SELECTION OF SUITABLE EQUATIONS IN FINAL ESTIMATION OF LOCAL SCOUR (SECOND EDITION)

Local scour is one of the most significant ca uses of bridges damaging and destruction, particularly on the flood time. hence determination of local scour around piers of bridges play an important role in design of bridge. In addition to the loss of lives and properties, damaged bridges lose their functions; and, lead to extra costs of maintenance. with the help of regression analysis Some equations have been obtained by different researchers using experimental observations and field data .The goal has been to obtain an equation with fewer gaps between observed values and predicted values. In this article , local scour and its parameters are introduced and then a comparison between scour equations, has shown .using dimensional analysis a general relation is obtained. From this relation, observed data and applying linear multiple regression analysis and polygon multiple regression analysis, 2 new formulas are obtained for the areas