A comprehensive review on fatigue mechanisms and design strategies in modern bridge engineering

Abstract

Fatigue has emerged as a critical determinant of structural durability and safety in modern bridge engineering, particularly under increasing traffic intensity and dynamic loading conditions. This study presents a comprehensive analysis of fatigue mechanisms in metallic, concrete, and composite bridge structures, incorporating historical failures, contemporary design methodologies, and cutting-edge modeling approaches. It explores how dynamic vehicle-bridge interactions, amplified by road surface roughness, temperature fluctuations, and environmental degradation, induce complex stress cycles that surpass traditional static assumptions. Advanced fatigue assessment frameworks, such as fracture mechanics-based modeling, probabilistic reliability analysis, and finite element-based dynamic simulations, are examined to address the shortcomings of conventional S-N curve methodologies. Additionally, experimental studies using real-time bridge health monitoring systems reveal critical insights into crack initiation and propagation, informing maintenance and retrofitting decisions. The integration of high-performance materials, such as HPS and UHPC, and fatigue-strengthening techniques like HFMI, further enhances the resistance of bridges to cyclic degradation. The study highlights that fatigue is not merely a material issue but a systemic design, maintenance, and operational challenge that demands interdisciplinary strategies combining material science, structural analysis, dynamic modeling, and environmental engineering.