Study of Time‐Depenbent Local Scour around Bridge Piers

Yanmaz, A. Melih; Altinbilek, Hilmi D.

doi:10.1061/(asce)0733-9429(1991)117:10(1247)

Cited by 205 publications

(67 citation statements)

References 9 publications

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“…A new empirical relation, the most compatible with our experimental results, was investigated by using the dimensionless time parameter proposed by Yanmaz and Altinbilek (1991). The proposed relation was obtained by using the least squares method which minimizes the sum of squared residuals.…”

Section: Discussion Of Results and Comparisonsmentioning

confidence: 89%

“…Most of the existing studies are focused on the equilibrium scour depth values and the experiments about the temporal variation of the scour depths are rather scarce. Yanmaz and Altinbilek (1991) studied the timedependent scour depth in steady flow conditions by using uniform bed material and a semi-empirical time-dependent analysis of local scour depths around bridge piers has been conducted using the sediment continuity equation for the scour hole around bridge piers. Kothyari et al (1992) proposed a method considering the primary vortex in front of the pier to compute the temporal variation of the scour depth.…”

Section: Introductionmentioning

confidence: 99%

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Study of the time-dependent clear water scour around circular bridge piers

Aksoy

Bombar

Arkis

et al. 2016

Journal of Hydrology and Hydromechanics

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Abstract:The local scour around bridge piers influences their stabilities and plays a key role in the bridge failures. The estimation of the maximum possible scour depth around bridge piers is an important step in the design of the bridge pier foundations. In this study, the temporal evolution of local scour depths as well as the equilibrium scour depths were analyzed.The experiments were carried out in a rectangular flume by using uniform sediment with median diameter of 3.5 mm and geometric standard deviation of 1.4. The diameters of the tested circular bridge piers were 40 mm, 80 mm, 150 mm and 200 mm. The flow and scour depths were determined by ultrasonic sensors. The experiments were realized in clear water conditions with various constant flow rates.The experimental findings were compared with those calculated from some empirical equations existing in the literature. A new empirical relation involving the flow intensity, the relative water depth and the dimensionless time is also introduced. The advantage of this proposed relation is that the only parameter requiring the calculation is the critical velocity, other parameters being known geometric and hydraulic parameters. The performance of this relation was tested by using experimental data available in the literature, and a satisfactory compatibility was revealed between the experimental and numerical results.

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Section: Discussion Of Results and Comparisonsmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Study of the time-dependent clear water scour around circular bridge piers

Aksoy

Bombar

Arkis

et al. 2016

Journal of Hydrology and Hydromechanics

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“…For the local scour at bridge pier under tidal action, in most cases, it is generalized into a constant flow test under limiting conditions [3]- [6] . In few cases, the inconstant flow test is given for specific projects [7]- [12] .…”

Section: Research Backgroundmentioning

confidence: 99%

Research on Local Scour at Bridge Pier under Tidal Action

Wang

2015

MATEC Web of Conferences

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The local scour of river bed around the bridge pier is affected by water flow state, bridge pier form, bed sand composition, river bed form and other factors. The maximum scouring depth directly threatens the safety of pier foundation [1] . The book, Hydrological Specifications for Survey and Design of Highway Engineering [2] (hereinafter referred to as Specifications) recommends the calculation method of scour at bridge pier in runoff river. With the development of national road network and improvement of highway design level, the road has been extended to the tidal river and offshore harbor. So the relevant content in the current Specifications could not meet the actual requirements.For the local scour at bridge pier under tidal action, in most cases, it is generalized into a constant flow test under limiting conditions [3]-[6] . In few cases, the inconstant flow test is given for specific projects [7]-[12] . However, there is a divergence in the development course and the maximum depth of local scouring pit at bridge pier under tidal action. The consistency between the maximum flow rate of ebb and flow tide and the mean flow rate of constant flow is a reference condition. One viewpoint believes that under the action of reverse flow, there are sediment erosion and deposition in the scouring pit, resulting that the maximum scouring depth is less than the maximum scouring depth under the action of constant flow. The other viewpoint believes that if the flow velocity is small, and the slack water period is longer in a tidal cycle, the effective acting time and effective acting velocity of flow will decrease, resulting that the formation of scouring pit is slow. Before the scour reaching an equilibrium state, the maximum scouring depth observed is less than the maximum scouring depth under the action of constant flow. However, both of the maximum scouring depth is basically the same. MODEL DESIGN AND CONSTRUCTION Model designThe test is carried out in a water tank, with the length of 35m and width of 2m. Due to little impact of suspended sediment on local scour at bridge pier, the movable bed model only considers bed sand. The plane scale of the model is 100, which is designed by the use of normal model according to the gravity similarity criterion and geometric similarity criteria, so as to meet the similarity of water flow movement and similarity of sediment movement.The bridge pier type adopts common pile groups with pile caps in the tidal river and harbor area. The pile group is arranged as quincunx, and the pile cap is dumb-bell shaped. During the test, the pile cap at the upper part of the pile group is always under the action of water flow. The model adopts the multiple-pump frequency-control closed loop water level control system. The system regulates and controls over the output frequency of transducer according to the given flow or hydrograph, regulates water yield of the water pump model to produce fluctuation tide, and make the flow rate and water level in the water tank meet the test requirements. T...

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“…Therefore, the prediction of local scour especially the maximum depth of scour hole, is critical for bridge design, maintenance and evaluation. Over the past decades, many experiments have been conducted to study this issue as Yanmaz [3], Ettema [4], and Sheppard [5,6]. However, the detailed vortex structure is difficult to be revealed based on experimental measurements.…”

Section: Introductionmentioning

confidence: 99%

Simulations of Local Scour Around a Cylindrical Bridge Pier And a Semicircular Abutment Using Unsteady k-ε Model Combined with σ-Grid

Shi¹,

Yang²,

Wu³

2017

TOCIEJ

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Introduction:Bridge scour is one of the major causes of bridge failure. Prediction of the maximum depth and shape of local scour plays an important role in bridge design and maintenance. In this paper, k-ε turbulent model combined with wall function was employed and complex flow fields are exhibited. The bed load transport model summarized by Qian and Wan [1] was applied to evaluate the development of local scour. Besides, σ-grid module was developed and embedded into the commercial solver FLUENT to fit the change of channel-bed. Method:In this module, the change of the elevation of the channel bed is calculated through using user defined functions(UDF), and the motion of the grid system is realized based on a program developed through C++ language, which extends the applications of FLUENT. The evolution of local scour hole for two cases, i.e., local scour around a cylindrical pier and a semicircular abutment, was simulated. Results and Conclusion:The depth and the shape of local scour as well as the flow fields were predicted. Numerical result conforms well to the experimental measurement. Especially, it provides fairly reasonable prediction on the key issue of the maximum scour depth. The satisfactory agreement validates the numerical method developed in the present study. In addition to the validation purpose, the different performance of this method for predicting local scour around the cylindrical pier and the semicircular abutment was discussed.

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Study of Time‐Depenbent Local Scour around Bridge Piers

Cited by 205 publications

References 9 publications

Study of the time-dependent clear water scour around circular bridge piers

Study of the time-dependent clear water scour around circular bridge piers

Research on Local Scour at Bridge Pier under Tidal Action

Simulations of Local Scour Around a Cylindrical Bridge Pier And a Semicircular Abutment Using Unsteady k-ε Model Combined with σ-Grid

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