A method for monitoring the state of support structures using fiber Bragg grating sensors is proposed to address the phenomenon of axial force variation affecting structural safety under loading conditions. By incorporating load design, sensor installation, multi-sensor monitoring, strain data processing, and thermal decoupling and correction, real-time monitoring of structural strain states and axial forces is realized. Experimental results demonstrate good correspondence between measured strain and load changes when the temperature exceeds 10 ℃. The error in axial force calculation when compared to manual measurement methods is less than 8%, validating the accuracy of the strain correction approach. This method can meet the demand for monitoring axial forces in support structures under dynamic temperature variations, providing an important experimental reference for related research in civil engineering.