Characteristics of reducing local scour around cylindrical pier using a horn-shaped collar

Abstract

Local scour is the major cause of bridge water damage. The sediment in the riverbed around the pier is eroded and transported by water flow, leading to a loss of bridge foundation stability. In this study, a horn-shaped collar was proposed to mitigate local scour around bridge piers. The three design parameters (bottom diameter, vertical height, and curvature shape index) of the horn-shaped collar were studied under clear water condition, and the number of experimental tests was reduced to 25 by using Taguchi’s method. Main effect analysis was used to determine the optimum design parameters for the horn-shaped collar. The results show that the three design parameters have a significant effect on the scour reduction capacity of the horn-shaped collar, with the bottom diameter of the collar making the greatest contribution. The optimum values for the bottom diameter, vertical height, and curvature shape index are 5D, 0.25D, and 4, respectively (D represents the diameter of the pier), and the optimized shape of the horn-shaped collar reduces the maximum scour depth around the pier by 100% compared to the unprotected case. Based on the experimental data, prediction equations are developed for the maximum scour depth protected by a horn-shaped collar.

Numerical Investigation of Local Scour Protection around the Foundation of an Offshore Wind Turbine

“…After the flume test and numerical model simulation studies, it can be determined that a more obvious effect of scour prevention can be discerned [31]. On the basis of the circular type, there are also other forms with more complicated shapes and structures, such as by changing the circular shape into a wing-type washer guard ring [32]; or increasing the thickness of the guard ring to form a neck ring [33] and changing the outer diameter of the guard ring on the basis of the neck ring to form a narrower flare at the top and a wider flare at the bottom [34]. These optimization schemes have improved the anti-scouring effect of the guard ring to varying degrees.…”

Statistical Analysis Approaches in Scour Depth of Bridge Piers

“…Also, because of the expensive price of these devices, such as an ultrasound velocity meter, the pier shape effect on local scour was studied by some researchers (e.g., Laursen & Toch (1956) [7], Neil et al (2002) [8], Dietz (1972) [9], Melville (1975) [10], Komura et al (1977) [11]). Many researchers have studied the circular pier shape extensively in the literature, including Melville (1975) [10], Chiew (1984) [5], Omara (2022) [12], Luo et al (2022) [13], Reddy (2022) [14], Farooq & Ghumman (2019) [15], Jan & Lone (2022) [16], etc. The square-nose pier has the highest scour depth, and the sharp one has the lowest.…”