Laboratory investigation of deflector structure effect on bridge pier scouring

Document Type : Research Paper


1 Department of Water Sciences,Water Science and Environmental Research Center, Shoushtar Branch, Islamic Azad University, Shoushtar, Iran.

2 Water Science and Environmental Research Center, Shoushtar Branch, Islamic Azad University, Shoushtar, Iran.

3 Assistant Professor civil department, Islamic Azad University, Sepidan Branch, Sepidan, Iran.


Bridge pier local scouring is a crucial factor in bridge destruction. Studies from different researchers have presented solutions to control this phenomenon. These solutions are divided into two parts, namely, direct and indirect protection. In the direct method, the bed is armoured against scouring whereas in the indirect methods the flow pattern around the pier is changed with geometric parameters. This study defined an element called the deflector structure (flow diverter) to divert the bed’s flow streamline in front of the pier. Experimental scenarios were defined by stabilizing the flow conditions with 0.70, 0.83, and 0.97 relative velocities ( ) and 15-, 30-, and 45-degree wedge deflector structure angles with flow direction for two piers with square and circular cross-sections. The results showed that the dimensionless scour depth parameter ( ) close to the particle movement threshold ( ) was reduced by 70 to 75%, respectively relative to the control model for square and circle cross-section. Changing the angle from 45 to 30 and 15 degrees reduces the local pier scouring and increases the deflector structure’s effectiveness.  


Main Subjects

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Volume 43, Issue 4
March 2021
Pages 91-104
  • Receive Date: 09 January 2021
  • Revise Date: 08 February 2021
  • Accept Date: 21 February 2021
  • Publish Date: 21 December 2020