## 5 Seismic Vulnerability Assessment of the Area
### Application of Vulnerability Index Method at the Test Site  
The vulnerability indices for 111 buildings with known architectural, structural, and material features (75 in the old city center and 35 outside of the center) were calculated by the vulnerability index method. The distribution of the vulnerability index is shown in Figure 6. The vulnerability indices were included into a web map based on the geographical information system (GIS). The vulnerability index map is shown in Figure 7. Figure 7a shows the buildings divided into four vulnerability classes: low vulnerability for I\({}_{\rm v}\) < 30, from medium to low \begin{table}
\begin{tabular}{l c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multicolumn{4}{c}{**Score (s\({}_{vi}\))**} & \multirow{2}{*}{**Weight (w\({}_{i}\))**} \\ \cline{2-2} \cline{4-5}  & **A** & **B** & **C** & **D** \\ \hline Type and organization of the resistant system (P1) & 0 & 5 & 20 & 45 & 1.50 \\ Quality of the resistant system (P2) & 0 & 5 & 25 & 45 & 0.25 \\ Conventional resistance (P3) & 0 & 5 & 25 & 45 & 1.50 \\ Position of the building and foundation & 0 & 5 & 25 & 45 & 0.75 \\ (P4) & 0 & 5 & 15 & 45 & 0.50–1.25 \\ Typology of floors (P5) & 0 & 5 & 25 & 45 & 0.50 \\ Planimetric configuration (P6) & 0 & 5 & 25 & 45 & 0.50–1.00 \\ Elevation configuration (P7) & 0 & 5 & 25 & 45 & 0.25 \\ Maximum distance among the walls (P8) & 0 & 5 & 25 & 45 & 0.5–1.5 \\ Roof (P9) & 0 & 15 & 25 & 45 & 0.25 \\ Non-structural elements (P10) & 0 & 0 & 25 & 45 & 0.25 \\ State of conservation (P11) & 0 & 5 & 25 & 45 & 1.00 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Vulnerability parameters and their weights. Figure 6: Distribution of I\({}_{\rm v}\) for a sample of 111 buildings. vulnerability for \(30<\text{I}_{\text{v}}<45\), from medium to high vulnerability for \(45<\text{I}_{\text{v}}<60\), and high vulnerability for \(\text{I}_{\text{v}}>60\). The range of the values of vulnerability indices are taken according to the GNDT vulnerability classification used in the study of reconstruction of the Municipality of Arsita following the seismic event of 6 April 2009 [2,43]. More insight into the vulnerability of buildings erected in the period 1950 to 2000 can be obtained from the division of the vulnerability index map into 10% intervals (Figure 7b). The lowest vulnerability index, equal to 2.6, belongs to a two-story house with regular layout and elevation, made as a confined masonry structure with horizontal and vertical confining elements (RC ties and RC columns) and rigid horizontal diaphragms, all designed according to EC-8. The highest vulnerability index, equal to 76.9, was obtained for the Cambi Tower, a stone masonry building dating from the 15 th century. The Cambi Tower is characterized by having poorly connected walls, flexible floors, an irregular layout and elevation. A vulnerability index of 45 and beyond is ascribed to medium-high and high vulnerability buildings, respectively. Typically, high vulnerability buildings turn out being mainly located in the old city center and made of stonemasonry. In the northern part of the settlement, which does not belong to the historical center, there is a number of stone masonry buildings. Therefore, most of the buildings belong to high, medium-high and medium-low vulnerability classes. Only two buildings belong to the low vulnerability class. In the eastern and western parts of the test site, the buildings are built with concrete or clay blocks, with different confining methods: (1) without confinement; (2) with horizontal tie beams, (3) with horizontal and vertical confinement. They mostly belong to the low vulnerability class (I\({}_{\text{v}}<30\%\)). Within this class, however, there are visible differences in vulnerability. Newer buildings with brick blocks and horizontal and vertical confinement generally have the lowest vulnerability (less than 10%). Older buildings with concrete blocks and horizontal confinement approximately have an index between 10% and 20%.