Author(s): M. Qi; H. Guo; J. Wu
Linked Author(s):
Keywords: Sediment reduction; Flood; Existing bridge; Overall scour; Reevaluation; Three Gorges Dam
Abstract: This paper intends to reevaluate the scour of an existing bridge which is located at 60 Km downstream of the Three Gorges Dam. Since the dam blocks large quantity of sediment in the stream, the channel bed around the bridge may be scoured increasingly. On the other hand, since the 100-year flood peak discharge will reduce 36% at the bridge, the scour of the bridge for the design flood may be reduced. Field investigations were conducted for several flood events to determine the scour depending on time. A 1D model described by flow motion, sediment transportation, and river bed evolution was employed to estimate the channel bed scour at the bridge (including river bed evolution and contraction scour). Local scour was estimated using the existing empirical equations. The impacts of the Three Gorges Dam on the overall scour depths of the bridge were reevaluated for the longer return period floods, considering the changed conditions including both of the sediment reduction and the peak discharge storage.
Year: 2011