###### Abstract
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**ID** & **Method** & **Accuracy** & \
\begin{tabular}{c} **Scope of** \\ **Application** \\ \end{tabular} & **Number of Points** & **Benchmark** &
\begin{tabular}{c} **Results** \\ **Representation** \\ \end{tabular} & **Application** \\ \hline
1 & dial indicator & um & SD & \
\begin{tabular}{c} single or multiple \\ points/each time \\ \end{tabular} & GD &
\begin{tabular}{c} changes relative \\ to the earth \\ changes from \\ horizontal line of sight \\ \end{tabular} & commonly \\
2 & level & mm & SD & \
\begin{tabular}{c} single point/ \\ each time \\ \end{tabular} & GD &
\begin{tabular}{c} changes from \\ horizontal line of sight \\ changes from \\ horizontal line of sight \\ \end{tabular} & commonly \\
3 & theodolite & cm & SD & \
\begin{tabular}{c} single point/ \\ each time \\ \end{tabular} & GD &
\begin{tabular}{c} changes from \\ horizontal line of sight \\ changes from the initial \\ line of sight \\ \end{tabular} & commonly \\
4 & total station & mm & SD & \
\begin{tabular}{c} single point/ \\ each time \\ \end{tabular} & IP &
\begin{tabular}{c} changes from the initial \\ line of sight \\ \end{tabular} & commonly \\
5 & inclinometer & cm & SD/DD & \
\begin{tabular}{c} single or multiple \\ points/each time \\ \end{tabular} & IR &
\begin{tabular}{c} change from \\ initial state \\ \end{tabular} & not much \\
6 & photo-electric imaging & mm–cm & SD/DD & \
\begin{tabular}{c} single point/ \\ each time \\ \end{tabular} & OA &
\begin{tabular}{c} change from \\ initial position \\ \end{tabular} & commonly \\
7 & connecting pipe & mm & SD & \
\begin{tabular}{c} single or multiple \\ points/each time \\ \end{tabular} & HP &
\begin{tabular}{c} change from \\ initial state \\ \end{tabular} & commonly \\
8 & \begin{tabular}{c} differential GPS \\ method \\ \end{tabular} & cm & SD/DD & \
\begin{tabular}{c} single or multiple \\ points/each time \\ \end{tabular} & GD &
\begin{tabular}{c} variation with respect \\ to geodetic coordinates \\ variation relative to \\ collimated laser beam \\ \end{tabular} & commonly \\
9 & laser method & mm & SD/DD & \
\begin{tabular}{c} single point/ \\ each time \\ \end{tabular} & CL &
\begin{tabular}{c} variation relative to \\ collimated laser beam \\ \end{tabular} & not much \\ \hline \hline \end{tabular}  
* Note: scope of application: SD—static deflection, DD-low frequency dynamic; benchmark: GD—geodetic datum, IP—initial position line of sight reference, IR—inertial reference, OA—optical axis reference of imaging system, HP—horizontal plane. CL—collimated laser beam reference.  
\end{table} 
Table 1: Comparison of different displacement sensors. monitoring. Therefore, it is necessary to upgrade the existing deflection monitoring products to reduce costs and simplify on-site installation. Analysis of the Requirements for Displacement Monitoring Indicators of Short and Medium Span Bridges  
In this paper, some short and medium-span, simply supported, girder bridges in practical engineering were selected to establish a finite element calculation model to study the constant live load ratio [11; 16]. Using Midas Civil software, the finite element model of the traditional beam element was analyzed according to the Chinese highway bridge design code and the general load code. The software automatically loaded the influence line according to the layout lane based on the Pingli Highway project in Jiashan Town, Zhejiang Province, which is a first-class highway with two lanes. The design load grade is autoload-20 and trailer-load-100. The upper structure of the bridge is mainly composed of reinforced concrete and post-tensioned, prestressed, concrete hollow slabs [17].