Field measurement of damping and natural frequency of an actual steel-framed building over a wide range of amplitudes

doi:10.1016/0167-6105(96)00015-3

Journal of Wind Engineering and Industrial Aerodynamics

Volume 59, Issues 2–3, March 1996, Pages 325-347

https://doi.org/10.1016/0167-6105(96)00015-3 Get rights and content

Abstract

In order to understand the dynamic characteristics of a prefabricated steel building, several vibration tests with a wide range of amplitudes were carried out. Under excitation with relatively small amplitude levels, four different construction stages are prepared. The dynamic properties such as natural frequencies and damping ratios are evaluated using several identification methods based on observation records. The variability in the results due to the differences in identification methods and excitation conditions is examined. By comparing the results at different construction stages, the effect of non-structural members on the structural stiffness and damping ratio is studied. Using a mechanical exciter, forced vibration tests were carried out for several high excitation levels (100–3000 kgf). Free vibration tests using a wire cutting method were also carried out for several initial displacement levels (5–25 tonf, as initial tensile force levels). Based on the results of these vibration tests with various amplitude levels, the effect of non-structural members on dynamic characteristics is studied from the view point of amplitude dependence.

References (4)

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J. Struct. Constr. Eng. AIJ
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K. Okada

There are more references available in the full text version of this article.

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Meanwhile, as indicated by Aquino and Tamura (2013), the amplitude of most damping measurements is quite low (xh/H ≈ 10−6 – 10−5), whereas that for structural wind-resistant design (xh/H ≈ 10−4 – 10−2) far exceeds the “critical tip drift ratio” (xh/H ≈ 10−5 – 10−4), not to mention that for seismic design (xh/H ≈ 10−2 – 10−1). In addition, the phenomenon that the damping ratio first increases, then decreases, and might decline to a low-amplitude plateau (Fukuwa et al., 1996) further increases the difficulty of assessing the amplitude effect. Due to the lack of sufficient sequential observation data of individual buildings, the amplitude dependence of the damping ratio is not discussed in this study.
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¹: Associate Professor.

²: Graduate student (JSPS Research fellow).

³: Graduate student.

⁴: Research Engineer.

⁵: Professor.

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Field measurement of damping and natural frequency of an actual steel-framed building over a wide range of amplitudes

Abstract

J. Struct. Constr. Eng. AIJ