Structural Performance of a Six-Span Pratt Steel Truss Bridge Under Combined Horizontal and Vertical Loading with Multiple Member Loss

This study investigates the structural performance of a six-span Pratt steel truss bridge subjected to combined horizontal and vertical loading in the presence of multiple member loss. A detailed finite element model was developed in Abaqus to simulate the simultaneous removal of two critical diagonal members in the central spans, representing a severe damage scenario that could result from events such as collision, fatigue, or progressive deterioration. The bridge was analyzed under concurrent application of a ۲۰۰ kN lateral force and a ۲۰۰ kN vertical load, reflecting realistic operational and accidental load combinations. The results reveal that the loss of two key members drastically alters the load transfer mechanisms, leading to significant increases in vertical displacements and pronounced stress concentrations throughout the affected region. The interaction of combined loading with reduced structural redundancy exacerbates the risk of local and global instability, highlighting critical zones susceptible to further failure. These findings underscore the heightened vulnerability of truss bridges with multiple member loss under multi-axial loading conditions and emphasize the need for robust assessment methodologies to ensure structural safety and resilience.

کلیدواژه ها:

global instability ، Pratt truss ، accidental load combinations