Structural Analysis of a Six-Span Pratt Steel Truss Bridge under Combined Horizontal and Vertical Loading with a Damaged Member

The structural reliability of steel truss bridges is heavily dependent on their capacity to redistribute internal forces under adverse conditions. While individual lateral or gravity loads are commonly analyzed, the interaction of these loads in the presence of structural damage remains a critical concern for bridge safety. This study presents a numerical investigation into the structural performance of a six-span Pratt steel truss bridge subjected to combined horizontal and vertical loading with a single damaged diagonal member. A finite element model was developed in Abaqus to evaluate the synergistic effects of gravity and lateral actions on the bridge’s structural response. The analysis focuses on stress distribution, displacement patterns, and the redistribution of internal forces within the truss system following the removal of a central diagonal member. The results demonstrate that the application of combined loading significantly amplifies the stress concentrations in the members adjacent to the damaged region compared to isolated loading scenarios. Furthermore, the findings indicate that the interaction between gravity and lateral forces leads to more pronounced structural deformations and highlights the critical sensitivity of the Pratt configuration to member loss under multi-axial loading. This study provides valuable insights into the robustness of steel truss bridges under realistic, complex loading environments, offering a foundation for enhanced safety assessment and maintenance strategies.

کلیدواژه ها:

Steel truss bridges ، Pratt truss ، complex loading environments