Limitations in Structural Identification of Large Constructed Structures

Çatbaş, F. Necati; Ciloglu, S Korhan; Hasançebi, O.; Grimmelsman, Kirk A.; Aktan, A. Emin

doi:10.1061/(asce)0733-9445(2007)133:8(1051)

Cited by 94 publications

(40 citation statements)

References 18 publications

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“…Since then, there has been an increasing popularity for Bayesian-updating methodologies [3,4]. Many applications of dynamic monitoring of bridges can be found in the literature, for example [3,9,13,14,23,26,31,33,38,40,41,46,49]. Some of these studies, such as [3] and [14], explicitly included uncertainties in the identification process.…”

Section: Introductionmentioning

confidence: 99%

Hybrid probabilities and error-domain structural identification using ambient vibration monitoring

Goulet

Michel²,

Smith

2013

Mechanical Systems and Signal Processing

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For the assessment of structural behavior, many approaches are available to compare model predictions with measurements. However, few approaches include uncertainties along with dependencies associated with models and observations. In this paper, an error-domain structural identification approach is proposed using ambient vibration monitoring (AVM) as the input. This approach is based on the principle that in science, data cannot truly validate an hypothesis, it can only be used to falsity it. Error-domain model falsification generates a space of possible model instances (combination of parameters), obtains predictions for each of them and then, rejects instances that have unlikely differences (residuals) between predictions and measurements. Models are filtered in a two step process. Firstly a comparison of mode shapes based on MAC criterion ensures that the same modes are compared. Secondly, the frequencies from each model instance are compared with the measurements. The instances for which the difference between the predicted and measured value lie outside threshold bounds are discarded. In order to include "uncertainty of uncertainty" in the identification process, a hybrid probability scheme is also presented. The approach is used for the identification of the Langensand Bridge in Switzerland. It is used to falsify the hypothesis that the bridge was behaving as designed when subjected to ambient vibration inputs, before opening to the traffic. Such small amplitudes may be affected by lowlevel bearing-device friction. This inadvertently increased the apparent stiffness of the structure by 17%. This observation supports the premiss that ambient vibration surveys

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Section: Introductionmentioning

confidence: 99%

Hybrid probabilities and error-domain structural identification using ambient vibration monitoring

Goulet

Michel²,

Smith

2013

Mechanical Systems and Signal Processing

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“…Although some researchers have pointed out the intrinsic difficulties in performing vibration testing in large bridges, such as nonstationary excitation (Catbas et al 2007), nonlinear boundary or continuity conditions, and nonideal connections/interfaces between structural members and components (Farhey 2005), it is unquestionable that dynamic testing stands as an innovative way of great potential in the structural identification of bridges for condition assessment (Aktan et al 1997;DeWolf et al 2002). It becomes imperative when assessing the seismic vulnerability of a structure and corresponding retrofit design (Cheung et al 2007), and can play a decisive role in the rehabilitation of centenary steel bridges, both in supporting the project design and validating their performance for the new structural condition.…”

Section: Dynamic Testing In the Assessment Of Old Steel Bridgesmentioning

confidence: 99%

Modal Analysis for the Rehabilitation Assessment of the Luiz I Bridge

et al. 2014

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Dynamic testing in the condition assessment of existing bridges to support their rehabilitation and strengthening designs is becoming a common procedure, yet additional dynamic testing after rehabilitation is rare. Nevertheless, combining the results of dynamic testing before and after bridge rehabilitation produces unique and valuable information regarding changes occurred in a bridge's dynamic properties. Such dual testing would allow researchers to verify the behavior predicted at the design stage and to assess the stiffness variation, which would eliminate the need for mandatory field static testing. This article reports the modal analysis of a unique centenary steel-arch bridge that was recently rehabilitated and strengthened. The ambient vibration test conducted after the construction works is described, and the data are compared with those collected before the rehabilitation. Structural identification is completed by means of experimentally validated threedimensional (3D) finite-element (FE) models simulating both phases. The results bring to light important findings concerning variation in bridge stiffness, changes in the modal parameters, and the impact of support conditions and structure of decks in bridge dynamic properties.

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“…The sequence adopted in the analysis follows the real chronology observed during the construction (Table 1) [14]. Errors are inevitable in the construction of numerical models concerning large structures, namely due to data input [15]. Therefore, in order to mitigate potential errors, CAD tools were specifically developed and used during the scanning of the drawing pieces, with benefits on time expended [16].…”

Section: General Considerationsmentioning

confidence: 99%