1.21N HYDRAULIC GATES (Continued) HINGED-TYPE GATES (Continued) N. Wall plates are placed in the side walls to provide a track for the seals and guide rollers. The wall plates are supported on clip angles and anchor bolts. The assembly is adjustable so that the plates can be lined up before grouting. Tolerances should be shown on the installation drawing for the distance between the wall plates as follows: O. Molded rubber seals are bolted to the upstream side of the faceplate along both sides and the bottom. The side seals are installed in contact with the wall plates. The bottom seal should have 1/4-inch compression when the gate is closed. P. The following are drawings showing radial gate installations: Wall Plates Rubber Seals Reference .22 Large-type radial gates are now designed to serve the particular needs of large The largest radial gate designed by the Bureau is 50 feet in width and 70 feet Designs of large-type radial gates are illustrated on the following drawings: RADIAL GATES-SPECIAL TYPES The high-head radial gate is employed for flow control in submerged openings. or sluiceways. The limits of operating head on this gate are governed by practical limitations of spouting velocity and other hydraulic behavior, which HYDRAULIC GATES (Continued) HINGED-TYPE GATES (Continued) have not been fully explored. However, promising hydraulic and economic 22-foot by 19-foot High-head Radial Gate-- 351-D-637 A. The principal moving gate members of the special-type gates consist of To assure trouble-free operation and proper functioning of the seals, The location of the pin bearing and anchorage must be outside the discharge The discharging gate is free from drawdown effect or "flutter" as long The gates are closed by force of gravity, thereby permitting the use of steel ropes for hoisting. In certain instances of high-head installations, fixed links for hoisting are advantageous. (See Figure 35.) If severe winter conditions cause ice thrust in front of the gates, the leaf members must be sufficiently reinforced to absorb the thrust. In case operation of gates under such conditions is required, it will be necessary to keep ice clear from the face of the structure. This can be effectively accomplished by agitating the water in front of the gate with compressed air and installing electrical resistance heat elements near wall plates and seals. C. The resultant water pressure on large structures is a function of horizontal and positive and negative vertical forces. The component forces are separately computed by derived mathematical formulas. For preliminary design analysis, it is usual to evaluate the resultant water 1.22D HYDRAULIC GATES (Continued) HINGED-TYPE GATES (Continued) pressure by graphical methods. This can be rapidly and accurately D. Contrary to the usual practice in the design of standard canal gates, the larger type structure is not provided with a corrosion allowance. In the majority of applications, an opportunity to service the units internally and externally is provided. The upstream skin plate on large-type units is usually supported by continuous horizontal stiffeners. The bending stress of the continuous member, consisting of skin plate and stiffener, must be combined with the primary plate stress to obtain the maximum equivalent design stress. Secondary stresses due to weight reactions on the bottom part of the skin plate must also be considered. The skin plate loads are transmitted through the intermediate diaphragms into the main girders, which are supported by the arm diaphragms. The girders are designed in a conventional manner to resist moments and shears created by the hydraulic loads. The intermediate diaphragm plates are investigated for possible buckling due to the concentrated loads on relatively thin plates. The arm diaphragms are investigated for stresses caused by distributed hydraulic loads and concentrated loads from the girders. In order to reduce seal friction and hoisting effort, end seals are The bottom sill and side wall plates are grouted in place prior to the E. The geometric location of gate arms must be such as to obtain approximately On gate structures having extended arms for concrete balancing weights, F. Arm loads are transmitted through bearings into protruding trunnion pins, Design of Gate Leaf & Seals Design of Gate Arms Pin Anchorage 1.23 Pin Anchorage (Cont.) DRUM Operating Characteristics Size, Shape, & HYDRAULIC GATES (Continued) HINGED-TYPE GATES (Continued) Horizontal and vertical pin anchorage component forces are further absorbed by heavy anchor bolts which are mounted in two principal directions. These anchor bolts are of sufficient length to develop full bond strength and are formed to distribute the respective loads in the mass concrete. Large-diameter anchor bolts are provided with upset ends. The maximum anchor bolt stresses depend on the load distribution caused by the gate during the entire cycle of operation. The successful operation of gates and seals depends to a great extent on accurate alinement of pin anchorages and bottom sill and side wall plates. Therefore, ample adjustment provisions prior to, as well as during gate erection are necessary .23 Drum gates afford a movable crest in a spillway, thus permitting either an increase in the active storage capacity of the reservoir simultaneously with an increased operating head at the turbines in the power plant, or the drawing down and regulation of the reservoir in case of impending floods. Since the flow is over the top of the gate, the discharge height is not limited and trash and debris can flow over without difficulty. The drum gate is operated by reservoir pressure, thus eliminating the need of hoists or external power supply. The control is either automatic, manual, or remote electric. A general installation drawing of a 100- by 18-foot drum gate is shown in Figure 36. A. The gate is a buoyant vessel and is anchored through hinges to the upstream B. Conventional drum gate sizes vary from 12 to 28 feet nominal height and Basically, the shape of the crest contour of the lowered drum gate is The discharge capacity of the fully lowered gate is computed from the 1.23C HYDRAULIC GATES (Continued) HINGED-TYPE GATES (Continued) C. The structural-steel gate, when floated, is loaded by water pressure and auxiliary forces. The gate will be held in any position as long as all forces are in equilibirum and satisfy the fundamentals of statics: The composite curvature of the upstream face does not allow a direct solution for the upstream loading. It is therefore recommended that the resultant water load, R1, on the upstream face of the gate be computed through a combined analytical and graphic method, assuming that the curvature is composed of a series of straight-faced panels or elements loaded in a trapezoidal manner. By selecting the element length 3.2 feet and the element width 1 foot, the panel load can then be determined quite speedily and accurately by plotting the gate curvature and head ordinates to scale. The value p should be determined for each element of length of the upstream face of the gate, and the evaluation of the resultant load R1 required simply a graphic integration. For intermediate gate positions and actual overflow, the true pressure heads of the element loads are experimentally obtained through piezometer tests applied on a hydraulic model and plotted in the form of curves for various gate positions. Through interpolation of values, the resultant water load R1 can therefore be determined for any gate position and any quantity of discharge. D. By summation of moments about the hinge-pin center, the gate-seat reaction can be directly evaluated: Water Loads & Reactions on |