A pre-study of the dynamic behavior of a single diagonal timber arch bridge

Abstract: The aim of this Master’s thesis was to study the dynamic behaviour of a special type ofpedestrian timber bridge with a single diagonal arch - a design proposal made in a previousstudent project. The bridge is intended to be built as a gateway to the Alfred Nobel’s Björkbornin the municipality of Karlskoga. The original plan for this thesis was to build and test adownscaled model in order to verify theoretical investigations. The laboratory testing washowever not possible to be performed, therefore the study was conducted only by means ofanalytical and numerical tools. Both a downscaled model and a full-scale bridge model wereanalysed and compared in order to find proper scale parameters. Different studies wereperformed on the models by means of the finite element method in order to investigate theinfluence of relevant parameters on dynamic behaviour of the bridge. A scale factor wasdetermined which allows for the translation of results from the downscaled model to the fullscale model. Results showed that the dynamic behaviour of this type of bridge is rathercomplicated, and the original design needs to be somewhat modified to meet the comfortcriterion for pedestrians. An increase of the width of the arch, a proper arrangement of thecables, and adoption of longitudinal steel beams under the deck were found to be efficientmethods to improve the dynamic performance of the bridge. Future work should includeexperiments on a downscaled model to validate these theoretical solutions.