the Impact (monetary losses, fatalities, injuries, collapse of buildings, resilience…) à impact on population
  3. Indirect damage and losses (interruptions of productive and social activities, function of inactivity time)
• Typical Output of Risk Assessment Studies: 3Ds (Dollar, Deaths, and Downtime)

Topic 10 - The IRMA (Italian Risk MAps) v2 platform

• The structure of the platform that integrates tools to perform damage scenarios and risk maps for the Italian territory. It has been developed by EUCENTRE for the Italian Department of Civil Protection

·       Computer classroom exercise:

1. Influence of fragility curves on the different types of consequences;
2. Performance of different types of buildings;
3. The difference of a Risk analysis in the Italian Region, varying the hazard, the vulnerability and the exposure;
4. Regionalization of vulnerability.

Topic 11 – Economic loss analysis

• The reconstruction process of the L’Aquila 2009 Earthquake (Dolce and Manfred 2015). The analysis of the actual cost related to: repair with improvement; the temporary house; hotel accommodation.

Topic 12 – Resilience improvement: Risk mitigation strategy at territorial scale  

• Influence of the application of seismic improvement of buildings at territorial scale, following different strategies: 1) strength increased; 2) ductility increased; 3) increase of both.
• Interventions on different types buildings: 1) significant improvement of a few very vulnerable buildings; 2) light improvement but more widespread on less vulnerable buildings; 3) demolition and reconstruction of the most vulnerable buildings.
• The evaluation of the net present value (NPV) and the breakeven time.
• Cost-benefit evaluations varying the hazard
• Estimation of downtime and repair time

Topic 13 – SISMABONUS: Italian “Guidelines for the seismic risk classification of constructions”

• Seismic risk classification
• The conventional and simplified approach: theoretical basis and criticality of its actual application
• The fiscal incentives promoted by the government: procedural aspects
• Masonry buildings: intervention solutions that can be implemented without an excessive impact on the construction (allowing use during construction).
• Reinforced concrete (r.c.) buildings: intervention solutions that can be implemented without an excessive impact on the construction (allowing use during construction). Criteria for the selection of the most critical element in a r.c. frame, in order to certify the improvement (SLAMA method).

TESTI/BIBLIOGRAFIA

Appunti del corso su Aulaweb.

Registrazione delle lezioni sulla piattaforma Teams.

Riferimenti bibliografici di articoli su riviste internazionali forniti dal docente all'inizio dell'anno.

DOCENTI E COMMISSIONI

LEZIONI

INIZIO LEZIONI

https://corsi.unige.it/corsi/11428/studenti-orario

ESAMI

MODALITA' D'ESAME

La prova orale consiste nella discussione di un elaborato svolto dallo studente, relativo ad una analisi di rischio sismico a scala territoriale, e in domande sul programma sviluppato nel corso.

MODALITA' DI ACCERTAMENTO

La modalità di accertamento della preparazione dello studente riguarderà in particolare:

• la capacità di esprimere i contenuti con chiarezza e precisione terminologica
• la capacità di collegare la discussione orale agli argomenti trattati nel programma
• la capacità di sintetizzare e discutere criticamente la procedura applicata e i risultati ottenuti dalle esercitazioni pratiche

ALTRE INFORMAZIONI

Tutte le informazioni sono fornite in classe, attraverso Aulaweb o sulla piattaforma Teams.