Optimisation of the Construction Closure Temperature for Large-Span Steel Roof Structures Based on the Minimisation of In-Service Internal Forces

The closure process of a large-span steel roof directly determines the initial temperature effect during the service life of the structure and affects its internal force, particularly for parts with strong constraints. Therefore, it is essential to elucidate the influence mechanism of the stress response of large-span steel roofs for different closure processes and develop methods for closure optimisation in these structures. In this study, we proposed a novel method to determine the construction closure temperature of such structures by minimising in-service internal forces. Firstly, the surface temperature of the steel components was defined as the sum of the air temperature and temperature increase due to solar radiation. Subsequently, we determined the extremely high, extremely low, and annual average temperatures at the structure location. We then obtained the service temperature conditions of the structure by subtracting the construction closure temperature from these three temperature values. The structural response was subsequently simulated under various construction closure temperatures, and the relationship between the structural response and construction closure temperature was established, using the temperature corresponding to the minimum structural response as the construction closure temperature. Lastly, the proposed method was applied to the roof closure of the sub- and overall structures of the Shenzhen Bay Stadium. Subsequently, we evaluated the reaction reduction effect of the closure optimisation process on the constraint position of the bearings in the structure. The results indicate that the proposed method effectively reduces the influence range and degree of the construction process on the structural response during the service stage.