US1896259A - Sheet piling - Google Patents

Description

Feb- 7, 1933- G. E. THACKRAY 1,896,259

SHEET FILING Filed May 2l, 1929 2 Sl'leets-Shec-:wl l

14 L'' P0 y ealye l.'

Feb. 7, 1933. G, E1HAKRAY 1,896,259

SHEET FILING l Filed May 21, 1929 2 Sheets-Sheet 2 66012176 E T 12am@ Patented Feb. 7, 1 933 UNITED STA rras PATENT OFFICE N.

GEORGIE. E. THACKRAY, 0F BETHLEHEM, PENNSYLVANIA SHEET PILIIN'G Application Vfiled Hay 21,

1 formed in a rolling mill.

Piling arranged in this manner is not adapted to develop in use its full flexural strength to resist the forces or loads to which it is subjected, comprising the pressures of earth, water, mud, sand, loose rock or mixtures of such or other materials.

Joining the piling by merely transversely interlocking the sections thereof at or near the center of the piling wall, causes such an arrangement to be structurally weak for the reason, that in fiexure, the longitudinal shear is the maximum along the practically loose interlock at or adjacent to the center line of the combined sections or near what is known as the neutral axis of the combined sections, and thus causes the different and opposing sections to slide past each other under the conditions of use and in such a way that the combined strength of the sections is not developed. Such a wall has a flexural strength only equal to that of a series of single sections not interlocked or joined. In order to. obviate this diiiculty I provide piling,of sections which can be produced by rolling in a rollin mill, and before driving or putting them 1nto position Isecure two ormore of said sections together along what will be conllle the intermediate portion of the piling Vwa c Such joined sections form a piling wall which when subject to flcxurc, will develop their full or combined strength and such construction may bc about twice as strong in fiexure as a combination ot the sections considered separately as they must be when merely loosely interloeked, as previously described.

In calculating the strength ot such sections `tegral and of much greater strength than 1929. serial 110,364,904.

the cross section of a member in flexure2 ordinarily calculated about the neutral axls of the section passing through its center of gravity. The flexural strength of a member 1s directl lus, which 1s a function generally expressed in inches to the third power. v

This section modulus is determined from what is known as the moment of inertia of proportional to its section modu- 55 the cross section which is the sum of the products of all the infinitesimal or elementary areas of the cross section by-multiplying these areas by the squares of their respective distances from the neutral axis.

This expression ofthe moment of inertia is generally stated in inches to the fourth power. The section modulus is derived from the moment of inertia by dividing it by the normal distance in inches from the neutral axis to that portion of the section most remote from that axis, producing then an expression of function which is, as before stated, in` inches to the cube or third power.

Each of the piling sections is substantially as large or deep as certain rolling mills can produce and these, as heretoforeassembled in a piling wall do not develop the flexural strength which could be had by their combination. Y

By securing these togetherv by welding or i otherwise, I vproduce a combined section which is larger and deeper 4than such rolling mills can produce but substantially inthe prior piling walls which is only that of the separate members.

@ne of the forms of sheet piling which I use may be of channel or trough shape with hooked or interlocking portions of various shapes at the ends of its legs adapted to be locked thereby to the adjacent section by sliding lengthwise thereof.

Such a joint however by reason of the construction, method of assembling or so-called interlocking, has substantially'no structurai, strength, to resistv the longitudinal shear,A and in order to provide this I weld or otherr by engineering mutlmmlties the section modwise join two or more sections together at ulus is used, which is a function of the area of or near their interlocking portions. The

.Y when this is ends of the joined legs may also be plain, provided with hook joints or otherwise.

The welds may be comparatively short, but preferably arranged and distributed at such distances apart as to best withstand the longitudinal shear attheir respective locations. j

In other words I may make more welds at the locations where the longitudinal shear is greatest and arrange them substantially in number or proportion to the longitudinal shear stress.

I may either make the welds of the same length and space them at different distances as indicated, or space them substantially equally and make them larger where the longitudinal stress is greater.

The longitudinal shear is the stress lengthwise of the legs or of their junction, which has a tendency to cause one section to move longitudinally of the adjacent section and, not resisted by firmly securing the sections together, the flexural strength of the combination is not developed. This invention, however, is such that, by securing the two adjacent sections together by welding or otherwise, the full strength of the combination is had and is several times greater than that of the two sections not so joined.

The method of calculating the longitudinal shear by engineering mathematics is based upon the cross section and arran ement of the piling and a knowledge of t e pressures to be resisted, the locations and characters of the supports of the piling sections including the resistance of the earth or other material at their lower ends, and the supports given by tie rods or other bracing near the top or elsewhere.

The resistance of the piling to flexure is proportional to the sectional modulus, and the longitudinal shear at various locations throughout the length of the piling when acting as a unit, is determined from a knowledge of the perpendicular shear or that at right angles to and at various points along the longitudinal axis of the piling, produced by the various ports,

The longitudinal shear at any location is the product of the aforesaid perpendicular shear by the statical moment of the area of the section included between the longitudinal surface of shear at that point and the extremity of the section on the same side of the longitudinal axis, divided by the moj ment of inertia of the section around its neutral axis through that point.

I may use other means of securing the sections together including riveting, if the sections lend themselves to such joinder, but in other cases may use welding or other means,- whereby two or morevsections may be joined driving in position, or in together before forms of loading and supwould be avoided on account of the unnecessary amount of trouble and expense.

y securing the sections together in the manner indicated I provide a wall the section modulus of which is about twice as great as l that of the sections when not so secured.

Having thus given a general description of my invention I will now, in order to make the matter more clear, refer to the annexed sheets of drawings which forms part of this specification and in which like characters refer to like parts Fig. 1 is a vertical cross sectional elevation through a bulkhead provided with my piling.

Fig. 2 is an elevation of the same looking from thel outer or water side.

j Fig. 3 is a cross section on a larger scale of onel form of my piling, showing the sections in interlocked position.

Fig. 4 is a front elevation of two sections of piling showing the approximatelocations of the welds or other fastenings for securing the two sections together.

Fig. 5 is a cross section, on a larger scale, of one form of interlocking joint, providedy with welds for securing two sections together.

Fig. 6 is a cross section on a larger scale of the interlocking ends of two sections secured together by welding to filler bars and to the sections.

Figs. 7 and S'are cross sections of other forms of my sheet piling showing two sections secured together.

Fig. 9 is a cross section of a ball and socket type of joint, some of which may be welded or secured together and others not so secured.

Fig. 10 is a cross section of a hook type of jointi some of which may be welded or secure The styles of joints shown in Figs. 7, 8, 9'

and l0 have the joint portions made as small as possible to conserve material, as little steel is needed at or near the neutral axis, but it must be secured together in order to produce proper resistance to shear.

F ig. 11 is a cross section showing the plain legs of two sections secured together by rivets.

Referring now to the characters of reference on the drawings A section of piling in general is indicated by 1, and is provided with legs 2 and llange 3, while the ends of the-legs are formed to provide the interlocking portions 4 and 5. As shown in the modified forms of Figs. 7 and 1l, the end portions 6 ofthe legs are straight and overlapping as shown, while in Fig. 8 the interlocking or hooked portions 7 are somewhat smaller and lighter for the sake of economy.

Preferably two of these piling sections are secured together by the welds 8 or otherwise as desired. 'or more than two can be secured together in cases where a greater number can be handled, driven and put into final position.

As illustrated in Fig. 6 filler pieces or bars 9 maybe introducedwith a weld 8 on either side tov facilitate the joinder.

As illustrated in Fig. 4 the welds or joinings of two sections are indicated at 8 and at other locations similarly marked by dark lines and these are shown as of approximately the same length but spaced at distances apart corresponding to the extent of the longitudinal shear of the piling in flexure, due to the pressure of the earth or other material which it holds in position.

This arrangement of joining will be different for different cases for the reason that the positions and amounts of the longitudinal shear will vary with changed proportions and dimensions of the structure, the pressure of the fill and loading, the relative locations, character and resistance of the earth or other support for the lower ends of the piling, and

the -number and positions of the anchors or other bracing for the other and upper portions of the piling.

The arrangement of welds or joinings therefore is merely suggestive and subject to such modification as may be desirable.

The Welds as shown are arranged to properly resist the longitudinal shear and where the s ear is less they are arranged at greater distances apart for the purpose of economy, but where needed they are closer together.

It should also be noted that longer welds are shown at the top and bottom of the piling to more securely join the ends together to better resist the stresses of driving.

The welds or joinings can also be arranged at substantiallyv equal distances apart, but of different lengths or strengths sufcient to properly resist the shear stresses.

The earth or other bottom of a harbor is indicated at 10, the water surface is l1, while 12 and 13 indicate timber fenders secured to the upper part of the piling Wall; 14 is a waling ystrip composed of two channels extending longitudinally of the piling wall and 15 is one of a series of tie rods which, in connection with the waling strip, holds the upper portion of the wall, the inner ends of the tie rods being securedto a braced system composed of the approximately vertical piles 16, the batter piles 17 and the horizontal timbers 18 and 19 as illustrated.

The fill of earth or other material retained by the wall is indicated as 20 and the pavement on top of the-bulkhead is indicated as 21.

The approximate location of Hm maximum bending moment and the zero or minimum shear is indicated at 22.

Referring to Fig. 9, one or more piling sec4 tions may be welded or secured together at the location indicated as 23 and referring to Fig. 10 one' or more piling sections may be welded or secured together at the loca-tion indicated as 24;

As shown in Fig. 11 the end portions 6 of the plain legs are secured together by a row of rivets indicated as 25.

The number of sections which may be secured together will depend upon the ability to handle and place them in position, that is:-to interlock one of the outer ones with an outer section of the piling.

In general however the piling wall will have its fullfiexural strength to resist shear ifonly two of the piling sections are secured together.

In order to produce apilingwallof the' greatestefficiency and maximum of strength witha minimum amount or Weight of pilm metal I prefer to make the leg portions n each pilingpsection as, thin and the flange portions as {thick as practicable dependent upon the possibilities of producing fthe same in a rolling mill and straightening or finishing them'after rolling, and also with due regard to the relative proportions of these parts to perform the duty required.

I also prefer to make the interlocking tions of my piling sections need not beas` strong as those of the prior forms` for the reason that my unitary construction, provided'by rigidly securing two or more sec-- tions together, will obviate the necessity of the heavier and stronger types of hooks or interlocking members.

Such a construction provides the greatest practicable amount of metal the farthest removed from the neutral axis of the piling wall and also uses the least amount of hook and leg metal at or near the said axis. all of which conduces to economy of material by furnishing the maximum of strength and section modulus per pound of metal.

Where great strength is necessary I prefer to make the separate sections of deep trough form as the strength in fiexure is proportional to the square of the depth. f

But where flexibility is desired, -in order that the sections will, due to pressure of use, be forced together to close the interlocking joints and thus make the walls more water tight, I the-n make them of less depth for this reason.

Each portion of piling will consistof a plurality of' sections rigidly united by their inner legs. and morelloosely connected to the adjacent portions by the interlocking of their outer legs.V

Having thus described my invention what `vtrough orm,.each having 4' Lacasse I claim and desire to secure by Letters Patent 1s:`

1. Sheet piling composed of at least two trough sections having theiredges joined toether by two part interlocking portions gormed thereon, and welds arranged'at varied intervals along the interlocking portions', in proportion t'o the stresses produced by the longitudinal shear du to the tendency to flexure thereof.

2. Sheet pilin composed of two'or more sections of troug `form, each provided with twopart interlocking hook portions, adapted to hold them togethertransversely, and welds arranged'along the interlocking portions in proportion to theflongitudinal shear due to the tendency-to `exure,=said welds being adaptedto resist relative longitudinal movement.' of `thcjoinedsections. l

n3.nA' lurality of Ysheet piling sections of a flange and t-wo legs lprojecting therefrom, said legs each havingA twofpart hook mutuallyinterlocke ,v said sectionsI being further :secured i together 'by welding 'their f-interlocking'hooks vsaid: welds bemy of trough-shaped sections, each provided withl integral two' part hook ends, adapted to join tudinalshearing vstresses due to the tendency strength in proportion 'to` the lon 'tuV 'nal shearing stresses-,due tothe ten ency to flexure.

4. Sheet piling composed of aplurality of adjacent sections toresist transverse stresses, groups comprisin tionssecured y together by welds which are of-'strf'mgths proportional to the longi-` to mme' l 1 f V1 mi f 5. heet pi ing composed o a p u ity o trough-shaped sections rovided with in- 6. Sheet piling'1 composed of'a plurality of sections of troug form, each hav a flange and two thinner legs projecting t erefrom, two art hook ends on sald legs adapted to inter ock and hold the sections transvemely, two or more ad'acent sections being secured firmly together y means whose resistance is proportional vto the longitudinal shear due toV ilexure'.

7.' Sheet piling composed of a plurality of sections of trough form, each having a vflange and two thinner legs projecting therefrom, v two part hook ends on said legs adapted to interlock and hold the sections transversely, two or more ad'aoent sections being rmly together l) secured y means whose reslstance 1s rtions at their ends two or more adjacent secf proportional to the longitudinal shear due to exure the end portions ing more stron ly secured to ether lon 'tudinally to furter resist the riving an resistance stresses.

8. Sheet piling, comprising a plurality of trough sections, each havin a two part hook on one edge and a one partlook on the other edge adapted to interlock with the adjacent sections on each side thereof, the one part hooks being further and firmly secured toget-her by means adapted to resist longitudinal shear due to lexure.

, 9. Sheet trough sections each of which has a two part hook on one edge and a plain unhooked other edge, a pair of which are interlocked by their hooked edges, the other plain edges being adjacent and secured firmly together at intervals b means proportional to the longitudinal s ear at their respective locations.

.Bethlehem Pa., April 18, 1929..

GEORGE E. THACKRAY.

'tegral two part hook e ges adapted to be piling composed of a plurality of

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