## 6 Conclusions  
This study presents an experimental and numerical study for evaluation of the structural safety of a deck plate bolted with truss girder. This deck-plate system has been proposed to resolve the welding issues. In total, six tests on a full scale were performed to examine the structural performance of the proposed system. The test specimens were evaluated for the specified construction loads based on the deflection criteria provided in AIK [16], which is more conservative than those of ASCE [17]. The local responses of the specimens were investigated using the strain-gauge measurements. Numerical simulations for all test specimens were then conducted to ensure that the test results are reliable and to further investigate the responses, which could not be clearly accounted for in the tests. The key findings and recommendations are as follows:  
1. The structural safety of the proposed truss girder-bolted deck-plate system has been validated through experimental and numerical studies. All test specimens and the relevant numerical models met the provided design deflection criteria for given construction loads.
2. The restoration capability has been experimentally validated. Most members of the test specimens remain nearly elastic, noting that the restoration rates were greater than 97% for all specimens.
3. The numerically-predicted deflections were very similar to the measured values until the specified loads is reached, ensuring the reliability of the test results. Some differences were observed after the specified loads due to the use of the elastic-plastic material models, but this is insignificant because the evaluation of the deflection is aimed at the specified loads.
4. A few test specimens failed due to the buckling of the center upper rebar, but the relevant numerical results indicate that the specimens can show different failure modes of the buckling of the lower rebar and the lattice steel wire near the end, noting that the test specimens were loaded using the step-by-step loading method conservatively from the center to the ends.  
Figure 22: von Mises stresses and effective plastic strain for deck plate and truss girder in the vicinity of the support for 135-EDI-3.2. (**a**) von Mises stress for deck plate. (**b**) Effective plastic strain for deck plate. (**c**) von Mises stress for truss girder. (**d**) Effective plastic strain for truss girder.  
5. The test results showed that the welding issues between the deck plate and truss girder can be resolved with the bolted system, but other welding problems in the region of joints between the lower rebar and lattice steel wire can be posed, even though the welding failures occurred after the specified loads. Stress localization was also observed in the numerical simulations in the locations of the welding failures in the tests, which indicates that the details in these areas need to be modified to improve the structural performance of the proposed deck-plate system.  
The authors contribute as follows: Conceptualization, J.S., J.L., and B.K.; data curation, Y.L.; Formal analysis, J.S. and J.L.; funding acquisition, J.S.; investigation, J.S. and B.K.; methodology, Y.L. and B.K.; project administration, B.K.; resources, J.L.; software, J.S.; validation, J.S. and B.K.; visualization, J.S. and J.L.; writing--original draft, J.S.; writing--review and editing, Y.L. and B.K.  
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean Government (MSIT) (No. NRF-2018R1C1B6006275).  
The authors declare that they have no conflicts of interest.