RESILIENCE OF THE BUILT ENVIRONMENT
5 credits during the 2nd year of 10720 ENVIRONMENTAL ENGINEERING (LM-35) GENOVA
The impact of natural hazards on the built environment is not limited to direct damage but involves indirect damage, linked to the interruption of production and social activities. Modern risk analyzes must consider these aspects and evaluate the resilience of the community, namely: 1) the ability to limit the damage produced by the event (robustness of buildings); 2) better manage the emergency phases; 3) react promptly, favoring a rapid return to normality (limiting the "down time").
After a framing of the problem with regard to the various natural hazards (earthquake, floods, fires, etc.), the course will focus on seismic resilience.
Seismic risk analysis of the built environment in relation to natural events: hazard, exposure and vulnerability. Probabilistic seismic hazard assessment: occurrence of earthquakes, mitigation laws. Taxonomy and classification of the exposed assets. Vulnerability models: observational (macroseismic method), mechanical based (analytical or numerical) and hybrid methods. Evaluation of fragility curves from nonlinear dynamic analyzes (IDA, MSA and cloud method). Probabilistic framework for the calculation of risk. Analysis of economic consequences and losses (direct and indirect damage). The resilience of the built environment and the society: robustness and recovery time. Risk assessment, prevention and management of the seismic emergency in the case of monumental building: LV1 models, vulnerability and damage survey forms.
AIMS AND LEARNING OUTCOMES
The course will be carried out with a strong involvement of the students.
In the lectures, since the subject is constantly evolving, the sites of the main world institutions (for example UNESCO) that have developed programmatic manifestos on resilience (Sendai Framework for Disaster Risk Reduction) will be visited.
In addition, an exercise will be carried out through the IRMA (Italian Risk Maps) platform, developed by EUCENTRE for Civil Protection, in which students will be able to perform a risk analysis on different territorial areas (municipalities, provinces, regions): 1) implement the fragility curves of the different types of buildings; 2) estimate the expected damage to buildings (number of collapses and unusable buildings), the consequences for the population (deaths and serious injuries, homelessness) and the costs necessary for reconstruction; 3) compare different prevention intervention strategies, through cost-benefit analyzes.
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)
- 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
- 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:
- Hazard: Intensity measure (MMI, PGA etc.) at a given coordinate for a given earthquake (magnitude, location), for example
- 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
- Physical phenomenon, faults types, wave propagation, amplified ground shaking, …
- The measure of the earthquake: Magnitude, macroseismic intensity, instrumental intensity, …
- Earthquake Catalog Data (Instrumental and Historical) and the geophysical evidence
- Response spectrum, Ground motion prediction equations (GMPEs)
- Probabilistic seismic hazard analysis – hazard curve
- The secondary effects
- Other hazards
Topic 5 – Exposure information
- Single building VS Portfolio of buildings
- Portfolio of assets:
- Population, Buildings (residential, commercial, public), Infrastructure (bridges, dams, ports, etc.), …
- 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
- 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?
- 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:
- AEDES survey form (Baggio et al. 2007)
- ATC 20 Building Safety Evaluation Forms and Placards (Rapid and Detailed evaluation)
- Building Safety Evaluation During a State of Emergency, prepared by the New Zealand Society for Earthquake Engineering
- 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)
- creation of sub-types or or grouping macro-types
- need to have homogeneous types
- Fragility curves and corresponding damage levels distributions:
- 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).
- Damage probability matrix using Macroseismic Intensity as input
- 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)
- Recalling the hazard curve and the fragility curves;
- 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
- 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:
- Influence of fragility curves on the different types of consequences;
- Performance of different types of buildings;
- The difference of a Risk analysis in the Italian Region, varying the hazard, the vulnerability and the exposure;
- 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).
Course notes, available on AulaWeb.
Recording of the lessons on Teams.
References to journal papers provided by the teacher at the beginning of the year.
Ricevimento: In attendance, by appointment required by email at the address: firstname.lastname@example.org In telematic mode, on Teams, by contacting the teacher in advance via the platform.
L'orario di tutti gli insegnamenti è consultabile su EasyAcademy.
The oral exam consists in the discussion of a report carried out by the student, relating to a seismic risk analysis on a territorial scale, and in questions on the program developed in the course.
All course information is given in the classroom, through Aulaweb or on Teams.