# Vulnerability and Seismic Exposure of Residential Building Stock in the Historic Center of Alcamo
## 3 Exposure of the Historic Center of Alcamo
In Compartment C02, there were also buildings belonging to the CAR3 type, which are more modern and taller, built from the late 1990s with 4 or 5 floors, with a resistant system and structural characteristics similar to CAR2, classifiable as infilled frame structures with generally sturdy masonry, rarely light, and regular in plan and height dimensions. Table 2 shows the estimated distributions of the different types in the two compartments obtained through estimates from the interviewed technicians and compared with ISTAT data from the 2001 and 2011 censuses. For the two Compartments, C01 and C02, sub-type MUR2/3_SCA, collecting buildings with masonry walls and cast-in-place RC floors, and sub-typology MUR2/3_CONF, collecting buildings with reinforced concrete floors and mixed confined masonry structure, were generated from the MUR2 and MUR3 typologies. This classification was adopted for reasons that are clarified below. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & **Tot. Buildings** & **Typology** & **\%** & **Tip EMS98** & \(\mathbf{V_{I}}\)* & \(\mathbf{\Sigma w_{I}}\)**DVI\({}_{M}\)** & \(\mathbf{V_{I}}\) \\ \hline \multirow{10}{*}{**C01**} & \multirow{4}{*}{640} & MUR1 & 18\% & M1 & 0.873 & 0.093 & 0.966 \\ \cline{3-6}  & & MUR2 & 26\% & M3 & 0.74 & 0.124 & 0.864 \\ \cline{2-6}  & & MUR3 & 22\% & M3 & 0.74 & 0.076 & 0.816 \\ \cline{2-6}  & & MUR2/3\_SCA & 5\% & M6 & 0.616 & 0.076 & 0.692 \\ \cline{2-6}  & & MUR2/3\_CONF & 3\% & M7 & 0.451 & 0.174 & 0.625 \\ \cline{2-6}  & & CAR1 & 21\% & RC1 & 0.644 & \(-\)0.02 & 0.642 \\ \cline{2-6}  & & CAR3 & 5\% & RC3 & 0.324 & \(-\)0.02 & 0.322 \\ \hline \multirow{10}{*}{**C02**} & \multirow{4}{*}{2465} & MUR1 & 10\% & M1 & 0.873 & 0.1 & 0.973 \\ \cline{2-6}  & & MUR2 & 20\% & M3 & 0.74 & 0.088 & 0.828 \\ \cline{1-1} \cline{2-6}  & & MUR3 & 7\% & M3 & 0.74 & 0.038 & 0.778 \\ \cline{1-1} \cline{2-6}  & & MUR2/3\_SCA & 17\% & M6 & 0.616 & 0.038 & 0.654 \\ \cline{1-1} \cline{2-6}  & & MUR2/3\_CONF & 11\% & M7 & 0.451 & 0.136 & 0.587 \\ \cline{1-1} \cline{2-6}  & & CAR1 & 20\% & RC1 & 0.644 & 0.063 & 0.707 \\ \cline{1-1} \cline{2-6}  & & CAR2 & 10\% & RC2 & 0.484 & \(-\)0.01 & 0.474 \\ \cline{1-1} \cline{2-6}  & & CAR3 & 5\% & RC3 & 0.324 & \(-\)0.03 & 0.294 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Vulnerability indices and percentages of wall types. The performed analyses showed that (see Table 2), in Compartment C01, there is a prevalence of masonry buildings with pseudo-regular rough-hewn stone MUR2 (26%) or squared MUR3 (22%), with a reduced presence of sub-types MUR2/3_SCA (5%) and MUR2/3_CONF (3%). All of the abovementioned typologies were made of good quality masonry; reduced, however, is the presence of irregular stone masonry irregularly textured MUR1 (18%). There was also a significant presence of reinforced concrete buildings, with the oldest in the CAR1 typology, constituting 21% of the total, and the newest in CAR3, constituting 5%. In Compartment C02, the presence of MUR2 masonry was still significant (20%); however, the overall preponderant was the percentage of types characterized by the presence of reinforced concrete floors (17%) or confined masonry (11%), along with 7% of MUR3. About a third of the buildings in the compartment were made of reinforced concrete (35%), with a predominance of the most vulnerable CAR1 buildings (20%), constructed without an adequate earthquake-proof design. With reference to the height, for buildings in Compartment C01, 58% were 2- or 3-story masonry (44% in C02), while only 15% (14%) were 4-story masonry, a feature that increases their seismic vulnerability. The reinforced concrete buildings in the two compartments were predominantly 3-4 stories, while only 2.5% in Compartment C02 had more than 4 stories.