Environment-assisted fatigue of steel bridges: A conceptual framework for structural integrity/life assessment
Master thesis
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https://hdl.handle.net/11250/2779022Utgivelsesdato
2021Metadata
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Sammendrag
The purpose of this thesis is to propose a framework/methodology based on a recently proposedfatigue strength curve of corroded steel to assess the life of an existing steel bridge exposed toenvironment-assisted fatigue. A fatigue assessment using damage accumulation method isperformed on an ageing steel bridge located in a marine environment in Sri Lanka. Theassessment is performed using both the newly proposed method and conventional approachescovered in the framework. The difference of the estimated fatigue lives emphasizes theimportance of considering the interactions of corrosion and fatigue mechanisms.
The newly proposed method includes a formula and corresponding S-N curves to predict fatiguestrength of corroded structural elements of steel structures. Parameters of the S-N curve forboth marine and urban environments are provided for detail categories in the Eurocode and theDNV-GL code. The formula does not require any other material parameters than the fatiguecurves given in the codes. The applicability and significance of this method is discussed bycomparison of the fatigue lives obtained by both the conventional method from the Eurocodeand proposed method.
Prior to the fatigue assessment, a thorough literature review regarding forms of corrosion onsteel bridges, their effects and causes are first studied. Environment-assisted cracking (EAC)and how it affects the structural integrity of steel bridges are introduced. Research gaps andshortcomings in the literature regarding the issue are investigated.