Field measurements of amplitude‐dependent damping in a 79‐storey tall building and its efects on the structural dynamic responses

Abstract

This paper describes some results obtained from full-scale measurements of wind effects on a super-tall building, Di-Wang Tower, located in Shenzhen, China. This tall building has 79-storeys with a height of approximately 324 m. Field measurements including wind speed, wind direction and wind-induced acceleration responses have been made. The amplitude-dependent characteristics of damping are obtained by using the random decrement technique from the detailed analysis of the field acceleration measurements. The main objective of this paper is to present detailed investigations into the effects of nonlinear damping on the dynamic responses of the tall building subjected to various types of applied loads based on the measured amplitude-dependent damping characteristics. The predicted dynamic responses of the building obtained by using the measured damping characteristics were compared with those computed by using constant damping parameters assumed by the structural designers. It is concluded from the investigations that knowledge of actual damping characteristics are very important in the accurate prediction of the dynamic responses of a tall building when the major harmonic components of the applied loads overlap with the lowest natural frequencies of the building. The design damping level for tall building structures currently used by structural engineering practitioners appears to be high and not conservative.

Nonstructural Partitions and Floor Vibration Serviceability

“…Ventura et al (2002) used ambient vibration results to update a FE model of a building including non-structural elements. Li et al (2002) highlighted that measured natural frequencies of a 79 storey building were higher than those calculated from the FE model, concluding that this difference was due to the presence of non-structural elements.…”

How Are the Equivalent Damping Ratios Modified by Nonlinear Engineering Demand Parameters?

“…Indeed, the identification is performed on quasi-static loadings whereas damping ratio is used for seismic loadings. In addition, several studies have emphasized the fact that the viscous damping depends on the response amplitude for RC buildings [11,12,8], which contradicts the hypothesis of a linear equivalent viscous damping. To verify if the previous observations made on buildings comply with RC components, beams in the present study, and evaluate the influence of different excitation and material parameters, an experimental campaign described in the following section has been carried out and is followed by numerical experiments calibrated on experimental data.…”

Ambient vibration tests of a cross-laminated timber building

“…Such tests have been widely used to extract modal properties from structures (Ceravolo and Abbiati, 2012;Beskhyroun et al, 2013;Farrar and James III, 1997;Magalhães et al, 2010;Snaebjörnsson and Ingolfsson, 2013). Jeary (1992Jeary ( , 1996 showed that outputonly techniques can be used not only to assess the modal properties of such structures, but also how those properties vary with amplitude of vibration, and his work led to studies to quantify that variation for tall buildings as wind speed varies (Li et al, 2002(Li et al, , 2003Tamura and Suganuma, 1996). In this study, the building was tested at two stages during construction, which allowed analysis of the influence of the non-structural elements added between the two tests on the measured modal properties.…”