Study of Thermal Effects on Large-Span Ring-Shaped Steel Structures

To investigate the thermal effects of solar radiation on annular steel structures with non-uniform spans, this study implemented a methodology combining numerical simulation and monitoring. Electronic strain gauges and temperature monitoring points were installed at mid-span of three lifting segments (TS1–3) of “Sky Hall” project to simultaneously record thermal stress and temperature data. The data of temperature was imported into Midas-GEN, where structural thermal stresses were computationally generated through a simplified non-uniform temperature field model. Comparatively analysis showed the following: (1) Thermal stress shows a strong linear correlation with temperature increase, with a Pearson correlation coefficient of r = 0.989; (2) Constraint intensity is a critical factor affecting the magnitude of thermal stress in annular structures—TS3 with lower constraint density exhibits better deformation compatibility, leading to effective stress dissipation (stress increase of 6 MPa per 1 °C rise), while TS1 under strong constraint conditions shows limited deformation capacity, resulting in significantly intensified stress concentration (with 18 MPa increase per 1 °C rise); (3) The variation trends of simulation and monitoring results are highly consistent, though significant deviations exist in some members (the peak monitored stress was 2.31 times the simulated value) due to factors such as structural geometry, material properties, member dimensions, constraint conditions, and the simplified non-uniform temperature field model; (4) According to the most unfavorable combination specified in the Standard for Design of Steel Structures (GB 50017-2017), the design stress value is 203.5 MPa, which is quite less than the yield stress, thus meeting the safety requirement.