Numerical study of countermeasures against the local scour around bridge pier using flow-3D software

Scour is one of the most protruding factors in bridge failures worldwide. Investigating the causes of scouring will offer a view of the solution probabilities. Countermeasure methods attached to the bridge piers greatly influence reducing the local scour, mainly when it deflects water and weakens the vortices that affect the bed sediment around the pier. In this study, Flow-3D was used to simulate the three-dimensional model to investigate local scouring around the pier, after controlling and ensuring by calibrating the model using a single-circular pier model in FLOW 3D with a circular pier from an experimental study was carried out by Adnan et al., 2015 in the same conditions. The purpose of this study is to examine the performance and the reflection of adding two countermeasures by CFD modeling, namely collar and slot, in the reduction of scour depth around the bridge pier. In the first scenario, four cases slot were used, namely (UHS, MHS, LHS, FWD) respectively. The second scenario circular types of collars attached to the pier added to a pier with two collars diameter at the bed sediment were 20 and 30 cm for CAB-2Dp and CAB-3Dp. Finally, the best-case of previous scenarios compound FWD & CAB-3Dp were analyzed. Adding a collar and slot has significantly reduced local scour around the pier. The collars act more useful than a slot in terms of controlling and weakening the downflow, also lowering the scour depth around the pier. When combining both FWDS and CAB-3D cases, the scour was eliminated in the front and rear of the pier, also noted an increase in the reduction percentage, reaching 56% compared with the exact location on the reference models.