000013131 001__ 13131 000013131 005__ 20161114160328.0 000013131 04107 $$aeng 000013131 046__ $$k2009-06-22 000013131 100__ $$aSui-Kui, Au 000013131 24500 $$aDynamic characteristics of a tall building during typhoons 000013131 24630 $$n2.$$pComputational Methods in Structural Dynamics and Earhquake Engineering 000013131 260__ $$bNational Technical University of Athens, 2009 000013131 506__ $$arestricted 000013131 520__ $$2eng$$aThis paper presents work on modal identification of a tall building using ambient vibration data collected during two recent typhoons, namely Nuri (22-23 August 2008) and Hagupit (21-22 September 2008). The paper discusses the procedure and difficulty encountered during instrumentation and data analysis phase. Cross-correlation functions among measured degrees-of-freedom are estimated from the ambient vibration data, which can be used for modal identification as if there were free-vibration data, assuming uncorrelated random excitations. A method based on least-square fitting of the correlation functions is adopted for modal identification. It is found that the building has closely-spaced translational modes in its principal directions, which agree with their finite element model estimates established at the design stage. As a result of the closely-spaced modes, the principal directions of the identified modeshapes vary across different time segments. The modal properties of the building are tracked during the typhoon events, spanning periods from normal to high winds. Investigation of identified frequencies versus the corresponding modal vibration level indicates a significant inverse trend. 000013131 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb. 000013131 653__ $$aAmbient vibration test; Modal testing; System identification; Tall building. Abstract. This paper presents work on modal identification of a tall building using ambient vibration data collected during two recent typhoons, namely Nuri (22-23 August 2008) and Hagupit (21-22 September 2008). The paper discusses the procedure and difficulty encountered during instrumentation and data analysis phase. Cross-correlation functions among measured degrees-of-freedom are estimated from the ambient vibration data, which can be used for modal identification as if there were free-vibration data, assuming uncorrelated random excitations. A method based on least-square fitting of the correlation functions is adopted for modal identification. It is found that the building has closely-spaced translational modes in its principal directions, which agree with their finite element model estimates established at the design stage. As a result of the closely-spaced modes, the principal directions of the identified modeshapes vary across different time segments. The modal properties of the building are tracked during the typhoon events, spanning periods from normal to high winds. Investigation of identified frequencies versus the corresponding modal vibration level indicates a significant inverse trend. 000013131 7112_ $$aCOMPDYN 2009 - 2nd International Thematic Conference$$cIsland of Rhodes (GR)$$d2009-06-22 / 2009-06-24$$gCOMPDYN2009 000013131 720__ $$aSui-Kui, Au$$iHing-Lun, Yip$$iHeung-Ming, Chow 000013131 8560_ $$ffischerc@itam.cas.cz 000013131 8564_ $$s531267$$uhttps://invenio.itam.cas.cz/record/13131/files/CD179.pdf$$yOriginal version of the author's contribution as presented on CD, section: Identification methods in structural dynamics - iii - (MS). 000013131 962__ $$r13074 000013131 980__ $$aPAPER