Dynamic analysis of a suspension bridge

Abstract

This master thesis is the final part of my Master degree in structural and material science at the University of Stavanger. The thesis consists of collecting and studying data for the Lysefjord Bridge in light of the deterioration of the main cables and to carry out some static and dynamic analysis of the bridge to see if any load case could indicate reasons for the wire breakage. Data is given from the Norwegian Public Roads Administration (Statens Vegvesen) The existing finite element model of the bridge is modeled in ABAQUS. The model is analyzed with emphasis on the dynamic aspects of the bridge. Studies of the eigenfrequencies and eigenmodes have been done, both from the finite element model results and by simpler theoretical calculations. Wind loading and vortex induced vibrations of the bridge girder has been looked into. Cables forces from the loads have been checked. The wire fractures observed in the main cables have been summarized and analyzed with respect to weather conditions in the area. Data on the weather in the area has been provided by the Lysefjord Weather Station, downloaded through www.wunderground.com. The thesis consists of; • A presentation of the static and dynamic characteristics of a suspension bridge • A summary of the wire fractures in the main cables on Lysefjord Bridge • A weather analysis at the time of the wire fractures • Verification of the existing finite element model in ABAQUS • An eigenvalue, wind, temperature and traffic analysis of the bridge model • A verification of the finite element model results by theoretical calculations