# Refined 3D Solar Temperature Field and Effect Simulation of Ultra-High Steel Bridge Pylon
## 7 Conclusions  
A refined simulation method of solar temperature field for an ultra-high structure has been presented in this paper. The temperature field and corresponding thermal stress and deformation have been calculated under typical meteorological conditions. Results show that:  
1. A fine numerical simulation model for the 3D bridge temperature field was established based on the proposed automatic sunshine shadow recognition method and the pylon-height related convection modification method, which can accurately calculate the solar temperature field and temperature effect of super-high structures.
2. After the modification of convective coefficient of the outer surfaces with different wind speeds at different pylon heights, the temperature gradually decreases from the top to the bottom of the pylon with temperature difference of 4 \({}^{\circ}\)C and 8 \({}^{\circ}\)C in spring (autumn) and winter. After correcting the convection coefficient, the real temperature field and temperature effect can be more accurately mastered.
3. The maximum temperature differences between outer surfaces of pylon can reach 19 \({}^{\circ}\)C and 16 \({}^{\circ}\)C and exceed the recommended value of \(\pm\)5 \({}^{\circ}\)C in Chinese Specification. The maximum displacements can reach 370 mm and 110 mm in longitudinal and transverse directions of the bridge, respectively. The maximum stress of the east and south walls can reach 20 MPa and 27 MPa, and the west and north walls can reach 21 MPa and 10 MPa.
4. By considering the shadow effect, the maximum temperature difference can reach 12 \({}^{\circ}\)C between the adjacent sunshiny and shaded areas and can reach 14 \({}^{\circ}\)C between two pylon columns, and the maximum stress can be reduced by 13 MPa. The asynchronous deformation for pylon columns is obvious, and the maximum asynchronous displacement can reach 18 mm and 42 mm in the longitudinal and transverse directions respectively. After superimposing the construction error caused by segment splicing, the maximum construction error in longitudinal and transverse directions can reach 17 mm and 45 mm.
5. On the basis of the research on the temperature field of the super high bridge tower, further carrying out the real bridge test and grasping the relationship between the deformation of the bridge tower and the temperature will effectively guide the construction and ensure the alignment of the bridge tower.  
Conceptualization, Y.L. and S.H.; methodology, Z.W., Y.L., S.H. and J.L.; software, B.G.; validation, B.G. and Z.W.; formal analysis, B.G. and Z.S.; investigation, S.H. and J.L.; supervision, Y.L.; project administration, J.L.; writing--original draft preparation, B.G. and S.H.; writing--review and editing, B.G., Z.W., Y.L., J.L., S.H. and Z.S. All authors have read and agreed to the published version of the manuscript.  
This research was funded by the Key Research and Development Project of Qinghai Provincial Science and Technology Department (Grant No. 2023-SF-110), National Natural Science Foundation of China (51978061, 52108111) and the Special Fund for Basic Scientific Research of Central College of Chang'an University (Grant No. 300102219310, 300102212102).  
Not applicable.  
**Data Availability Statement:** All datasets are publicly available.  
The authors declare no conflict of interest.