*Article* **Bridge Pier Scour under Ice Cover**

**Christopher Valela \*, Dario A. B. Sirianni , Ioan Nistor , Colin D. Rennie and Husham Almansour**

Department of Civil Engineering, University of Ottawa, 161 Louis Pasteur Drive, Ottawa, ON K1N 6N5, Canada; dsiri029@uottawa.ca (D.A.B.S.); inistor@uottawa.ca (I.N.); colin.rennie@uottawa.ca (C.D.R.); husham.almansour@nrc-cnrc.gc.ca (H.A.)

**\*** Correspondence: cvale034@uottawa.ca

**Abstract:** Bridge pier scour is a complex process, which is influenced by many parameters, including the presence of ice cover around piers. To better understand the influence of ice on bridge pier scour, an artificial ice cover, equipped with either a smooth or a rough surface, was constructed and tested experimentally. The ice cover was positioned on the surface of the water and submerged to specified depths in order to replicate floating and fixed (pressurized) ice cover conditions, respectively. During each test, a velocity profile was collected beneath the ice cover, and after each test, a three-dimensional scan of the bed was collected to compare the resulting scour. It was discovered that the presence of an ice cover around a bridge pier increased pier scour under all conditions. Furthermore, as the ice cover was submerged deeper into the flow, the flow velocity increased, and greater scour resulted. For each level of submergence, the rough ice cover yielded increased scour depths compared to the smooth ice cover.

**Keywords:** local scour; ice cover; ice jam; bridge pier; sediment transport; river ice hydraulics
