## 3 Description of the Case-Study Hospital Building
### Numerical Models and Analysis Methods
The force-deformation relations (capacity curves on Figure 12) for the structural elements and acceptance criteria for the performance requirements were defined in accordance with Eurocode 8-3 [44], but considered also the guidelines provided by National Institute of Standards and Technology (NIST) [46; 47; 48], Federal Emergency Management Agency (FEMA) [49; 50; 51; 52] and ASCE [45] for the derivation of the cyclic backbone curves. Furthermore, guidelines [53] and scientific papers presenting the experimental testing of walls (e.g., [54; 55; 56; 57]) were considered for squat walls, because of the unreliability of their failure mechanisms and ductility calculation. Large structural redundancy causes significant robustness, although failure mechanisms of primary elements are mostly non-ductile shear failures, which was taken into account during analyses. The shear capacities of structural elements were calculated on the basis of the concrete strength and as-built reinforcement. Different design regulations [44; 45; 58; 59] were accounted for and critically compared, based on an engineering judgement. The capacity curves and acceptance criteria for lightly reinforced walls were also supplemented by experimental studies presented in [60; 61]. The selected values were then used for the definition of the shear hinges. Column capacity to interaction of the moment and axial force was calculated according to the s  
Figure 12: Typical force–deformation relation for concrete non-ductile elements. For nonlinear time-history analyses, the local nonlinear behavior of elements was defined using hysteretic capacity curves with loading and unloading branches (degradation of the material due to cyclic loading). The vertical load was defined on the basis of the as-built structure and comprises the self-weight, additional dead loads from non-structural elements and 20% of the live load. A structural analysis for vertical loads is essential for further analyses (static or dynamic) and it is necessary to determine the internal forces and, generally, structural conditions before applying earthquake loading. The element stress state is directly linked to the stiffness and ductility of elements, and consequently their seismic performance. The level of axial force significantly affects the rotation and shear capacity of columns and walls. Because of the large number of data and model complexity, the results for vertical load will not be presented in the paper. The following methods were applied in the seismic analysis of the hospital building: a lateral force analysis (linear) according to the first vibration mode, modal response spectrum analysis (horizontal elastic and design), nonlinear static (pushover) analysis, accounting for three different load patterns, and nonlinear time-history (dynamic) analysis, using synthetic accelerograms. The first performed analysis was the lateral force analysis according to the first vibration mode of the cracked structure, although the building does not comply with all the necessary conditions for applying this method according to valid regulations, because it is irregular in terms of its height and plan. However, this method was used in the original seismic design, so it should have been accounted for. The second method applied was the modal response spectrum method, with the assumption of linearly elastic structural behavior, using uncracked and cracked sections. The structure was considered as non-ductile in calculations (DCL) and a behavior factor of q = 1.5 was used. The pushover method was applied with three load patterns tested on this building: a uniform pattern, triangular pattern (linearly varying in height) and modal pattern, taking into account the first modal shape in the considered direction. The calculation was performed by using the static method, using displacement control. Material nonlinearity was accounted for in the analysis, while geometric nonlinearity was not, because it was shown that this effect was minor due to the building stiffness and small displacements at failure.