A wavelet based method for estimating the damping ratio in statnamic pile load tests

Tsai, Pei-Hsun; Zhang, Feng; Lin, Shang-Yuh

doi:10.1016/j.compgeo.2010.11.007

Cited by 16 publications

(5 citation statements)

References 5 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Since the Fourier amplitude is challenging to identify the exact well-defined peak, the locally weighted linear regression algorithm 55 is used to generate a smoothed curve as again plotted in Figure 4 for easy inspections. The damping ratio, ζ, is then estimated using the half-power bandwidth method 56 as expressed in Equation (1):…”

Section: Frequency and Damping Of The Soil-bridge Systemmentioning

confidence: 99%

Shake‐table investigation of scoured RC pile‐group‐supported bridges in liquefiable and nonliquefiable soils

Wang

Shang

2019

Earthq Engng Struct Dyn

View full text Add to dashboard Cite

Summary This paper presents results of one‐g shake‐table tests on scoured pile‐group‐supported bridge models in saturated (liquefiable) and dry (nonliquefiable) sands. The primary objective is to reveal the influence of liquefaction on seismic demands and failure mechanism of scoured bridges. To this end, two identical models, each consisting of a 2 × 2 reinforced concrete pile‐group with a center‐to‐center spacing of 3 times pile diameter, a cap and a single pier with a lumped iron block, were constructed and embedded into saturated and dry sands, respectively, with the same scour depth of 4 times pile diameter. Typical test results, including excess pore pressure, acceleration and displacement demands are interpreted first, followed by the focus on curvature demands and associated seismic failure mechanism identification. Finally, inertial and kinematic effects on pile curvature demands are estimated using cross‐correlation analyses. Results show that near‐pile liquefied soils exhibit more remarkable dilation tendency as compared to far field. For bridges under the given scour depth, soil liquefaction tends to significantly affect the failure modes via transferring damage positions from pier bottom to pile head and meanwhile from underground pile to pile head. In addition, pile group effects appear to be significant in nonliquefiable soils while to be relatively inessential in liquefied soils. Moreover, the inertial effect is more prominent in nonliquefiable soils, while the kinematic effect itself generally appears to be more significant in liquefiable soils. The test results can be used to validate numerical models for future studies.

show abstract

Section: Frequency and Damping Of The Soil-bridge Systemmentioning

confidence: 99%

Shake‐table investigation of scoured RC pile‐group‐supported bridges in liquefiable and nonliquefiable soils

Wang

Shang

2019

Earthq Engng Struct Dyn

View full text Add to dashboard Cite

show abstract

“…This feature enables the method to overcome the typical deficiency in time-domain methods of proneness to noise during damping estimation. (ii) It can estimate the instantaneous damping of structures [103], which makes it feasible for characterizing nonlinear damage that induces changes in structural dynamic properties in a nonlinear manner. This function cannot be realized in either timedomain or frequency-domain methods.…”

Section: Damping Estimation In the Time-frequency Domainmentioning

confidence: 99%

Structural damage identification using damping: a compendium of uses and features

Cao

Sha

Gao

et al. 2017

Smart Mater. Struct.

129

View full text Add to dashboard Cite

The vibration responses of structures under controlled or ambient excitation can be used to detect structural damage by correlating changes in structural dynamic properties extracted from responses with damage. Typical dynamic properties refer to modal parameters: natural frequencies, mode shapes, and damping. Among these parameters, natural frequencies and mode shapes have been investigated extensively for their use in damage characterization by associating damage with reduction in local stiffness of structures. In contrast, the use of damping as a dynamic property to represent structural damage has not been comprehensively elucidated, primarily due to the complexities of damping measurement and analysis. With advances in measurement technologies and analysis tools, the use of damping to identify damage is becoming a focus of increasing attention in the damage detection community. Recently, a number of studies have demonstrated that damping has greater sensitivity for characterizing damage than natural frequencies and mode shapes in various applications, but damping-based damage identification is still a research direction ‘in progress’ and is not yet well resolved. This situation calls for an overall survey of the state-of-the-art and the state-of-the-practice of using damping to detect structural damage. To this end, this study aims to provide a comprehensive survey of uses and features of applying damping in structural damage detection. First, we present various methods for damping estimation in different domains including the time domain, the frequency domain, and the time-frequency domain. Second, we investigate the features and applications of damping-based damage detection methods on the basis of two predominant infrastructure elements, reinforced concrete structures and fiber-reinforced composites. Third, we clarify the influential factors that can impair the capability of damping to characterize damage. Finally, we recommend future research directions for advancing damping-based damage detection. This work holds the promise of (a) helping researchers identify crucial components in damping-based damage detection theories, methods, and technologies, and (b) leading practitioners to better implement damping-based structural damage identification.

show abstract

“…12. There are a number of ways to estimate damping such as logarithmic decrement method [12,20,41,42], half-power bandwidth method [43,44] and curve-fitting, as well as numerous others. In this paper, damping was estimated using a curve fitting technique, whereby an exponential decay function is fit to the oscillation peaks of the time-domain signal in a least-squares sense [41].…”

Section: Experimental Frequency Response and Damping Ratiosmentioning

confidence: 99%

A comparison of initial stiffness formulations for small-strain soil–pile dynamic Winkler modelling

Prendergast

Gavin

2016

Soil Dynamics and Earthquake Engineering

View full text Add to dashboard Cite

A wavelet based method for estimating the damping ratio in statnamic pile load tests

Cited by 16 publications

References 5 publications

Shake‐table investigation of scoured RC pile‐group‐supported bridges in liquefiable and nonliquefiable soils

Shake‐table investigation of scoured RC pile‐group‐supported bridges in liquefiable and nonliquefiable soils

Structural damage identification using damping: a compendium of uses and features

A comparison of initial stiffness formulations for small-strain soil–pile dynamic Winkler modelling

Contact Info

Product

Resources

About