An investigation of the effects of traffic induced local dynamics on global damping estimates using operational modal analysis

Brewick, Patrick T.; Smyth, Andrew W.

doi:10.1016/j.ymssp.2013.07.013

Cited by 24 publications

(16 citation statements)

References 22 publications

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“…Moreover, variations in natural frequencies and mode shapes that are identified from real measured data are good examples of aleatory uncertainties. Variations of identified modal properties due to environmental effects such as temperature() and traffic() are commonly observed during structural dynamic tests. Stochastic model updating methods can more efficiently manage aleatory uncertainties.…”

Section: Introductionmentioning

confidence: 99%

Bayesian model updating of a full-scale finite element model with sensitivity-based clustering

Jang

Smyth

2017

Struct Control Health Monit

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Summary Model updating based on vibration response measurements is a technique for reducing inherent modeling errors in finite element (FE) models that arise from simplifications, idealized connections, and uncertainties with regard to material properties. Updated FE models, which have relatively fewer discrepancies with their real structural counterparts, provide more in‐depth predictions of the dynamic behaviors of those structures for future analysis. In this study, we develop a full‐scale FE model of a major long‐span bridge and update the model to improve an agreement between the identified modal properties of the real measured data and those from the FE model using a Bayesian model updating scheme. Sensitivity‐based cluster analysis is performed to determine robust and efficient updating parameters, which include physical parameters having similar effects on targeted natural frequencies. The hybrid Monte Carlo method, one of the Markov chain Monte Carlo sampling methods, is used to obtain the posterior probability distributions of the updating parameters. Finally, the uncertainties of the updated parameters and the variability of the FE model's modal properties are evaluated.

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Section: Introductionmentioning

confidence: 99%

Bayesian model updating of a full-scale finite element model with sensitivity-based clustering

Jang

Smyth

2017

Struct Control Health Monit

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“…e results for the damping ratio show as higher variability as their standard deviations indicate. is result is not surprising, and higher excitation seems to be required in order to obtain reliable measures of damping [25]. e damping values obtained by the EFDD method are even less reliable than those obtained by the SSI method, as can be extracted from their higher standard deviation values.…”

Section: Analysis and Comparison Of Resultsmentioning

confidence: 98%

Operational Modal Analysis: A Tool for Assessing Changes on Structural Health State of Historical Constructions after Consolidation and Reinforcement Works—Jura Chapel (Jerez de la Frontera, Spain)

Romero

Pachón

Compán

et al. 2018

Shock and Vibration

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Today’s society is sensitive to the architectural heritage conservation. This implies to perform works to maintain these buildings and to assure their structural security. In the last years, the structural analysis of historical masonry constructions has experienced a great progress, thanks to the use of techniques based on the study of the dynamic properties of building structures. In this context, changes on the structural health state of a building are one of the elements that can be assessed considering changes on their dynamic properties. This is useful to evaluate the effectiveness of structural interventions on this kind of buildings by analysing these properties before and after it. This paper focuses on the Jura Chapel, in Jerez de la Frontera (Spain). This chapel is part of San Juan de los Caballeros Church and is dated from the 15th century. In 2015 and after the identification of some structural damages in the chapel vault, an intervention was initiated to improve its structural behaviour and to recover its original appearance. The present work reports the evaluation of the effects that this intervention has on the structural health state of the building, using nondestructive techniques based on ambient vibration tests (AVT) and Operational Modal Analysis (OMA). The AVT were performed for both prerestored and restored states and under environmental loads. A discussion about the validity of doing AVT from extrados when a vault presents disconnection between ribs and web is included in the paper. As a result, the first five natural frequency values have increased while the corresponding mode shapes have not changed significantly. This proves a structural health improvement caused by the repairing process without changing the original behaviour of the structure. This work shows OMA capabilities for evaluating the effectiveness of intervention works on the health state of a historical masonry structure.

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“…Through a peak-picking of peaks and valleys in the selected time window, it is possible to evaluate the logarithmic decrement as δ = (2/ k ) ln ( r 0 / | r k |), where k is an integer index counter of the k th extreme of the ACF, k = 1,2,…, while r 0 and r k are the initial and the k th extreme value of the ACF, respectively. Then, a linear relation can be obtained in terms of counter k (Brewick and Smyth, 2013), as well as plotted and fitted with a straight line; its slope provides an estimate of the logarithmic decrement δ . Finally, from the estimated logarithmic decrement δ = δ q of mode q the corresponding modal damping ratio ζ q can be classically evaluated as ζq=δq/(4π2+δq 2)1/2 (Brincker et al., 2001b).…”

Section: Modal Damping Ratio Estimates By the Refined Fdd Algorithmmentioning

confidence: 99%

“…Mainly, the adoption of preselected fixed parameters (i.e. MAC value for the bell ID and selected range of amplitudes for the ACF, as explained in Section 3.1), as usually done in standard EFDD, suffers for these tough conditions (Brewick and Smyth, 2013; Magalhães et al., 2010). Also, the present use of seismic input makes it harder for the correct detection of the SDOF system associated to the identified mode.…”

Section: Modal Damping Ratio Estimates By the Refined Fdd Algorithmmentioning

confidence: 99%

“…., while r 0 and r k are the initial and the k th extreme value of the ACF, respectively. Then, a linear relation can be obtained in terms of counter k (Brewick and Smyth, 2013), as well as plotted and fitted with a straight line; its slope provides an estimate of the logarithmic decrement . Finally, from the estimated logarithmic decrement ¼ q of mode q the corresponding modal damping ratio z q can be classically evaluated as (Brincker et al, 2001b).…”

Section: Classical Enhanced Fdd Algorithmmentioning

confidence: 99%

See 1 more Smart Citation

Earthquake structural modal estimates of multi-storey frames by a refined Frequency Domain Decomposition algorithm

Pioldi

Ferrari

Rizzi

2015

Journal of Vibration and Control

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This paper targets the frequency domain identification of current structural modal properties under earthquake excitation. A new refined Frequency Domain Decomposition (rFDD) algorithm is implemented towards the output-only modal dynamic identification of heavy-damped frame structures, which are subjected to a wide set of strong ground motions. In fact, both seismic excitation and/or high damping values shall not fulfil traditional FDD assumptions. Despite that, with the present rFDD implementation quite limited errors in the modal parameter estimates have been achieved, including for the modal damping ratios (ranging from 1% to 10%). At first, the identification technique is formulated and explored analytically, by proving its potential effectiveness with seismic response input. Then, all strong motion modal parameters are consistently identified. As a fundamental necessary condition, synthetic response signals are adopted. These have been generated prior to dynamic identification from computed numerical seismic responses of a set of shear-type frames. The efficiency of the present original implementation is highlighted, by proving that consistent rFDD modal dynamic identification of structures at seismic input and simultaneous heavy damping looks feasible. Thus, the paper delivers a robust method for inspecting current structural modal properties of frame buildings under earthquake excitation and for observing their possible variation along experienced seismic histories.

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An investigation of the effects of traffic induced local dynamics on global damping estimates using operational modal analysis

Cited by 24 publications

References 22 publications

Bayesian model updating of a full-scale finite element model with sensitivity-based clustering

Bayesian model updating of a full-scale finite element model with sensitivity-based clustering

Operational Modal Analysis: A Tool for Assessing Changes on Structural Health State of Historical Constructions after Consolidation and Reinforcement Works—Jura Chapel (Jerez de la Frontera, Spain)

Earthquake structural modal estimates of multi-storey frames by a refined Frequency Domain Decomposition algorithm

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