Evaluation and Comparison of Methods of Bridge Piers and Abutments Protection against Local Scour

One of the most important reasons for the instability and failure of river bridges is the scouring around its piers and abutments during floods. In the recent years, the issue of local scouring has been widely studied by various researchers and different methods have been proposed to control scouring, such as the use of riprap, gabion, collars, concrete blocks, sacrificial piles, groove and cables. In this article, firstly, various methods of protection against scouring have been introduced and previous studies have been reviewed. In the following, from a practical and executive point of view, the use of riprap, concrete blocks, gabion and the construction of apron and cut off wall, which are among the existing and common methods to reduce bridge scouring in the presence of shallow foundations (foundations without piles) are reviewed and compared. All the mentioned methods are classified in the category of bed-armoring. The design and executive considerations are presented in each case and the advantages and disadvantages of each method are stated. Finally, according to the different conditions of the river and the bridge structure, the most appropriate method has been proposed in terms of execution, economy and maintenance.