## 3 Procedure, Structural Models, and Strong Motions
### Strong Motion Records  
The models are excited by fifteen strong motion records, which are representative of the area where the structural models are located; their main characteristics are given in Table 5 and are denoted as Strong Motions 1 to 15. It is worth mentioning that, for example, ASCE 7-16 establishes a minimum of eleven motion pairs to achieve reliable estimates of mean structural response in nonlinear dynamic analysis. The data of the seismic records were obtained from the Data Set of the National Strong Motion Program (NSMP) of the United States Geological Survey (USGS). The horizontal seismic component with the greater peak ground acceleration (PGA), as well as the vertical component and the tributary gravity load, are simultaneously applied to the PMRF oriented in the \(EW\) structural directions. Then, the horizontal component with the greater PGA is replaced by the other horizontal component (with the lower PGA), which together with the vertical component and the gravity loads are applied to the PMRF oriented in the \(NS\) direction. It must be noted that the PMRF oriented in the \(EW\) direction of the three-story building, or of the nine-story building, is identical to that of the \(NS\) direction, but they are not identical for the twenty-story building. The pseudo-acceleration response spectra for both horizontal components and 3% of critical damping are shown in Figure 4a,b for the \(NS\) and \(EW\) directions, respectively. The spectra are scaled to have a \(\mathrm{S_{a}/g}=1.0\) at a period of 1.03 s. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Designation**} & \multirow{2}{*}{**Record Information**} & **Magnitude** & **PGA (m/s2)** & \multicolumn{3}{c}{**Period (s)**} \\  & & **(Mw)** & **NS** & **EW** & **NS** & **EW** \\ \hline LA1 & Imperial Valley, 1940 & 6.9 & 4.52 & 6.63 & 0.53 & 0.46 \\ LA2 & Imperial Valley, 1979 & 6.5 & 3.86 & 4.78 & 0.16 & 0.34 \\ LA3 & Landers, 1992 & 7.3 & 4.14 & 4.17 & 0.73 & 0.33 \\ LA4 & Kern, 1952 & 7.3 & 5.11 & 3.53 & 0.25 & 0.23 \\ LA5 & Loma Prieta, 1989 & 7 & 6.53 & 9.50 & 0.21 & 0.2 \\ LA6 & Northridge, 1994, Newhall & 6.7 & 6.65 & 6.45 & 0.31 & 0.31 \\ LA7 & Northridge, 1994, Rinaldi & 6.7 & 5.23 & 5.69 & 0.39 & 0.29 \\ LA8 & Northridge, 1994, Sylmar & 6.7 & 5.59 & 8.03 & 0.31 & 0.36 \\ LA9 & North Palm Springs, 1986 & 6 & 10.01 & 9.68 & 0.17 & 0.21 \\ LA10 & Coyote Lake, 1979 & 5.7 & 5.79 & 3.28 & 0.15 & 0.21 \\ LA11 & Morgan Hill, 1984 & 6.2 & 3.12 & 5.36 & 0.18 & 0.16 \\ LA12 & Parkfield, 1966, Cholame 5W & 6.1 & 7.65 & 6.20 & 0.37 & 0.3 \\ LA13 & Parkfield, 1966, Cholame 8W & 6.1 & 6.81 & 7.75 & 0.17 & 0.21 \\ LA14 & North Palm Springs, 1986 & 6 & 5.08 & 3.71 & 0.13 & 0.21 \\ LA15 & Whittier, 1987 & 6 & 7.54 & 4.70 & 0.7 & 0.28 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Seismic records. In order to have different levels of deformation, which range from elastic to significant inelastic behavior, the strong motions are scaled in terms of the spectral pseudo-acceleration evaluated at the fundamental vibration period of the structure (\(S_{a}\) (\(T_{1}\))). The values of \(S_{a}\) vary from 0.2 g to 1.2 g with increments of 0.2 g for the three-story building, from 0.1 g to 0.5 g for the nine-story building with increments of 0.1 g, and from 0.1 g to 0.25 g for the twenty-story building with increments of 0.05 g. For the lowest strong motion intensities mentioned above, the buildings' behavior was essentially elastic (maximum drift of about 0.5%), particularly for the three- and nine-story buildings; for the intermediate seismic intensities, moderate yielding occurred (maximum drift of about 1.6%), while for the highest intensities, a deformation state very close to collapse was developed for some strong motions; the maximum drifts were about 3.5% for a few particular strong motions. Therefore, the largest seismic intensities of 1.2 g, 0.5 g, and 0.25 g produced, for some seismic records, a maximum drift of about 3.5% in the three-, nine-, and twenty-story models, respectively.