Mohammad Vaghefi

In this paper, in order to investigate the e?ects of abutments in presence of a pier on scour depth and bed topography alteration,aseriesoftestswerecarriedoutconsideringabutmentswithalengthtwicethatofthepierandverticalandinclined pierswiththeirinclinationtowardsupstream,downstream,innerandouterbanks.Theresultsshowthatthemaximumscour depth is formed at the upstream side of the outer abutment in all tests. Maximum scour depths are formed at the angle of 89 degrees if the bend section between 92% and 94% of the channel’s width from the inner bank in all tests except in the case of abutments with one pier which is inclined towards downstream. In the latter case, maximum scour depth is formed at the angle of 90 degrees and at the point 88% of the channel’s width from the inner bank.