Introducing, Examining and Optimising Flow Diversion Structure as an Innovative Countermeasure against Local Scour around Bridge Piers

Publication Type:
Thesis
Issue Date:
2019
Full metadata record
Previous investigations have indicated that local scour around bridge piers and abutments is a common cause of waterway bridge failures with around 60% of bridge collapses due to this phenomenon. To reduce local scour, a new flow-altering device referred to as a flow diversion structure (FDS) has been introduced, experimentally examined with optimised characteristics determined. The effectiveness of this innovative countermeasure was examined through a wide-ranging series of experimental studies. Different dimensions, locations, and submergence ratios were examined experimentally. Using Taguchi’s method to minimise the number of alternative tests, 27 alternative tests were undertaken to ascertain the optimum size and location for the structure. Compared to the no flow diversion structure situation, it was found that the optimised structure resulted in a 40% reduction in the maximum scour depth and a 60% reduction in scour volume. Also, an experimental study of the flow field was conducted to investigate the influence of the structure on flows. Results showed that the structure influenced the down-flow and horseshoe vortex and consequently reduced the scour. Based on the investigation presented herein, a flow diversion structure is a simple and easy approach for mitigation of scour at existing and new bridges.
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