Suspension bridge response due to extreme vehicle loads

Westgate, Robert; Koo, Ki-Young; List, David

doi:10.1080/15732479.2013.767844

Cited by 19 publications

(8 citation statements)

References 18 publications

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“…The towers were constructed from reinforced concrete and sit on caisson foundations founded on rock so are extremely stiff and experience only minute vertical deformations induced by extreme traffic loads (Westgate et al, 2013) and temperature variation . Hence, the true tower deformation would be dominated by low-frequency components small in amplitude compared with the mid-span displacement.…”

Section: Example: Mid-span Deformation Test At Tamar Bridgementioning

confidence: 99%

Vision-Based Bridge Deformation Monitoring

Brownjohn

Hester

2017

Front. Built Environ.

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Optics-based tracking of civil structures is not new, due to historical application in surveying, but automated applications capable of tracking at rates that capture dynamic effects are now a hot research topic in structural health monitoring. Recent innovations show promise of true non-contacting monitoring capability avoiding the need for physically attached sensor arrays. The paper reviews recent experience using the Imetrum Dynamic Monitoring Station (DMS) commercial optics-based tracking system on Humber Bridge and Tamar Bridge, aiming to show both the potential and limitations. In particular, the paper focuses on the challenges to field application of such a system resulting from camera instability, nature of the target (artificial or structural feature), and illumination. The paper ends with evaluation of a non-proprietary system using a consumer-grade camera for cable vibration monitoring to emphasize the potential for lower cost systems where if performance specifications can be relaxed.

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Section: Example: Mid-span Deformation Test At Tamar Bridgementioning

confidence: 99%

Vision-Based Bridge Deformation Monitoring

Brownjohn

Hester

2017

Front. Built Environ.

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“…Currently available sensors for measuring structural vibrations can be classified into contact and non-contact sensors. Contact sensors, such as accelerometers [ 9 , 10 ], linear variable differential transformers (LVDT) [ 11 ], and strain-type displacement sensors (STDS) [ 12 ] are widely used in monitoring systems to obtain valuable structure vibration information. Non-contact sensors such as global position system (GPS) [ 13 ], laser Doppler vibrometers [ 14 ], and radar interferometry system [ 15 ] are less used because they are expensive, complex, and not very accurate [ 16 , 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

A High-Speed Target-Free Vision-Based Sensor for Bus Rapid Transit Viaduct Vibration Measurements Using CMT and ORB Algorithms

Wang

et al. 2017

Sensors

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Bus Rapid Transit (BRT) has become an increasing source of concern for public transportation of modern cities. Traditional contact sensing techniques during the process of health monitoring of BRT viaducts cannot overcome the deficiency that the normal free-flow of traffic would be blocked. Advances in computer vision technology provide a new line of thought for solving this problem. In this study, a high-speed target-free vision-based sensor is proposed to measure the vibration of structures without interrupting traffic. An improved keypoints matching algorithm based on consensus-based matching and tracking (CMT) object tracking algorithm is adopted and further developed together with oriented brief (ORB) keypoints detection algorithm for practicable and effective tracking of objects. Moreover, by synthesizing the existing scaling factor calculation methods, more rational approaches to reducing errors are implemented. The performance of the vision-based sensor is evaluated through a series of laboratory tests. Experimental tests with different target types, frequencies, amplitudes and motion patterns are conducted. The performance of the method is satisfactory, which indicates that the vision sensor can extract accurate structure vibration signals by tracking either artificial or natural targets. Field tests further demonstrate that the vision sensor is both practicable and reliable.

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“…Relatively few have identified shifts in the bridge's natural frequencies, which are a result of the location and mass of the vehicles, as well as their suspension system (Li et al, 2003;Yang, 2004;Westgate et al, 2013). For long span bridges the effect of vehicle-bridge interaction has a negligible contribution, since the frequencies of the first few modes (up to 1Hz) are much lower than the range of dynamic forces excitation frequencies due to vehicle body-bounce modes (2-5Hz).…”

Section: Physics-based Investigation Of Effects Of Vehicle Mass On Brmentioning

confidence: 99%

Effect of vehicular loading on suspension bridge dynamic properties

Westgate

Koo

2014

Structure and Infrastructure Engineering

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Effect of vehicular loading on suspension bridge dynamic propertiesSince the 1970s many researchers have attempted to use changes in natural frequencies as means for condition assessment of large civil engineering structures such as bridges, but have faced the challenge of decoupling frequency variations apparently caused by changing operational conditions. In the case of the Tamar Bridge in southwest England, time series of natural frequencies exhibit diurnal variations resulting from a combination of thermal and vehicular loading, whose effects would need to be compensated for in dynamics-based assessment.By examination of several years of monitoring data, the effects of traffic mass have been characterised and compared with other operational effects. While temperature changes appear to have a greater influence for lateral modes, traffic mass is a strong factor in all modes and the dominant factor for the vertical and torsional modes evaluated.Physics-based explanations for the variable effects of vehicle mass have been sought using a finite element model calibrated against experimental data. As a caution for performance prediction in structural dynamics, while acceptable reconciliation of natural frequencies from FE model and measurements was achievable, reconciling simulated effects of changing mass with observed behaviour has not been straightforward due to the complexity of the retrofitted suspension bridge structure studied.Keywords: bridges, long-span; bridges, suspension; cables; damage assessment; finite element method; roads & highways; structural dynamics; structural engineering; suspended structures; traffic engineering. Introduction: variations in bridge loading and dynamic response characteristicsStructural Health Monitoring (SHM) implementations on civil infrastructure (Brownjohn, 2007) have many purposes that include the tracking of time varying loads and responses in order to identify, characterise and diagnose anomalous performance. In particular, changes in dynamic response parameters, e.g. modal properties such as natural frequencies, have been regarded by many researchers as a possible indicator of structural 'damage' (Brownjohn et al., 2011). SHM systems may also be used to validate design assumptions, for example regarding thermal and vehicular loads. Hence there are strong motives for studying time series of structural loads (wind, vehicles and temperature) and dynamic response parameters and their relationships.For long span bridges in particular wind-structure interaction can result in modification of modal parameters and lead to catastrophic instability due to the phenomenon of aero-elasticity (Wyatt, 1992). Such effects can be observed not only in wind tunnel testing but also at full scale, using SHM systems (Diana at al., 1992) and there is a large body of research on the topic.Rather fewer studies have examined the link between thermal loads (diurnal and seasonal temperature variations) and dynamic properties, which are reviewed by Xia, Chen, Weng, Ni and Xu (2012). Of these only a...

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Suspension bridge response due to extreme vehicle loads

Cited by 19 publications

References 18 publications

Vision-Based Bridge Deformation Monitoring

Vision-Based Bridge Deformation Monitoring

A High-Speed Target-Free Vision-Based Sensor for Bus Rapid Transit Viaduct Vibration Measurements Using CMT and ORB Algorithms

Effect of vehicular loading on suspension bridge dynamic properties

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