# Investigation of Structural Seismic Vulnerability Using Machine Learning on Rapid Visual Screening
## 2 Materials and Methods  
### Dataset Description  
The dataset employed in the present work consists of a collection of Rapid Visual Screening measurements pertaining to 457 structures. These were drawn after the 7 September 1999 Athens earthquake [17]. The samples in the dataset exhibited a varying degree of damage across the spectrum, ranging from partial or total collapse to moderate or minimal damages. To enhance the dataset diversity, the structures were drawn from various regions in the greater Athens Metropolitan area. This mitigated the influence of local effects, such as distance from the earthquake epicenter or ground conditions, on the observed damage states. The authors in [17] took further steps to mitigate these effects; when one structure was selected from a specific building block, structures across the damage spectrum were also selected from the same area [18]. The observed damage states were classified into four distinct classes, namely:  
* \"Black\": The category suffering the most severe damages. Structures belonging to this label suffered partial or total collapse during the earthquake, crossing the so-called Collapse Limit State (CLS). * \"Red\": While the structures belonging to this label did not cross the CLS, they suffered extensive damages to their structural members and crossed the so-called Ultimate Limit State (ULS). * \"Yellow\": Structures of this category suffered only moderate damages to their structural members. While these structures did not cross the ULS, they did cross the so-called Serviceability Limit State (SLS). * \"Green\": The structures of this class suffered only minor damages. The distribution of structures across the damage spectrum is shown in the following Table 1. Table 2 shows which attributes have been considered by each Seismic Code. It is a fact that each code considers its own vector of structural aspects [3; 4; 5; 6; 7; 8; 17]. 1. Structural type: In general, Seismic Codes distinguish buildings according to their structural type, e.g., framed structures or frames with shear walls [8]. 2. Significant height: This is an attribute that most Seismic Codes take into consideration. It affects structures whose height exceeds a predefined threshold. However, this threshold varies between Seismic Codes. For example, FEMA sets this threshold at 7 stories, while this threshold for OASP equals 5. In addition to the above, some Seismic Codes, e.g., that of India, distinguish structures with \"moderate height\" as a separate category. 3. Poor condition: This attribute accounts for potential deterioration in the design seismic capacity of the building. This may be due to corroded reinforcement bars or due to poor concrete quality (e.g., aggregate segregation or erosion) [8]. 4. Vertical irregularity: This attribute pertains to structures with significant variations in their height, which leads to discontinuities in the paths of the vertical loads. 5. Horizontal irregularity: This feature affects structures whose floor plans exhibit sharp, re-entrant corners, such as \"L\", \"T\", or \"E\", which have the potential to develop higher degrees of damage [8]. 6. Soft story: This pertains to structures wherein one story has significantly less stiffness than the rest; for example, due to a discontinuity of the shear walls. 7. Torsion: Structures with high eccentricities suffer from torsional loads during an earthquake. This could lead to higher degrees of damage. 8. Pounding: This attribute is considered when two adjacent structures do not have a sufficient gap between them and especially when the buildings have different heights, which may lead to the slabs of one structure ramming into the columns of the other. Heavy non-structural elements: While they are non-structural, the displacement of such elements during an earthquake can lead to eccentricities and to additional torsion. * Short columns: This attribute refers to columns wherein modifications have resulted in a reduction in their active length.