# Experimental and Numerical Study on Dynamics of Two Footbridges with Different Shapes of Girders
## 3 Results and Discussion
### Assessment of Pedestrian Effects
#### 3.2.2 Example 2  
In the case of the arch footbridge above the University Route in Bydgoszcz, the peak acceleration values were much higher (see Table 7). The highest accelerations occurred for the synchronous march. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Walk**} & \multicolumn{4}{c}{**Run**} & **Jump** \\ \cline{2-10}
**Sensor** & \multicolumn{2}{c}{**Synchronous**} & \multicolumn{2}{c}{**Free**} & \multicolumn{2}{c}{**Synchronous**} & \multicolumn{2}{c}{**Free**} & **Synch.** \\ \cline{2-10}  & **6 ped.** & **12 ped.** & **6 ped.** & **12 ped.** & **6 ped.** & **12 ped.** & **6 ped.** & **12 ped.** & **6 ped.** \\ \hline  & \multicolumn{4}{c}{Vertical acceleration (m/s\({}^{2}\))} & \\ a1z & 0.21 & 0.31 & 0.13 & 0.12 & 0.21 & 0.25 & 0.11 & 0.12 & 0.36 \\ a2z & 0.20 & 0.31 & 0.17 & 0.14 & 0.20 & 0.23 & 0.13 & 0.15 & 0.43 \\ a3z & 0.24 & 0.31 & 0.13 & 0.14 & 0.40 & 0.48 & 0.13 & 0.15 & 0.48 \\ a4z & 0.14 & 0.22 & 0.05 & 0.06 & 0.37 & 0.53 & 0.13 & 0.20 & 0.48 \\ a5z & 0.20 & 0.28 & 0.11 & 0.12 & 0.30 & 0.42 & 0.11 & 0.14 & 0.39 \\ a6z & 0.18 & 0.30 & 0.15 & 0.14 & 0.18 & 0.21 & 0.12 & 0.12 & 0.40 \\ a7z & 0.23 & 0.32 & 0.13 & 0.12 & 0.15 & 0.20 & 0.12 & 0.13 & 0.36 \\  & \multicolumn{4}{c}{Horizontal acceleration (m/s\({}^{2}\))} & \\ a2y & 0.02 & 0.02 & 0.01 & 0.01 & 0.02 & 0.02 & 0.01 & 0.01 & 0.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Peak recorded acceleration due to human-induced loading acting on the arch bridge above expressway S8. \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Walk**} & \multicolumn{4}{c}{**Run**} & **Jump** \\ \cline{2-10}
**Sensor** & \multicolumn{2}{c}{**Synchronous**} & \multicolumn{2}{c}{**Free**} & \multicolumn{2}{c}{**Synchronous**} & \multicolumn{2}{c}{**Free**} & **Sync** & **Free** \\ \cline{2-10}  & **6** & **9** & **12** & **6** & **12** & **6** & **9** & **12** & **6** & **12** & **6** & **12** \\ \hline  & \multicolumn{4}{c}{Vertical acceleration (m/s\({}^{2}\))} & \\ a1z & 0.93 & 1.83 & 1.19 & 0.05 & 0.07 & 0.42 & 0.58 & 0.62 & 0.22 & 0.48 & 1.24 & 2.16 \\ a2z & 0.83 & 1.84 & 1.08 & 0.09 & 0.08 & 0.45 & 0.68 & 0.59 & 0.23 & 0.37 & 1.31 & 2.23 \\ a3z & 0.72 & 1.49 & 0.93 & 0.06 & 0.07 & 0.41 & 0.65 & 0.70 & 0.21 & 0.40 & 1.12 & 1.59 \\ a4z & 0.91 & 1.83 & 1.14 & 0.05 & 0.04 & 0.35 & 0.56 & 0.55 & 0.22 & 0.40 & 1.17 & 2.20 \\ a5z & 0.40 & 1.12 & 0.50 & 0.07 & 0.08 & 0.31 & 0.50 & 0.39 & 0.13 & 0.18 & 0.73 & 1.16 \\ a6z & 0.35 & 0.75 & 0.41 & 0.05 & 0.05 & 0.29 & 0.37 & 0.37 & 0.12 & 0.17 & 0.71 & 0.80 \\ a7z & 0.34 & 0.59 & 0.46 & 0.07 & 0.03 & 0.30 & 0.29 & 0.29 & 0.09 & 0.12 & 0.53 & 0.57 \\  & \multicolumn{4}{c}{Horizontal acceleration (m/s\({}^{2}\))} & \\ a1y & 0.18 & 0.19 & 0.16 & 0.01 & 0.01 & 0.08 & 0.09 & 0.11 & 0.03 & 0.06 & 0.22 & 0.37 \\ a5y & 0.13 & 0.24 & 0.17 & 0.02 & 0.02 & 0.12 & 0.13 & 0.13 & 0.04 & 0.05 & 0.31 & 0.26 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Peak recorded acceleration due to human-induced loading acting on the arch bridge above University Route in Bydgoszcz. It was induced by a group of nine persons with a value equal to 1.84 m/s\({}^{2}\). However, increasing the number of pedestrians did not increase the acceleration level; instead, its reduction was observed. This is due to difficulties with ensuring synchronization among pedestrians with larger groups. Lower acceleration levels occurred for the run. It was caused by the frequency of excitation, which is not close to any of the bridge's natural vibrations. The peak acceleration values, irrespective of the type of excitation, occurred in the part where the steel girder was lower above the deck. This is due to the lower stiffness of the structure, and thus the occurrence of the maximum amplitude of first four mode shapes in this area. The horizontal levels of the deck acceleration were significantly smaller than vertical ones, but they could not be considered negligible.