## 2 Experimental Study of a Human Mass-Spring-Damping Model
### Identification of Pedestrian Dynamics Model Parameters  
In this study, four walking cases were selected for the single person walking test. The walking step frequency was 1.5, 1.7, 1.9 and 2.1 Hz, respectively. Two tests were conducted for each walking case, and the final results were obtained by taking the average of the two tests. To investigate whether pedestrians of different stature have an effect on human parameters, we divided the subjects into two groups by their height. The first group is the high stature group (Group 1), whose stature is greater than 170 cm. The second group is the short stature group (Group 2), whose stature is less than 170 cm. The identification results of the dynamic parameters of the coupled pedestrian-structure system for various walking cases are analyzed in the following part. Tables 7-10 give the results of the identification of the dynamic characteristic parameters of the system for each walking case, where \(f_{s}^{{}^{\prime}}\) is the frequency of the coupled human-structure system; \(\zeta_{s}^{{}^{\prime}}\) is the damping ratio of the coupled human-structure system; \(f_{h}\) is the frequency of the pedestrian MSD model; and \(\xi_{h}\) is the damping ratio of the pedestrian MSD model. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Group** & **Macras** & **Free Vibration Decay Method** \\ \hline Test 1 & 0.82\% & 0.86\% \\ Test 2 & 0.93\% & 0.90\% \\ Test 3 & 0.86\% & 0.89\% \\ Average & 0.87\% & 0.88\% \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Comparison of damping ratio identification results. Figure 11: Floor acceleration response before and after filtering: (**a**) before filtering; and (**b**) after filtering. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Mode**} & \multicolumn{2}{c}{**Test 1**} & \multicolumn{2}{c}{**Test 2**} & \multicolumn{2}{c}{**Test 3**} & \multicolumn{2}{c}{**Average**} \\ \cline{2-9}  & \(f_{s}\) **(Hz)** & \(\xi_{s}\)**(\%)** & \(f_{s}\) **(Hz)** & \(\xi_{s}\)**(\%)** & \(f_{s}\) **(Hz)** & \(\xi_{s}\)**(\%)** & \(f_{s}\) **(Hz)** & \(\xi_{s}\)**(\%)** \\ \hline
1 & 4.100 & 0.82 & 4.100 & 0.93 & 4.140 & 0.86 & 4.113 & 0.87 \\
2 & 8.850 & 0.53 & 8.800 & 0.55 & 8.800 & 0.53 & 8.817 & 0.54 \\
3 & 10.900 & 0.78 & 10.900 & 0.98 & 11.000 & 0.81 & 10.933 & 0.86 \\
4 & 13.400 & 0.81 & 13.400 & 0.75 & 13.400 & 0.67 & 13.400 & 0.74 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Identification results of the modal parameters of the floor slab. Based on the results of the parameter identification given in Tables 10 and 11, it can be noticed that the parameters of the MSD model for a walking pedestrian are significantly different from those of a stationary human body [39]. The human body exhibits a significantly lower dynamic frequency in walking process than in a standing position and closer to its single-legged bent position [52], a result consistent with the physical mechanisms of the walking process. When the pedestrian walks at a 1.5 Hz step frequency, the mean dynamic frequency of the subjects in Group 1 is 2.1353 Hz with a damping ratio of 29.02%, and the mean frequency of the subjects in Group 2 is 2.2144 Hz with a damping ratio of 26.17%. When a single walker walks at different pacing frequencies, his/her dynamic frequency exhibits different values. The results of the MSD model parameter identification for each walking condition are presented in Table 10, together with the results of other researchers' parameter identification of the human MSD model. As can be observed in Table 10, the frequencies and damping ratios of the pedestrian MSD model are less than those of the standing position, and, in particular, the human body frequencies are significantly lower than those of the standing position.