US1898095A - Dam - Google Patents

Description

F. A. NOETZLI Feb. 21, 1933.

DAM

Filed Nov. 2 1930 Patented Feb. 21, 1933 PATENT OFFICE FREI) A. NOE'IZLI, OIF LOS ANGELES COU1\T TY, GALIFORNIA 'IDAMI Application filed November 25, 1930. Seria1 N0. 498,078.

This invention relates to daitos, and the primary object of the invention is toprovide a dann of the gravicy type which Will be less expensive und ab the same time safer than gravity clams as heretofore constructed.

In ehe orclinary type 0f uniform section gravity dam the pressure of the water is resistecl merely by the weight of the structure. Exoept in very high gravity dams ehe material is subjeotecl to relatively small stresses ancl iS therefore usecl mhe! inefllciently. This is especially true for the material in the interior 0:E the dann, Furthermor6, solid gravity clams are subject co up-lift pressure or" water in the joint between dann ai1cl bed rook, or in joints between pours of concrete.

One object of the invention is to provide a gravicy dann in which hollow spaces of suitable shape are substitutecl for .some of the concrete in the interior of a solicl clam. These spaces Will also serve to reduce uplift pressure in the interior of the dann. Safety against overturning is provicled in my improved structure loy building it with a markecl upstream slope anal by inoreasing its thiokness at the hase.

Another objeot of the invention is 130 builcl n1y improvecl dann es a oombination of Walls which' are structurally substantially indepenclent of each other ancl which have their upstream und downstream portions enlargecl laterally so as to form continuous upstream and clownstream faces of the dann.

Another objeot of the invention is to eliminate tension stresses in a lateral direction in the enlargecl upstream portions of ehe aforesaicl Walls.

Other objects 0f the invention are to pro- Vicle novel ancl advancageous joint construotions anal drainage systems. v

WVith the foregoing and other objeots in view which Will be macle manifest in the following cletailecl clescription ancl specifically pointed out in the appendecl claims, reference is hacl to the aocompanying clrawing for an illustrative embocliment 0f the invention, wherein:

Figure l is a schematic elevation of the dann emboclying the invention.

Figure 2 is a vertical section through the dann shown in Fig. 1 anal may be considered as having been nahen upon the line 22 of Figure l.

Figure 3 is a partial horizontal section along the line 33 through the dam shown in Fig. 1.

Figure 4 is a. partial horizontal seotion through a dem curved in plan, and may be considerecl als having been taken upon the line depenclent of each other, and in the design v are usually oonsidered as .structural vertioal elements aot1ng hke cant1levers m supporting the water pressure agzunst their upstream face.

Figure 2 illustrates how such a gravity type dann appears in section hzwing a hollow drein space 3 in the interior extencling substantially in the direotion of a contraction joint 2 from near the base to a, certain distanoe below the crest und from points near the downstream side D so points near the upstream sicle U of the dem. Such hollow spaces 3 may odour at difl'erent places in a clam ancl preferably in the planes 01 direc tio-ns 0-f sonne or all of the contraction j oints. They serve for clraining some of' the water from the concrete which m3y enter from the upstream side into the pores of tl1e concrete or into horizontal construotion joints and thus they tencl to recluce uplift pressure. At the same time, they permit 0f the saving of a considerable quantity 0f material at places where in a solid gravity dam the stresses are relatively 10W ancl the material is usecl rather ineffioiently.

The drain spaces 3 may be of any shape but preferably are elongated in an upstream and downstream direction such as shown, for instance, in Fig. 3. They may extend from a certain distance below the crest down to a base slab 4 or complet-ely down to the founclation material 5 as inclicated in Fig. 1. In orcler to recluce underpressure uncler the dam and uncler the base slab 4 I may provicle drain holes 7 reaehing down into the foundation 1naterial 5. v

Fast experience in concrete dann constrnction l1as shown the necessit 'y of providing in gravity dams transverse contraction joints 2 about 40 ft. to 60 ft. apart in orcler toprevent vertical cracks in the dam clue to sl1rinkage of the concrete. It 1s common practice to place a water stop 6 ac1oss the joint near the upstream face. In my improvecl dan1 the drain spaces 3 Will collect all water tl1at may pass through 01 around the stops 6. I may also place clrain conduits 8 leacling from the interior of the Walls 1 into the drain spaces 3, thus furtl1er reclucing the tencl'ency cf uplift pressure in the concrete. In Order t-o prevent excessive accumulation of water in some of the clra1n spaces 3 whicl1 might 111- duce undue lateral pressure upon the acljacent Walls 3, I provicle openings 9 in the Walls 1 for facilitating the circulation of air and water between acljacent spaces 3 ancl f'or the remo-val of excess water towuds the clownstream side.

Tl1e contraction joints 2 ancl the hollow spaces 3 may be considerecl as clividing the dann into Walls 1 resemloling the louttresses of a buttressed type 013 dam. From the structural point of view the function of these structures is very si1nilar indeed. In my 1111- proved dam the individual walls 1 are structurally indepenclent of each other ancl the; may be considerecl as Walls having tl1eir 11pstream ancl elownstream portions enlargecl laterally so as to form continuous upstrea1n and downstream faces of the dam. Thus, certain portions 11 of a Wall 1 in a horizontal plane extencl near the upst1eam face lat erally beyoncl the face o1': the Wall 1. The pressure of the water in the reservoir has tl1erefore a tenency of proclucing a bending moment ancl tension stresses in a lateral (lirection in the. portions 11 extencling laterally beyond the face of the Wall 1. If the upstream face cf the portions 11 has such a shape that the water pressure acting upon tl1ese portions is transmitted by direet compression upon the Wall 1 no such lateral bencling moment ancl tension stresses Will occur. Tl1is was recognizecl in Letters Patent N0. 1,681427 issued to me uncler date of August 21 1928. An improvement over the sonstruction describecl in the aroresaicl Letters Patent is clisclosecl in the present appication whereby special n1eans are provicled at sn1all expense to procluce such lateral pressure upon the portionsll as to offset or compensate bending moments and tension in a lateral direction.

Referring to Fig. 3, I provicle a seal or Water stop 6 across tl1ejoint 2 a certain distance downstream of the upstream face. 1Vl1en the reservoir fills, water Will then enter into the joint ancl procluce lateral pressure upon the portions 11. The clistance 12 cf the water stop 6 from the upstrearn face of the clam sl1ould preferably be such that the tension stressesin the portion 11 due to the water pressure 011 the upstrea1 face are materially rerlucecl o1 entirely eliminatecl loy the lateral pressure of the water in the joint 2.

In orcler to insure access of water into the joint 2 upstream 013 the stop 6 I may provicle a notch 22; I may also provicle an open slot 20 insteacl of a 1ne1e joint 2. Near the crest of thedam it will loe preferable not to prov icle any drain spaces 3. In this portiontl1e clam .is then of the usual uniform section gravity type.

I may also force cement grout uncler pressure 111to the joint 2 by means of pipes 21 over all o1 a part of the area between upstream face ancl drain space 3. I1 the joint 2 is thus filled witl1 cement grout no dangerous lateral bencling can result in the portions 11. I 1nay also use other means for proclucing lateral pressure in the joint 2 t0 reduce tension in the portions 11. In the case of gravity dams curved. in lan the grouting of the joints 2 near the upstream face anal in the upper portions of the clan1 may malre horizontal arch act1on feasible 111 the dam over the groutecl portions. The eflective arch sect1on would be relatively thin but nevertheless very eflicient in transferring a ortion cf the water pressure laterally upon the canyon Walls.

I may build my improved dem straight 01 curvecl 111 plane. In case of a curvecl clam the drain spaces 8 are preferably cf such a shape that in certain horizontal planes the average wiclth of the spaces 8 is larger nea1 the upstream face of the dam than near the downstream face. This results in a better proportion of the Walls l.

In a curvecl gravity clam the thickness of the Walls 1 is greater near the upstream s1cle tl1an near the clownstream s'1cle of the dam. I may therefore place vertically extencling l1ollow slots 13 in the interior of some or all of the Walls 1 cf the clam and provide sl1ortcontraction joints 14 between the slots 13 and the upstream face. The joints 14 extend 011 the upstream side practically fro1n the base of the dann or of the slot 13 to the crest, but on the clownst-ream sicle they extend only part of the clistance from the crest Clownwarcl. I place reinforcing bars 15 in the lower parts of the dann to prevent the slots 13 o1 joints 14 from extencling beyoncl the desirecl points.

Various changes may be macle in the cletails of the structure herein clescribecl without cleparting from the spirit or soope of the invention as clefinecl by the appenclecl claims.

For instance, there may loe at one or several points intermecliate vertical Walls W or floors F er both of any thickness across the hollow space 3 or there may be other braces B between the Walls 1.

Joints 2 or open slots 20 in cornbination with other means for proclucing hydraulic or other pressure in a lateral clirection upon the Walls l may l0e usecl to accomplish objects of my invention.

I clai1n:

l. In a clam two Walls each Wall having a flat upstream face, certain portions 0f saicl Walls near tl1e upstream face extencling laterally towarcls each other ancl being proviclecl with a jolnt joining saicl portions, 0ertain arts of saicl joint being open to water pressure fron1 the reservoir, a water stop aoross said joint, the distance of saicl water stop from the upstream face bearing a definite relation to the lateral extension 0f saicl 'portions beyoncl the faces 0f saicl Walls ancl to the pressure of tl1e water aoting thereon, substantially as clesoribecl.

2. In a clan1 two acljoi ing vertical strnc tural elements clisposecl substantially per penclicularly to the axis of the clarn, certain portions 0f saicl elements near the upstream face extendin laterally from saicl elements, ancl being joinecl l0y a substantially open joint between saicl portions, certain parts of saicl joint being open to water frorn the reservoir, water pressure acting upon the upstrea1n face of saicl elements tending to procluce tension stresses in saicl portions in a lateral clirection, a water stop placecl across saicl joint at such a distance from the upstream face that the lateral pressure of water entering from the reservoir into tl1e joint upstrean1 of the water st0p substantially eliminates saicl tension stresses.

3. A dann of the character clefinecl by claim 2, in comloination with a uniform section gravity type clam extencling along the Crest ancl fron1 tl1e crest clownwarcl for a 'portion 01 tl1e height 0]? the dam.

4. In a clam two 'acljoining Walls ex tencling transversely to the clirection of the dann ancl having substantially flat upstream r"aees certaln portions 0'f saicl Walls near the npstrea1n face extencling laterally from said Walls ancl being proviclecl *ith an open slot between sairl portions, a wacer stop near the clownstream encl 0:" saicl slot, the distance of saicl water stop fron1 tl1e upstream face bearing a definite relation to the lateral extension of saicl portions.

5. In a dann two wallsextencling trans- "ersely to the clirection of the dann certain portions 01 saicl Walls nea1 the upstream faoe extenrling laterally ancl being provirlecl with an upwartlly extencling open slot approximately one to -six inches wicle extending from the upstream face rearwardly, and means forconfining water from the reservoir over certain portions of saicl slot.

6. In a clam a Wall extenclingsubstantially transversely to the direction of the clam and having portions near the upstream face extencling laterally, the upstream face of said portions extending in a horizontal plane substantially perpenclicularly to the clirection of saicl Wall, pressure means acting in a late'ral clirection upon saicl portions procluci-ng stresses in saicl portions to the exclusion of tension stresses.

7. In a dann a Wall having a heacl with an uptream face extencling in a horizontal plane substantially perpenclicularly to the dir ction 0f saicl Wall, certain portions of saicl he'acl near saicl upstream face extencling later ally b'eyoncl saicl Wall; means for procl cing pressure 0f such a size in a lateral clirection upon saicl portions whereb-y saicl heacl is compressecl t0 the exclusion of tension stresses in a lateral direction.

8.In a dann a plurality 0f wallhaving heacls joinecl wi th each other and for1ning a continuousi upstrearn face extencling in a horizontal plane substantially perpenclicularly to the direction of saicl Walls, the pressure 0f tl1e W21l361 in the reserv0ir aoting upon the upstream face of saicl heacls tencling to procluce tension stresses in the heacls in a lateral direction, ancl means interposecl at the juncture between saicl heacls substantially eliminating said tension stresses.

9. In a clarn a plurality of buttress Walls having buttress heacls near tl1e upstream face ext-ending laterally beyoncl saicl buttress walls ancl being oinecl by vertically extending joints, the upstream face of saicl buttress heacls in a horizontal plane extenclihg substantially perpenclicularly to tl1e clirection of said louttress Walls, means in saicl joints for proclueing pressure upon saicl buttress heads 130 the eflect that the pressure of the water in the reservoir acting upon the upstream face 0f the buttress heacls in combination with the S2L1Cl pressure in the joints procluces substantially only cornpresslon stresses in saicl lauttress heacls.

10. In a darn two acljoining Walls extencling sub stantially transversely to the clirection of tl1e dann certain portions of saicl Walls near the upstream face extencling laterally and being joined by an upwarclly extending joint, saicl joint admitting water from the reservoir, 1neans for confining the water over a certain area of the joint, the upstream face of saicl Walls having such a configuration that the pressure of tl1e water in the reservoir acting upon the laterally extencling portions of saicl Walls tencls to procluce tension stresses in a lateral direction in saicl portions, said certain area of saicl joint being of such a size that the pressure of the water in said j eint at least eliminates said tension stresses.

11. In a dann two Walls, certain portions of said Walls near the upstream face extending towards euch other and forming a continuous upstream face but being separated by an open joint, said upstream face having such a shape that the water pressure in the reservoir tends to produce tension stresses in a lateral direction in said portions, means for confining water from the reservoir over such an area 0f said joint that the pressure of the water in the j oint substantially eliminates said tension stresses.

12. In a dann two Walls, certain portions 0f said wa1ls near the upstream side extending towards each other and being joinecl by a joint which in part is subj ected to water pressure, the pressure of the water in the reservoir acting upon the upstream face of said portions. tending produce tension stresses in a lateral direction in said portions, the combined pressure of the water upon said pstream face and in said joint stressing said portions to the exclusion of tension stresses in a lateral direction.

In testimony whereof I have signed my name to this specification.

FRED A. NOETZLI.

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