ABSTRACT

Fatigue crack and corrosion are two significant factors which could affect fatigue performance of steel bridge members. In this study, a reliability based assessment procedure for determining remaining fatigue life is proposed. Both fatigue crack propagation and progress of corrosion are simultaneously considered for the assessment. Three scenarios simulating progress of steel bridge deterioration are established and fatigue assessment was performed accordingly. As corrosion progresses, stress concentration effect around the corroded area increases and may cause fatigue crack initiation. By utilizing stress-strain approach and linear elastic fracture mechanics, pit depth threshold which can be transformed as fatigue crack is determined. To develop relation between pit depth threshold and fatigue crack initiation, an equation estimating the stress concentration factor for corrosion pit is formulated by parametric study based on finite element analysis Proposed fatigue assessment method could establish reliability based deterioration levels, which may lead to reasonable and efficient maintenance strategy.