PERFORMANCE EVALUATION OF STEEL HIGHWAY BRIDGES UNDER INCREASING FREIGHT TRAFFIC DEMANDS

Abstract

The global highway infrastructure network is currently facing an unprecedented convergence of challenges: an aging inventory of steel bridges and a relentless, exponential increase in freight traffic demands. Driven by the expansion of global supply chains, the e-commerce boom, and the shifting of freight volumes from rail to road, the gross vehicle weights (GVW) and axle load spectra traversing steel highway bridges have significantly exceeded the design assumptions of mid of twenty-century engineering. This comprehensive article provides an in-depth performance evaluation of steel highway bridges subjected to these evolving freight demands. It explores the structural vulnerabilities inherent in aging steel networks, including high-cycle fatigue, fracture mechanics, corrosion, and dynamic amplification. Furthermore, the paper critically reviews state-of-the-art methodologies for performance evaluation, ranging from Non-Destructive Testing (NDT) and Structural Health Monitoring (SHM) to advanced Finite Element Analysis (FEA) and the emergence of Digital Twins. By integrating probabilistic reliability analysis with modern load rating protocols, this article demonstrates how increasing freight loads accelerate structural deterioration and compromise target reliability indices.