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چکیده
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Yearly, several bridges are damaged due to scour phenomena around the pier foundation in the world. In the present study, scour process around the bridge pier group has been investigated using the installation of submerged vanes with a quasi-triangular arrangement (of heights 0, 4, and 6 cm), eppi, and sills (of height 4.5 and 9 cm). tests were performed in a rectangular slope-less flume covered with sediment particles of mean size 1.8 mm. temporal and equilibrium scour depth states were conducted and measured for four Froud numbers 0.15, 0.2, 0.25, and 0.6. Results showed the additive effect of the eppies on the scour depth due to flow section contraction and increase in the critical velocity. To decrease sediment particles transportation, submerged vanes and sill were set up. The measurements indicated that the superior function belongs to the vane of height 4 cm. The sill of height 4.5 cm raised the positive effect of the vane so that a significant decrease was seen at the foundation of the first pier. because of the supportive effect of the first pier for two other piers, more scour depth was seen around the first pier than the third one.
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