Identification of Structural Parameters Based on HHT and NExT

Yongli Zhang (School of Architecture and Civil Engineering, Zhongyuan University of Technology)
Ruixin Li (Henan Xinhanhai Real Estate Co., Ltd.)

Abstract


Signal processing approaches are widely used in the field of earthquake engineering, especially in the identification of structural modal parameters. Hilbert-Huang Transformation (HHT) is one new signal processing approach, which can be used to identify the modal frequency, damping ratio, mode shape, even the interlayer stiffness of the shear-type structure, incorporating with Natural Excitation Technique (NExT) method to take information from the response records of the structure. The stiffness of the structure is of great importance to judge the loss of its bearing capacity after earthquake. However, all of modal parameters are required to calculate the stiffness of the structure by use of HHT and NExT, which means that the response records shall contain all of modal information. However, it has been found that the responses of the structure recorded only contain the former order modal information; even it is excited by earthquake. Therefore, it is necessary to found a formula (formulas) to calculate the stiffness only using limited modal parameters. In this paper, the calculation formulas of the interlayer stiffness of shear-type structure are derived by using of the flexibility method, which indicate that all of interlayer stiffnesses could be worked out as long as any one set of modal parameters is obtained. After that, Taking Sheraton-Universal Hotel subjected to North Bridge earthquake in 1994 as an example, HHT and NExT are used to identify its modal parameters, the derived formulas are used to calculate the interlayer stiffnesses, and their applicability and accuracy are verified.


Keywords


Structure; HHT; Natural frequency; Damping ratio; Mode shape

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References


[1] Liu Zhen, Tang Dai-xin. Research on diagnostic method of damage on building structures[J]. Journal of Harbin University of Civil Engineering and Architecture,2000, 33 (1): 37-40.

[2] Xu Xiu-zhong, Hua Hong-xing, Chen Zhao-neng. Review of Modal Identification Method Based on Ambient Excitation[J]. Journal of Vibration and Shock, 2002,21 (3): 1-6.

[3] N.E.Huang, Z.Shen,S.R. Long, M.L.et al.. The empirical

[4] mode decomposition and Hilbert spectrum for nonlinear and non-stationary time series analysis[J]. Proc. Royal Society of London. A, 1998(454): 903-995.

[5] Yang,J.N, Lei Y. Identification of natural frequencies and damping ratios of linear structure via Hilbert transform and empirical mode decomposition. Proc. of International Conference on Intelligent Systems and control. IASTED/Acta press, Anaheim, CA, 1999:310-315.

[6] James G H,Game T G, Lauffer J P, et al. The nature excitation technique (NExT) for modal parameter extraction from operating structures[J]. Modal Analysis,1995, 10 (4): 260-277.

[7] Li Zhong-fu, Hua Hong-xing, Song Han-wen, Chen Zhi-yan. Modal Parameters Identification of Linear Structures Undergoing Non-Stationary Ambient Excitation[J]. Journal of vibration engineering, 2002, 15 (2): 140-142.

[8] Chen Jun, Xu You-lin. Application of HHT for Modal

[9] Parameter Identification to Civil Structures[J]. Journal of vibration engineering,2003, 16 (3): 383-387.

[10] Li Hong-quan, Ou Jin-ping. Identification and Test Analysis of Earthquake Damage Of Reinforced Concrete Frame Structures[J]. World Earthquake Engineering,1996(4): 37-42.



DOI: https://doi.org/10.30564/frae.v4i1.2746

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