Abstract：
This paper took steel beam constrained at both ends as example to determine the bearing capacity of steel beam at ordinary temperature after applying evenly distributed load on the beam. Thereafter, the model was re-established to apply load according to different bearing capacities at normal temperature respectively, and temperature of the steel beam was simultaneously increased to analyze the limiting temperature of steel beam at different load ratios and under normal service conditions. It was found that load ratio has important influence on the limiting temperature of steel beam under normal service conditions, namely flexibility of steel beam changes faster and faster and the limiting temperature of steel beam is also reduced when the load ratio increases.
