Scouring Around Bridge Abutments: A Review of Reduction Methods
摘要
Countermeasures of local scour at bridge abutments can be divided into two categories: countermeasures that alter the flow and countermeasures that reinforce the bed. In this review paper, a search was conducted in the Scopus and Web of Science databases to investigate the mechanism of scouring around abutments, and research on reducing or preventing scouring around abutments was reviewed. The results of the surveys showed that the most popular countermeasure—from the bed armoring category—is putting the riprap stones around the abutment. Notwithstanding the good performance of riprap, it can be unstable in a flood; thus, geo-bags as a useful alternative placed beneath a riprap are introduced. However, the stones in riprap can be dislodged or displaced by flow forces. In NCHRP/NC research flume experiments, instances of toe instability and upstream edge failure of riprap were reported. Regarding the various flow-altering devices’ performance, results showed that the scour reduction in the presence of the slot and collar can be reached 100%. Collars can be most effective when carefully optimized and, in some cases, used in combination with complementary countermeasures. Despite the limited number of studies on combined countermeasure methods, research has demonstrated their superior effectiveness. Due to the difference between the effects of effective forces on water flow and sediment and their interaction, it is notable for modeling river conditions in the laboratory that geometric, kinematic, and dynamic similarities should be considered. It is concluded that more experimental, field, and certainly numerical studies, due to fewer implementation problems and more maneuverability, are needed to study the structure of the flow around the historical bridges and use scouring reduction methods.