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Publication numberUSRE24837 E
Publication typeGrant
Publication dateJun 14, 1960
Filing dateJul 29, 1957
Publication numberUS RE24837 E, US RE24837E, US-E-RE24837, USRE24837 E, USRE24837E
InventorsErnest M. Usab
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Floating wharf structure made of concrete float units
US RE24837 E
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

E. M. USAB June 14, 1 960 FLOATING WHARF STRUCTURE MADE OF CONCRETE FLOAT UNITS Original Filed July 29, 1957 3 Sheets-Sheet 1 IN VENTOR ERNE5TM. USFIB MALL/QM C. BQBCOCK ATTORNEY FLOATING WHARF STRUCTURE MADE OF CONCRETE FLOAT UNITS Original Filed July 29, 1957 E. M. USAB June 14, 1960 3 Sheets-Sheet 2 I I T- l 1g, 6 I1 8 mmvron ERNES TM. 1750B WILL/EM C. Bnacocz AT-i-oRN EY June 14, .1960 s. M. USAB Re. 24,837

FLOATING WHARF STRUCTURE MADE OF CONCRETE FLOAT UNITS Original Filed July 29, 1957 3 Sheets-Sheet 3 INVENTOR E RNE5T M US PB ATTORNEY United States Patent Ofi ce Reissued June 14,


Claims. (Cl. 114-.5)

Matter enclosed in heavy brackets II] appears in the original patent but forms no part of this reissue specification; matter printed in italics indicates the additions made by reissue.

The present invention relates to a floating wharf struc ture made up of concrete float units and in which the walkway is provided by the surfaces of the float units themselves.

In constructing marinas or small boat harbors it is desirable to utilize a floating wharf structure which is accessible to land and has one or more fingers extending out into the body of water. In the past, various types of pontoons and floats have been used for this purpose. The types of structures used heretofore have been found, however, to be unduly expensive and to have a short useful life, particularly when used in salt water locations as is often the case.

An object of the present invention, therefore, provide a floating wharf structure having low initial cost and a long useful lite.

Another object of the invention is to provide a floating wharf structure which may be assembled in domino fashion, that is, which is made up of a number of similar separate units which can be combined together in any one of a variety of patterns as may be desired.

A further object of the present invention is to provide, for use in a floating wharf structure, a novel float unit having many years of useful life under constant exposure to salt water and the accompanying salty atmosphere.

Yet a further object of the present invention is to provide, for use in a floating wharf structure, a float unit which is made entirely of concrete and other low-cost materials.

Still another object of the present invention is to pro. vide, for use in a floating Wharf structure, novel float units which can be combined together in any one of a variety of patterns, and connecting means, for tying the float units together, arranged in such a way that partial disassembly thereof for the purpose of maintenance or repair can be conveniently and quickly accomplished.

A still further object of the invention is to provide a concrete wharf structure that not only floats at. a desired position on a body of water, but has the necessary flexibility to permit it to yield 'to the wave motion of a large body of water without impairment of its function or sustaining any damage.

Yet another object of the invention is to provide a wharf structure that is in the main, formed from concrete, a material ideally suited for this purpose due to its resistance to deterioration by water or moisture, but a material which has heretofore been rejected for wharf structures due to its lack of resiliency and low tensile strength.

In accordance with the present invention the above and other objects are accomplished by providing a float unit-in the :form of a waterproof hollow box whose top, bot-tom and walls are made entirely of reinforced concrete. Along each side of the box and adjacent to its top surface there is provided a row of fastening means,

is to such as bolts, which are imbedded in the concrete and protrude outwardly. The top surface of each float unit is coated with an abrasive non-slip material in order to serve as a walkway. A number of individual float units may be permanently fastened together by utilizing wooden tie rails placed along the sides of the respective float units, and fastened .to the bolts or other fastening means.

The above and other objects of the invention will be more readily understood from the following description in conjunction with the accompanying drawing, in which:

Figure 1 is a perspective view of a floating wharf structure as provided by the present invention, comprising three interconnected float units; I

Figure 2 is a plan view of the ri-ght hand side of the wharf structure of Figure 1 illustrating how the two adjacent flloat units thereof are interconnected by means of a tie rai Figure 3 is an elevational view of the adjacent float units and interconnecting tie. rail of Figure 2;

Figure 4 is a plan view of a corner bracket used in the wharf structure of Figure 1 to connect a finger exten-. sion to the main walkway;

Figure 5 is an elevational view of the corner bracket of Figure 4;

Figure 6 is a plan view of any one of the float units used in the wharf structure of Figure 1;

Figure 7 is a side elevation view of the float unit of Figure 6;

Figure 8 is a partial vertical section view taken on the line 8-8 of Figure 6;

Figure 9 is a partial vertical section view taken on the line 99 of Figure 6;

Figure 10 is a perspective view of an anchor ring suitable for connection to an iron pipe piling; [and] Figure 11 is a perspective view of an anchor ring suitable for connection to a large wooden piling; and

Figure 12 is a perspective view of the wharf structure shown in Figure 1 with additional units added thereto.

Reference is now made to Figure 1 illustrating one form of floating wharf structure in accordance with the present invention. In Figure l the wharf A is shown as including separate float units B-l, B-2 and B3. Float units B-1 and B2 are aligned in a straight line to provide a main walkway while float unit B-3 provides a finger extending therefrom at a right angle. Corners C-1 and C-2 connect float unit B-3 tothe main walkway The Wharf structure of Figure 1 is tied together by means of a tie rail D extending all the way around the exposed sides and ends of the float units as well as the corner sections C-1 and C-2. Anchor means for the floating wharf includes iron pipe pilings E-l and E-2 to which the main walkway is movably fastened by means of anchor couplings F-1 and F-2, respectively. A boat G tied to the wharf illustrates the manner of usage thereof. The entire surface S of the wharf 'stmic ture, exclusive of the tie rail, is a coating of an abrasive non-slip material. I i

In describing in detail the floating wharf structure of- Figure 1 it will be of great convenience to refer to Figures 2 to 10 of the drawings concurrently, and in order to preclude any ambiguity of description, like reference numerals are used throughout the drawings to identify like parts.

Each float unit B consists essentially of a hollow box whose length and width are substantially greater than its depth and whose top, bottom and walls are made of reinforced concrete. A top slab 11 and a bottom slab 12' are exactly parallel to each other since the boxhas a uniform depth throughout. End walls 13a, 13b intro-' connect the top and bottom portions of the box, whose basic structure is completed by side walls 14a, 14b.

.The inner portion of the box contains transverse partition' walls 15a, 15b which are parallel to end walls I 3 13a, 13b and serve to divide the box into three waterproof compartments 16a, 16b, 160. On the top surface of the box are provided a number of inspection plugs, one for each Water-tight compartment, and identities as 17a, 17b, 17c.

A reinforced concrete flange protrudes outwardly from the sides and'ends of the box and provides an extension of the top surface thereof, the flange portions at the ends o f the box being identified as 20a, 20b and those at the sides of the box as 20c, 20d. These flanges effectively forrn a ,b'ufier means to receive impacts and to space propellers on boats being docked away from the adjacent vertical wall of a float unit. The side flanges have imbedded therein a plurality of outwardly protrudnlg', spaced-apart threaded bolts which are aligned with the top surface of the box. Thus bolts 21a 21h protrudefrom flange 20c while bolts 22a 22h pronude from flange 20d. In each portion of the box structur the concrete is reinforced at approximately the center line thereof by a galvanized wire mesh screen 23. Asshown in Figure 8, the reinforcing screen in top slab 11 is curled over at the outer edges thereof to provide reinforcement for the adjoining flange portion, such as flange 20d. As shown in Figures 8 and 9, the reinforcing screen although arranged in a number of separate pieces has sufiicient interweaving, overlap or other interconnection of adjoining screen portions so as to assure a firm structural. support for the entire float unit.

Tie rail D of Figural includes a number of separate segments such as 30, 31, 32, 33, 34. Those segments such as 3-1, 32, 33 which pass along a side flange of one or. more of the float units are provided with holes adapted to fit over the corresponding bolts. As illustrated. by segment 32, it is convenient to have each segment of the tie rail extend from approximately the middle of one float to approximately the middle of the next. The ends of each tie rail segment instead of being square are cut at an angle from the horizontal so as to provide strength of the interconnections, but at the same. time to permit convenient and rapid removal of a particular tie rail segment without disturbing adjoining segments.

' Each tie rail segment is provided with belt holes such as 32a, 32b (as shown in Figures 2 and 3), which are recessed to receive nuts which may then be tightened down on the respective bolts. It is convenient to thereafter fill the bolt hole with some type of water-repellent material to preclude the bolts and nuts from rusting. It may also be convenient to cover the tie rail with rubber or other weather-stripping to provide the maximum protection thereof against the water and the weather. If maintenance or repair work needs to be done, a particular segment of the tie rail may be removed simply by removing the nuts from the bolts to which they are fastened. The tie rail segment may then he slipped horizontally off the bolts.

Each corner section C includes a bracket 40 having first and second mounting surfaces 41 and 42 arranged at a right angle to each other, and a third mounting surface 43 providing the hypotenuse of a triangle for which surfaces 41 and 42 represent the legs. As shown in Figure 4, the corner bracket may be utilized for joining two float units by fastening mounting surface 41 to bolts 21f; 21g, 21h and mounting surface 42 to bolts 21d, 21e, 21f. These connections correspond to those used for corner section C-2 of Figure 1. For corner section (3-4 the connections (not shown) would include the fastening of mounting surface 42 to bolts 22f, 22g, 22h of float, B3, and the fastening of mounting surface 41 to bolts llc, 21d, 21c of float unit B-l.

Corner bracket 40 is made of steel in order to provide the necessary strength. As shown in Figure 4tie rail segments such as 36, 37 associated with the sides of the corresponding float units are cut in a vertical plane at a suitable angle to abut against mounting surface 43 of corner bracket 40, while tie rail segment 38 lies along the main portion of mounting surface 43 and intercom nects the other two tie rail segments. The structure of the corner section is completed by a cover member 45 whichmay be reinforced concrete or other suitable material and which fits over the top of corner bracket 4% to provide an integral portion of walkway surface S.

In Figure 10 there is illustrated a perspective view of an anchor coupling such as F- l, E4 of Figure l. A horizontal angle bracket 51 is fastened by any suitable means such as bolts 52 to the corresponding tie rail. An anchor ring 53 provided on its inner surface with a pad 54 is fitted around an iron pipe piling 55 and is then fastened by suitable means such as bolts 56 to the horizontal bracket 51. An alternative version suitable for use with a large Wooden piling is shown in Figure 11, in which the ring is formed from a section of pipe 57 which is suitably bent to fit around the piling and whose length may be adjusted to conform to the piling diameter at the water surface.

In constructing float units in accordance with the present invention it is imperative that the concrete have high strength, low weight, and be waterproof in the presence of salt water. Concrete of the type known as Rocklite has been found satisfactory for this purpose. The only portion of the wharf structure subject to appreciablc deterioration is the tie rails, for which a suitable material is treated Douglas fir. The surface of the float units'may be supplied with a coating of abrasive materials, or the concrete itself may be finished in such a manner as to provide the desired non-slip characteristics.

The particular floating wharf structure illustrated in Figure l is of course only exemplary, and it is possible in accordance with the described techniques to interconnect a great many float units to provide numerous basic walkways, fingers extending therefrom, and so on. It has also been found convenient from the commercial standpoint to provide the float units in several sizes, such as 3' x 8, 4' x 8' and 6 x 8'. It may also be desirable to omit the transverse dividing walls such as 15a, 15b, depending upon the size and other characteristics of the particular float unit.

Through suitable adjustment of the design parameters it has been found possible to provide concrete float units of the type herein described which are safe and reliable, having an anticipated useful life in salt water locations of twenty years, and whose flotation capacities are equal to those of prior type float units. At the same time the concrete float units are smaller in size, have substantially lower initial cost, and are far more economical when the expense is evaluated over the useful life span of the structure. As an example of the flotation capacities, a unit of the type described having a length of approximately eight feet, width of approximately six feet, and depth of one foot, seven and one-half inches has been found to rise above the water eleven inches under conditions of no load; and to be able to sustain a load of fifty-two pounds per square foot of surface area before submerging. In view of these performance characteristics the float unit has been found far superior to comparable units of the past.

Concrete, as is well known, has little strength in tension, but very substantial strength in compression. Wharf structures are in most instances installed in bodies of water in which the structures are at least periodically subiected to excessive wave action, strong wind and currents, and occasionally a severe laterally directed shock due to a boat inadvertently contacting the structure. Unified wharf structures formed of concrete have in the past been unsuccessful, for the stresses imparted thereto by wave action, stfong'c'urrent's and other shocks have set up tensional forces therein that break and crack the concrete, and with Subsequent weakening and disintegrafion of the structure.

There are several reasons for supplying the float unit of the present invention with a flange surrounding its top surface, First the flange is approximately twice as thick as the top slab,-or main deck; and being thoroughly reinforced it provides a heavy beam which protects the top slab from bending or breaking. In this connection it may be noted that the reinforcing material is arranged in the form of a hollow square tube (see Figure 8) whose sides lie near the respective surfaces of the flange. A second reason for the flange is to provide a point of strength or bufler means to receive impacts, as from a boat which is being docked. A third reason is to protect the main body of the float from being damaged by any protruding object such as, for example, the propeller of a boat. A fourth reason is to support the bolts or other fastening means, and to distribute the forces received therefrom throughout the structure. In this connection it maybe noted in Figure 6 that tie bars 25, 26 run almost the entire length of the respective side flanges and are welded to the inner ends of the bolts mounted therein. A fifth reason is to provide a space between adjacent float units at the water surface, so that tides or currents may readily pass therethrough.

Although the float unit has been described as comprising a wire mesh screen arranged to form a fully enclosed rectangular structure, it is actually preferred not to reinforce the float unit at cetain points. More particularly, it is preferred to omit the wire mesh screen reinforcing material in the exterior walls of the unit near the water line. The region in which it is thus preferred to omit the reinforcing screen is indicated in Figure 8 by a bracket and the numeral 28. This particular portion of the reinforcing screen is not needed for structural purposes, and is subject to undesirable oxidation because the concrete is periodically changing from wet to dry and vice versa, and for those reasons it is preferable to omit the reinforcing material altogether.

In the preceding description it has been stated that the stud bolts are on the sides of the float unit, and this has been illustrated in Figure 6 of the drawing, however, it is sometimes advantageous to connect two or more float units together so that the longer dimension of each becomes the width of the walkway. The sides of the float unit are then its shorter edges, and the stud bolts are mounted thereon. Where a particular float unit is intended to be used at the end of a walkway or pier it is preferred to incorporate stud bolts on both sides and on one end of the float unit so that tie rails can be fastened thereon accordingly.

In Figure 1 of the drawing there has been illustrated a main Walkway with a finger consisting of a float unit B-3 extending therefrom at a right angle. While the finger may be connected to the walkway at a juncture between two float units, such as the juncture between float units B-1 and 8-2 as illustrated in Figure 1, it is also possible to have the finger connect to the side of a single float unit at the middle portion thereof.

One of the hazards of boating or sailing in small craft is the danger of fire. The present invention provides a substantially fireproof wharf structure in which the only combustible portions are the tie rails. Thus a small boat in which the motor has caught fire, for example, may land at the wharf of the present invention and bring its occupants to safety since there is practically no danger whatsoever of burning up the wharf.

The floating wharf structure provided by the present invention has the necessary flexibility so that it can yield to the wave motion of a large body of water, without impairment of its function and Without sustaining any damage. Where float units having a length of eight feet are used, relatively violent water produces a maximum deflection at each joint of three-fourths of a degree. All of this deflection is taken up by the wooden tie rails. The fact that the abutting flanges of adjoining float units have a depth which is relatively small compared to the length of each float unit is necessary in order to permit proper flexing of the Wharf structure to occur.

concrete-deck or walkway has many advantages,

including long life'and the ease of providing a non-slip surface. In the float unit of the present invention the sub-structure has two important functions: first, to support the main deck and protect it against distortion and breakage, which would otherwise inevitably occur where a thin slab of concrete is subjected to constant agitation; and second, to provide the Water displacement necessary for flotation.

. Another float pattern is shown in Figure 12 that not only illustrates the versatility of the invention as being arrangeable in any desired configuration, but also illustrates the flexibility of the wharf structure within predetermined limits when subjected to a strong wave action in the direction of the arrow 60. The arrangement of the float units shown in Figure .12 is the same as illusstrated in Figure 1, but with two additional float units B-4 and B-5 having been disposed in longitudinal alignment with float 8-3. The tie rails D have been extended along the sides of float units B-4 and B-5, and removably aflixed thereto in the same manner as previously described in connection with floats E-I, B-2 and 8-3.

For clarity of explanation, the tie rails D connecting float units B-3, B-4 and B-5'have been further identified by the notations D-1 and D-2.

When the wharf structure is subjected to a strong wave motion in the direction of the arrow 60, the structure of course tends to move in the direction of the arrow, but is restrained from so doing by the piles E-I, 15-2 and anchor couplings F-J, F-2.

The positioning of the piles E-J, E-2 and anchor couplings F-J, F-2 prevents the float units 3-] and B-2, shown in Figure 12, from pivoting relative thereto when subjected to wave motion in the direction of the arrow 60. However, with the couplings F-1, F-2 being slidably movable relative to the piles E-I, E-Z, the float units B-1 and B-2 can move upwardly and downwardly when subjected to such wave motion, or changes in the water level brought on by tide action.

The tie rails D-1 and D-2 previously mentioned are resilient. This resiliency is of the utmost importance, for when the wharf structure is subjected to a sudden shock by wave action, inadvertent bumping by a boat or the like, the tie rails are stressed in tension and temporarily deformed from their normally straight alignment. .T he stress imparted to the tie rails D-] and D-2 by such sudden shock is transferred to the buffer portions 20a, 20b, 20c and 20d of each float unit as a compressive force which the concrete defining same can withstand.

Float unit B-3 likewise will not be moved appreciably by a current in the direction of the arrow 60, for unit B-3 is connected cantilever fashion to units B-1 and B2 by the rigid corner sections C.1 and C2. Obviously, float unit B-3 cannot be moved by a current in the direction of arrow 60 if the float units 3-] and B-2 to which it is rigidly connected remain stationary when subjected to the current.

The float units B-4 and B-5 are'connected to float unit 5-3 by the resilient tie rails D--] and D-2.

Although my invention is fully capable-of achieving the results and providing the advantages hereinbefore mentioned, it is to be understood that it is merely the presently preferred embodiment thereof, and that I do not mean to be limited to the details of construction above described other than as defined in the appended claims.

I claim:

[1. A float unit comprising a wire mesh screen arranged to form a fully enclosed rectangular structure whose width and length are substantially greater than its depth; a layer of waterproof concrete of substantially uniform thickness encasing said wire mesh screen to provide a waterproof hollow box having a bottom surface adapted to be normally submerged in a body of water and a normally upwardly facing top surface; a concrete flange protruding outwardly from the sides and ends of prising: a plurality of hollow float units having flat horizontal upper surfaces which cooperatively provide said walkway when said units are sequentially disposed and floating on said body of water, each of which units include a partially submerged concrete box having a bottom with side walls and end walls extending upwardly therefrom, a continuous horizontally disposed buffer that is connected to and extends around the upper portions of said side walls and end walls, and a rectangular concrete slab supported by said walls, with said slab defining said flat upper surface; two elongate, laterally spaced, resilient tie rails of substantial thickness that abut against said buffers and project outwardly from said boxes sufficiently to protect the same from inadvertent contact with a boat; and fastening means connecting said tie rails to said bufiers to hold said units together in said sequential relationship, with said structure when said units are so held being capable of yielding to wave action within a limited range, which range is determined by the degree of resiliency of said tie rails.

12. A wharf structure as defined in claim 11 wherein said fastening means comprise a plurality of threaded members that project outwardly from the portions of said buflers against which said tie rails abut, said tie rails having a plurality of bores formed therein through which said members project, and a plurality of nuts is provided which engage the outer extremities of said threaded members to removably aflix said rails to said units.

13. A wharf structure as defined in claim 12 wherein the surface area of said walkway is increased by the provision of a rigid metal frame that extends between two of said units, said frame having openings formed therein through which at least a portion of said threaded members on said two units project to support said frame thereon, and a concrete slab is provided of such configuration as to be supported by said frame and is of such thickness that when so supported the upper surface thereof is flush with the upper surfaces of said slabs on said two units.

References Cited in the file of this patent or the original patent UNITED STATES PATENTS 933,314 Lackey Sept. 7, 1909 1,018,488 Gorsuch Feb. 27, 1912 1,310,461 Williarhs July 22, 1919 1,457,006 Simpson May 29, 1923 1,474,336 Long Nov. 13, 1923 2,157,959 Knight May 9, 1939 2,604,866 Alcorn July 29, 1952 FOREIGN PATENTS 29,939 Great Britain 1912 489,444 Great Britain July 27, 1938

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3128737 *Sep 18, 1961Apr 14, 1964Usab Ernest MFloating wharf structure
US3157144 *Dec 27, 1962Nov 17, 1964De Jarnett A BMarine float
US3426537 *Nov 5, 1965Feb 11, 1969Hill Ingman Chase & CoFloating breakwaters
US6205945Oct 25, 1999Mar 27, 2001Eastern Floatation Systems, Inc.Floating dock including buoyant wharf modules and method of making such modules
US6230644Jan 27, 2000May 15, 2001Eastern Flotation Systems, Inc.Dock and buoyant module adapted to be connected to a pile
US6364576Jan 27, 2000Apr 2, 2002Eastern Floatation Systems, Inc.Floating dock including clips for utility lines
US6755142Dec 28, 2001Jun 29, 2004Thomas RiceModular pontoon system