A topology optimization algorithm of steel beams under the influence of elevated temperature, considering the geometrically nonlinear analysis of imperfect structures, is proposed in this work. The proposed methodology is developed for addressing topology optimization problems in the presence of initial geometric imperfections and thermoelastic-plastic analysis by developing the bi-directional evolutionary structural optimization (BESO) method. Two comprehensive examples of lipped channel beams and steel I-section beams are provided to demonstrate the effectiveness of the proposed approach. The considered examples explore the impact of elevated temperature on the topology optimization of imperfect steel beams, considering the interplay between thermal effects, structural imperfections, and nonlinear behavior. The results highlight the significance of integrating temperature effects in achieving optimal and robust steel beam designs. Furthermore, the openings generated by the proposed algorithm can efficiently disrupt the continuous heat flow within the material, leading to regions with reduced thermal conductivity compared to solid regions.