US 2322846 A
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Description (OCR text may contain errors)
June 29, 1943. J. P. GROWDON ETAL 2,322,846
' HYDRAULIC GATE STRUCTURE AND THE LIKE Filed June 19, 1940 J T .l 4 '6 H R n I I 31 I I I Rig n F l, U e l i n 1 5 26 i l l n 1 R6 i U I HF -R9 3 R65 1 32 j 31 l i 15-}: g I 25 U u I v a H $43 ..l l l l l g7 21 IN] I H James Paul Growdon 9 BY Donald J Bleifuss v A TTORNEY.
Patented June 29, 1943 HYDRAULIC GATE STRUCTURE AND LIKE THE
James Paul Growtlon and Donald J. Bleifuss, Mount Lebanon, Pa., assignors to Aluminum Company of America, Pittsburgh, Pa., a corporation of Pennsylvania Application June 19, 1940, Serial No. 341,290
6 Claims. (01. 61-26) The present invention relates in general to hydraulic dam construction. The invention pertains particularly to new and useful in1provements in spillway or sluiceway gate structures.
Dams are ordinarily constructed with provision for the passage of flood waters beyond the capacity of the reservoir to store. Such provision may be:
(a) A spillway of fixed discharge capacity with no gates or flashboards.
'(b) A spillway provided with gates or flashboards.
(c') Other devices, such as siphons or sluice gates.-
Incase (a), when a flood occurs, the water levelin the reservoir simply rises until the water spills out as fast as it comes in. Thus property is subject to flooding to a certain elevation above thecrest of the dam, or, conversely, the dam mustnot be built above a certain elevation, depending on property held. Thus, with this type of construction, it often would be impossible to realize the maximum benefit in developing a dam site.
In case (b), the dam may be built up to the highest elevation the site and owned property permit. When a flood occurs, suflicient gates are opened to permit water to flow past the dam as fast as it enters the reservoir, the reservoir level not being raised. Construction of this type permits building a higher dam at a given site than construction of type (a); it is therefore often possible to realize considerably more benefit from a site.
Construction of type (c) is not pertinent to the present invention.
The inception and use of spillway gates is based on the assumption that these gates will be manually or mechanically opened wherever and to the extent necessary to prevent the water in the reservoir from rising above the maximum head or elevation for which the dam has been designed or constructed. Otherwise the dam would have been designed for the same conditions that would obtain if an open spillway, with its crest at the top of the gates, had been adapted, with the result that all benefits of the gated spillway would be lost.
Many ingenious devices have been employed for the purpose of causing spillway gates to open automatically when required. Such known and available devices have depended for their operation and function upon mechanism which has been known to fail in an emergency and, for this reason, cannot be relied upon to satisfactorily react to open the spillway under any and all circumstances.
Exemplary of an available mechanism which has been employed in association with spillway gates is a power-operated gate provided with one or more emergency sources of power for opening the same when the occasion arises. Such gates require the presence and attendance of an operator who is killed in his art and who has ready access to, or communication with, the dam at all times. Unfortunately, the circumstances requiring the operation of spillway gates are not always favorable, and through personal inability, accident, or fear, an operator may be rendered incapable of performing his task, with possible attendant damage to life and property.
Consideration of the numerous factors, both personal and structural, affecting emergency op.- eration of spillway gates has led to the conclusion that the maximum efliciency and ultimate safety of a dam, provided with a gated spillway, depend upon the particular design and construction of 'the spillway gates which will provide for infallible opening of the gates when required.
It is, therefore, an object of the present invention to provide a spillway gate structure which will serve to close the spillway under normal conditions of maximum head for which a dam has been designed, but which will fail and the spillway be cleared of obstruction to the passage of water when the gate has been overtopped a predetermined amount.
A further object of the invention is to provide a spillway gate structure having a normal low initial stress, under the head conditions for which it has been designed, but which will be predeterminately overstressed well above its yield point immediately the water rises above a.
predetermined elevation or head.
Another object of the invention is the provision of a completely automatic spillway gate structure devoid of reliance for its operation upon manual or power-operated instrumentalities or the presence or action of anoperator.
These and other advantages, will be fully understood and appreciated following a con sideration of the following description and explanation of the invention when taken in the light of the drawing forming a part hereof, in
Fig. 1 illustrates a top plan view of a spillway equipped with a gate structure incorporating the features of the present invention;
Fig. 2 illustrates a sectional elevation taken along the line IIII of Fig. 1;
Fig. 3 illustrates a partial downstream or rear view of the structure of Fig. 2 as viewed in the direction of the arrows III-III in Fig. 2;
Fig. 4 illustrates a sectional elevational view to smaller scale through a spillway equipped with the gate of this invention, and showing in more detail associated mechanism for manipulating the gate; and
Fig. 5 illustrates diagrammatically a portion of the dam structure looking in the .direction of the arrow in Fig. 4 and showing two adjacent gates having fiashboards of different heights.
Although the invention is in no way confined to any particular type of spillway gate structure, it has been elected to describe and illustrate the invention in its association and adaptability to a gate of the Tainter type. In its broadest aspect a gate structure of this type comprises a suitable radial type gate presenting a curved or arcuately shaped upstream surface supported by radial arms or frames pivoted on the downstream Th bottom angles 26, on the other hand, merely serves as bracing members for tanks 28 and only extend inwardly a sufficient distance to provide for suitable connection to the tanks, as by welding or the like.
In the operation of the gate structure of this invention, the head and reservoir waters, over and above that for which the dam has been designed, will overtop the fiashboard 24 and flow into the tanks 28 which are preferably disposed in parallelism and behind the fiashboard 24. As previously stated, the fiashboard does not extend across the entire width of a gate and, as such, will not serve to impound water at any elevation higher than the normal head for which a gate has been designed. Further, where more than side of th dam. The gate is here illustrated as being mounted in a spillway of an ordinary masonry or concrete darn along the crest of which there may be any desired number of spillways provided with similar gate structures. The present invention involves the provision of a device or structure designed to fail in response to water passing over the gate, which failure reacts to completely destroy the gate-supporting means and permits the gate proper to be swept clear of the spillway by the upstream, impounded head waters.
More specifically, and referring to the drawings forming a part of the present invention, l0 represents the crest of a spillway in a masonry or concrete dam. There may be any desired number of spillways across the face of a dam, the spillways being preferably separated by integral columnar portions I2, which are normally bridged as indicated at [4 (Fig. 4)
A gate proper comprises an arcuately curved deck plate I5 which is suitably reinforced and secured to a skeleton frame composed of spaced,
horizontally disposed members l6 and spaced, vertically disposed members I! on the downstream side of the plate l5. Secured to the downstream side of the gate are two diverging sets of rearwardlv converging radial arm members or struts l8, which members l8 of each set are, in turn, secured to gusset plates 20 which serve to provide and support hubs or bearings 2| in which the gate proper is pivotally supported. The arms l8 may be reinforced and strengthened by suitable cross bracing members 22.
A fiashboard 24 is mounted, as by means of angles 25, on the front face I5 of the gate. This fiashboard does not extend the full width of the gate, as will be more fully explained hereinafter.
The present invention incorporates a transverse beam'structure incorporated in the gate framing. In the preferred form of the invention, this transverse beam comprises four transverse angles 26 which are secured to clip angles 21 which, in turn, are suitably fastened to the two uppermost struts or radial arm members l8 (Fig. 2). The two uppermost angles 26 extend the entire distance across oppositely disposed members [8 and constitute a simple beam support for two tanks 28 which are spaced apart adjacent the middle of the beam where the same is preferably weakened by notches 29 in the vertical legs of these two top angles 26 (Figs. 1 and 3).
one gate is employed across the width of a dam, which is a, customary and normal practice, the flashboards secured to each gate would be of different heights, as shown in Fig. 5, in order that no two or more gates would be initially overtopped simultaneously.
Filling of the tanks 28 by the head waters flowing over the top edges of the flashboards causes the simple notched beam member 26 to fail, and each tank 28 becomes a cantilever which exerts a. twisting moment upon the struts or radial arms i8 supporting the same. The strength of the two uppermost supporting members I8 of each set is destroyed by the aforementioned twisting moments and they, in turn, fail, with the result that the entire water load against the upstream face of the gate is carried by the two lowermost members [8 of each set of the same. The resulting increased load now carried by the lowermost members l3 stresses these members beyond their ultimate strength, and the water impounded against the gate 15 sweeps the entire gate structure through the spillway opening. As a result of the removal of the gate structurev as aforedescribed, maximum opening to an abnormal water level is provided for by the automatic removal of the spillway gate.
The tanks 28 are preferably provided with generous drain apertures 32 such that neither rain' nor snow, nor casual slopping over of water, as by Wave action, will fill the said tanks and cause the gates to break, but a definite and considerable volume of water passing over the fiashboard is' required.
stream water level in the reservoir does not rise more than a predetermined amount above the normal head for which a dam and gate structure have been designed, the gate is subjected to normal stress and will operate in a satisfactory and normal manner. If the head water does rise above the normal head for which the dam and gate structure have been designed, an emergency condition arises and the gate having the lowest extending fiashboard will first fail. If the increased discharge because of the failure of the first gate is sufiicient to prevent a further rise in the reservoir water level, the remaining gates having higher extending flashboards will remain in place. On the other hand, if the water level continues to rise following the failure of the first gate, additional gates will fail until the water level in the reservoir is brought under control. It will be manifest that the successive failure of the gates in accordance with the height of their flashboards prevents an unnecessary loss of head impounded by a dam, as well as preventing the creation of an artificial and sud den downstream flood.
It is to be understood that the gate of this invention is of normal construction in so far as the provision of means for opening and closing the gate under normal operating conditions is concerned. By reference to Fig. 4, it will be seen that a suitable cable and winch mechanism 30 have been illustrated for raising the gate as desired. In this connection, a suitable cable to gate attachment is employed which is automatically severed on failure of the gate. Also, if required, diagonal tension tie rods 3| (indicated in Fig. 1 as broken away to more clearly illustrate the present invention) may be incorporated in the gate structure. It should also be understood that the gate structure of this invention incorporates its automatic emergency feature for the primary purpose of insuring safety of a dam under any abnormal condition.
Although the invention has been herein described in its association and adaption to a particular form of spillway or sluiceway gate, it is to be understood that the invention should not be interpreted as limited thereto except as defined in the claims appended hereto.
What is claimed is:
1. A spillway gate structure comprising a water-impounding face, oppositely disposed radial frame members connected to the downstream face of the gate and to the spillway for supporting and normally restraining said gate in the spillway passage, cross ties joining said oppositely disposed radial frame members, and water-collecting means associated with and supported by said cross ties in position to receive water overflowing the gate, the capacity and location of said water-collecting means being such that substantial gate-overflow loading thereof stresses to rupture said cross ties, whereby said oppositely disposed radial frame members are distorted and the gate-supporting effect thereof is reduced below the force exerted by the impounded water against the gate.
2. A spillway gate structure comprising a water-impounding face, oppositely disposed frame members connected to the downstream face of the gate and to the spillway for supporting and normally restraining said gate in the spillway passage, preweakened cross ties joining said oppositely disposed frame members, and water-collecting means associated with and supported by said cross ties in position to receive water overflowing the gate, the capacity and location of said water-collecting means being such that substantial gate-overflow loading thereof stresses to rupture said preweakened cross ties, whereby said oppositely disposed frame members are distorted and the gate-supporting effect thereof is reduced below the force exerted by the impounded water against the gate.
3. A spillway gate structure comprising a suroverflowing said gate, the capacity and location of said receptacle being such that substantial gate-overflow loading thereof stresses to rupture said preweakened beam structure, whereby said gate-supporting means are distorted and the gate-supporting effect thereof is reduced below the force exerted by the impounded water against the gate.
4. In a dam, a gate structure for impounding head waters, means for supporting said gate in water-impounding position including cross members normal to the direction of impeded flow, and water-collecting means secured to said cross members in position to collect water overflowing said gate, the capacity and location of said water-collecting means being such that substantial gate overflow loading thereof stresses to rupture said cross members, whereby the remainder of said gate-supporting means is distorted and the gate-supporting effect thereof is reduced below the force exerted by the impounded water against the gate.
5. A spillway gate structure comprising a water-impounding face, means for supporting said gate in water-impounding position including two sets of frame members connected to the downstream face of the gate and each set to a side of the spillway for supporting and normally restraining said gate in the spillway passage and cross members normal to the direction of impeded flow between said sets of frame members, the mounting of said frame members on the spillway being such as to permit the gate to be raised and lowered in the normal fashion, a flashboard surmounting the top edge of the gate, and water-collecting means supported by said cross members in position to collect water overflowing said fiashboard the capacity and .location of said water-collecting means being such that substantial flashboard overflow loading thereof stresses to rupture said cross members, whereby the remainder of said gate-supporting means is distorted and the gate-supporting effect thereof is reduced below the force exerted by the impounded water against the gate.
6. In a dam construction, the combination of a spillway and gate structure therefor, said gate comprising a water-impounding face and a skeleton frame for supporting the same including cross members normal to the direction of impeded flow, and means in the form of a tank secured to said cross members in position to collect water overflowing said gate, said tank having drain apertures of such size as to prevent substantial accumulation in the tank of water other than that steadily overflowing said gate,