عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Road or railway crossing over the rivers is limited to the particular reach of the rivers which is determined by the general direction of the road or railway. Moreover, the general direction of the road or railway determines the position of the bridge over the river. Selection of the bridge path angle relative to the river flow direction is very important. Sometimes, due to the geographical conditions of the region and the general direction of the road or railway, the bridge crossing directly perpendicular to the flow direction is impossible. In this case, the bridge deck diagonally crosses over the river and the bridge group piers are angled relative to the flow direction. In such case, the distance between the piers, the flow direction relative to the piers and the piers submergence are very important parameters which affect the scour depth. Therefore, in this study, the effect of the angle of the bridge group piers on the maximum scour depth at deferent angles relative to the flow direction (0, π/18, π/9 and π/6) at the clear water condition and for the three Froud numbers (0.13, 0.15 and 0.17) were experimentally investigated. The results showed that with increasing of the angle of the group piers (0 to π/6) the maximum scour depth increases so that the maximum scour depth has the greatest amount at the angle of π/6 and for the Froud number 0.17.