Laboratory investigation of flow pattern and scour around bridge abutment with rectangular section

Document Type : Complete scientific research article

Authors

1 Faculty member/birjand university

2 Faculty member/shahid chamran university

Abstract

Already various studies have been done on the mechanism of scour around hydraulic structures especially bridges. In the field of scour around bridges, researches are more focus on scour of piers in comparision with abutments. While the review of available information on the bridge required cost, the major problems are related to abutment. Therefore most costs have to spent in this regard. Literature review shows that abutment form has considerable impact on the scour depth around it. Among various abutment forms, the maximum scour depth occurs in the case of rectangular abutment. Therefore in this research rectangular form for abutment was selected and the effects of froude number and non dimensional abutment length (Width to length ratio) were investigated on scour development. Result shows, that increasing froude number and decreasing non dimensional abutment length, will increase the amount of scour. Following this research, three-dimensional components of velocities were determined with electromagnetic velocimeter and then used for drawing flow pattern. Result shows, that vertical vortex in upstream corner of abutment is an effective factor on maximum depth of scour at this point. Also result confirms that, down flow and generated vortex are effective parameters on abutment bridge scour.

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