Experimental Investigation of Local Scour Protection for Cylindrical Bridge Piers Using Anti-Scour Collars

Abstract

Local scour of bridge piers is one of the main threats responsible for bridge damage. Adopting scour countermeasures to protect bridge foundations from scour has become an important issue for the design and maintenance of bridges located in erodible sediment beds. This paper focuses on the protective effect of one active countermeasure named an “anti-scour collar” on local scour around the commonly used cylindrical bridge pier. A cylindrical pier model was set up in a current flume. River sand with a median particle size of 0.324 mm was selected and used as the sediment in the basin. A live-bed scour experimental program was carried out to study the protective effect of an anti-scour collar by comparing the local scour at a cylindrical bridge pier model with and without collar. The effects of three design parameters including collar installation height, collar external diameter and collar protection range, on the scour depth and scour development were investigated parametrically. According to the experimental results, it can be concluded that: the application of an anti-scour collar alleviates the local scour at the pier effectively; and the protection effect decreases with an increase in the collar installation height, but increases with an increase in the collar external diameter and the protection range. Design suggestions for improving the scour protective effect of the anti-scour collar are summarized and of great practical guiding significance to the development of anti-scour collars for bridge piers.

Review of annual progress of bridge engineering in 2019

“…Adopting scour countermeasures to protect bridge foundations from scour has become an important issue for the design and maintenance of bridges located in erodible sediment beds. Wang et al (2019n) studied the protective effect of one active countermeasure named an "anti-scour collar" on local scour around the cylindrical bridge pier by a live-bed scour experimental program. The effects of three design parameters including collar installation height, collar external diameter and collar protection range, on the scour depth and scour development were investigated parametrically.…”

A laboratory study of the effect of asymmetric-lattice collar shape and placement on scour depth and flow pattern around a bridge pier

“…Based on the above studies, it is inferred that installing the collar at lower levels and larger dimensions of the collar has the greatest effect on reducing the scour depth. Wang et al (2019) river sand with a median particle size of 0.324 mm was selected and used as the sediment. According to their experimental results, it can be concluded that: the application of an antiscour collar alleviates the local scour at the pier; and the protection decreases with an increase in the collar installation height, but increases with an increase in the collar external diameter and the protection range.…”

An Overview: Modern Countermeasures Against Local Scour at Bridge Piers—Applicability in Vietnam

“…On the contrary, active countermeasures are designed to decrease the intensity of the incoming flow by such as deflecting Fig. 1 Flow around a circular pier in a scour hole [5] the incoming flow, reducing the flow velocity to reduce the effects of downflow and horseshoe vortex, and thus protecting the bridge foundation from local scour [6,7].…”