Evaluation the Performance of Bed Sill, Collar and Their Combination in Scour Protection of Cylindrical Bridge Pier

One of the main causes of the destruction of marine structures, is creating erosion in its pier foundation. The uncontrolled spread of scour hole undermines the foundation and thereby will threaten the entire structure. In this study, the performance of countermeasure strategies include bed sill, collar and then combination of them were evaluated. Experimental assessment for cylindrical pier has been conducted under the clear water condition. Based on the recommendations resulting from the studies reviewed, bed sill was attached to the downstream side of the pier, the width of the channel, vertically from floor to sediments and circular collar with an outer diameter equal to 3 times the pier diameter, was installed in the bed level. Also in the combination method the integration of last two solutions was used, while bed sill was placed tangent to the downstream of collar.