Analysis of the hysteresis effect between temperature and bearing displacement of a steel truss bridge

Temperature-induced bearing displacement in steel truss bridges often exhibits nonlinear hysteresis behavior, where displacement lags behind structural temperature changes. This study investigates this temperature-displacement relationship, with a focus on the effects of thermal hysteresis and non-uniform temperature distribution. Field monitoring data and finite element simulations are integrated to analyze the thermal behavior of both an H-shaped steel member and the full bridge structure. A temperature field simulation method is developed based on heat transfer boundary theory, enabling comprehensive analysis of temporal lags and spatial gradients. The key findings include: (1) For H-shaped steel members, while intra-plate temperature differences are negligible, inter-plate temperature variations exhibit significant time lags (70–130 min); (2) Full-bridge simulations reveal spatially dependent temperature gradients, though the distribution is more uniform than in steel box girders; (3) Hysteresis loop characteristics vary substantially depending on the selected temperature measurement points, demonstrating that both non-uniform temperature distribution and sensor placement critically govern the hysteresis phenomenon. These results provide new insights into the thermal response mechanisms of steel truss bridges.