US2000311A - Jetty - Google Patents

Description

May 7, 1935. s. M. woon Er AL JETTY 2 snets-sheet 1 Filed Jan. 6,' 1954 ATTORNEY im, w um.

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Patented May 7, 1935 y t y oNrrr-n STATES PATENT oFF-ICE Sydney M. Wood, 'Lake Bluff, 'Ill., and Harry A.y

"Schmitt, Milwaukee, Wis.

Application January 6, 1934, Serial No. 705,494

t 12 claims. (01.'61-42 This invention relates tolixnprovementsin the lscouring will take place at the outer end of the art of iorming protective beaches. jetty due to `the accelerated velocity of the lit- 'I'he problem oi protectinglake .front property toral currents around said end. is one which has presentedinnumerable diflicul- Itis, therefore, kone of the objects ofthe pres- -ties particularly along "the shores of .the .Great ent invention to provide an improved method of *5 'Lakes Where great property destructionhas Aoc- `forming protective' beaches which results in the curred. An important factorin causing a recedformation of a long, gradually sloping beach on ingishore line is the erosive .action uof the lakes bothzsides of the jetty, and in the elimination of forces. Necessarily, this erosive action is most scouring action at the outer end.

1o damaging during va period when the nlake level A further objectof the invention is to pro- T10 is high, and in view of the fact that statistics vide an improved jetty for eiecting commercial show'that high levels Aoccur in vregular cycles, exploitation vof theabove method. there is always a period of :transition betweena Other objects of :the invention areto provide a '10W evel'and a high level during Which'moSl jetty which greatly. accelerates the ydeposit of 15 -property owners are inadequatelyprotected. beach building materialywhichnullifles the wave i5 Heretofore, it has been attemptedto check 'this action and reduces the energy of littoral curel'OSVe O-'fl by building retaining Walls WhCh rents, and `which causes the deposit of a greater parallel the edge'o'f the hillside. There is, `howpercentage of line sand. lever, no wall strong enough to permanently with- A furtherv object of the invention is to provide stand the action of the lakes `fo1ce's,1and this a jetty adapted to produce a'beach whichl is ad- #.20 type of protection is therefore efficacious for a vantageous, not only inthat it protects the shore short time only.` A long, gradually slopingbeach line, but also .in that it renders `theshoreun- Well suppliedvwith lsand and vgravel,is'the best usually suitable for bathing purposes. 'protection against erosive action,a'siithas the In Wood Patent #1,928,473, rdatedrSeptember ability to rob a storm of-,its destructive power, 26, 1.933, one type of jetty for forming a pro- ,25 and il? iS t0 the fOImaOIl Ofi-'Sibeadh 0f `thiS`type .ftective beach is shown and described. The presthat this invention particularly relates.` o Y yent invention relates to a jetty of a particular A The D'fnC-pal 'fOrCeSoallSng erosion 10h a lake shape wherein permeability is utilized in connec- ShOIe are COIllJIbU-ted t0 by the vSfl andJOy the tion therewith for accomplishing the desired ob- Water itself, and the two movementsset up by ject. In the `patent above referred-to `thisper- $0 the ail are WaVe aeton and 1tt1`aTCu1`1`entS me'ability is accomplished by the use oi'rock laid 'With a Wind blowing directly at Tight angles-"t0 in relatively loose formation. However, rock'fi's the shore, denudation of the beach takes Lpla'ce, not always easy to obtain and it is always dimas there is a surface drift shoreward `and an ook, to transport it tothe lake Shon undertow lakeward, which, assisted by the fact The prosentinvonon contemplates the fol-M 35 that'the'waves stir up sedimentyis able to convey tion of Va jetty from units which may be oost of material from the Shore out to deeper Water' Portland cement or the like and this casting may The most common'conditionis when the wind be done on the beach so that hauling of Vthe is blowing at an oblique angle `to theashore, and heavy units is eliminated Y 40 when this 1S th? case the Sand and other par' Aiurther object of the inventionis to provide 40 *tides held in Suspension'in )n.he wat@ are paused a novel form of shore structure for use in conto travel along the shore line.L 'With this fact *mention with a .jetty of the type dosorbed Said in mmd 1t may be .Seen that the particles can shorestructure being of a relatively inexpensive be accumulated by theconstruction of anobstacle nqturewherein repairs can be oasyvmade and across their path, that is, by the construction of yt possessing great Strength 45 a jetty o? groin extending into t-he lake .a'tlght With the above and other objects in view the angles to the bafnk The formatl'lon of a Sulltla'ble invention Iconsists of the art of forming protective type of protectwe beach Py 'ths' method OW- Vbeaches and all its parts and combinations as set ever, cannot be accomplished with the ordinary e 1 1 t thereof y y A u found that While deposits .forth in the claimsand al equiva en s p 7gg; fcrrrltl sltibilrsnside ci the jetty they will In the accompanying drawings illustrating one Y complete embodiment of the preferred form of tend to concentrate to provide a relatively steep the invention in which the Same reference nuslope adjacent the jetty on this side, and-on the i y -lee side objectionable scouring will take place. merals deslgnate the Same DallS 111 al1-Of the ,Itis alsoiound that with most types oijetties, views: o y l o f 55 y Fig. 1 is a side elevational view of the improved jetty;

Fig. 2 is a plan view thereof;

Fig. 3 is an enlarged cross-sectional view taken on line 3-3 of Fig. 2;

Fig. 4 is a plan View on a reduced scale, of a lake shore, showing a plurality of parallel jetties installed;

Fig. 5 is an enlarged cross-sectional view taken through the unit formed part of the jetty, none of the units of the jetty, however, being cut through;

Fig. 6 is a plan view showing the method'ofl assembling a group of the units; and

Figs. 7 to 13 are plan views showing the different types of units which may be utilized in the structure.

Referring more particularly to the drawings, the numeral l5 designates a hillside leading down to a beach bordering a lake or other body of water. In cases where there is an artificial barrier such as a retaining wall paralleling a hillside the jetty may be laid in the same relation with respect thereto as it is with respect to the hillside I5. The numeral I6 designates the sand beach and the numeral I1 the water level of the lake.

With the present invention in order to obstruct the littoral currents to cause the deposit of particles of sand in proper formation to provide along, gradually sloping beach, one or more jetties may be extended from the hillside or wall I5 outwardly into the lake at approximately right angles to the hillside. In View of the fact that permeability is unimportant on the portion of the beach .close to the hillside which is not ordinarily reached by the water of the lake, it is preferred to construct this portion of the jetty ina different manner from .the portion which actuallyy extends into the Water.

As shown in Fig. 2 and Fig. 3, a plurality of supporting wings |8 which may be molded from cement or the like, are positioned in pairs as shown, there being a space |9 between each pair of wings. In order to provide a foundation for these relatively heavy wings it is preferred to drive piles of wood or concrete into the sand as indicated by the numeral 20 and metal rods or the like 2| may be caused to project from the piles and to extend through apertures in the wings in order to iirmly anchor the latter in position.

Elongated beams of concrete or any suitable material 22 may be laid in superimposed horizontal position in the spaces I9 between the wings, the ends of said beams being preferably dovetailed as at 23. These beams therefore form a `durable wall structure which is resistant to turn- 1ng movement or other forces because of the fact that the laterally extending wings form an effective brace therefor. v

The jetty proper consists of a plurality of units of irregular shape which are cast from cement or the like and these various units used are designated by the numerals 24, 25, 26, 2l, 28, 29 and 30, shown in Figs. 7 to 13 inclusive. Before the units are laid, piles 3| should be driven into the sand beneath the water to form a base structure and on these piles foundation slabs of cement or the like maybe laid as at 32. Next a plurality of the longest units 24 are laid to form a row on topof the foundation 32. These units are formed with sets of` projections 33 and 34 and it will be noted that the projections 33 are spaced a greater distance from one end than the projections 34 are spaced from the other end. This provides for laying of the units in the manner shown in Fig. 6 to produce a staggered formation and provide a baled channel 35 between each pair of units. After approximately three layers of the units 24 have been laid, a new layer is begun, using the units 25 shown in Fig. 12. These units differ only in that their ends are of beveled formation as at 36. Next a row of the units shown in Fig. 11 is laid, these units 26 being somewhat shorter in length than the units 25 and also having beveled ends 31 for alinement with the beveled ends 36 of the units 25. Next a row is laid with each of the blocks 21, 28 and 29 shown in Figs. 10, 9 and 8, to thereby form the structure shown in Fig. 5 wherein the sides taper preferably on a slightly curved line 38 as illustrated on said iigure. On top of the row of units 29 may be laid a row of the strips 30 to thereby form a structure on which a person can walk.

The first three rows, or any desired number for that matter to suit particular requirements, may extend the full length of the jetty. Subsequent rows, however, may be shorter to provide a structure of decreasing height outwardly. Accordingly, the row of units 25 may terminate at the point 39 as indicated. The next row of units 26 may terminate at the point 40, the row of units 2'! at point 4|, the row'of units 28 at point 42, and the row of units 29 at point 43.

Each of the units is formed with apertures 44 therein and the various superimposed layers of units may therefore be connected together by running rods of metal or thelike 45 through registering apertures 44 of the superimposed layers.

The apertures may be plugged with cement in order to hold the rods in place. The method of laying units in a superimposed row is shown by dot and dash lines in Fig. 6. This gure also indicates the manner in which the apertures 44 aline.

As a result of this structure it will be seen that the water can pass through the sides of the jetty at any point but that its passage is retarded due to the fact that the projections 33 and 34 form baiiles around which the water must travel. Thus, the force of the littoral currents will be considerably checked to cause the deposit of particles of sand in proper formation to provide a long, gradually sloping beach.

By referring to Fig. 1 it will be seen that the major portion of the length of the jetty projects above the water line but that the outer end is submerged. This is for the purpose of allowing the shore currents to pass at reduced speeds through and over the submerged end and to cause the retardation of currents passing inwardly or outwardly along the sides to prevent scouring at the ends and along the sides.

It is found that the character of the beach may be still further improved by laying a plurality of jetties of the type described in parallel relation to one another and spaced apart a substantial distance as indicated in Fig. 4.

s Where a solid or impermeable jetty has been used, the littoral currents carrying the sand and other fine particles in suspension are obstructed by the sides of the jetty, but the velocity of the currents is accelerated to cause a rather abrupt turning of the ow of the littoral currents from a direction parallel to the shore line to a direction parallel to the sides of the jetty, the currents therefore fiowing around the end of the jetty with accelerated velocity. When the lit'- toral currents strike the sides of an impermeable acca-3.11 f3 jetty,there is likely to 3be a momentary' and rather abruptchange Vthe direction of "travel of thecurrents which causes a deposit'inqarather abrupt `manner close to the windwardside'fof the jetty, and inasmuch as 4this deposit will-bel con-- centrated adjacent` the jetty, -any beach Ade- Velopedfwill `have anabrup't slope and Awill not be desirable. Furthermore, due to the'accelerated velocitylof the littoral currents yas they move around the end of the impermeable -jett-y, the -ne sands are carried lwith, .the current, and the majority of the ll adjacent the jetty -Will be of coarser material. In addition, the'action'o'f the currents around the end of an impermeable jetty wherein the velocity is greatly accelerated will cause a marked scouring to take place at the outer end of the jetty, and thereby develop a deep water spot objectionable for bathing purposes.

With the present invention, it is to be noted that the major portion of the length ofthe jetty is permeable, and as a result, while `the littoral .currents are obstructed in a manner to cause the deposit oi sand and othermater-ial held in suspension, nevertheless, due to the permeable nature of the wall, the watercan flow through the spaces 35 so that there is not the tendency for the'ourrents to move in a direction parallel to the jetty Aand travel around the outer end with accelerated velocity such as is the case with the jetty of the impermeable type. Thus scouring at the outer end is eliminated. Furthermore, due to the fact that the currents are slowed down in a uniform manner by the permeable jetty and can trickle through, an even deposit of fine material is encouraged on both sides of the jetty, and this deposit will gradually build up, not only directly adjacent the sides, but for a substantial distance laterally therefrom to cause the formation of a long, gradually sloping beach composed of ne particles of sand. With the impermeable type of jetty, the littoral currents which rush around the outer end and there cause scouring and which then move inwardly toward the shore on the other side of the jetty, will cause a scouring on the lee side.

By referring to Fig. 4, it will be seen that with applicants type of jetty, that when the wind is travelling in an oblique direction toward the shore, as indicated by the arrow A, that the littoral currents indicated by the arrows B will flow somewhat in the manner indicated, that is, approximately parallel to the shore. As said currents strike the permeable jetty, instead of changing direction and traveling at right angles to the sides of the jetty and around the outer end at accelerated velocity, they will pass through the permeable jetty and there will only be a slight tendency to direct the currents outwardly. The currents will then continue as indicated, passing approximately parallel to the shore between each pair of jetties and through the next successive jetty. The result will be a gradual slowing down of the littoral currents to cause a gradual deposit of sand and the formation of an ever widening beach composed of fine material, as indicated by the numeral I6 wherein `the angle of the beach is relatively flat, and wherein the tendency for the beach to concentrate directly adjacent the sides of the jetty, is minimized.

It will further be seen that with the present invention, the area of new land formed will be much greater per foot of jetty than would occur with an ordinary type of construction, and that the sloped sides of the jetty shown in the crossvsections -tends -to nullify :wave action-and to re- `duce the energy of the littoral currents.

' Although only one lform lof the invention has Jbeen'shown and described, it is -to`` be understood that various changes 4and modifications may be `made, and -that'all ofsuch changes are contemplated as may come vwithinl the scope of `the claims.

What we'claim is:

'1. A jetty comprising an Aelongated .wall `extending .outwardly -at an angle to the shore, said -wall ibeing formed Aof transversely laid spaced apart units, some of said units having vlateral `projections spaced `from portions ofan adjacent -funittoprovide a bafileffor `water passing between tending outwardly-atan angle tothe shoreysaid wall beingfcrmed of -superimposed layers-of similar transversely Vlaid units, each Yuni-t being formed with lateral projections, the units "being laid in spaced apart relation with the projections of one unit staggered 'with respect to the projections of an adjacent unit to provide a vcircuitous path for water.

4. A jetty comprising an elongated wall extending outwardly at an angle to the shore, said wall being formed of superimposed layers of similar transversely laid units, each unit being formed with lateral projections, the units being laid in spaced apart relation with the projections of one unit staggered with respect to the projections of an adjacent unit to provide a circuitous path for water, upper layers being of less width than layers therebelow to provide tapered sides.

5. A jetty comprising an elongated wall extending outwardly at an angle to the shore, said wall being formed of superimposed layers of similar transversely laid units, each unit being formed with lateral projections, the units being laid in spaced apart relation with the projections of one unit staggered with respect to the proj ections of an adjacent unit to provide a circuitous path for water, upper layers being of less width than layers therebelow to provide tapered sides and being of less length to provide for an outwardly decreasing height for the jetty.

6. A jetty comprising an elongated wall extending outwardly at an angle to the shore, said Wall being formed of superimposed layers of similar transversely laid units, each unit being formed with lateral projections, the units being laid in spaced apart relation with the projections of one unit staggered with respect to the projections of an adjacent unit to provide a circuitous path for water, the units of each layer being oiset with respect to the units of an adjacent layer.

7. A jetty comprising an elcngatedwall extending outwardly at an angle to the shore, said Wall being formed of similar transversely laid units, each unit being formed with a lateral projection near each end, one of the projections being nearer its end than the other whereby like adjacent units may be laid in reversely extending position to cause staggering of the projections thereon and thereby provide a circuitous path for water.

8. A jetty comprising an elongated wall extendspo ing outwardly at an angle to the shore, said Wall being formed of similar transversely laid units, each unit being formed with a pair of oppositely extending projections near each end, one of said pairs of projections being nearer its end than the other whereby like adjacent units may be laid in reversely extending position to cause staggering of the projections thereon and thereby provide a circuitous path for Water.

9. A jetty comprising an elongated wall extend ing outwardly at an angle to the shore, said wall being formed of superimposed layers of similar transversely laid units, each unit being formed with a lateral projection near each end, one of the projections being Ynearer its end than the other whereby like adjacent units may be laid in re versely extending positionto cause staggering of theprojections thereon and thereby provide a circuitous path for water, the units of each layer being offset with respect to the units of a layer below and the projections on the units of the adjacent layers cooperating to form support for the units of each layer in said offset relation.

10. A jettycomprising an elongated wall extending outwardly at an angle to the shore, said wall being formed of superimposed layers of similar transversely laid units, each unit being formed with a lateral projection near each end, one of the projections being nearer its end than the other whereby like adjacent units may be laid inv reversely extending position to cause staggering of the projections thereon and thereby provide a circuitous path for water, the units of each layer being oiset with respect to the units of .a layer below and the projections on the units of the adjacent layers cooperating to form support for the units of each layer in said offset relation, and connecting means extending through overlapping parts of a plurality of layers of the units.

l1. A unit for forming a permeable jetty comprising an elongated body portion having a pair of oppositely extending projections near one end, and having a pair of oppositely extending projections spaced a greater distance from the other end than said iirst pair of projections is spaced from its end.

12. A unit for forming a permeable jetty comprising an elongated body portion having a pair of oppositely extending projections near one end, and having a pair of oppositely extending projections spaced from the other end a distance greater than the spacing of the rst pair of projections from its end by at leastl the width of one of the projections, there being an aperture in each projection of the rst pair and an aperture in the body portion of the unit between the other pair of projections and the adjacent end,

SYDNEY M. WOOD. HARRY A. SCHMITT.

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