US1573986A - Spillway - Google Patents

Description

Feb. 23 19260 A. F. MEYER SPILLWAY Filed Jan. 5, 1925 7 Sheets-Sheet 1 [NYE/V708 flaoLF-w E MEYER v Feb. 23 1926.

A. F. MEYER SPILLWAY Filed Jan. 5, 1925 7 Sheets-Shet 2 {/5 IJIAKJJAK m f/v YEA 70R A2001: PH f. MEYER GM PM vh -zng,

' Feb. 23 1926.

- SPILLWAY Filed Jan. 5,. 1925 7 eets-sh 3 am A MEYER,

IN YENTOR Br @aMQ Paul- .0

TOR/Vtvs 1,573,986 A- F. MEYER Feb. 23 1926.

A. F. MEYER SPILLWAY Filed Jan. 5, 1925 M" I N VENTOR ADaLPH fi MEYER Feb. 23 ,1926. A. F. MEYER SPILLWAY 7 Sheets-Sheet 5 Filed Jan. 5, 1925 l/vvz/vro/e flDoLPH fr MEYER Feb. '23 1926.

A. F. MEYER SPILLWAY 7 Sheets-$het 6 Filed Jan. 5, 1925 [N VEN 7-0/2 H00; PH E ME YER j W TM I v F eb. 23 ,1926. 1,573,986

- A. F. MEYER I SPILLWAY Filed Jan. 5, 1925 mul 7 Sheets-Sheet 7' Br vulva A TToRA/E Y6 Patented Feb, 23, 1926.

PATENT titFFlClil.

SPILLVAY.

Application filed January 5, 1925. Serial No. 615.

To all whom it may co'nccm:

'Be it known that I, Anonrrr F. Merlin, a citizen of the United States, resident of St. Paul, in the county of Ramsey and State of'Minnesota, have invented certain new and useful Im rovements in Spillways, of which the following is a specification.

This invention relates to an improved spillway as well as to the novel method of designing and building the spillway.

at, present practically all spillways are built according to the ogee profile and with a curvature to cause the overfalling water to be discharged in a horizontal direction. The fillet or bucket at the toe of the dam or spillway is usually provided to assure thishorizont-al deflection of the discharged sheet for the ostensible purpose of protecting the bed of the stream against undercut ting and erosion at the lower end of the toe particularly when severe floods are passedr Insuch )resent spillway designs,

scour and uplift under the apron are cominon sources of trouble. Uplift occurs when thetailrwater below the spillway (the terms overfall dam, weir and dam with crest gates are to be understood as included in the term persists for long distances downstream from present spillway structures, which necessitates long andexpensiye aprons, cribs, inattresses, riprap or other forms of ri "er Jed protection. The overfalling water follows the profile of the present-day spillwayand, since the line of action of the cynamic presthan the line of action of the static back-pressure of the tail-water,

a couple is formed causing rotation and hence the formation of large eddy on top of the swiftly moving water. In this case the surface currents beyond the spillway are ba kward for a considerable. distance down- 11, high velocities usually persist in the r currents until beyond the end of the dee apron anc scour continues, whereby expensive repairs are necessitated.-

Among those skilled in the art to which this invention relates there appears a pres-' what may be termed a hollow bucket, that is, the bucket or curved face of the fore slope at the downstream toe of the spillway, is recessed or hollowed to provide a basin whose dimensions are substantially corre' lated with the height of the dam, the amount of overflow, and the natural depth of the tail water below the dam. The spillway is constructed preferably so as to lead the water, just before it enters the pool provided by the hollow bucket, in as nearly a vertical direction as its initial horizontal velocity and the structural features of the design permit. By doing so, the dynamic pressure of the overflowing water is exerted tore nearly directly in opposition to the static pressure of the pool. In consequence, the swiftly moving water is quickly slowed up, the surface eddy is greatly reduced in size, and the water acquires a downstream direction of motion throughout the full depth of the natural stream within a short distance from the toe of the dam.

A feature of the novel invention, which it is desirable to use in most spillways, resides in the shaping of the hollow bucket to provide a portion which extends in an upstream direction underneath the front slope or face of the spillway. This bucket portion permits the formation of a back eddy behind the swiftly flowing water, so thatthc overfalling water is attacked on the underside and more rapidly retarded.

Another novel feature, above suggested, consists in the proper dimensioning of the hollowrbuckot in correlation with the energy possessed by the overfalling water as it enters the bucket substantially at the elevation of the center of gravity of the tailwater. Atthe foot of the fall the swiftly moving water is capable of exerting a continuous pressure in the direction otits motion equal to its mass times its velocity. This is known as the dynamicpressure of the flowing water. In addition, this water exerts a static pressure in every direction proportional to its depth. This latter pressure of the swiftly moving water is usually very small in proportion to the former. To slow up the swiftly moving water and to destroy its excess energy so that it will flow down the natural channel again at the same depth and velocity as it did before the dam was built, it is necessary to apply to it a static baclzqnessurc at least substantially equal to the dynamic pressure plus the static pressure of the swiftly moving water minus the residual dynamic pressure which the waterpossesses in a downstream direction after it has been slowed up. The greater thestatic baclepressure provided and the more eti ectirely it applied to tlie swiftly moving water, the more quickly will that water be robbed of its excess energy. The depth oi. water which provides this necessary static back-pressure is herein designated by the capital letter D and is made the principal basis for the dimensioning ot the novel hollow bucket. Hence, for sake of clarity and brevity, such letter B is, in the specification and claims, employed to des nate and spcciiy such linear dimension.

The object therefore of the invention is to provide an improved spillway and method of designing and building); the same.

Other objects of the invent-ion will appear from the following description and the accompanying d "awinp's and will be pointed out in the annexed claims.

In the accompanying dra ings there have I been disclosed a series of structures designed to carry out the objects of the invention but itis to be understood that the invention is not confined to the exact features shown as various changes may be made within the scope of the claims which follow.

In the drawings:

Figure 1 is a vertical sectional view through a spillway constructed in accord ance with the invention, the spillway being of the hollow type and of medium or average height;

Figure 2 a vertical sectional view of a low solid-type of spillway embodying the invention and adapted to a very large discharge;

Figure 3 is a view of a spillway similar to that shown in Figure 1 but of the solid type and adapted to a larger discharge;

Figure 4 is a similar view through a solid spillway of the high type showing the invention as applied thereto;

Figure 5 is a solid spillway of the type employing gates and adapted to a relatively large discharge;

those buttresses or cross-walls are evaese ing the invention in such full, concise and exact terms as to enable any person skilled in the art to which it up Jertains, to carry out the method and to construct and use spillways, embodying the invention.

The invention is shown in Figure 1 as applied to a well-known form of dam or spillway ot the hollow type which is preterably of concrete construction, desirably steel-reinforced, as this is the most practical material for construction and one with which those skilled in this art are most familiar, although it-is to be understood that other ii'iaterial may be used.

The base 9 of the spillwayhas an upstream deck-at. its'heel 11 with its lower portion 12 substantially vertical while the major portion 13 thereof is upwardly inclined in a downstream direction to the crest 1%. The upper portion of the apron or fore slope 15 of the spillway has, in profile, the common ogee curve. At the toe or downstream end of the fore slope, it is theusual practice to provide a solid curvedllillet or bucket which, as above stated, causes the overfalling water to be discharged in a horizontal direction for the ostensible purpose of protecting the stream-bed against undercuttin'r and erosion at th lower end of the toe.

In this novel invention there is provided a recessed or hollowed bucket 16 atthe downstream toe and su hollowliucket extends substantially the whole length of the spillway. that across the stream-bed occupied by the spillway. The over ial eu water may il -erein form a pool at the spillway toe and static pressure thereof opposes the dyic pressure ot the OVJllitllllng water as it e; rs the pool with the result that the swiftly moving; water is sudden slowed up and the water acquires a downstream direction of motionthroughout the full depth of the natural stream within a short distance of the spillway toe.

lVhilethe hollow bucket maybe separate structure it is preferable to construct it as an integral part of the spillway strengtheninn" it with a plura v of s a'ed buttresses or cross-walls it). in r spillway of th' opposit the usual cross-walls 5Z0 the .1 i

' v structure. r unong the advanta es ral construction are a greater ease in designir or laying-out, a reduction in expense of construction, the spillway foundation is widened, a more uniform distribuend of the rim 19, an apron 22 may be extended and this may be integral with the bucket or not, as desired, although it is here shown as the latter. It may be noted that the apron 22 is shown in the. drawings as being unusually short for the spillway illustrated and such showing is intentional as the employment ofthe novel hollow bucket with its water-slowing function permits the use 0i such inexpensive short apron.

The novel-undercutting of the fore slope of the spillway is also shown in Figure 1 wherein the lower portion of the fore slope 15 is re -entrantly designed to provid a recess 23 forming an upstream continuation of the hollowbucket 16. Thus. this lmcket portion or recess 23 extends upstream underneath the fore slope or downstream face of the spillway. The result of such shaping; of the bucketis to cause the formation of a back eddy behind the water swiftly descending into the bucket pool. Home, the overfalling water is attacked on the underside and is more rapidly retarded and the greater the thickness of the overfalling water, the more valuable becomes the undercut rece'ss 23.v

In the spillway' embodying the inve .ticn, the fore slope is shaped to lead the overfalling water, just before it enters the hollow bucket pool. in as nearly a vertical (lirect-ion as itsinitial horizontal velocity and the structural features of the des n permit. The purpose to cause the dynan'iic pressure of the overtallinc' water to be exerted more nearly directly in opposition to the static "pressure of the pool.

dam or spillway to be constructed.

While the precise dimensions of this novel hollow bucket may be varied for difl'erent installations. the dimensions ot a particular bucket for a given installation are substantially correlated to the height of the selector: dam or spillwa-y, the amount of overflow and the natural depth of tail-water below the dam. In this art these three factors height amount and depth) for any given instalIation. are always determined as accurately as possible in advance of the designing of the IJllTO- wise one skilled in this art, may quickly and easily determine with a curacy for any proposed proiect the tltllJi'll'O'f tail-water which will provide the static back-pressure neces sarvto destroy the excess energy of the overfalling water so that it will flow down the natural channel below the fall at the same depth and velocity as it naturally does without the progected dam or spillway. Such predetermined de th of tail water 1s hercm specified by D for sake of clarity and conciseness. Incident to the determining of the dimension I)" there is also determined the thickness of the overfalling sheet of water assuming that it has had an unobstructed fall to substantially the level of the center oi gravity of the tail-water. Such prede termined thickness will be herein specified by T. The effective dimensioning of the hollow bucket is principally based upon such dimensions D' and Ti Therefore, in carrying out this novel method oi designing a SPlllYl'Ely for a particular project or installation, there is first determined as closely as possible the relation between the volume of water discharged. the drop thereor, and the natural ater level below the dam for all flood discharges. By all flood discharges is meant not only the maximum flood discharge which the spill vay must ac connnodate' but also lesser flood discharges which sometimes govern at least some of the dimensions of the novel hollow bucket. The dimensions D and T are then deter mined for the various flood conditions. After determination oi such basic dimensions, the hollow bucket proportionately designed.

In the preferred form of hollow bucket, its downstream width from the median plane of the overtalling water during the maximum flood discharge is substantially equal. to said dimension D and never less than substantially one and a half tin'ies the thickness T oi the ovcrtalling' water during; ijnaxiniuni flood discharge as it enters the hollow bucket. The top of the hollow bucket at the upstream side is below the level of the tail-water (llll'll! maximum flood conditions and, particularly for the purpose of determining the dimension T is preterably taken as substantially at the level of the center of gravity of the tail-water during maximum flood conditions. The bottom 17 of the bucket must be below the downstream rim 19 a distance greater than the thickness or widthTof the overfalling' water during maximum flood discharge it enters the hollow bucket. The downstream rim ot the bucket is designed to be below the is it is prcwhich is adapted to a lesser vein in this connection that, i

In the form of spillway shown in Figure 2, there is graphically illustrated the solid type of spillway adapted to discharge a 1 tiv'ely larger volume of water at a l sser drop than is shown in Figure 1 and there is also suggested the shape of the novel hollow bucket res iltant from the application thereto of the teaching of this invention.

Figure 3 illustrates solid type spillway and a greater drop than is shown in Figure 2 but to a larger volume and only a slightly greater drop than is shown in Figure 1 The comparison of the shayes suggested of he hollow buckets respectively illustrated will aid those skilled in the art in visualizing readily the results obtained by the applicm tion of this invention to such variant l'orins of spillways.

The solid type of spillway is also shown in Figure 4 as well as in all the remaining l ures. lhis'particular tigure illustrates a relatively high spill ray and, from a comparison of the UHCJBl'CHtt ng extensions of the buckets 111 the different e lanatory views, it will be noted that as the height ot' the drop increases, the undercut portion is reduced because with increas and less desirable. v

The form sho vn in Figure known as the gate type and;-

r- (3 0 mm shown as entirely open, h l would have the same desirable {lCLlOll if tl gate were partially closed. The princi a dimension D for this type of bncke should preferably be c onuguted upon 1hassumption that only part of the gates wil be opened a large amount thus discharging a laro'e volume of water at one portion of the width of the spillway without a proportionate raising of the depth of tail-water 'wl ich will thinly spread out over the down-' stream river bed. Under such conditions the downstream rim of the bucket must be placed relatively lower than i't all of the gates were opened the same amount. In other words, when designing such. a hollow bucket, there will initially be determined the depth of tail-water over th rim which will provide the above specified static back presure when only part of the gates opened. Such dimension D so obtained will obviously necessitate lowering the rim of the bucket below an elevation obtained from a computation from conditions obtaining when all of the gates are opened.

Figures 6 and 7 are more particularly useful as illustrati -Fe of the novel hollow bucket spillway wherein the bucket is reduced substantially to its minimum practicable dimensions while still carrying out theobjects of the invention. It will be noted that Figure o {W767 hollow bucket 7 omits the undercut feature of tie bucke and as a result the cross-wallor buttress 10 is also omitted. On account of the upward currents on the downstream side of thenovel hollow bucket 16, logs and other debris are deflected upward and'the tendency for such debris to strike the downstream wall 18 ot the hollow bucket is minimized. When user. as a part of the hollow bucket, the buttress 10 also acts to deflect logs,

other large floating debris, downstream. Such debris, however, can not long lodge in the .l'il'ltlll eddy next to the dam as it will soon be caught by the downstream currents. Tfhere large quantities of logs must be passed over a spillway dam instead of through sluices special y provided for that purpose the hollow bucket with slightly increased cost, may advantageously be widened downstream, dependent upon the length of ted in the given stream.

thus d scribed my invention what desire to secure by Letunderneath the 7 downtrees, ice I having a portion exa. in a spi ray of the adherent 'rappe type. a hollowl rcket having a portion extending upstretun underneath the downst cam face or" the spillway and the bottom bucket bein below the level of the.

wardly terminating below the level of the tail-inter correspondm to ZHZLXEHHHH flood discl'nirge of the spillway.

. n a soillway of the adherent ,nappe dimensioned to proed dinjiension D for all 5 oi ow bucket having a portion CX- tend upstream underneath the downllltl whereby some of the water pressure against the back of the spillway is carried to the foundation through said hollow bucket.

7. In a spillway of the adherent nappe type, a hollow bucket at the downstream toe of the spillway, the bottom of the bucket being below the natural level of the downstream bed, and a plurality of reinforcing members connecting the bucket with the front of the spillway making said bucket an integral part thereof whereby some of the water pressure against the back of the spil way is carried to the foundation through said hollow bucket.

8. In a spillway of the adherent nappe type, a hollow bucket at the downstream toe of the spillway, said bucket having a portion extending upstream underneath the downstream face of the spillway, and a plurality of reinforcing members connecting the bucket with the front of the spillway making said bucket an integral part thereof whereby some of the water pressure against the back of the spillway is carried to the foundation through said hollow bucket.

9. In spillway of th adherent nappe type, a hollow bucket adjacent its downstream toe and extending substantially the length of the spillway and a plurality of reinforcing members connecting the bucket and front of the spillway making said bucket an integral part thereof whereby some of the water pressure against the back of the spillway is carried to the foundation through said hollow bucket.

10. In a spillway of the adherent nappe type a hollow bucket adapted to confine the surface eddy to the overfallen water above the bucket and the bottom of the bucket having a depth below its downstream run 'at least substantially equal to the specified dimension T for maximum flood discharge and the downstream width of the bottom of the bucket being at least equal to substantially twice the specified dimension T for maximum flood discharge, and said bucket having its downstream rim below the level of the tailnvater a distance at least equal to the specified dimension D for all discharges of said spillway.

11. In a spillway of the adherent nappe type a hollow bucket adapted to confine the surface eddy to the overfallen water above the bucket and the bottom of the bucket being a depth below its downstream rim at least substantially equal to the specified di mension T for maximum flood discharge and the downstream width of the bottom of the bucket being at least equal to substantially twice the specified dimension T for maximum flood discharge, said bucket haw ing a portion extending upstream underneaththe downstream face of the spillway, and also having its downstream rim below the level of the tail-water a distance at least equal to the specified dimension D for all discharges of said spillway, and a plurality of reinforcing members connecting the bucket with the front of the spillway making said hollow bucket an integral part structurally and functionally of said spill vay structure.

A monolithic spillway having an adherent nappe face for the discharge of the o falling water, said spillway being formed with an integral hollow bucket at the downstream toe of the spillway and with the bottom of the bucket below the natural level of the downstream I'lVGldJCKl, and said bucket having a portion extending upstream underneath the downstrean'i face of the spillway.

In witness whereof, I have hereunto set my hand. this 29th day of December 1924- ADOLPH F. MEYER.

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