Performance Evaluation of Strip Seal Expansion Joints on Callender-Hamilton Steel Bridges

Abstract

Expansion joints of the strip seal type are essential structural components in modular steel truss bridges, functioning to accommodate movements caused by thermal expansion, structural deformation, and repeated traffic loading. Over time, these components are significantly affected by cumulative material degradation mechanisms, making fatigue evaluation necessary to ensure their reliability. This study presents a comprehensive assessment of the fatigue performance of strip seal joints by implementing the Constant Amplitude Load Factor (CALF) approach, a correction factor that converts variable traffic load spectra into equivalent constant-amplitude cyclic loading. The research methodology includes mapping traffic loads into Equivalent Single Axle Load (ESAL) units and axle load spectra, calculating CALF values based on the Palmgren–Miner cumulative damage theory, and applying S–N (stress–life) curves for steel and elastomer materials, each having different fatigue exponents. In addition, a damage contribution distribution analysis for each load class is conducted to determine the component’s sensitivity to variations in heavy traffic intensity. The results indicate that strip seal expansion joints exhibit satisfactory fatigue resistance under normal traffic loading conditions; however, an increased proportion of heavy axles significantly accelerates damage accumulation and shortens the designed service life. Therefore, this study emphasizes the importance of considering actual load spectra through the application of the CALF concept during the planning stage, supported by quality control in installation details and construction procedures to prevent potential failures in strip seal expansion joints