| dc.description.abstract | The purpose of this thesis is to investigate the fatigue life of a steel railway bridge in Norway.
Fatigue life is usually determined by conventional approaches such as the λ-coefficient method or the Miner’s damage accumulation method.
These methods are pertinent for most of the bridge cases, however they were design for current bridges. Many of the bridges in use nowadays were built at the beginning of the 20th century. These bridges are maintained in life because they are cheaper to keep and maintain them than constructing new bridges. These bridge experience an increase in traffic loads and are exposed to continuous environmental deterioration due to corrosion. This lead to a phenomenon known as corrosion fatigue (CF).
These old bridges, therefore, necessitate new approaches for fatigue life assessment, adapted to their characteristics and current conditions. New fatigue curves (S-N curves) has been developed by Adassoriya et al. for riveted details exposed to a corrosive environment, and adapted to railway bridges.
This method is applied to some members of the bridge, and the results are compared to the Miner’s damage rule. A total of 10 members are studied.
The results has revealed a reduction of fatigue live in the range of 12-83 %. The main observed factors that influenced the percentage loss of fatigue life are: the cross-sectional parameters (i.e cross-sectional area, second moment of area), the type of cross-sections, the locations of the members, and the applied traffic load (traffic mix).
To simplify the analysis, some assumptions were made, such as the bridge design and members remaining unchanged from 1906.
The new method developed by Adassoriya et al. [1] propose an innovative approach for the fatigue life assessment of old bridge exposed to corrosion fatigue. | |
