Laboratory investigation of the effect of using riprap and vegetation on the scour around the bridge abutment

One of the most important factors of damage and failure of hydraulic structures is the occurrence of local scouring around them. Scour is a natural phenomenon that occurs due to the flow of water in rivers and streams. If a hydraulic structure such as a bridge pier or abutment is placed against the flow of water, the flow pattern near the structure changes and causes scouring phenomenon locally around these structures.To control scouring around the bridge abutments, various methods have been proposed, which are generally divided into two categories: flow pattern modification methods and bed protection methods. Among the substrate protection methods that have been examined in this research is the use of riprap and vegetation, because riprap and vegetation are both fully available and inexpensive tools for protecting The base and abutment of the bridge are known to be washed away.The experiments were carried out in the hydraulics and water structures research laboratory of the water engineering department of Shahid Bahonar University of Kerman. In this study, two 90-degree rectangular abutment and a rectangular abutment with circular walls were used, both of which are galvanized and 10 cm long, 45 cm high and 6 cm wide was used (the abutment which is perpendicular to the flow was chosen as the width of the abutment). By conducting a long-term test of 12 hours at a flow rate of 34 liters per second for each of the abuments, the equilibrium time was estimated to be 5 hours.