OPTIMISATION OF DESIGN OF SPILLWAY GATES

Abstract

Hydraulic gates are essential hydro mechanical control equipment required for spillways in the water resources projects. Several types of gates are developed, out of which vertical lift gate and radial gate are in use in general. Without sacrificing the operational requirements like failure free performance, water tightness, rapidity in operation and convenience in installation and maintenance, it is desired that the cost of the gate should be minimum with lesser weight of gate and hoisting capacity. To achieve this goal, the design of various components of the gates is to be optimized. The number of horizontal girders which controls the skin plate thickness and hence the quantity of steel for the vertical lift gate besides the heads of water, spacing of vertical stiffeners with their size, radius of radial gate which controls the quantity of steel used for radial arms besides the skin plate length and hence the quantity of steel used for the gate are subject to optimization. In the dissertation, a study has been -done for the optimization of spillway crest' . gates of vertical lift and radial types. A computer program has been developed in `C++' and adopted for cost analysis of gates of both, fixed wheel vertical lift type and radial type for 2, 3 and 4 number of horizontal girders in each case. The analysis indicates that radial gate is cheaper than the fixed wheel vertical lift gate. Basically, heads of water govern the numbers of horizontal girders. The optimized number of horizontal girders is found to be 2 up to 8.5m of head, 4 above 13.5m and 3 in between this range for vertical lift gate, while slightly lower values of head have been established for radial gate.