| dc.description.abstract | There is a lack of documentation about the material in century-old railway bridges in Norway, with many of which are still in operation, approaching what is conventionally deemed as their design working life. Along with the ever-changing demands on the infrastructure, there is a growing concern regarding the remaining service life of these bridges and their capacity to accommodate modern traffic loads. To answer these questions, knowledge concerning the material and microstructural properties are essential.
This thesis aims to answer those questions by investigating the material composition and mechanical properties of a railway bridge of steel built in 1908 in Norway. The aim is to compare these findings with current steel standards and align the results with existing studies to enrich the understanding of their unique characteristics. This investigation involved a series of tests on the structure’s four beams, one of them were used to extract specimen samples from, while the remaining three underwent buckling tests. Other testing included tensile, charpy impact, and hardness examination to determine mechanical properties. Spectroscopy were used to determine the chemical composition of a beam (Beam 2). Microstructure was assessed using light optical microscopy (LOM) and scanning electron microscopy (SEM). SEM was employed to gain insights into the fracture mechanisms, while energy-dispersive x-ray spectroscopy (EDS) was utilized to analyze the composition of non-metallic inclusions.
The results derived from these microstructural and mechanical assessments were then contrasted with those of prevalent structural steel alloy like S235, but also compared with those properties reported in literature of materials from same period. The study also explored potential enhancements to the bridge's strength via welding methods and compared theoretical and experimental buckling values.
As an exploratory study, this thesis aims to enrich the current understanding of century-old railway bridges in Norway by providing comprehensive data on the materials used in their construction. The research is intended as a pilot project to the analysis of other similar early 20th-century bridges. The findings could not only form a basis for the development of precise evaluation techniques, but could also impact strategic decision-making regarding the safe, economical, and environmentally responsible preservation of these historic structures. | |
