Italian experiences in earthquake risk reduction: mitigation tools

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Workshop 2 30th June 1st July 2005, Certu

• Italian experiences in earthquake risk reduction
  mitigation tools
• V. Pessina1 and E. Faccioli2

With the collaboration of L. Finazzi2, L.
Frassine2, S. Lagomarsiono3
1 Istituto Nazionale di Geofisica e Vulcanologia
2 Department of Structural
Engineering, 3 DISEG,
Genoa University, Italy Sezione di Milano,
Italy
Politecnico di Milano, Italy
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GLOBAL SEISMIC HAZARD ASSESSMENT PROGRAM
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Outline of presentation

• Distinctive features of Catania
• Earthquake hazard assessment
• Vulnerability assessment of current buildings
• Seismic risk scenarios
• Appropriation of seismic problems by the city
  representatives

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Scope and main tools

• Knowledge transfer between seismic research
  community and local administrators
• Providing useful risk indicators to local
  administrators for planning purposes and
  emergency action response

• DESCRIPTION OF THE WORK
• Choice of the most significant elements at risk
• Generation of a damage scenario for M7.2 maximum
  historical event
• Damage assessment for residential buildings
• Assessment of loss estimation (casualties and
  severely injured, homeless)
• Proposal of a simplify method for debris
  assessment
• Identification of safety routes
• Hazardous fire zones identification
• Assessment of potential seismic hazard for
  hospitals

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Choice of the test area
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Earthquake hazard assessment deterministic
approach
Level I scenario M7.3 earthquake of January 11,
1693, a destructive event
Historical intensity map
X-XI
ground shaking maps for amax (g)
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Vulnerability assessment of current buildings
VI VI DVR DVm
MASONRY buildings
REINFORCED CONCRETE buildings
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Residential buildings high level of incertenties
on the data collection
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Vulnerability Index
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Seismic risk scenarios estimation of direct
physical losses Level I method Vulnerability and
damage maps for the 1693 event
Mean damage grade d is estimated for each census
tract, as average damage for all building
categories present in the tract.
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Seismic risk scenarios estimation of direct
physical losses Map of probability of collapse
1693 event
Probability of collapse
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Casualties estimation
Test area
0 Casualties
Tot. Residents 6548
Estimation of victims for the surveyed area of
Catania (about 70 of the total buildings)
123 Casualties 160877 Homeless
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Strategic buildings
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Gas network risk assessment
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The traffic flow
Cars/hour
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Debris assessment MASONRY buildings
hypothesis
F ? 45 friction degree of debris
Isolated building
Confined building
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Safety routes
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Vulnerability assessment of lifelines and
essential facilities Transportation accessibility
assessment of roadways
RESULTS Assuming that routes adjacent to
buildings with very heavy damage or collapse
are obstructed, the transportation accessibility
results reduced to 60 in zone shown (for 1818
scenario earthquake)
APPLICATION Estimation of minimum distance
(minimum travel time) between a school and a
hospital
Travel before earthquake 124 seconds
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First conclusions
Important indicators of seismic risk level have
been provided for
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Appropriation of seismic problems by the city
representatives

• Meetings with Catania representatives during the
  project
• July 2002 meeting with the Mayor and city
  administrators
• September 2002 Risk-UE meeeting in Catania
• February 2004 meeting with the Mayor and city
  administrators

The Mayor of Catania has special powers for
handling traffic emergencies, which enable him to
plan and operate interventions on the roadway
system in order to improve the seismic safety of
the city.

• Decisions already taken to decrease the seismic
  risk in the future
• improvement of highway transportation system
• construction of new hospitals and relocation of
  existing ones
• improvement of critical structures for civil
  defence and
• emergency management

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Rapid visual screening of Catania hospitals for
potential seismic hazards

• RVS Procedure (Rapid Visual Screening) data
  collection based on visual observation of the
  building from outside, and if possible, from
  inside (FEMA 154 handbook).
• The RVS procedure enables to classify the
  surveyed buildings into two categories
• buildings that may be seismically hazardous S ?
  2
• buildings with acceptable seismic performance S
  gt 2

The final score S has been calculated for every
building belonging to each hospital the global
evaluation of the condition of each hospital
Saverage is defined as weighted average of final
scores S
Hospital Saverage 1
Policlinico 2.5 2 Ascoli-Tomaselli 2.3 3
Cannizzaro 2.9 4 S.Luigi Currò 2.4 5
Garibaldi 2.9 6 Ferrarotto 2.4 7 Vittorio
Emanuele 1.4 8 S.Bambino 2.6 9 S.Marta 2.1
Saverage
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Improvement of highway transportation system
Infrastructures under improvement
main road
Infrastructures under costruction
main road roundabout
exchange parking
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Improvement of critical structures for civil
defence and emergency management

• Existing buildings
• 9 hospitals (medium-high vulnerability)
• 1 Civil Defence centre
• 1 Fire Brigade centre

Buildings under construction

• 2 hospitals S.Marco and New Garibaldi

• 1 provincial centre of Civil Defence

• 2 Fire Brigade centres

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Local Plan of Civil Defence structures for
seismic emergency management
Issue of an alarm
First evaluation of emergency
Activation of rescue operation
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Exposition factor inhabited centres in Imperia
province and historical elements
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Exposition factor monumental structures in
Castellaro
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Damage analysis masonry average damage
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Damage analysis reinforce concrete average
damage
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Damage analysis average damage in Taggia for
residential buildings
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Damage analysis average damage in Taggia for
aggregate and historical monuments
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Reference web sites