Download Feasibility Study for Reconstruction of the Village of Mevale di Visso

Feasibility Study for Reconstruction
of the Village of Mevale di Visso
Using Seismic Isolation and Original
Materials
Alberto Bertocchi1, Riccardo Cami1, Arianna Procaccio1
and Maurizio Indirli1
1
Italian Agency for New Technology, Energy and Environment (ENEA), Bologna, Italy
ABSTRACT
New activities for the development of Innovative Antiseismic Techniques (IATs) applicable
to Cultural Heritage Structures (CUHESs) are now in progress at the Italian Agency for New
Technology, Energy and Environment (ENEA), with the collaboration of the Faculties of
Architecture of Ferrara and Naples “Federico II”, concerning the use of Seismic Isolation
(SI) for the reconstruction of collapsed or severely damaged historical villages at their
original site and using original methods and materials. In particular, the Marche Regional
Government and its Technical-Scientific Committee entrusted to ENEA (2001) a feasibility
study regarding the application of SI at Mevale di Visso (Macerata, Marche Region), a
medieval village almost completely destroyed by the 1997-98 Umbria-Marche earthquake.
1. INTRODUCTION
Large R&D and application efforts are going on at ENEA for the seismic protection of the
various kinds of structures through IATs, namely seismic isolation (SI), passive energy
dissipation (ED), hydraulic coupling by means of shock transmitters (ST), coupling through
shape memory alloy (SMA) devices, and semi-active control (SAC). This work is performed
by the ENEA Section “Prevention of Seismic Risks and Mitigation of Their Effects”
(PREV), in the framework of the ENEA Program RITA (1999). ENEA began devoting
particular attention to IATs applicable to CUHESs within both national and international
collaborations (Martelli and Indirli, 2000). In this framework, the EC-funded ISTECH
Project allowed for the development of SMA devices capable of improving the stability, in
particular seismic protection, of CUHESs (Indirli et al, 2001 and 2002). It is worthwhile
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INDIRLI, BERTOCCHI, CAMI AND PROCACCIO
stressing that CUHESs seismic protection is quite an important issue in a country like Italy,
characterized by ancient and precious buildings and a non-negligible seismicity in a large
part of its territory. In fact, CUHESs are seismically rather vulnerable: earthquakes, even
those with moderate intensity, may cause collapse or heavy damage of many of them. An
additional issue concerns the reconstruction of collapsed or severely damaged historical
villages at their original site and using original methods and materials. Unfortunately, the
CUHESs rehabilitation problems, in order to make them capable of resisting violent
earthquakes, are much more difficult to solve than those related to modern r.c. or steel
structures, because there are specific conservation requirements for the interventions on
CUHESs (i.e. integrity, compatibility, reversibility and durability), not very easily
compatible with seismic requirements. It is also noted that, in addition to R&D, large efforts
are being devoted by ENEA to promote IATs pilot applications in various Italian Regions,
seeking formal agreements with Local and Regional Governments.
2. SEISMICITY IN MARCHE-UMBRIA AND THE 1997-98 EARTHQUAKE
Several earthquakes hit the Appennino Mountains in Umbria and Marche in the history and
the principal events are reported in the following Table 1.
Table 1. Historical Seismicity in Marche-Umbria Regions
year
217 a.C.
174 a.C.
1279
1298
1328
1349
1352
1458
1639
1695
1703
1730
1741
1751
1781
1785
1789
1799
1832
1917
1930
day
month
jun.
30 apr.
1 dec.
4 dec.
9 sep.
25 dec.
26 apr.
8 oct.
11 jun.
14 jan.
12 may
24 apr.
27 jul.
3 jun.
2 oct.
30 sep.
28 jul.
13 jan.
26 apr.
30 oct.
time
GMT
23:00
06:15
16:00
12:15
00:35
02:20
17:55
05:00
10:00
01:00
06:25
21:10
10:45
22:05
13:00
09:35
07:13
Lat.
Long.
I0
Imax
epicenter
Me
43 15
42 15
43 16
42 33
42 51
42 38
43 29
43 31
42 38
42 37
42 41
42 45
43 25
43 14
43 35
42 33
43 31
43 08
42 59
43 28
43 40
11 15
12 40
12 47
12 50
13 01
12 07
12 09
12 11
13 16
12 07
13 05
13 07
13 0
12 45
12 34
12 47
12 13
13 08
12 36
12 07
13 16
X
X
IX
VIII
X
VIII-IX
VIII-IX
VIII-IX
X
IX
XI
IX
IX
X
IX-X
VIII-IX
IX-X
IX
X
IX-X
VIII
X
X
IX
IX-X
X
VIII-IX
VIII-IX
VIII-IX
X
IX
XI
IX
IX
X
X
VIII-IX
X
IX-X
X
IX-X
VIII-IX
Etruria (Trasimeno)
Sabina
App. Umbria-Marche
Reatino
App. Umbria
L’Aquila-Viterbese-Umbria
North. Tiberina Valley
North. Tiberina Valley
Laga Mountains
North. Lazio
App. Umbria-Norcia
App. Umbria-Norcia
App. Marche-Fabriano
App. Umbria-Gualdo Tadino
App. Marche-Cagli
South. Umbria -Piediluco
North. Tiberina Valley
App. Marche-Camerino
Topino Valley-Spello
Tiberina Valley
North. Marche-Senigallia
6.3
6.3
6.6
6.3
6.7
6.7
5.7
5.4
5.4
5.7
6.5
6.4
6.4
6.0
6.0
5.4
5.4
5.6
5.7
5.7
5.7
I0: Epicentral Intensity MCS; Imax: Maximum Intensity MCS; Me: Magnitudo.
On September 26th, 1997 the first seismic event of a long series happened near Serravalle del
Chienti and Colfiorito (epicenter in Cesi-Collecurti, Lat. 43.0 N e Lon. 12.9 E, Figure 1) on
INDIRLI, BERTOCCHI, CAMI AND PROCACCIO
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the border between Marche and Umbria Regions. The Italian Institute of Geophysics and
Volcanology (INGV) spoke about three principal shocks: ML 5.5 Richter and VIII MCS
(local time 02:33); ML 5.8 and VIII-IX MCS (11:40 - MM 6.0 by CALTECH, California responsible of the vaults collapse in the St. Francis Basilica of Assisi); ML 4.7 and VII MCS
(11:46). After those events, thousands of aftershocks followed for months, striking the
epicentral towns of Nocera Umbra, Casenove, Forcatura, Sellano, Preci, Gualdo Tadino, etc.,
located along the activated fault. A large part of Marche and Umbria was subjected to
relevant seismic excitation and damage, especially concentrated in historical buildings and
CUHESs. In October-November 1997, an ENEA team (M. Indirli, B. Carpani, A. Poggianti)
supported the Civil Defense during the emergency phases, with the specific role to perform
investigations on damaged CUHESs in the area of the city of Camerino (Indirli et al. 1998).
Figure 1: Damaged buildings in the epicentral area of Cesi
The medieval village of Mevale di Visso is located in Valnerina, on the top of a hill in a
beautiful mountain landscape. It was important, due to its strategic and environmental
position, since ancient times and it is proven by the presence of a beautiful frescoed
Romanesque church, together with the ruins of an old castle (Figure 2).
Figure 2: Mevale di Visso before the 1997-98 earthquake
Mevale seismic history is intense and disastrous at the same time. The 1328 seismic event
ruined it almost completely and the following 1703 earthquake struck also very strongly,
causing many casualties, the complete collapse of the castle and the destruction of several
houses. In recent times, the 1979 earthquake was responsible of generalized damage of
buildings (some of them were not rebuilt anymore). Furthermore, the 1997 seismic event
reduced the village near to a heap of rubble; in fact, the 87% of the houses collapsed or was
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INDIRLI, BERTOCCHI, CAMI AND PROCACCIO
subjected to extensive damage, including those reconstructed or rehabilitated after 1979.
Figure 3: Mevale di Visso after the 1997-98 earthquake
3. GEO-SEISMOLOGICAL PRELIMINARY DATA IN THE MEVALE AREA
Thanks to preliminary investigations in the area (Figure 3), performed by Geoequipe
Company and University of Camerino, under request of the Marche Regional Government
and its Technical-Scientific Committee, a complex fault system has been detected in the
INDIRLI, BERTOCCHI, CAMI AND PROCACCIO
5
Mevale area. In addition, the center of the village lays on a deep stratification of fractured
rocks and a superficial bed of debris (about 10 m), probably due to the accumulation of
filling and collapsed materials after the periodic seismic events. Thus, the place is subjected
to particularly adverse site conditions, i.e. quite a significant local amplification factor FA of
the seismic motion. The ongoing in situ campaigns are confirming the preliminary data (FA
up to 2.4 in the frequency range of interest for masonry structures, University of Camerino
and Geoequipe, 2001).
a)
b)
c)
d)
Figure 4: Geo-seismological preliminary data: fault system a), substrate stratification b), amplification
data c) and site spectra.
4. THE ENEA FEASIBILITY STUDY
In the past, the usual politics in Italy, in case of relevant seismic hazard, was not to
reconstruct in original site, but to move the villages to a different location and rebuild them
using modern methods and materials, like reinforced concrete (r.c.). By going on in this way,
more and more parts of the Italian cultural heritage will be fully lost forever. In order to
avoid this contingency, ENEA suggested to the aforesaid Regional Institutions the possibility
to rebuild the village in its original site using original methods and materials (masonry,
stone, wood, etc.), bringing the village back to its original appearance as much as possible,
but also taking the opportunity for reconstructing parts of it that had collapsed during
previous earthquakes and getting rid of some illegally built modern constructions. In order to
find ways for reconstructing these villages where they are and, at the same time, making
them capable of resisting violent earthquakes, ENEA, based on preliminary studies
(Bertocchi, 2000; Procaccio, 2001), suggested the application of the SI innovative technique.
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INDIRLI, BERTOCCHI, CAMI AND PROCACCIO
In fact, masonry constructions, if in good conditions, are the structures for which SI provides
the best behavior (since they are the most stiff) and the largest protection advantages (since
they have no ductility). The feasibility study, entrusted to ENEA (Indirli, 2001), is now in
advanced progress. It is including: on-site investigations and observations; SI system design
and buildings’ response calculation for a significant part of the village (such as to be easily
extended to the entire village); evaluation of the decrease of seismic risk (Figure 4) with
respect to more conventional reconstruction (r.c. structures or steel reinforced masonry);
quantification of costs related to the use of SI and the possible kinds of conventional
reconstruction leading to at least an adequate (if not equal) level of seismic protection (Table
2). The so far obtained numerical results demonstrate SI effectiveness.
Red: conventional reinforcement
and SI
Blue: conventional reinforcement
and fixed base
Yellow: reinforced concrete frame
and fixed base
Acceleration amplification
(roof/base)
Figure 5: Analytical study for a sample building located at Mevale and first benefit evaluation of SI
Table 2. Preliminary costs comparison for two building typologies and three reconstruction techniques
Single building with foundations at
the same level
Reconstruction Technique
%
Row building with foundation at
different levels
Reconstruction Technique
%
14.3
SI/TT
19.4
SI/TT
RC/TT
16.9
RC/TT
4.8
SI/RC
2.1
SI/RC
9.1
Major costs (in percentage) for reconstruction Techniques SI (Seismic Isolation) and RC (Reinforced
Concrete) in comparison with Traditional Techniques (TT) and reciprocal
5. CONCLUSIONS
Preliminary results of the feasibility study, entrusted to ENEA by Marche Region,
concerning SI application to the reconstruction of the medieval village of Mevale di Visso,
almost completely destroyed by the 1997 earthquake, have been summarized. It is worth
noting the importance of this work, because it suggests the possibility to rebuild the village
in its original site using original materials, bringing it back to its original appearance as
much as possible, and making it capable, at the same time, of resisting violent earthquakes.
On the contrary, it was usual in the past in Italy moving such villages to a different location
in case of relevant seismic hazard, reconstructing them using modern methods and materials,
INDIRLI, BERTOCCHI, CAMI AND PROCACCIO
7
like reinforced concrete, or restoring them by the use of conventional techniques, often not
sufficiently capable to improve the masonry CUHESs seismic resistance (as proven by
earthquakes damage patterns and unsatisfactory interventions).
ACKNOWLEDGEMENTS
Special acknowledgements to: our ENEA colleagues B. Carpani, P. Clemente, M. Forni, A.
Martelli, A. Poggianti, B. Spadoni, G. Venturi; to C. Alessandri (University of Ferrara) and A.
Baratta (University of Naples "Federico II"). Special thanks to A. Cherubini (President of the
Technical-Scientific Committee of Marche Region) and M. L. Polichetti (Director of the
Italian Central Institute for Catalogue and Documentation and member of the aforesaid
Committee), M. Ripepe (University of Camerino), F. Pontoni (Geoequipe) and M. Canzian
(consultant).
REFERENCES
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