## 5 Conclusions  
The bridge single-pier jacking retrofit will make the bridge undergo large deformation, so the bridge single-pier jacking retrofit for the bridge is a severe test; this paper uses a built model to analyze the bridge power response when the vehicle is travelling at different speeds, vehicle weights, and lanes, including the case of multi-lane traffic; secondly, the \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Eccentric Position** & **Lane 4** & **Lane 5** & **Lane 6** \\ \hline \multirow{2}{*}{Impact factor \(\mu\)} & Bridge median span & 0.67 & 0.68 & 0.71 \\  & Span center of the lane & 0.69 & 0.72 & 0.76 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Bridge impact factors for different deflection loads. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Pavement Grade** & **Smooth** & **Grade A** & **Grade B** & **Grade C** \\ \hline \hline Impact factor \(\mu\) & 0.57 & 0.67 & 0.73 & 0.86 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Impact coefficients in spans of bridges with different levels of unevenness. bridge power response is compared before and after the bridge jacking retrofit; lastly, the impact coefficient of the bridge is analyzed. The effect of the single-pier jacking retrofit on the impact coefficient of the bridge was analyzed. Finally, the effect of single pier jacking on the impact coefficient of the bridge was analyzed; the following conclusions are drawn:  
(1) Increases in vehicle speed, vehicle weight, and deck unevenness led to an enormous vibration response and impact coefficient of the bridge, but when the vehicle speed exceeded 80 km/h, the impact coefficient of the bridge decreased rather than increased; the more significant the distance of deflection under the same vehicle speed, load and deck unevenness level, the larger were the vibration response of the bridge and the corresponding impact coefficient. (2) After the single-pier jacking modification, the dynamic deflection of the bridge increased from 0.6105 mm before jacking to 0.62 mm after jacking, but the increase was only 1.56%. Therefore, the single-pier jacking of the bridge had no significant effect on the excitation of the bridge when the vehicle was travelling on it; this effect could be ignored. (3) The comparison of the dynamic response and impact coefficient before and after the bridge's single-pier jacking reveals that the bridge's single-pier jacking modification increased the bridge's dynamic and impact coefficient. However, the increase was negligible at 3.07%. Therefore, the single-pier jacking modification of the bridge increased the bridge's capacity under dynamic impact and also enhanced the durability and safety of the bridge. (4) The single-pier jacking modification of bridges can improve the bearing capacity of bridges under dynamic impacts and simultaneously improve the durability and safety of bridges. Since the four-ade engineering transporter is the vehicle that travels the most on bridges, only one vehicle was considered in this study, and the impacts of multi-vehicle combinations or fleets of vehicles travelling on bridges might be considered in the next step. For the evaluation of driving comfort before and after the jacking of a single pier, the next step may be to consider the coupling of people-vehicles-bridges and to refine the study of driving comfort. Conceptualization, Z.Y. and C.Y. ; methodology, Z.Y. ; software, Z.Y. ; validation, Z.Y., C.Y. and H.L. ; formal analysis, Z.Y. ; investigation, Z.Y. ; resources, Z.Y. ; data curation, Z.Y. ; writing--original draft preparation, Z.Y. ; writing--review and editing, Z.Y. ; visualization, Z.Y. ; supervision, Z.Y. ; project administration, Z.Y. ; funding acquisition, C.Y. All authors have read and agreed to the published version of the manuscript. This research was funded by [Natural Science Foundation of Hebei Province] grant number [E2018201106]. This research relies on the single-pier jacking reconstruction project of Dongzhuang Bridge in Xushui District, Baoding City, Hebei Province.