## 4 Case Study Definition
### Design Situations and Loads  
Even though Seville is not a high seismic activity in a worldwide context, it has been struck by several earthquakes throughout history. Among them, the 1755 Lisbon earthquake can be highlighted, leaving about 10 people dead and causing severe damage to many ancient buildings such as the Salvador Church and the Cathedral [34]. For this reason, two design situations have been considered for geotechnical verifications of the case study: (i) persistent situation, which corresponds to the usual condition of use; and (ii) seismic situation, which includes the exceptional condition caused by an earthquake. For each design situation, safety against overturning, sliding, and bearing is evaluated independently by using the CTE and the Eurocode expressions.  
The first situation (i) considers the weight of the wall itself, the static lateral earth pressure of the backfill on both sides of the wall, a uniform surcharge of 5 kN/m\({}^{2}\) on the street and the action of the wind. For all the resistance verifications, two leading variable actions have been considered, namely the uniform imposed load on pavement and the wind, acting in both cases on the side of the wall next to the street. To compute the latter, a return period of 50 years has been considered. For the city of Seville, the fundamental value of the basic wind velocity is 26 m/s. As the case study is located in an urban area, terrain category IV is selected in accordance with CTE-DB-SE, \(k\), \(L\), and \(Z\) parameters being equal to 0.22, 0.3, and 5.0 m respectively. In the case of Eurocode 1, terrain category III is chosen due to the low height of nearby buildings. Thus, \(z_{0}\) is equal to 0.3 m whereas \(z_{min}\) takes a value of 5 m. It should be noted that the effect of wind for free-standing walls is not included in the CTE-DB-SE, taking pressure coefficient from Eurocode 1. Although the wall is divided into different zones, verifications is carried out for the one with the greater pressure coefficient. In a certain way, the large towers attached to the walls represent corners and, consequently, a value of 2.1 for the pressure coefficient has been taken.  
In the second situation (ii) the inertia forces on the wall and the dynamic lateral earth pressure derived from the backfills and the imposed load are considered, but the action of the wind is neglected as its quasi-permanent value (\(\psi\)2) equals to zero. Horizontal seismic action is directed towards the backfill on the street side. As for vertical seismic action, it has been considered to act upward and downward. According to NCSE-02, the basic seismic acceleration (\(a_{b}\)) is set equal to 0.07 g for Seville and the dimensionless risk coefficient is set to 1.3 because of the special importance of the structure. The soil coefficient (\(C\)) is obtained from survey data taken in the vicinity of the case study, taken a value of 1.39. The application of Eurocode 8 leads to a value of 0.088 g for the design ground acceleration on type A, considering the location of the structure. As the building is considered a cultural asset, the structure is considered to be of importance class IV and, thus, the importance factor (\(\gamma_{I}\)) is taken as 1.4. For gravity walls with weak connections to the towers as in the case of rammed earth ramparts, \(r\) factor is taken as 1.5 on the safety side. High values of this parameter result in a reduction of the dynamic thrust. Data from the abovementioned surveys reveal that the type of soil beneath the foundation of the rampart is of class B and the soil factor (\(S\)) is set equal to 1.23.