An evaluation of scour measurement devices

Fisher, Murray; Chowdhury, M. Nasimul; Khan, A. A.; Atamturktur, Sez

doi:10.1016/j.flowmeasinst.2013.05.001

Cited by 60 publications

(33 citation statements)

References 17 publications

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“…Measures of bed elevation require some further comments. Although echosounders are standard in marine environments and widely used for riverbed surveys, literature suggests that they may present some criticalities as permanent sensors of riverbed elevation; in particular, during high‐velocity flow conditions, signals may be disturbed by the turbidity of the water and/or presence of air bubbles; moreover, depending on the geometry of the bridge, it may not be easy to mount them in such a way that the echoes are not disturbed by the bridge foundations; finally, their periodical inspection may be critical, especially for bridges over large rivers. We consequently installed the sedimeter that, despite its lower spatial and temporal resolution with respect to the echosounder, does not suffer from flow disturbances, thus providing a robust cross‐check for the identification of the bed elevation.…”

Section: Alternative Approach To Structural Risk: Managementmentioning

confidence: 99%

Actions monitoring as an alternative to structural rehabilitation: Case study of a river bridge

Ballio

Franzetti

Crotti

et al. 2018

Struct Control Health Monit

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Summary A number of river bridges collapse worldwide every year during flood events, due to combination of actions including traffic loads, water and wind load, riverbed degradation, and accumulation of debris. Incidence of failure is higher for relatively old bridges that may have been designed without adequate consideration for some of such actions, in particular the scour potential at piers and abutments; in this case, consolidation of bridge foundations may be required. As an alternative to structural rehabilitation, we propose here real‐time management as a nonstructural risk‐mitigation measure: Data from a monitoring system aid the bridge managers to decide whether a bridge should be partially or totally closed to traffic in the case that forecasted environmental conditions indicate that the structure may exit its safe operational domain. A peculiar feature of the present proposal is that the monitoring system focuses on the evaluation of the environmental actions on the structure rather than on the health state of the structure itself: Such choice allows sufficient lead time for bridge closure. Bridge management may not prevent the damage of the structure but should avoid casualties. The methodology is presented with reference to the field case of a bridge over the river Po (Italy); its generalization to a larger variety of conditions is also discussed.

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Section: Alternative Approach To Structural Risk: Managementmentioning

confidence: 99%

Actions monitoring as an alternative to structural rehabilitation: Case study of a river bridge

Ballio

Franzetti

Crotti

et al. 2018

Struct Control Health Monit

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“…Simple systems such as Float-Out Devices and Tethered Buried Switches [6,7] float out of the soil when scour reaches their installed depth, triggering a signal. Time-Domain Reflectometry (TDR) systems use changes in dielectric permittivity to monitor the location of the soil-water interface relative to a fixed probe [8,9]. Similarly, Ground Penetrating Radar (GPR) can be used to detect scour holes using high frequency electromagnetic waves, which are partially reflected as they pass through different media [3,10].…”

Section: Direct Monitoring Of Bridge Scour Using Depthmeasuring Instrmentioning

confidence: 99%

“…Similarly, Ground Penetrating Radar (GPR) can be used to detect scour holes using high frequency electromagnetic waves, which are partially reflected as they pass through different media [3,10]. Sound wave devices such as Sonic Fathometers [5,9,11], Reflection Seismic Profilers [5,10] and Echo Sounders [10] emit sonic pulses to locate the soil-water interface and, hence, the scour depth, using a similar approach to the radar methods. A variety of methods rely on the installation of rods into the soil near a foundation.…”

Section: Direct Monitoring Of Bridge Scour Using Depthmeasuring Instrmentioning

confidence: 99%

Isolating the location of scour-induced stiffness loss in bridges using local modal behaviour

Prendergast

Gavin

Hester

2017

J Civil Struct Health Monit

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Detecting scour by analysing bridge vibrations is receiving an increasing amount of attention in the literature. Others have considered changes in natural frequency to indicate the presence of scour damage; however, little work has been reported on identifying the location of a scour hole based on vibration measurements. In this paper, a numerical study is carried out using a bespoke vehiclebridge-soil dynamic interaction model to examine how the first six vibration modes (Eigen frequencies) of a typical integral bridge are affected by scour at different locations. It is found that depending on the location of the scour hole, some modes are much more affected than others in terms of frequency changes. In fact, a clear pattern emerges as to which modes are affected by which scour location. Using this knowledge, the location of a scour hole can potentially be detected on a real bridge. However, recognising that it is not possible to undertake an eigenvalue analysis on an actual bridge, an analysis is performed by collecting acceleration signals from various points on the structure. The bridge is loaded by a realistic vehicle model, incorporating vehicle-bridge interaction effects, which leads to the generation of discrete acceleration signals at various 'sensor' locations on the bridge. In this paper, it is found that it is possible to detect the location of a scour hole using a relatively small number of 'sensors'. However, to achieve this, careful signal processing is necessary and advice on a number of pertinent issues is provided.

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“…To 3.3-5 overcome limitations in this assessment process, significant efforts have been made to design remote systems capable of relaying information about scour reducing the need for manual intervention. These systems can be broadly categorized as follows (Prendergast & Gavin 2014): single-use devices (NCHRP 2009;Briaud et al 2011), pulse or radar devices (Forde et al 1999;Yu 2009;Yankielun & Zabilansky 1999), buried or driven rod systems (NCHRP 2009;De Falco & Mele 2002;Zarafshan et al 2012;Fisher et al 2013), sound-wave devices (Nassif et al 2002;Fisher et al 2013;Anderson et al 2007), fiber-Bragg grating devices (Lin et al 2006;May et al 2002) and electrical conductivity devices (Anderson et al 2007). Table 1 gives an overview of the function and detection methodology of a number of types of instrument available.…”

Section: Shm For Scourmentioning

confidence: 99%

Structural Health Monitoring and Design Code compliance for performance assessment of bridges under scour and seismic hazards

Zanini¹,

Faleschini²,

Ademovic³

et al. 2017

Proceedings of the Joint COST TU1402 - COST TU1406 - IABSE WC1 Workshop: The Value of Structural Health Monitoring for the Reli

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Abstract. When dealing with asset management of infrastructural systems, maintenance planning of bridges and other critical structures has to be thought against natural deterioration due to environmental conditions, but also taking into account potential criticalities induced by the occurrence of seismic and flood hazards. The aim of this work is to focus on potential damage scenarios, assessment methods for common bridge structures potentially subject to earthquake loading and scouring phenomena due to flooding hazards.

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An evaluation of scour measurement devices

Cited by 60 publications

References 17 publications

Actions monitoring as an alternative to structural rehabilitation: Case study of a river bridge

Actions monitoring as an alternative to structural rehabilitation: Case study of a river bridge

Isolating the location of scour-induced stiffness loss in bridges using local modal behaviour

Structural Health Monitoring and Design Code compliance for performance assessment of bridges under scour and seismic hazards

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