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dc.contributor.authorStatens vegvesen
dc.coverage.spatialNorway, E39 Bjørnafjordenen_US
dc.description.abstractThe main purpose of phase 5 of the E39 Bjørnafjorden project is to identify and document which of the four described bridge alternatives that may be regarded as the best solution. In this context, AMC have assessed the concepts’ robustness with regards to parametric excitation. Parametric excitation is considered as an effect that may be crucial for the safety of the concepts. In contrast to traditional resonance, where an external force applied at or near a natural frequency of the structure causes resonance, parametric excitation is caused by an oscillating variation of one or more of the system properties. Parametric excitation may be far more aggressive and more dangerous than traditional resonance due to the exponential growth of response over time even for a system with damping [1] [2]. The focus for the Bjørnafjord Bridge has been parametric excitation caused by an axial force variation that induces variation in the geometric stiffness of the system. An attempt to give a simple description of a complex and challenging problem may be as follows: the variation of the axial force in the slender girder of the Bjørnafjord Bridge concepts is a source to stiffness variation that leads to amplification of the load effects at frequencies other than the loading frequencies. The challenge has thus been addressed by the looking into the following topics: • Determination of the axial force variation for the different concepts and for different loadings • Applying the defined criterion for possible onset of parametric resonance on the possible concepts • Establishing a criterion for evaluation of a threshold (denoted terminal in the current document) level for the parametric resonance response taking into account the effect of present nonlinear/quadratic damping • Establishing how the stochastic nature of the loading should be treated • Establishing procedures for evaluating the effects of: o the magnitude of the external force o the external static forces o the effect of wide-bandednessen_US
dc.description.sponsorshipStatens vegvesen Vegdirektorateten_US
dc.publisherStatens vegvesenen_US
dc.relation.ispartofseriesStatens vegvesens rapporter;
dc.rightsAttribution-NoDerivatives 4.0 Internasjonal*
dc.subjectStatens vegvesen Vegdirektorateten_US
dc.subjectE39 Bjørnafjordenen_US
dc.titlePreferred solution, K12 – Appendix S - Parametric excitationen_US

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Attribution-NoDerivatives 4.0 Internasjonal
Except where otherwise noted, this item's license is described as Attribution-NoDerivatives 4.0 Internasjonal