Experimental Study of Scour Around Pier with Inclined Head

Subject Areas : Article frome a thesis

Mohsen Solimani babarsad ¹ , Abbas Safaei ²

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,

Received: 2019-09-10 Accepted : 2021-04-26 Published : 2021-04-21

Keywords: Scour, Bridge pier, head angle, incipient motion,

Abstract :

Introduction:The leading cause of damages on bridge is local scouring around piers. Many studies were carried out to control and reduce this phenomenon and suggested more solution methods to protect bridge piers. Protection is divided into direct and indirect methods. In this study, to reduce scouring depth around the pier, an indirect method is used by changing the pier's head angle in a flow direction.
Materials and Methods:An experimental study on clear-water at a different angle of piers head under steady flow is presented. Experiments were used to assess the ability to change the head angle of piers to protect them. Toward this end, five angles (α) 90, 85, 80, 75, 70-degree with the flow direction were considered. The bed material size d₅₀ was 0.9 mm and all experiments were done in Gunt hydraulic standard flume.
Findings:The results showed that the pier with a 70-degree attack angle could reduce the scour depth more than others. This happens due to diverting part of streamlines to downstream, and it can have a 36 per cent reduction overall.
Conclusion:The scouring depth and sediment point bar created around the pier with an inclined head compared with the control pier (α=90-degrees) have less scouring depth due to minor deviation of flow streamlines and reduction of disturbances around the pier.

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