A Vision System for Vibration Monitoring of Civil Engineering Structures

Caetano, Elsa; Silva, S.; Bateira, J.

doi:10.1111/j.1747-1567.2010.00653.x

Cited by 122 publications

(57 citation statements)

References 17 publications

(32 reference statements)

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“…Vibrations decayed to less than 0.3 mm within 2 s and showed a modal frequency of approximately 4.5 Hz. The displacement measurement shown in Figure 7a includes data during several stationary periods (i.e., the time intervals of [0,12], [17,24], [31,38], and [46,55] s). The data samples collected during these periods were used to evaluate the measurement accuracy of the vision-based system.…”

Section: Measurement and Analysis Resultsmentioning

confidence: 99%

“…The feature of distributed sensing has been used in laboratory structures [17,19,29,30] for multistorey displacement measurement and system identification, as well as for cable vibration monitoring [31][32][33][34] aimed at the estimation of modal frequencies or cable tensions, but applications in bridge deformation measurement are limited, with only a few examples. [27,35] …”

Section: Distributed Sensingmentioning

confidence: 99%

“…The bridge provides cyclist and pedestrian access to Sandy Park Stadium (south side of bridge), the home ground of Exeter Chiefs [17,24], [31,38], and [46,55] s), STD = standard deviation.…”

Section: Bridge Descriptionmentioning

confidence: 99%

See 2 more Smart Citations

A non-contact vision-based system for multipoint displacement monitoring in a cable-stayed footbridge

Brownjohn

Kong

2018

Struct Control Health Monit

145

106

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SummaryVision-based monitoring receives increased attention for measuring displacements of civil infrastructure such as towers and bridges. Currently, most field applications rely on artificial targets for video processing convenience, leading to high installation effort and focus on only single-point displacement measurement, for example, at mid-span of a bridge. This study proposes a low-cost and non-contact vision-based system for multipoint displacement measurement based on a consumer-grade camera for video acquisition and a custom-developed package for video processing. The system has been validated on a cablestayed footbridge for deck deformation and cable vibration measurement under pedestrian loading. The analysis results indicate that the system provides valuable information about bridge deformation of the order of a few centimetres induced, in this application, by pedestrian passing. The measured data enable accurate estimation of modal frequencies of either the bridge deck or the bridge cables and could be used to investigate variations of modal frequencies under varying pedestrian loads. KEYWORDSbridge displacement, cable vibration, cable-stayed bridge, pedestrian loads, vision-based system | INTRODUCTIONStructural health monitoring is aimed at providing valuable information about structural performance and characterisation of structural defects to the asset owners, especially for those civil infrastructures beyond the design life. Vibrationbased modal tests are a common way for structural condition and serviceability assessment, providing a direct view about the structural stiffness, mass properties, and their distributions. [1] As well as for validating designs of civil structures, modal parameters extracted from vibration data obtained in short-term or long-term measurements are widely believed to have potential for identifying changes in structural condition or "damage." [2] The sensitivity of these parameters to damage depends on the nature of the damage, for example, local deterioration of material, for example, due to corrosion, may not be detectable against background effects of environmental variability, whereas boundary conditions are known to have a relatively strong effect, for example, fixity of bridge supports.[3]This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Section: Measurement and Analysis Resultsmentioning

confidence: 99%

Section: Distributed Sensingmentioning

confidence: 99%

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A non-contact vision-based system for multipoint displacement monitoring in a cable-stayed footbridge

Brownjohn

Kong

2018

Struct Control Health Monit

145

106

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“…22 shows the daily variation of maximum 20-min amplitude observed in a set of stay cables. This allows the detection of episodes of cables vibrations, characterising the corresponding duration and the correlation with direction and wind velocity, according to information provided by a local meteorological station [20]. A second example regarding the assessment of cable vibrations respects an overhead transmission line.…”

Section: Assessment Of Damping and Vibrationsmentioning

confidence: 99%

Dynamic testing of cable structures

Caetano

Cunha

2015

MATEC Web of Conferences

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Abstract. The paper discusses the role of dynamic testing in the study of cable structures. In this context, the identification of cable force based on vibration measurements is discussed. Vibration and damping assessment are then introduced as the focus of dynamic monitoring systems, and particular aspects of the structural behaviour under environmental loads are analysed. Diverse application results are presented to support the discussion centred on cable-stayed bridges, roof structures, a guyed mast and a transmission line.

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“…The diameter of the cable and the coordinates of the camera were adopted as references for determining the actual displacement of ROI in the 3D object space. The optical flow method considers the motion of object at pixel level according to the change in the image intensities on the image plane [16] and requires an iterative approach [17] for calculating optical flow vector that indicates the magnitude and direction of motion of the ROI in the image plane. Kim et al [18] developed a vision-based monitoring system for measuring the dynamic characteristics of remote stay cables by means of the template matching method using the normalized cross correlation.…”

Section: Introductionmentioning

confidence: 99%

Experimental Verification for Cable Force Estimation Using Handheld Shooting of Smartphones

Zhao¹,

Ri²,

Wang³

2017

Journal of Sensors

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Currently, due to the rapid development and popularization of smartphones, the usage of ubiquitous smartphones has attracted growing interest in the field of structural health monitoring (SHM). The portable and rapid cable force measurement for cablesupported structures, such as a cable-stayed bridge and a suspension bridge, has an important and practical significance in the evaluation of initial damage and the recovery of transportation networks. The extraction of dynamic characteristics (natural frequencies) of cable is considered as an essential issue in the cable force estimation. Therefore, in this study, a vision-based approach is proposed for identifying the natural frequencies of cable using handheld shooting of smartphone camera. The boundary of cable is selected as a target to be tracked in the region of interest (ROI) of video image sequence captured by smartphone camera, and the dynamic characteristics of cable are identified according to its dynamic displacement responses in frequency domain. The moving average is adopted to eliminate the noise associated with the shaking of smartphone camera during measurement. A laboratory scale cable model test and a pedestrian cable-stayed bridge test are carried out to evaluate the proposed approach. The results demonstrate the feasibility of using smartphone camera for cable force estimation.

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A Vision System for Vibration Monitoring of Civil Engineering Structures

Cited by 122 publications

References 17 publications

A non-contact vision-based system for multipoint displacement monitoring in a cable-stayed footbridge

A non-contact vision-based system for multipoint displacement monitoring in a cable-stayed footbridge

Dynamic testing of cable structures

Experimental Verification for Cable Force Estimation Using Handheld Shooting of Smartphones

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