Author(s): I. Carnacina

Linked Author(s): Iacopo Carnacina

Keywords: Ice jam; Bridge piers; Flow field; Turbulence; Scour

Abstract: This work investigates the flow field and turbulence characteristics around bridge piers in presence of ice jam. Comparison between flow fields with and without ice jam highlights the potential negative impact and possible cause for enhanced bridge failure. Localized accumulation of ice in a river forms large clustered structures of ice called ice jam. Ice jam normally forms within rivers either in cold climate, mountain streams or at very high latitudes. They can heavily constrain a river cross section by either accumulating at bridge crossings and form during extreme cold periods, where water mainly precipitates in form of snow and relatively small quantity of runoff is available for river base flow. This reduction of flood cross may pose a serious threat, in terms of additional flooding and pressure on bridge components such as piers and abutments. Several studies aimed at understanding the formation of ice jam in rivers and in presence of bridge piers showed how ice jam forms and develops. Given the important impact ice jam may have on bridge resilience and safety, this work aims at providing more information on the hydrodynamic field around a bridge pier at early stage of formation of the ice jam, using an acoustic Doppler velocimeter (ADV) to measure both flow field and turbulence. Difference between velocity magnitude and shear stresses can help understanding how ice jam can increase the scour at the base of the pier and, consequently, increase the risk of failure that can result in connection with the hydrodynamic load of the ice jam.

DOI: https://doi.org/10.3850/978-981-11-2731-1_187-cd

Year: 2018