Förbättringsförslag pådaglig styrning
The Swedish Transport Administration manage nearly 4,000 railway bridges in different condition and age around the country. These bridges is in constant need of maintenance and requires continuous inspections. This thesis is designed as a damage investigation on a single-track railway bridge south of Solvarbo in Säter municipality. The railway bridge is in operation and serves over 10,000 trains a year, everything from speed trains to freight trains. The bridge is built as a beam bridge, simply supported over a road. The report is made in consultation with the company Reinertsen Sweden AB.An investigation of the bridge was carried out in 2013 by Reinertsen Sweden AB, which describes that the abutments lean onto the superstructure due to motion. The damage noted was that the movable bearings are seriously tilted, the superstructure is in contact with the breast wall and several cracks were found on the abutment. These damages were considered to affect the function of the structure and found needing further investigation to consider possible future actions.The objective of this thesis is to analyze how the bridge has changed since it was built and to find what may be the underlying causes to these changes. The report is aimed to constitute a foundation and a decision basis for further measures.To determine how the bridge has moved a surveying with a total station was performed. Thereafter updated drawings of the bridge were established and later compared with the existing original drawings. To understand why the bridge has moved a sliding control was performed with different loads. In addition an inspection of structural damages was carried out and evaluated.Comparing the drawings showed a significant displacement of the eastern abutment towards the western. The movement of the abutment has made the two bearing walls tilt. The sliding control showed that there is no risk of sliding when only earth pressure is considered, but when loads of the trains are applied there is a risk of sliding. Wear of the bridge has caused several damages in the bridge structure. The visible damages found were cracks, efflorescence, bearing misalignment and corrosion of bearings and visible reinforcement.What could be determined was that the bridge has moved horizontally and vertically and one reason for the movement in the eastern abutment could be the horizontal forces brought by a passing train. By examining the damage caused to the bridge and compare them with the requirements of the Swedish Transport Administration it could be established that some of these damages have raised due to lack of maintenance.