## 3 Case Study
### Selection of Near-Fault Records  
The seismic events that hit Italy in 2016 and 2017, known as the Central Italy earthquakes, had been a series of four seismic events occurred in Italy between August and October 2016 [22] with minor events in January 2017. The two major earthquakes were those that occurred on August 24 and October 30, 2016 with magnitudes Mw = 6 and 6.5, respectively. In both cases, many seismic stations close to the epicenters recorded the strong ground motion. In some cases, the records presented typical near-fault pulse-like behavior, as highlighted both in the joint report written by the ReLUIS-INGV Workgroup [23] and reported in the European Strong Motion Database [24]. Table 2 reports the ground motion parameters of the selected records for August 24. The Joyner and Boore distance (R\({}_{\text{jb}}\)) is the distance from the fault surface projection, and it is reported together with the epicentral distance (R\({}_{\text{epi}}\)).  
The characteristics of the main events were reported by many authors. The study by [PERSON] et al. [25] reports, among the other pieces of information, the strike of the causative fault of 156 degrees with respect to the North-South direction for the event of August 24. According to these indications, the horizontal records were rotated in order to obtain the Fault Normal and Fault Parallel components of the ground motion. Figure 3 reports the Fault Normal components of the acceleration time series of the selected near-fault ground motion records.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Load** & \multicolumn{2}{c}{**Value**} \\  & **[kh/m]** & **[kh]** \\ \hline Dead load & 200.0 & - \\ Live load (lumped)—vehicle & - & 1200.0 \\ Live load - distributed & 54.5 & - \\ \hline \hline \end{tabular}
\end{table}
Table 1: Loads and actions.  
Figure 2: Structural details of selected bridge: (**a**) longitudinal view, highlighting the piers and span length; (**b**) bridge pier, elevation view; bridge pier cross-sections: pier 1 and 3 (**c**), pier 2 (**d**).  
Figure 4 reports the velocity time series (black plots) of the FN components of the 6 seismic stations selected among those which recorded the strong ground motion on 24 August 2016. For each time series, the pulses (red plots) were extracted using the procedure provided by [PERSON] (2016). This method allows to also evaluate the period T\({}_{\text{p}}\) of the pulse. In addition, the peak-to-peak velocity, as given by the difference between the two peaks in one cycle of motion, was evaluated and reported for each record. This parameter can be more useful than PGV because generally, the pulses generated during near-fault strong motion are double-sided ([PERSON] et al., 2017).  
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Station** & **R\({}_{\text{epi}}\) (km)** & **R\({}_{\text{JB}}\) (km)** & **PGA\_EW** & **PGA\_NS** & **PGA\_Z** & **PGV\_EW** & **PGV\_NS** & **PGV\_Z** \\ \hline AMT & 8.5 & 1.4 & 0.87 & 0.38 & 0.40 & 43.5 & 41.5 & 33.7 \\ FEMA & 32.9 & 13.9 & 0.25 & 0.19 & 0.08 & 14.6 & 9.2 & 6.3 \\ MNF & 40.3 & 20.4 & 0.07 & 0.04 & 0.06 & 4.8 & 2.9 & 4.6 \\ NOR & 15.6 & 2.3 & 0.20 & 0.18 & 0.25 & 27.1 & 21.1 & 11.5 \\ NRC & 15.3 & 2.0 & 0.36 & 0.37 & 0.22 & 29.8 & 23.7 & 11.6 \\ RM33 & 21.1 & 13.0 & 0.10 & 0.10 & 0.04 & 9.3 & 6.2 & 5.0 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Ground motion parameters peak ground acceleration (PGA) ad peck ground velocity (PGV) of 24 August 2016 records for the different seismic stations which recorded the earthquake ground motion. Accelerations and velocities are expressed in g and cm/s, respectively. PGA = Peak Ground Acceleration; PGV = Peak Ground Velocity.  
Figure 3: Fault normal components of the acceleration time series of the selected near-fault ground motion records.