Experimental analysis of scour under circular pier

Abstract For economical design, scour around the bridge piers is required to be controlled. In the present study, an attempt has been made to minimize scour depth by placing a triangular prism on the downstream side of a circular pier (35 mm dia) with one of its noses facing the direction of flow and other facing opposite to the direction of flow. Three different bed samples collected from Ghaggar, Patialki-Rao and the Kotla super-passage have been placed in a rectangular flume. Discharge values were varied from 0.0015 to 0.0186 m3/sec. Results are compared for observed scour-depth for upstream (U/S) and downstream (D/S) piers with and without protection. Arrangement with a triangular prism of 2.5 times the diameter of the circular pier in the upstream direction of the flow is very effective in reducing scour depth. Further, it is possible to reduce the scour depth with an average efficiency of 65% for Ghaggar, 56% for Patialaki-Rao and 64% for the Kotla super-passage with respect to the circular pier. The comparison of observed values of scour-depth with computed values of Lacey's scour-depth was underestimated with a maximum of ±70%. Hence, a new site-specific relationship between scour depth, discharge intensity and silt factor has been proposed. Validation of the new proposed relationship with observed data is in a good agreement ±20%.

Download Full-text

Experimental Analysis of the Scour Pattern Modeling of Scour Depth Around Bridge Piers

Arabian Journal for Science and Engineering ◽

10.1007/s13369-017-2599-7 ◽

2017 ◽

Vol 42 (9) ◽

pp. 4111-4130 ◽

Cited By ~ 5

Author(s):

Mujahid Khan ◽

Muhammad Tufail ◽

Muhammad Ajmal ◽

Zia Ul Haq ◽

Tae-Woong Kim

Keyword(s):

Experimental Analysis ◽

Bridge Piers ◽

Scour Depth ◽

Pattern Modeling

Download Full-text

Effect of Soil Non-Uniformity on Scour For Circular Compound Bridge Piers

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.b2262.078219 ◽

2019 ◽

Vol 8 (2) ◽

pp. 2051-2059

Keyword(s):

Experimental Investigation ◽

Bridge Pier ◽

Bridge Piers ◽

Scour Depth ◽

Flowing Water ◽

Railway Bridges ◽

The Past ◽

Economical Design ◽

Circular Compound ◽

Bridge Failure

Bridge piers having a varying foundation diameter are known as compound bridge piers. In India for the construction of road and railway bridges circular compound bridge piers are mostly adopted. In past studies it has been concluded that 60-70% of bridge failure occurs because of scour around bridge pier across a river due to flowing water. Most of the past studies were done on the uniform bridge pier and a very few studies has been carried out so far on scour around compound bridge piers. For economical design of bridge pier foundation there is a need to determine the scour depth. In the present study, an experimental investigation has been carried out for computation of time variant change of scour depth for two different models of circular compound bridge piers over non-uniform soil for all possible cases of position of footing with respect to level of the bed, i.e., I. Footing at the level of bed, and II. Footing below the level of bed (1cm, 2cm, 3cm and 4cm) for non-uniform sediments

Download Full-text

Evaluation of Selected Pier-Scour Equations Using Field Data

Transportation Research Record Journal of the Transportation Research Board ◽

10.1177/0361198196152300123 ◽

1996 ◽

Vol 1523 (1) ◽

pp. 186-195 ◽

Cited By ~ 3

Author(s):

Mark N. Landers ◽

David S. Mueller

Keyword(s):

Field Measurements ◽

Bridge Piers ◽

Critical Ratio ◽

Scour Depth ◽

Flow Depth ◽

Clear Water ◽

Pier Scour ◽

Logarithmic Space ◽

State Highway ◽

Federal Highway

Field measurements of channel scour at bridges are needed to improve the understanding of scour processes and the ability to accurately predict scour depths. An extensive data base of pier-scour measurements has been developed over the last several years in cooperative studies between state highway departments, the Federal Highway Administration, and the U.S. Geological Survey. Selected scour processes and scour design equations are evaluated using 139 measurements of local scour in live-bed and clear-water conditions. Pier-scour measurements were made at 44 bridges around 90 bridge piers in 12 states. The influence of pier width on scour depth is linear in logarithmic space. The maximum observed ratio of pier width to scour depth is 2.1 for piers aligned to the flow. Flow depth and scour depth were found to have a relation that is linear in logarithmic space and that is not bounded by some critical ratio of flow depth to pier width. Comparisons of computed and observed scour depths indicate that none of the selected equations accurately estimate the depth of scour for all of the measured conditions. Some of the equations performed well as conservative design equations; however, they overpredict many observed scour depths by large amounts. Some equations fit the data well for observed scour depths less than about 3 m (9.8 ft), but significantly underpredict larger observed scour depths.

Download Full-text

Analysis of Scour Depth Around Bridge Piers With Round Nose Shape by HEC-RAS 5.0.7 Software

Journal of Physics Conference Series ◽

10.1088/1742-6596/1764/1/012151 ◽

2021 ◽

Vol 1764 (1) ◽

pp. 012151

Author(s):

C S Silvia ◽

M Ikhsan ◽

A Wirayuda ◽

Mastiar

Keyword(s):

Bridge Piers ◽

Scour Depth ◽

Nose Shape

Download Full-text

Hybrid Scour Depth Prediction Equations for Reliable Design of Bridge Piers

Water ◽

10.3390/w13152019 ◽

2021 ◽

Vol 13 (15) ◽

pp. 2019

Author(s):

Hossein Hamidifar ◽

Faezeh Zanganeh-Inaloo ◽

Iacopo Carnacina

Keyword(s):

Flow Velocity ◽

Critical Velocity ◽

Depth Estimation ◽

Hybrid Models ◽

Velocity Estimation ◽

Bridge Piers ◽

Critical Flow ◽

Scour Depth ◽

Critical Flow Velocity ◽

Estimation Equations

Numerous models have been proposed in the past to predict the maximum scour depth around bridge piers. These studies have all focused on the different parameters that could affect the maximum scour depth and the model accuracy. One of the main parameters individuated is the critical velocity of the approaching flow. The present study aimed at investigating the effect of different equations to determine the critical flow velocity on the accuracy of models for estimating the maximum scour depth around bridge piers. Here, 10 scour depth estimation equations, which include the critical flow velocity as one of the influencing parameters, and 8 critical velocity estimation equations were examined, for a total combination of 80 hybrid models. In addition, a sensitivity analysis of the selected scour depth equations to the critical velocity was investigated. The results of the selected models were compared with experimental data, and the best hybrid models were identified using statistical indicators. The accuracy of the best models, including YJAF-VRAD, YJAF-VARN, and YJAI-VRAD models, was also evaluated using field data available in the literature. Finally, correction factors were implied to the selected models to increase their accuracy in predicting the maximum scour depth.

Download Full-text

Comparison between the circular and square collar in reduction of local scouring around bridge piers

E3S Web of Conferences ◽

10.1051/e3sconf/20184003002 ◽

2018 ◽

Vol 40 ◽

pp. 03002 ◽

Cited By ~ 1

Author(s):

Saeed Reza Khodashenas ◽

Hossain Shariati ◽

Kazem Esmaeeli

Keyword(s):

Bridge Piers ◽

Scour Depth ◽

Circular Shape ◽

Level Elevation

In this study operation of two types of circular and square collars has been investigated on a single cylindrical pier. The results showed that using of these two types of collars cause to reduction of scour depth especially under the bed level (elevation). This research showed that the square collar is more effective than circular shape in decreasing of the scour depth). The square and circular collars showed 70% and 50% decrease in rate of scour depth, respectively in compared with simple pier without collar.

Download Full-text

Nose-Angle Bridge Piers as Alternative Countermeasures for Local Scour Reduction

The Baltic Journal of Road and Bridge Engineering ◽

10.7250/bjrbe.2018-13.405 ◽

2018 ◽

Vol 13 (2) ◽

pp. 110-120 ◽

Cited By ~ 2

Author(s):

Ibtesam Abudallah Habib ◽

Wan Hanna Melini Wan Mohtar ◽

Atef Elsaiad ◽

Ahmed El-Shafie

Keyword(s):

Froude Number ◽

Local Scour ◽

Bridge Piers ◽

Scour Depth ◽

Skew Angle ◽

Flow Angle ◽

Sediment Size ◽

Low Froude Number ◽

Skew Angles ◽

Depth Reduction

This study investigates the performance nose-angle piers as countermeasures for local scour reduction around piers. Four nose angles were studied, i.e., 90°, 70°, 60° and 45° and tested in a laboratory. The sediment size was fixed at 0.39 mm whereas the flow angle of attack (or skew angle) was varied at four angles, i.e., skew angles, i.e., 0°, 10°, 20° and 30°. Scour reduction was clear when decreasing nose angles and reached maximum when the nose angle is 45°. Increasing the flow velocity and skew angle was subsequently increasing the scour profile, both in vertical and transversal directions. However, the efficiency of nose angle piers was only high at low Froude number less than 0.40 where higher Froude number gives minimal changes in the maximum scour depth reduction. At a higher skew angle, although showed promising maximum scour depth reduction, the increasing pier projected width resulted in the increase of transversal lengths.

Download Full-text