Arabian Journal for Science and Engineering

, Volume 43, Issue 10, pp 5413–5421 | Cite as

Effect of Pier Inclination Angle on Local Scour Depth Around Bridge Pier Groups

  • Zafer BozkuşEmail author
  • Murat Can Özalp
  • A. Ersin Dinçer
Research Article - Civil Engineering


The primary objective of this study is to investigate experimentally local scours around bridge pier groups at various inclination angles of piers and also to develop empirical local scour depth equations. In the study, two bridge pier groups are used. In each pier group, the most upstream and downstream piers are placed in an inclined manner at \(10^{\circ }\) and \(15^{\circ }\). The vertical case was also employed for comparison purposes. Seventy-two experiments each lasting 6 h are conducted under uniform-flow and clear-water conditions for a range of water depths and velocities on the uniform bed material. This study confirms that inclination of cylindrical piers located at the most upstream and downstream locations of pier groups directly affects the local scour in a favourable manner, with a substantial reduction in the local scour, especially around the most upstream pier. Moreover, the flow intensity and relative flow depth are important factors that characterize the local scour. An empirical scour depth equation is developed for each pier inclination angle for design engineers. Comparisons with previous studies are made and results discussed.


Pier groups Local scour Inclination angle of bridge piers Clear-water condition 

List of symbols

\(d_0 \)

Uniform depth of approach flow (m)

\(\beta \)

Inclination angle


Pier diameter (m)

\(\rho \)

Density of water (\(\hbox {kg}/\hbox {m}^{3}\))

\(\mu \)

Viscosity of water (Pa s)


Gravitational acceleration (\(\hbox {m}/\hbox {s}^{2}\))


Mean approach velocity (m/s)


Critical mean approach velocity (m/s)


Mean sediment size (mm)

\(\frac{d_0 }{D}\)

Relative flow depth


Flow intensity


The degree of vorticity


Relative roughness




Time to equilibrium


Pier spacing (m)


Depth at the upstream face of the most upstream pier (m)


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Copyright information

© King Fahd University of Petroleum & Minerals 2018

Authors and Affiliations

  • Zafer Bozkuş
    • 1
    Email author
  • Murat Can Özalp
    • 1
  • A. Ersin Dinçer
    • 1
  1. 1.Department of Civil EngineeringMETUAnkaraTurkey

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