Operational deformations in long-span bridges

Brownjohn, James; Koo, Ki-Young; Scullion, Andrew; List, David

doi:10.1080/15732479.2014.951857

Cited by 75 publications

(29 citation statements)

References 29 publications

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“…As sensor and data‐acquisition technologies developed rapidly in the past few years, structural health monitoring (SHM) has been installed in more and more large civil infrastructures, especially long‐span bridges. Some well‐known bridges are the Golden Gate Bridge, Vincent Thomas Bridge, and Cape Girardeau Bridge in the United States; Tamar Bridge and Humber Bridge in the United Kingdom; and Higashi Kobe Bridge, Yokohama Bay Bridge, and Rainbow Bridge in Japan. SHM has made it possible to gain insight into performance of these bridges in real time.…”

Section: Introductionmentioning

confidence: 99%

Utilization of structural health monitoring in long-span bridges: Case studies

Sun

Zou

Zhang

2017

Struct. Control Health Monit.

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Summary Structural health monitoring (SHM) of bridges has gained rapid development in the past few years. This paper describes application of SHM on long‐span bridges in China, with the aim to illustrate its practical value. A short review of its development and practice is firstly introduced. Three case studies are subsequently presented on utilization of SHM data in engineering practice. In the first case study, a ship collision incident is analyzed using SHM data. An alarm is sent and confirmed when the collision occurred, and mode parameters are identified with GPS measurements to evaluate the bridge condition. In the second case study, damage of expansion joints in a suspension bridge is assessed with girder end displacement measurements. Malfunction of viscous damper is found to correlate with cumulative displacement. The results show that cumulative displacement can be used for condition assessment of expansion joints. In the third case study, the performance of tuned mass dampers is evaluated with wind and vibration measurements before and after tuned mass damper installation. Through explanation of these case studies, the paper illustrates how to distill useful insights from SHM data, which could be instructive for further research in this field.

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Section: Introductionmentioning

confidence: 99%

Utilization of structural health monitoring in long-span bridges: Case studies

Sun

Zou

Zhang

2017

Struct. Control Health Monit.

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“…These sensors are easy to install with no dependence on a fixed reference point other than their own (stable) location. Access to a test structure is sometimes still either necessary or recommended for the installation of assistant tools such as reflective tapes for LDVs (Lou et al 2017), reflective prisms for RTS (Brownjohn et al 2015) and artificial targets for vision-based systems (Xu et al 2016). Vision-based systems and radar interferometry both support multi-point simultaneous sensing, approaching true deformation monitoring, while distributions of test points in microwave interferometry systems are dependent on range resolution and less flexible.…”

Section: Review Of Displacement Sensing Techniquesmentioning

confidence: 99%

Accurate Deformation Monitoring on Bridge Structures Using a Cost-Effective Sensing System Combined with a Camera and Accelerometers: Case Study

Brownjohn

Huseynov

2019

J. Bridge Eng.

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Information on deformation is critical for bridge condition evaluation but accurate characterisation, usually via discrete displacement measurements, remains a challenging task. Vision-based systems are promising tools, possessing advantages of easy installation, low cost and adequate resolution in time and frequency domains. However, vision-based monitoring faces several field challenges and might fail to achieve the required level of working performance in some real-world test conditions e.g. involving low-contrast patterns and mounting instability of optical sensors. To make the best use of the potential of vision-based systems, a mixed sensing system consisting of a consumer-grade camera and an accelerometer is proposed in this study for accurate displacement measurement. The system considers automatic compensation of camera shake and involves autonomous data fusion process for noise reduction. The proposed system is demonstrated through a field monitoring test on a short-span railway bridge and is validated to offer higher accuracy and wider frequency range than using a camera alone. Displacement data by the mixed system are demonstrated to be viable for estimating bridge influence line, indicating the potential for bridge condition assessment.

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“…Figure 15 illustrates the estimation results for the signals recorded during three time intervals, that is, ([0, 400], [800, 1,200], and [1,600, 2,000] s). The first time interval ([0, 400] s) was at the end of the match (during stoppage time), and thus, few pedestrians crossed the bridge; the second duration ([800, 1,200] s) was after the Rugby match, and the bridge was almost fully occupied by pedestrians; and the third time interval was after most spectators had left, and still a few pedestrians were crossing the bridge.…”

Section: Frequency Components Of Vertical Displacementmentioning

confidence: 99%

“…The cable motion here corresponds to the motion of cable projection in the image in pixel units. The power spectral densities of the cable motions during the three time intervals (i.e., ([0, 400], [800, 1,200], and [1,600, 2,000] s) are indicated in Figure 18b,d for the cable targets C1 and C2, respectively.…”

Section: Measurement and Analysis Of Cable Vibrationmentioning

confidence: 99%

“…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.…”

Section: Introductionmentioning

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

169

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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Operational deformations in long-span bridges

Cited by 75 publications

References 29 publications

Utilization of structural health monitoring in long-span bridges: Case studies

Utilization of structural health monitoring in long-span bridges: Case studies

Accurate Deformation Monitoring on Bridge Structures Using a Cost-Effective Sensing System Combined with a Camera and Accelerometers: Case Study

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

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