Investigation of the Cable Performance and Efficiency in Controlling Local Scour of Round Corner Rectangular Bridge Piers

In this study, the performance and efficiency of cable in control of local scour around the pier of the rectangular bridge has been investigated by changing the flow collision angle. In this study, three types of piers, namely: 1.round corner rectangular without cables, 2.round corner rectangular with cable with 10 % of pier diameter with a 15-degree twist angle of cable (second type pier), 3.round corner rectangular with cable with 15 % of pier diameter with a 12-degree twist angle of cable (third type pier), were used with four different flow collision angles, including 0, 5, 10, and 15 degrees.The purpose of this study is wrapping the cable around the pier and changing the flow collision angle from the downstream flow water and then its effect for the reduction of the depth of the final scour measure. In this experimental study, the effect of flow angles on the pier was investigated, so that the first type pier under zero degrees angle was compared with the second and third types parallel to the flow direction. The maximum scour depth in experiments was achieved at the 15-degree angle with the flow direction, and the effect of the cable in reducing the scour depth in this angle for type-2 and type-3 piers was 10% and 22%, respectively. Also, for type-2 piers, in experiments under 5, 10, and 15-degree angles with the flow direction, the scour depth was increased by 3%, 21%, and 37%.