# Flexural Performance of Removable Deck Slabs with Fixing Device Details
## 4 Safety Evaluation of Removable Deck Plates during Construction
### Construction Load Test Results  
#### 4.2.1 Load-Displacement Relationship  
Table 4 depicts the test results, and Figure 15 displays the load-displacement curve for each specimen. The construction load was determined by adding a concrete dead weight, a working load of 2.5 kN/m\({}^{2}\), and a concentrated load of 1.5 kN on the worker, as suggested in the formwork and shore design standard (KDS 21 50 00) [16]. The load during construction was estimated as a coefficient load, considering the safety factor, with the concrete dead load treated as a dead load and the working load, calculated as 1.2D + 1.6L, as a live load. The total load amounted to 23.98 kN when computing the coefficient load, and up to 24.2 kN was applied to examine the brick's weight and its behavior after reaching the maximum load.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Specimen** & \begin{tabular}{c} **Peak Load** \\ **(kN)** \\ \end{tabular} & \
\begin{tabular}{c} \(\Delta_{c}\) \\ **(mm)** \\ \end{tabular} &
\begin{tabular}{c} **L/\(\Delta_{c}\)** \\ \end{tabular} \\ \hline D200-ST & & 8.8 & 341 \\ D300-ST & & 8.4 & 357 \\ D400-ST & 24.2 & 11.9 & 252 \\ D400-CR & & 10.4 & 288 \\ \hline \hline \end{tabular} \(L\): Clear span, \(\Delta_{c}\): midspan displacement at maximum load.  
\end{table}
Table 4: Construction load test results.  
Figure 14: Test configuration for construction load test: **(a)** 50% of peak load; **(b)** peak load.  
The maximum strength of the member and the displacement at that time can be derived through the load-displacement relationship, and the stiffness of the member can be evaluated using the slope. As shown in Figure 15, the stiffness decreased as the spacing of the fixing device increased, but the difference was not large. Unlike the other three specimens, the D400-ST specimen had significantly reduced stiffness, and the staggered arrangement of D400-CR showed the same level of stiffness as D200-ST and D300-ST. Accordingly, by changing the installation pattern of the fixing device, it will be possible to improve the bending performance of the detachable deck plate during construction.  
The experimental results revealed that the D200-ST specimen, with the fixing device interval arranged in a straight line at 200 mm, exhibited stable behavior due to the adequate number of fixing devices. The maximum displacement was 8.8 mm. Furthermore, the slope of the load-strain curve remained constant until the construction load was applied, indicating that the specimen behaved within the elastic region. This indicates that sufficient safety was ensured, as the specimen did not exhibit a rapid decrease in stiffness due to the failure of the fixing device.  
Although it is possible to compare the difference in stiffness of each specimen based on the test results, there is a limit to quantitatively evaluating the stiffness of the specimen because an accurate uniformly distributed load is not applied due to the nature of the experiment. Therefore, in future studies, a method that can accurately simulate uniformly distributed loads is needed.