## 3 Research Method
### Experimental Test
In the temperature monitoring system of the Tsing Ma Bridge [60; 61], several temperature sensors were embedded in the steel strands of the cables, and the effective temperature of a cable was taken as the average value of the temperatures monitored by these sensors; the specific locations of the embedded temperature sensors in the cable are shown in Figure 5.  
Figure 4: Temperature field test scheme of the Yujiabu Railway Station Building (structural diagram, measuring point layout) [119]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Bridge** & \begin{tabular}{c} **Number of Test** \\ **Sections** \\ \end{tabular} & \begin{tabular}{c} **Number of** \\ **Measuring Points** \\ \end{tabular} & **Test Time** & **Test Area** \\ \hline \hline \begin{tabular}{c} Incheon Bridge \\ [123] \\ \end{tabular} & 1 & 7 & \
\begin{tabular}{c} June, from September \\ to November, 2008 \\ \end{tabular} &
\begin{tabular}{c} Incheon, South \\ Korea \\ \end{tabular} \\ \hline \hline \end{tabular}  
Layout of measuring points at the cross-section  
\begin{tabular}{c c c} \hline \hline Sutong Bridge & 1 & 8 &
\begin{tabular}{c} From January to \\ December, 2011 \\ \end{tabular} & Jiangsu, China \\ \hline \hline \end{tabular}  
Layout of measuring points at the cross-section  
\begin{tabular}{c c c} \hline \hline Namxi Yangtze & 1 & 15 &
\begin{tabular}{c} From August 1 to \\ December 1, 2014 \\ \end{tabular} & Sichuan, China \\ \hline \hline \end{tabular}  
Layout of measuring points at the cross-section  
\begin{tabular}{c c c} \hline \hline Normandy Bridge & 1 & 12 & \
\begin{tabular}{c} From February, 1996 to \\ December, 1998 \\ \end{tabular} &
\begin{tabular}{c} Normandy, \\ France \\ \end{tabular} \\ \hline \hline \end{tabular}  
Layout of measuring points at the cross-section  
\begin{tabular}{c c c} \hline \hline Runyang Bridge & 4 & \(4\times 8\) & From 2005 to 2010 & Jiangsu, China \\ \hline \hline \end{tabular}  
Layout of measuring points at the cross-section  
\begin{tabular}{c c c} \hline \hline \
\begin{tabular}{c} T1 \\ Downstream \\ \end{tabular} &
\begin{tabular}{c} T2 \\ \end{tabular} & Top plate & T3 & T4 & T5 \\ \hline \hline \end{tabular}  
* **T6** &
\begin{tabular}{c} Bottom plate & T7 \\ \end{tabular}  
\end{table} 
Table 2: Five temperature field test cases for steel box girders. A radio telescope is a type of large and complex steel structure, and a large number of temperature sensors are usually needed to measure its temperature field. Some cases of temperature field measurement for radio telescopes are shown in Table 3. As can be seen from the table, the number of temperature sensors exceeds 100 in most test cases. The layout of a large number of measuring points needs a corresponding strategy, which will be dependent on the purpose of the test and the intended use of the data. A general layout strategy is to arrange the temperature sensors uniformly according to the mass, volume and surface area of the telescope's structure, whereby 89 temperature sensors were arranged throughout the VertexRSI 12-m prototype telescope. The sensors on the fork support and backup structure were respectively determined on the basis of their approximately equal surface areas and volume [127]. Figure 6a gives the temperature measuring points layout of the VertexRSI 12-m prototype telescope. [PERSON] proposed one method for selecting the installation positions of the temperature sensors based on finite element analysis; specifically, the installation positions are the thermally important FE nodes, those which are able to produce the largest thermal deformation under a given temperature variation [128]. These two methods are the most commonly used at present. For the IRAM 30-m Telescope, the measuring points of the backup structure were arranged with uniform distribution according to volume, with the selection of the temperature sensors in the yoke being carried out on the basis of [PERSON]'s method [129]. The layout of temperature measuring points for the IRAM 30-m Telescope is shown in Figure 6b.