COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
M. Indirli, ENEA, Bologna, Italy
VESUVIUS SPECIAL SESSION
OVERVIEW OF THE VESUVIUS CASE STUDY ACTIVITY
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The VESUVIUS case study in the framework of the EU COST Action C26 activity
In the Delft meeting (November 17 - 18, 2006), the goal of WG4 has been devoted to any natural hazard except earthquake
“Resistance to Infrequent Loading Conditions”
as flood, landslide, extreme wind and snow, avalanche, tsunami and storm surge, coastal erosion, volcanic eruption, etc.
The focus has been pointed on:
- identification, characterization and modeling of natural disasters (and their interrelations/scenarios);
- construction response and possible relevant consequences of combined extreme loadings in the built environment.
Since the beginning, the work seemed too huge without a robust “Ariadne's thread” to follow.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The VESUVIUS case study in the framework of the EU COST Action C26 activity
Therefore, three directions have been identified for the research:
a) the investigation on each single catastrophic infrequent event; b) the set up of a multi-hazard approach, together with the development
of a common methodology for risk assessment; c) the identification of a pilot study enough general to join several disciplines
in a transversal approach.
Delft meeting, November 17 - 18, 2006; Prague Workshop, March 30-31, 2006; Naples, June 8-9, 2007.
In Naples, the discussion was related to the organization of WG4, deciding to modify its scope and name, which changed in:
“Risk Assessment for Catastrophic Scenarios in Urban Areas”
The Vesuvius extreme dangerousness induced the WG4 to introduce the ‘Vesuvius case study’ within its research activities,
with particular regard to the effects on the constructions produced by a possible eruption.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The VESUVIUS case study in the framework of the EU COST Action C26 activity
The
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After a general discussion (Timisoara, October 26-27, 2007), a specific enlarged WG4 meeting was organized (Trieste, January 17-18, 2008), where the Vesuvius case study has been focused.
Not addressed to the issue of evacuation, the study has been restricted to the modelling of loads acting on structures and the corresponding construction response.
The work on Vesuvius continued in the following Action meetings, with the main result to find some paradigmatic sets of structures, to be investigated in the surrounding area of the
Neapolitan volcano.
(Vilnius, April 11-12, 2008; Naples, 19 May 2008;
Madeira, June 5-6, 2008; Malta Workshop, October 23-25, 2008;
Naples, January 23, 2009; Southampton, March 27-28, 2009;
Rome, June 22-24, 2009; Skiathos, September 4-5, 2009; Aveiro, November 27-28, 2009;
Nicosia, March 19-20, 2010).
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The VESUVIUS case study in the framework of the EU COST Action C26 activity
The work involved several experts of different disciplines and created an enlarged platform
for a free and productive discussion.
VESUVIUS 2000Project objectives
Flavio Dobran
GVES, Napoli, Italy
www.westnet.com/~dobran
Urban Habitat Constructions Under Catastrophic Events
Trieste, 17 January 2008
Earthquake scenarios for the Earthquake scenarios for the
determination of the seismic load on determination of the seismic load on
the structures surrounding Vesuvius.the structures surrounding Vesuvius.
Giuliano F. PanzaGiuliano F. Panza
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Trieste, 17-18 January 2008
COST C26 ACTIONCOST C26 ACTION
““URBAN HABITAT CONSTRUCTIONS UNDER URBAN HABITAT CONSTRUCTIONS UNDER
CATASTROPHIC EVENTSCATASTROPHIC EVENTS””
1717--18 JANUARY 200718 JANUARY 2007
TRIESTE, ITALYTRIESTE, ITALY
UNIVERSITY OF NAPLES UNIVERSITY OF NAPLES ““FEDERICO IIFEDERICO II””
Department of Structural EngineeringDepartment of Structural Engineering
PROF.PROF. Federico M. MAZZOLANIFederico M. MAZZOLANI
Dr. Beatrice FAGGIANODr. Beatrice FAGGIANO
ENG. Daniela DE GREGORIOENG. Daniela DE GREGORIO
VESUVIUS CASEVESUVIUS CASE
Università degli Studi di Napoli “ Federico II”
Presentazione delle Attività del Centro Studi
P.LIN.I.V.S.(Per L’INgegneria Idrogeologica Vulcanica e Sismica)
Giulio Zuccaro
Napoli
19 Febbraio 2008
Giornata Inaugurale del
Centro Studi PLINIVSCentro di Competenza del
Dipartimento di Protezione
Civile Nazionale
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
State-of-the-art on Vesuvius
Projects and papers
Timisoara, October 26-27, 2007
Trieste, January 17-18, 2008
Vilnius, April 11-12, 2008
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
State-of-the-art on Vesuvius
Principal eruptions of Vesuvius
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
State-of-the-art on Vesuvius
List
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s
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Typologies of the principal volcanic actions by Vesuvius on the constructions
Volcanic actions of Vesuvius
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Volcanic actions of Vesuvius
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hq
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COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Volcanic actions of Vesuvius
pyr
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low
s
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Volcanic actions of Vesuvius
tep
hra
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Volcanic actions of Vesuvius
lava
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Volcanic actions of Vesuvius
lah
ar
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Volcanic actions of Vesuvius
tsu
na
mi
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Identification of the target area
The red zone, the most dangerous area around Vesuvius
The investigated area: the Municipality of Torre del Greco
Coordinates 40°47’7’’N - 14°23’43’’E
Altitude 43m s.l.m.
Surface 30,66km2
Inhabitants 88.894 (2007)
Density 2.899,34 inhab./km2
Istat code 063084
Land register code L259
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Identification of the target buildings
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The survey team
- experts of University of Naples “Federico II”- experts COST ACTION C26- Experts of PLINIVS Centre, Naples
The support of PLINIVS Centre has been fundamenntal, for knowledge and experience
visual examination, the compilation of ad hoc forms
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The investigation methodology
1) volcanic vulnerability
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The investigation methodology
2) MEDEA: seismic damage mechanisms
3) Additional information specific for cultural heritage for the Vesuvian Villas
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The investigation methodology
The PLINIVS Study Centre developed:
computerized tool to build up the seismic impact in the volcanic areas around Vesuvius and Campi Flegrei
tools intended to evaluate a reasonable estimate of the cumulative damage impact scenario as a consequence of a Vesuvius eruption of assigned intensity
The model is integrated in a Geographic Information System (GIS) and refers to Vulnerability Functions and on cumulative damage on the buildings
The tool is intended to control the progressive impact up to the final impact scenario
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The investigation methodology
At the moment, EXPLORIS considers only three volcanic phenomena:earthquakes (EQ)ash falls (AF) pyroclastic flows (PF)
The eruptive event is studied from the first precursory seismic event up to the final pyroclastic flow, by evaluating the damage accumulated on the buildings and the distribution of damage on the territory at each step of the process.
The evaluation of the volcanic impact on the constructions is very complex and depends on the possible eruptive scenario, which has been assumed.
The combination of the three volcanic phenomena can increase the damage on buildings, in comparison with the effects of each phenomenon acting separately.
The ‘quick’ methodology for the volcanic vulnerability assessment and the survey form have been developed within the EXPLORIS European project (2002-2005)
developed by the PLINIVS Centre.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The investigation methodology
THE VOLCANIC VUNERABILITY ASSESSMENT
The methodology is based on the assignment of specific vulnerability classes with respect to each exceptional action, in function of the structural elements typology.
AF: 5 classes Ar, Br, C1r, C2r, Drwith vulnerability decreasing in function of roof typologies.
PF: 3 classes Ap, Bp, Cp for masonry buildings3 classes Dp, Ep, Fp for the RC buildings
with vulnerability decreasing in each group in function of vertical and horizontal structures.
EQ: 4 classes As, Bs, Cs, Ds with vulnerability decreasing according to the combinations
of horizontal and vertical structures.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Examples of building classification in the historic centre of Torre del Greco
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
The volcanic vulnerability assessment: examples of results
The impact of ash-fall is strongly dependent on the wind direction during the
eruption; the model considers 16 possible ‘sectors’ of
prevalent wind.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Mitigation actions
earthquake
Considering the high seismic vulnerability levels and the construction density in the Vesuvius area, cost-effective mitigation measures should be provided.
It is possible to choose cheap and reliable technical solutions (such as iron chains in masonry buildings, the insertion of infill panels or resistant elements in soft floors of reinforced concrete buildings), but also to adopt, in case of seismic reinforcement, specific solutions able to respond effectively also to other volcanic phenomena, such as pyroclastic flows or ash fall.
One solution is the construction of pitched roofs by overlapping light structures in CFS (Cold Formed Steel). This allows to chain vertical structures by increasing the resistance to seismic actions (box behaviour) and simultaneously prevent the deposit of ashes and the structural risks related to overloading of the roof, also in consideration of a possible earthquake following the ash fall phase.
Should be avoided the employ of widely used reinforcement systems not satisfying the conditions of volcanic risk, such as FRP (Fiber Reinforced Polymers) Global mitigation strategies related to seismic risk in case of a volcanic event may include planning for widespread interventions, defining the areas that require priority actions.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Mitigation actions
Pyroclastic flows
Pyroclastic flows can produce high damages to the built environment in areas near to the vent.
Although they would have a limited action range, the effects can be critical because of the combination of mechanical impact and thermal stress on the vertical surfaces of buildings.
The main damages come from the impact on openings.
Mitigation strategies mainly concern the reinforcement of infill panels in r.c. buildings and measures for the protection of openings.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Mitigation actions
Ash fall
Ash fall is one of the eruptive phenomena with greater risk for existing buildings and infrastructure, as the expected impact involves (with different levels of intensity) a very large area, which definition is strictly linked to the direction and intensity of the wind, as well as to the type of eruption.
Mitigation strategies, beside the need to develop an operational plan for the removal of ash on roofs and transport networks, mainly concern the repairing and reinforcement of roofing systems in order to increase the load carrying capacity.
Pitched roofs with wooden or steel structure, reducing the deposits of ashes, would be at risk only in proximal areas where the surface of the cover present disconnections or missing parts. In this case, given the adequate inherent fire resistance of commonly used coating materials is enough to replace the missing elements in order to prevent the passage of hot ashes under the roof covering.
In case of flat roofs it is possible to identify two main types of intervention: the reinforcement of the roof slab in order to increase the resistance according to the expected overload, or the realization of a sloped roof over the existing one.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Mitigation actions
Lahar
The lahars are a relevant risk factor for buildings and structures in volcanic areas.
The response of structures and buildings technical elements to the action of lateral forces produced by lahars depends mainly on construction type and materials employed, as well as specific characteristics such as size in plan and elevation, number, size and position of openings, spatial distribution and presence of protective elements around the building able to divert the flow, etc.
Structures, infill panels and ground floor openings are the technical elements most at risk in case of lahars. The reinforcement of these elements yet does not guarantee the survival of the building in case of direct impact with mudslide and debris, especially in the case of compact urban areas, where a "tunnel effect" can increase speed and height of the flow after the passage inside particularly narrow roads.
For this reason the most effective mitigation strategies are related to environmental engineering interventions, to be made in risk prone areas and designed to contain or divert lahars. Measures such as retention basins, alternative artificial canals, high-strength reinforced concrete containing structures, may be appropriate solutions to mitigate risk.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Conclusions
The mitigation of volcanic risk on buildings and infrastructure can significantly reduce the expected damage after an eruptive event.
Even the impacts of high destructive type of eruptions, such as Sub-Plinian, can be strongly reduced by the application of one or more mitigation measures, responding to the different phenomena involved.
It is therefore necessary to start from a comprehensive knowledge of the construction types available in risk-prone areas, providing specific interventions that take into account the cumulative effects given by the expected time history of the event.
Hence, an effective design approach aims to put in relation technological features of existing buildings, parameters and data from probable scenarios, opportunities given by mixing together conventional technologies and advanced materials.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Conclusions
Furthermore, considering the economical, political and social “weight” of the strategies for the mitigation of volcanic risk in densely populated areas, a valid evaluation method of the effectiveness of the proposed solutions can give scientific support to strategic choices and emergency plans.
Therefore, tools for assessment and comparison between different solutions and “mitigation scenarios” are needed, trying to put together the different factors involved, such as economical and social sustainability, cultural and historical value, implication on emergency plans and on post-eruption rehabilitation and reconstruction interventions.
COST Action C26
Urban Habitat Constructions under Catastrophic Events
FINAL CONFERENCE. Naples, 16th- 18th September 2010
Conclusions
In the case of the Vesuvius “red zone”, long-term strategies capable to reduce the urban density are also strongly necessary.
It shall be very important to transfer strategic buildings, to stop the increasing of illegal constructions, to convince the people to live in places far from the volcano.
Finally, a “safety belt” around the Vesuvius belt should be re-created, in order to reduce the consequences of an eruption.
THANK YOU
FOR THE ATTENTION
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