Structural Analysis of a Six Span Pratt Steel Truss Bridge under Combined Vertical and Horizontal Loads

Steel truss bridges are widely utilized in modern bridge engineering due to their high strength to weight ratio, structural efficiency, and suitability for medium span applications. Among various truss configurations, the Pratt truss is one of the most effective systems because of its balanced arrangement of tension and compression members. In the present study, the structural behavior of a six span Pratt steel truss bridge subjected to combined vertical and horizontal loading is investigated through finite element analysis using Abaqus software. The applied vertical load simulates traffic actions, while the horizontal load represents lateral effects such as wind or braking forces. The analysis focuses on evaluating the distribution of internal forces, stress patterns, and displacements under the combined load scenario.The obtained results indicate that the simultaneous application of vertical and horizontal loads substantially alters the internal force distribution within the bridge compared to the cases of single loading. Several diagonal and chord members exhibit increased stress levels due to the interaction of axial and lateral effects. The maximum stresses and displacements occur primarily in the central spans, whereas the edge spans show relatively smaller responses. Overall, the results confirm that the Pratt truss system maintains high stability and satisfactory strength performance even under complex combined loading conditions, demonstrating its reliability for modern steel bridge design.

کلیدواژه ها:

Steel truss bridges ، Pratt truss ، strength performance