Time-wise variation of scouring at bridge abutments

Abstract. Accurate estimation of the maximum possible depth of scour at bridge abutments is important in decision-making for the safe depth of burial of footings. Besides, investigation of the geometric features of scour holes around abutments provides useful information for the degree of scour counter-measure to be imple-mented against excessive scouring. Experiments have been performed to investi-gate time-dependent characteristics of scour holes around vertical wall abutments under clear water conditions with uniform bed materials. Temporal variations of scour depth and scour contours were measured. Using this information, an empir-ical relation was developed for temporal variation of scour depth. Additional rela-tions were also derived for time-dependent volume and surface area of the scour holes around abutments. The findings of this study may provide useful informa-tion for preliminary design of abutment footings and placement details of armoring counter-measures, such as riprap