Influence of cohesion on scour at wake of partially submerged spur dikes in cohesive sediment mixtures

Lodhi, A. S.; Jain, Rajesh Kumar; Sharma, Pramod Kumar; Karna, Nilav

doi:10.1080/09715010.2018.1525325

Cited by 8 publications

(1 citation statement)

References 36 publications

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“…Given that scour hole develops as a result of water flow pattern around the soil surrounding the pier, it seems intuitive to heavily focus on hydromechanical properties of soil to better understand the local scour mechanisms and its ultimate impact on bridge stability. Most of existing experimental studies have used non -cohesive sandy soils, and while some studies attempted to study the role of cohesion of soil on pier scour [58], the role of other soil characteristics (e.g. consolidation, friction angle, cementation) is not fully understood yet.…”

Section: Conclusion and Future Developmentsmentioning

confidence: 99%

Physical Modelling of Bridge Pier Scour and Its Effect on Dynamic Response: Towards Real-Time Monitoring of Bridges

Rahimi¹,

Keshavarzy²,

Askari³

2020

Preprint

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The generation of vortices around bridge piers can lead to removal of riverbed materials from around piers, especially during flood events and heavy rainfalls, which can compromise the stability of the bridge and consequently its failure, if not properly detected and mitigated. Bridge failures pose serious threats to the local socio-economic and public safety and can cost lives. As such, real-time monitoring and early warning systems for scour-induced bridge failure can serve as a vital tool to protect the community and civil infrastructure against disastrous events. Vibration-base monitoring of bridge scour is an attractive option due to its low cost and relatively easy installation without the need to block the road and close the bridge to traffic. While limited number of previous studies have shown the capabilities of acceleration-based monitoring techniques in this area of research, they generally lack a rigorous framework for data analysis within and relating those to evaluate scour. This paper is an attempt to provide such framework that would enable a fast and low-cost analysis of vibration data within a physical modelling study on a simplified bridge pier. To achieve this, three experiments were conducted on an ideal single-pier scaled model bridge in a hydraulic flume, where water flows at a velocity near the critical velocity for the sand bed which in turn generates a scour hole around the pier. Then, the vibration data recorded using two mounted wireless accelerometers, were used to conduct an operational modal analysis through which the natural frequencies are extracted. The extracted natural frequencies and measured scour depths are then used to provide a chart that relates these two parameters. The results of this study showed the promising capability of the vibration-based data analysis in finding this relationship, indicating an up to around 30-50% reduction in natural frequencies as a result of around 50% scour ratio (ratio of maximum scour depth to buried depth), and beyond 50% scour ratio the natural frequencies remain constant. While the data presented in this paper are preliminary, they clearly show a promising potential for application in real-time monitoring of bridge stability under the effect of local scour and further works are underway to enrich the experimental data and empower the proposed methodologies at the laboratory scale.

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Section: Conclusion and Future Developmentsmentioning

confidence: 99%