Interaction of Bridge Pier and Abutment on Local Scour Around Them

The local scour around bridge pier and abutment in recent years has been widely studied by different authors. Scant information exists as to how bridge pier proximity to abutment affects scour depth at an abutment and at a pier. Due to the fact that many bridges have a pier located close to an abutment, therefore, it is necessary to be study. This paper presents the effect of abutment length and pier shape on scour depth of them, by using wing-wall abutments with lengths 25, 37.5 and 50cm and circular, round edge and sharp edge piers in two distance, 17.5 and 35cm from the bank wall at the flood plain. The results of experimental study showed that the proximity pier to abutment, increases scour depth of them and the minimum scour depth related to the circular pier and maximum scour depth related to the sharp edge pier. For example, the sharp edge pier in distance 17.5cm from the bank wall at the flood plain, for abutment with length 50cm, increases scour depth of abutment and pier 50% and 61% respectively, compared with scour depth of them in isolation.