Study of Scour Control Around Bridge Abutments in Clear-Water Scour and Live-Bed Scour Conditions for Compound Channels

Scour is a natural phenomenon caused by erosion due to water flow at the base of alluvial channels and channel walls. In fact, the scour that occurs on bridge abutments is total scour, namely a combination of local scour, general scour, and constriction scour. This research aims to determine the effect of screens and poles on the scour process and scour depth near the abutment under live-bed scour and clear water scour conditions. This research was carried out using a recirculation flume. The channel model used is a compound channel and uses steady-uniform flow. The supporting models are Spillthrough type (ST) and Wing-wall type (WW). Filter and pole variations are used as a scour control model. The depth of scour near the abutment was measured every 6 hours. The research results show that live-bed scour conditions are the most critical conditions, and the depth of scour in this condition is greater than in clear water scour. The scour depth is strongly influenced by the flow Reynolds and Froude numbers. Screens placed upstream of the abutment at an optimal distance from the abutment point provide the greatest reduction in scour depth compared to other distances. The main result of this research is that if one pile is placed at the foot of the floodplain at the optimal distance, it will provide the best scour reduction. In general, the scour pattern that occurs around the abutment is the same, whether using protection or without protection. This can be seen in the scour contour pattern which is in the shape of a half horseshoe.