APPLICATION OF HAZARD RISK METHDOLOGY ON HISTORICAL BUILT ENVIRONMENT IN TIMISOARA

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APPLICATION OF HAZARD RISK METHDOLOGY ON
HISTORICAL BUILT ENVIRONMENT IN TIMISOARA
I. Onescu1; E. Onescu2; M. Mosoarca3;
1 Lecturer, Habil. Ph.D. Arch., Urban Planning and Architecture Research Center, Politehnica University of
Timisoara, and Academy of Romanian Scientists, Ilfov 3, 050044, Bucharest, Romania
iasmina.onescu@upt.ro
2 Ph.D. Stud. Arch., Politehnica University of Timisoara
eugen.eugen@student.upt.ro
3 Full Professor, Habil. Ph.D. Eng., Urban Planning and Architecture Research Center, Politehnica
University of Timisoara
marius.mosoarca@upt.ro
Abstract
The multi-hazard risk assessment of the built environment, especially in historical urban areas,
represents a common topic nowadays, with many challenges in the management process.
Timisoara, which will be the European Capital of Culture in 2023, has several historical areas
which present various vulnerabilities to hazards, especially to earthquakes. Heritage buildings
in Art Nouveau, Baroque, Secession architectural style present a poor state of conservation,
without recent consolidation work and also without a specific knowledge of their expected
damage state in case of an earthquake. Considering the fact that Timisoara is located in Banat
seismic area, which is characterized by shallow earthquakes of crustal type, the opportunity of
investigating the vulnerability of the most important districts of the city is highlighted.
The paper presents a multi-disciplinary empirical vulnerability assessment made on a historical
area of Timisoara city, which investigated the structural, architectural-artistic, urbanistic and
socio-economic vulnerability of the case-study area, in a simplified and efficient way. The
assessment methodology represents a complex, holistic methodology that was proposed by the
same authors recently, which aims to consider the cultural value of the heritage buildings in
the process of multi-hazard risk management of the built environment.
Keywords: masonry, hazard, vulnerability assessment, heritage buildings, risk management
2687
COMPDYN 2023
9th ECCOMAS Thematic Conference on
Computational Methods in Structural Dynamics and Earthquake Engineering
M. Papadrakakis, M. Fragiadakis (eds.)
Athens, Greece, 12-14 June 2023
Available online at www.eccomasproceedia.org
Eccomas Proceedia COMPDYN (2023) 2687-2697
ISSN:2623-3347 © 2023 The Authors. Published by Eccomas Proceedia.
Peer-review under responsibility of the organizing committee of COMPDYN 2023.
doi: 10.7712/120123.10593.20454

I. Onescu, E. Onescu and M. Mosoarca
1 INTRODUCTION
Historical buildings and historical cities represent one of the most valuable assets of the local
communities, as the base of their authenticity. Due to their age and building materials and
technology, implemented before the existence of any design codes, historical buildings are more
vulnerable to damage or collapse during an earthquake, so their susceptibility to this hazard
should be determined, to be able to ensure the preservation and safety.
For historical districts that are located in areas with seismic hazard, vulnerability is a concern
for many structures in the city. For increasing their resilience, it is important to be aware of the
vulnerability level, possible seismic scenarios and possible losses, to take the necessary
measures to minimize the damage and to ensure the safety of the inhabitants.
Seismic vulnerability assessment of heritage buildings is one of the most important tools in
the process of ensuring structural stability and preservation in case of an earthquake.
This paper aims to look at a small aggregate in Timisoara city, which has a rich historical
heritage, but which is also a seismic area. The aim of the paper is to highlight the importance
of conducting vulnerability assessment on those buildings, as a first step in the process of
preserving the cultural heritage of the city. The assessment methodology takes into
consideration more than just the structural features, so its findings are expected to contribute to
the development of strategy for the seismic risk management in Timisoara.
1 CASE STUDY AREA
The paper focuses on one aggregate in one of the most important historical districts of
Timisoara city. The name of the district is Iosefin and is located in the western part of the city,
on the left bank of the Bega river, as presented in Figure 1 [1]. The district is well-known for
its valuable architectural value, with many buildings in Art Nouveau and Eclectic style [2]. The
district was built in the 18th and 19th Century and was settled by nobility and wealthy merchants.
The most important districts palaces and mansions were built at the beginning of the 20th
Century and are well preserved even nowadays. In the context of Timisoara European Capital
of Culture 2023, a large number of historical palaces and urban areas in Iosefin district are
activated to host several cultural events and festivals [3], [4]
Figure 1: Main historical districts of Timisoara city [1].
IOSEFIN
DISTRICT
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I. Onescu, E. Onescu and M. Mosoarca
The specific aggregate that represents the case study of this paper is one of the most
important ones in Iosefin district, as it represents the first buildings that are seen coming from
the city center, the visual connection between Iosefin and Cetate districts. The aggregate is
located in the eastern extremity of the district, as shown in Figure 2a. An aerial view of the
buildings within this aggregate is presented in Figure 2b.
a) b)
Figure 2: Case study aggregate: a) position within the Iosefin district; b) aerial view.
The buildings in the investigated aggregate are all with historical and cultural value, built in
the years of 1900, in Art Nouveau principal architectural style and Eclectic secondary
architectural style, with decorated facades and several architectural-artistic assets, as illustrated
in Figure 3. The buildings are all made in burnt clay brick masonry with lime, with thick
perimetral masonry walls and thin transversal masonry walls, with masonry vaults above
basement and wooden floors [5] (in some cases concrete slabs as a retrofitting modern
intervention), with rigid wooden frameworks in German style [6].
Figure 3: The historical buildings within the case study aggregate.
2 SEISMICITY OF THE AREA
Timisoara is located in Banat seismic area, which represents the second most important
seismic region of Romania. The seismicity of Banat area is a moderate one, with earthquakes
of crustal type [7]. The magnitudes in the area are between MW = 0.2 ÷ 5.6 [8], as presented in
Table 1 [9], and according to the Romanian Design Code, the peak ground acceleration for
Timisoara is PGA = 0.20g [10]. Following the considered PGA, there was determined the most
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probable macroseismic intensity, based on Equation 1 [5], which is IX EMS-98, as presented
in Figure 4 [11].
Seismic intensity
V
VI
VII
VII-VIII
Year
1889
1973
1859
1879
1896
1879
1915
1902
1900
1991
1907
1941
1950
1959
Table 1: The most important seismic events in Banat area (MSK intensity scale) [9].
ln(PGA) = 0.24 x I
EMS-98
– 3.9
(1)
Figure 4: Correlation between the PGA and the expected macroseismic intensity EMS-98 [11].
3 VULNERABILITY ASSESSMENT
The vulnerability assessment of the investigated aggregate in Iosefin district was performed
following a methodology that was previously developed by the authors [12], that considers also
the importance and the impact of the cultural value in the process of vulnerability assessment
[13]. The aim of this procedure is to be able to calibrate the seismic vulnerability based on the
level of cultural importance of the building. This aspect could allow the local authorities to
prioritize the rehabilitation works not only based on the highest structural vulnerability, but also
based on the highest cultural value of the buildings. The preservation of the most important
architectural heritage of the city, is in accordance with the European guidelines for the
preservation of the cultural heritage assets [14] and also with the UNESCO program for the
cultural landscape [15].
3.1 Methodology
The methodology is an empirical ones, based on the visual inspection of the investigated
aggregate, appropriate for investigations of large urban areas, quick and simplified. It considers
four categories of parameters, such as structural, architectural-artistic, urbanistic and socio-
economic ones. Each category influences the vulnerability score in a smaller or higher
percentage, from 70% for the structural features to 5% for the social economic ones. The
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investigation form contains a total number of 42 parameters, from which the first 15 parameters
refers to the structural category.
This first category, the structural one, represents actually a well-known vulnerability
assessment methodology that was first proposed by profs. Bendetti and Petrini [16] for the first
10 parameters and developed by profs. Mazzolani and Formisano for the other 5 parameters
that considers the interaction within the aggregate [17].
The other three categories were proposed by the authors of this paper, following several
research and Romanian codes [12], [18], [19]. Those parameters are based on a personal
appreciation of the architectural-artistic, urbanistic and socio-economic value of each aspect,
following recommendations and guidelines from Romanian code for monument consideration
and several research contracts in the field. The weights of each parameter were calibrated
following the application of the form on more than 100 historical buildings.
The vulnerability index is obtained by fulfilling the final investigation form, which is
presented in Table 2, as the sum of each individual score of each parameter multiplied by a
corresponding weight, as in Equation 2 [20].
%
Criteria
No.
Element
Class
Weight
A
B
C
D
70
%
STRUCTURAL
1
Vertical structure organization
0
5
20
45
1.00
2
Vertical structure nature
0
5
25
45
0.25
3
Type of foundation and location/soil
0
5
25
45
0.75
4
Distribution of structural elements in plan
0
5
25
45
1.50
5
Regularity in plan
0
5
25
45
0.50
6
Regularity in elevation
0
5
25
45
1.00
7
Floor type
0
5
15
45
0.75
8
Roofing
0
15
25
45
0.75
9
Other details
0
0
25
45
0.25
10
Conservation state
0
5
25
45
1.00
11
Presence of adjacent buildings with different height
-20
0
15
45
1
12
Position of the building in the aggregate
-45
-25
-15
0
1.5
13
Presence and number of staggered floors
0
15
25
45
0.5
14
Effect of either structural or typological
heterogeneity among adjacent structural unit
-15
-10
0
45
1.2
15
Percentage difference of opening area among
adjacent façade
-20
0
25
45
1
15
%
ARCHITECTURAL
ARTISTIC
16
Representative architectural style for the area
0
10
15
25
1.50
17
Age, importance of the build époque
0
10
15
25
1.20
18
Original woodwork/joinery
0
10
15
25
1.00
19
Original stucco, brick, floors or ceilings
0
10
15
25
1.00
20
Original statues or bass-reliefs
0
10
15
25
1.00
21
Original gable/fronton
0
10
15
25
1.00
22
Original balconies and railings
0
10
15
25
1.00
23
Original mosaics or stonework
0
10
15
25
1.00
24
Original paintings or frescoes
0
10
15
25
1.00
25
Degradation state of artistic assets
-5
10
15
25
1.00
26
Authenticity/ originality (global, elements)
0
10
15
25
1.00
27
Official monument (national, regional, local,
protected area) status
0
10
15
25
1.50
28
Particular construction techniques/materials
0
10
15
25
0.50
29
Conservation state of original materials
-5
10
15
25
0.50
30
Representative historical events
0
10
15
25
0.50
31
Archaeological site
0
10
15
25
1.50
32
Representative/ original wooden framework
0
10
15
25
1.00
33
Past restoration work
-5
10
15
25
1.00
10
%
URBANISTIC
34
Importance in contouring the street profile
-5
10
15
25
1.50
35
Importance in contouring the urban silhouette
-5
10
15
25
1.50
36
Annexes, relation with the urban pattern
0
10
15
25
1.00
37
Location (central area, touristic area)
0
10
15
25
1.50
38
Representative/particular shape of the roof
0
10
15
25
1.00
SOCIAL
39
Public/social functions
0
10
15
25
1.50
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I. Onescu, E. Onescu and M. Mosoarca
5
%
ECONOMIC
40
Importance for the local community memory
-5
10
15
25
1.00
41
Economic value
0
10
15
25
1.50
42
Cultural functions
0
10
15
25
1.50
IV CULT
Table 2: The investigation form that considers also the cultural value [9].
    

     

     

  
  

   (2)
Following the seismic vulnerability index influenced by the cultural value, there is obtained
a normalized vulnerability index VCULT, based on Equation 3 . Later on, the mean damage is
obtained following Equation 4, which was previously calibrated for Banat seismic area by the
authors and the most probable damage state for each building, for the considered seismic
scenario, is obtained [5].
  
 (3)
 󰇣  󰇡
 󰇢󰇤 (4)
, where Φ is considered 2.3 because the residential predominant function of the investigated
buildings [21].
3.2 Results
The seismic vulnerability influenced by the cultural value, for each individual investigated
building, is illustrated in Figure 5 and shows expected damages states from D2 to D4, which
indicates possible damages from only to non-structural elements till consistent damages to
structural elements. The individual damage state, correlated with several other parameters, are
illustrated in Table 3.
Figure 5: Seismic vulnerability curves influenced by the cultural value for each individual investigated buildings.
No.
Street
Picture
Position
Ground
floor
(square
meters)
Floor no.
(with
basement)
IV CULT
Expected
damage
state
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I. Onescu, E. Onescu and M. Mosoarca
1
16th
December
Corner
1069.32
4
103.05
DS3
2
Tudor
Vladimirescu
End
389.23
3
92.9
DS2
3
Tudor
Vladimirescu
Line
356.47
3
133.85
DS3
4
Miron
Costin
Corner
770.88
3
87.175
DS2
5
Miron
Costin
Line
439.23
3
98.675
DS2
6
Miron
Costin
Line
349.55
3
87.925
DS2
7
16th
December
Corner
1375
4
163.175
DS4
8
16th
December
Line
342.35
4
111.225
DS3
9
16th
December
Line
349.79
3
100.025
DS3
Table 3: Correlation of each individual building to the expected damage state.
The mean vulnerability curve of the entire aggregate is presented in Figure 6, highlighting a
medium seismic vulnerability influenced by the cultural value, with a general D3 expected
damage state.
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I. Onescu, E. Onescu and M. Mosoarca
Figure 6: Mean seismic vulnerability curves influenced by the cultural value for the entire aggregate.
Moreover, there was investigated the relations between the vulnerability index for the
investigated buildings, with focus on the buildings that are on a corner position (Figure 7) or
with the most number of levels (Figure 8). After this correlation, there can be said that in
general, with some exceptions, the most vulnerable buildings are the ones that are the tallest
and in corner position.
Figure 7: Vulnerability index for all buildings, with highlight on the buildings located in a corner position in the
aggregate.
Figure 8: Vulnerability index for all buildings, with highlight on the highest buildings within the aggregate.
Building
1
Building
2
Building
3
Building
4
Building
5
Building
6
Building
7
Building
8
Building
9
0
30
60
90
120
150
180
Iv
Building
1
Building
2
Building
3
Building
4
Building
5
Building
6
Building
7
Building
8
Building
9
0
30
60
90
120
150
180
Iv
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I. Onescu, E. Onescu and M. Mosoarca
In the end, there was investigated the vulnerability index without the consideration of the
architectural-artistic, urbanistic and socio-economic parameters, to observe how much the
cultural value could influence the mean vulnerability of the case study buildings. The
comparison between the vulnerability curves with and without cultural value is presented in
Figure 9, showing that the consideration of the parameters that are not related only with the
structural system lead to the increase of the mean vulnerability with 6%, without changing the
expected mean damage state.
Figure 9: Comparison between mean vulnerability curves with and without the cultural value considered.
4 CONCLUSIONS
The case study building in Timisoara were investigated not only from a structural point of
view, but also from a cultural perspective, by considering some supplementary investigations
parameters that evaluates the architectural-artistic, urbanistic and socio-economic value of the
heritage buildings. The results of the assessment are concluded bellow, as follows:
• The investigated historical masonry buildings in Iosefin district, Timisoara, present a
medium cultural value, which influences the seismic vulnerability.
• The investigated buildings present a medium seismic vulnerability for the specific seismic
scenario (macroseismic intensity IX EMS-98).
• The less vulnerable building is expected to be in the D2 damage state, meaning only non-
structural damages, while the most vulnerable buildings is expected to reach D4 damage
state, meaning also extensive damages to structural elements.
• The general expected damage state for the entire aggregate is D3, which means significant
damage to non-structural elements and minor damage to the structural ones.
• Despite the D3 damage state for the aggregate, which isn’t dangerous for structural safety,
a lot of architectural-artistic assets could be damaged in case of an earthquake.
• The most vulnerable buildings are in general the ones that are the tallest and in corner
positions, but some exceptions occur due to the different levels of decay between buildings.
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