Structural Analysis of a Six Span Pratt Steel Truss Bridge under Horizontal Load with Two Damaged Members

The structural integrity of multi span steel truss bridges is highly dependent on the redundancy of their individual components. While single member damage may be manageable, the loss of multiple structural elements can lead to a more significant reduction in load carrying capacity and global stability. This study investigates the structural behavior of a six span Pratt steel truss bridge subjected to horizontal loading, focusing on a critical damage scenario involving the removal of two diagonal members. A detailed numerical model was developed in Abaqus to simulate the bridge system under a ۲۰۰ kN lateral load. The structural response, including displacement patterns, Von Mises stress distribution, and internal force redistribution, was evaluated and compared with previously analyzed single damage conditions. The results demonstrate that the simultaneous loss of two members significantly amplifies localized stress concentrations and vertical displacements compared to single member damage. The study reveals that the Pratt truss system exhibits reduced stiffness and heightened vulnerability in the affected spans, highlighting the importance of redundancy and structural robustness in the face of multiple component failures. The findings provide critical insights into the performance limits of steel truss bridges under extreme damage and lateral loading conditions, serving as a basis for improved inspection and maintenance protocols.

کلیدواژه ها:

Steel truss bridges ، Pratt truss ، horizontal loads