EP0072118A1

EP0072118A1 - Structural member for use in piling

Info

Publication number: EP0072118A1
Application number: EP82303830A
Authority: EP
Inventors: Robin Dawson
Original assignee: Dawson Construction Plant Ltd
Current assignee: Dawson Construction Plant Ltd
Priority date: 1981-07-31
Filing date: 1982-07-21
Publication date: 1983-02-16
Also published as: JPS5826112A; ZA824897B; AU8603582A; GB2103263A; GB2103263B; EP0072118B1; DE3271352D1

Abstract

The member (2) has at least one longitudinal flange (6a to 6d) having, on a longitudinal edge thereof, a plurality of portions (7) deformed out of the plane of the remainder of the flange. The deformed portions (7) alternate with portions (8) which are undeformed or are deformed to a different extent. In making a piling structure using the above members (2), adjacent members (2) are locked together by means of a locking bar (9).

Description

This invention relates to a structural member for use in piling. The invention has particular application to piling having greater rigidity than conventional piling, but is not limited to high rigidity piling.
In circumstances where piling is required which has greater rigidity than conventional sheet piling, it is known to use piling which, as seen in plan view, has the overall appearance, in whole or in part, of a series of hollow boxes. Figures la and Ib of the accompanying drawings show in plan view piling which is formed wholly or partly, respectively, of such boxes. Figures lc and ld show the main structural members, 1,2 of which the piling of Figures la and lb is formed, and Figure Ie shows an interlock 4 which is used to connect together those structural members.
As will be seen in Figures lc and Id the structural members 1 and 2 have lips 3 formed thereon for engagement by the interlock 4. The lips 3 are formed during the hot-rolling process in which the structural members themselves are formed. Rolling the lips 3 is very difficult, as in order to produce an even lip on each edge it is essential to prevent any "float" in the rolls. If any such float occurs the lips are uneven and connect poorly with the interlock 4.
Furthermore, a special roll configuration is required for each shape and size of structural member. This adds very considerably to the cost of the structural members and makes it uneconomic for any manufacturer to produce more than a limited range of different sizes and shapes. This in turn considerably limits the range of uses to which this form of piling can be put.
Various other forms of high rigidity piling are also known, but these all suffer from drawbacks which are at least as severe as those of the known piling described above.
According to the present invention there is provided an elongate structural member for use in the construction of piling, the said member having at least one longitudinal flange having, on a longitudinal edge thereof, a first plurality of portions deformed out of the plane of the remainder of the flange, the said deformed portions alternating with a second plurality of portions which are undeformed or are deformed to a different extent. The expression "deformed to a different extent" is intended to cover not only deformation through a different angle but also deformation in the opposite direction. The term "flange" as used herein is intended to cover any free edge portion which can be deformed as aforesaid.
In the accompanying drawings:

Figures la to Ie as described above, show piling and components therefor, known in the prior art;
Figure 2 shows a structural member according to the invention, in the form of an I-beam;
Figure 3 is a plan view, on a larger scale than Figure 2, of the edges of two structural members according to the invention connected to one another by means of a locking bar;
Figure 4 is a plan view of a length of piling constructed using the present invention;
Figure 4a shows an alternative to what is shown in Figure 4;
Figure 5 shows another form of piling constructed using the present invention;
Figure 6 shows yet another form of piling using the present invention;
Figure 7 shows a modified form of locking bar:, and a modified form for the flanges of the structural members, so as to produce a flush face on one side of the piling;
Figure 8 shows piling constructed using the arrangement of Figure 7;
Figure 9 shows yet another form of piling constructed using the present invention;
Figures 10 and 11 show two forms of sheet piling constructed according to the invention;
Figure 12 is a front elevational view of a machine for deforming edge portions of a beam to produce a structural member according to the invention; and
Figure 13 is a side elevational view of the machine of Figure 12.

Turning now to Figure 2, this shows an I-section beam 5 having a pair of flanges 6a and 6b and an opposed pair of flanges 6c and 6d. As indicated on the flanges 6c and 6d, the edges of the flanges have portions 7 which are deformed out of the plane of the remainder of the flange, alternating with portions 8 which are not deformed in this way. For convenience the deformed portions are referred to below as crimps, since the process by which they can most conveniently be formed is analogous to crimping. The crimps are indicated only along part of the length of the flanges 6c and 6d, but it is to be understood that in practice they would be present along the whole length of each of these flanges as well as along the whole length of each of flanges 6a and 6b if interlocking is required on both flanges. The angle of crimping, that is to say the angle between the planes of the portions 7 and 8, may vary according to circumstances, but can conveniently be from 15 to 45 degrees, preferably from 20 to 30 degrees. The length of the portions 7 and 8 can also vary, but each of these may conveniently be, for example, from 25 to 100 mm, preferably 75 mm.
Allowing for the lengths of the transitional portions between crimped and uncrimped portions, the pitch length of the crimping, i.e. the distance between the centres of adjacent crimped portions is preferably from 100 to 300 mm.
The crimps 7 can be formed in a cold process, for example, by use of a hydraulically operated ram acting on a beam held in an appropriate jig. Thus, the formation of the crimps is not an integral part of the process of the formation of the beam itself and the crimps can be formed on the flanges of any flanged beam which it may be desired to use in the formation of piling. Accordingly, it is a straightforward matter to produce structural members with crimps formed thereon in a very wide variety of sizes and shapes, according to particular requirements of a customer. The versatility of the present invention is illustrated later on in this description by reference to some of the types of piling which can be produced using the invention.
The effect of the formation of the above- mentioned crimps is that the edge of each flange has the appearance, as viewed end on, of a divergent wedge. This is shown in Figure 3, which also shows a locking bar 9 for locking together two flanges. For the sake of illustration the two flanges have been shown as being of different thicknesses, the left hand flange being thicker than the right hand flange, though it will be appreciated that in normal operation the two flanges joined by a given locking bar would be of the same thickness, though they need not be. The locking bar 9 has the general shape of an H, with the inner faces lOa and lla of two of the arms 10 and 11 running generally perpendicular to the cross piece 12, and the inner faces 13a and 14a of the remaining two arms 13 and 14 being angled towards the arms 10 and 11. The arms thus define a pair of slots whose width decreases outwardly. The strength of the crimps is sufficient to prevent the flanges being pulled laterally out of the locking bar except in extreme conditions of pile driving in hard ground.
Figure 4 shows a section of piling formed from I-beams 5 with crimped flanges, and locking bars 9. It will be seen that the piling consists of a succession of hollow box-shaped portions. Figure 4a is similar to Figure 4 except that it uses deeper I-beams 5', alternating with T-beams 5". The structure of Figure 4a uses less steel than that of Figure 4 whilst having comparable strength. Figure 5 shows piling similar to Figure 4, but arranged to follow a curve. This is achieved by cutting off the edges of the flanges 6a and 6b, for example by a plasma cutter, before the crimps are formed thereon. The radius of curvature of the piling thus produced naturally depends on the amount which is cut off the flanges 6a and 6b. Figure 6 shows yet another form of piling, this time a form in which there is a right angle. As can be seen, this is achieved by the use of an angle iron 15 on the edges of which are formed crimps similar to those described above with reference to Figure 2. The angle iron 15 forms the inside of the corner, and the outside of the corner is formed by a section 16 which has a central portion 17 and two outer portions 18 directed at 45° to the portion 17. The outer edges of the portions 18 are formed with crimps in the same manner as the angle iron 15.
A further variation is shown in Figure 7, which illustrates a locking bar 9' which is arranged to enable the production of piling having a substantially flush surface. As will be seen, the flanges which are engaged by the locking member 9' have crimps 7' alternating with crimps 7" which take the place of the uncrimped portions 8 in Figure 2. The crimps 7' have a larger crimping angle than the crimps 7" so as to produce the wedge effect described above. As can be seen in Figures 7 and 8, the piling thus formed has a substantially flush face 19. This is particularly desirable in certain applications. One such application, which is given here by way of example, is the use of piling to form the wall of a sewage tank within which there may be mounted a rotatable agitator which serves to stir the contents of the tank and scrape sludge from the walls of the tank. In such a case it is clearly important that the wall which is scraped should be as smooth as possible, and the wall 19 meets this requirement.
Turning now to Figure 9, this shows I-beams 5 interconnected by a complete Larssen pile 20 and two half-Larssen piles 21 formed by cutting a complete Larssen pile longitudinally down the middle. As can be seen, the piles 20 and 21 interlock with one another by means of the conventional Larssen interlock, whilst the half-Larssen piles 21 interlock with the I-beams 5 by means of crimps formed on the edges thereof and engaged by locking bars 9.
Although the above description refers mainly to the using of the invention in constructing high rigidity piling, it is also applicable to ordinary sheet piling. This is shown in Figures 10 and 11. Figure 10 shows a piling structure which comprises a plurality of structural members 22 which are in the form of right-angled angle irons, adjacent angle irons being turned through 180° with respect to one another. The free edge portions of the angle irons 22 have crimps 23 formed thereon. In the structure illustrated in Figure 10 the crimps extend outwardly on both sides of the plane of free edge portions. In practice this can be achieved by deforming adjacent sections of the edge in opposite directions, for example, +15° and -15° as shown. The free edge portions are held together by locking bars 24 which are shaped to receive the particular form of crimping used.
Figure 11 shows a piling structure which is similar to that of Figure 10 except that it uses U-shaped channel sections 25 instead of angle irons.
It will be appreciated that numerous other arrangements of piling can be constructed by forming crimps on the edges of appropriate steel sections.
Figures 12 and 13 show a machine for deforming the flanges of a beam to produce a structural member according to the invention. The machine comprises a main frame 30 which carries a pair of hydraulic rams 31. A thrust transmitting member 32 is secured to the lower end of each ram 31. Each thrust transmitting member 32 has a part-spherical lower surface 33 which bears against a corresponding upper surface 34 of a thrust receiving member 35. Each thrust transmitting member 32 is surrounded by a respective collar 40 which serves to raise and hold up the top die block 36 off the beam 4 after the crimping as the hydraulic rams 31 retract. The thrust receiving members 35 are mounted on top of an upper die holder 36 which carries a pair of dies 37. A pair of opposite lower die holders 38 carry a pair of dies 39. The dies are horizontally adjustable in their respective holders, this adjustability being necessary to allow for beams of different widths and different flange thickness.
In use the flanges 6a and 6b on which crimps are to be formed are introduced between the opposed dies 37 and 39, which are then brought into deforming engagement with the flanges 6a and 6b by moving the dies 37 through operation of the hydraulic rams 31. The dies 37 are then withdrawn from engagement and the beam 5 indexed along to bring it into position for the next crimps to be formed. By way of example Figure 12 shows part of an I-section beam 5 having flanges 6a and 6b on which crimps are to be formed.
It will be appreciated that the process can be speeded up by having a plurality of pairs of longitudinally spaced dies in a given machine so that a plurality of crimps can be formed simultaneously on each flange.

Claims

1. An elongate structural member for use in the construction of piling, the said member having at least one longitudinal flange having, on a longitudinal edge thereof, a first plurality of portions deformed out of the plane of the remainder of the flange, the said deformed portions alternating with a second plurality of portions which are undeformed or are deformed to a different extent.

2. A structural member according to claim 1, wherein the angle between the said first portions and the said second portions is from 15 to 45 degrees.

3. A structural member according to claim 2, wherein the said angle is from 20 to 30 degrees.

4. A structural member according to any preceding claim, wherein each of the said first portions is from 25 to 100 mm in length.

5. A structural member according to claim 4, wherein the said length is approximately 75 mm.

6. A structural member according to claim 4 or 5, wherein the distance between the centres of adjacent first portions is from 100 to 300 mm.

7. A piling structure which comprises a plurality of elongate structural members according to any preceding claim, the said flanges of adjacent structural members being locked together by locking members.

8. A piling structure according to claim 7, wherein each locking member is in the form of a bar having a cross-section which has the general form of an H.

9. A piling structure according to claim 8, wherein each locking member has a first pair of arms defining inner faces running generally perpendicular to the cross piece of the H and a second pair of arms defining inner faces which are angled towards the inner faces of the first pair of arms, thereby to define a pair of slots whose width decreases outwardly.

10. A piling structure according to claim 8, wherein each locking member has a first pair of arms defining inner faces angled outwardly with respect to the line of the cross piece of the H and a second pair of arms defining inner faces which are angled more steeply outwardly than the inner faces of the first pair of arms, thereby to define a pair of slots whose width decreases outwardly.

11. A piling structure according to any one of claims 7 to 10, wherein the elongate structural members are I-beams which are locked together by the locking members to form an array of box sections.

12. A piling structure according to claim 11, wherein the I-beams have arms at one end thereof which are longer than the arms at the other end thereof, whereby the piling structure is curved as viewed in plan.

13. A piling structure according to any one of claims 7 to 10, wherein the elongate structural members are alternately formed by I-beams and T-beams.

14. A piling structure according to any one of claims 7 to 10, which comprises two sections forming a right angle, the inside of the angle being formed by a right-angled structural member and the outside of the angle being formed by a structural member having two outer portions at right angles to one another and an intermediate portion at 45° to the outer portions.

15. A piling structure according to any one of claims 7 to 10, which comprises a repeating pattern of an I-beam having deformed portions on the flanges at one end of the I, a half-Larssen pile formed by cutting a complete Larssen pile longitudinally down the middle and then forming deformed portions on the cut edge, a complete Larssen pile, and a further half-Larssen pile.

16. A piling structure according to any one of claims 7 to 10, wherein the structural members are right-angled and adjacent members are turned through 180° with respect to one another.

17. A piling structure according to any one of claims 7 to 10, wherein the structural members are U-shaped channel sections and adjacent members are turned through 180° with respect to one another.