Operational modal analysis on a lighthouse structure subjected to ice actions

Torodd S. Nord*, Knut Andreas Kvåle, Oyvind W. Petersen, Morten Bjerkås, Eliz Mari Lourens

*Corresponding author for this work

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

7 Citations (Scopus)
47 Downloads (Pure)


The sea ice interaction with a structure may cause system changes and affect the feasibility of common approaches to track modal parameters. In this paper, a covariance-driven stochastic subspace identification method is used to identify the natural frequencies from 190 time series of ice actions against a lighthouse structure. The results are sorted into groups defined by the observed ice conditions and governing ice failure mechanisms during the ice-structure interaction. The identified natural frequencies vary substantially within each individual group and between the groups. Recordings with flexural failures and a north-south ice-drift direction consistently rendered the same identified frequencies, whereas crushing seemed to create large amounts of variability in the identified frequencies. The results show the need for more high-fidelity data to assess whether modern system identification methods can be used to monitor system changes and support decision-making for operations of structures in ice-infested waters, such as offshore wind structures.

Original languageEnglish
Title of host publicationX International Conference on Structural Dynamics, EURODYN 2017
EditorsFabrizio Vestroni, Vincenzo Gattulli, Francesco Romeo
Number of pages6
Publication statusPublished - 2017
Event10th international conference on recent advances in structural dynamics - Faculty of Civil and Industrial Engineering of Sapienza University of Rome, Roma, Italy
Duration: 12 Jul 201014 Jul 2010
Conference number: 10

Publication series

NameProcedia Engineering
ISSN (Electronic)1877-7058


Conference10th international conference on recent advances in structural dynamics
Abbreviated titleEURODYN 2017
Internet address


  • Ice-structure interaction
  • Operational modal analysis
  • System identification


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