Question

An overflow ogee crest for a spillway is to discharge 20,000 cfs. The upstream face of the crest is sloped 1:1 and a bridge is to span the crest. Flow over the spillway is to be controlled by a series of Tainter gates. Bridge piers 18-in wide (pier contraction Kp = 0.05) with rounded noses are to be provided to support the gates. The bridge spans (center to center of piers) are not to exceed 30 ft. The maximum expected head He = 10 ft. Neglect velocity of approach head. The distance from the spillway crest to the reservoir bottom P = 18 ft. The abutment coefficient Ka = 0.10. Assume that your design head is equal to the maximum expected head. Determine:

(a) The crest length required (b) The number of Tainter gates to be used (c) The width of each gate

Answer 1