Damage Identification of Truss Bridge Under Temperature Variations Based on Stiffness Separation Method

Structures are continuously subjected to the combined effects of temperature variations and other environmental factors during service, leading to changes in their structural responses and severely compromising the accuracy of damage identification. To address this temperature-induced interference, this study proposes a damage identification method that jointly identifies damage and temperature parameters. Temperature variations are treated as unknown parameters and identified simultaneously with the damage parameters. The inverse problem is defined by an objective function that quantifies the discrepancy between measured and analytical strains. To enable the analysis of large-scale structures, a stiffness separation method accounting for temperature variation is introduced, which divides the structure into substructures for damage identification. This method is numerically demonstrated through a case study of a steel truss bridge, and the applicability of the combined temperature identification and stiffness separation method is evaluated under different temperature conditions.