STEEL PIPE PILES AND PIPE PILE STRUCTURES

Abstract

A pipe pile, for use in a foundation or a retaining wall, comprises a substantially cylindrical, and preferably steel, pipe body extending longitudinally between two opposite ends, the pipe body being formed of a plurality of pipe sections, interlocked or welded together end-to-end and arranged on a common central longitudinal axis between the two ends. All of the pipe sections have substantially the same outside diameter; however, two or more pipe sections have differing inside diameters, and thus a differing wall thickness, between the two ends of the pipe pile.

Claims

1. A retaining wall adapted to be driven into the earth for use as a structural element, comprising: a first pipe pile; a connecting element welded to a side of the first pipe pile; and a second pipe pile connected to the first pipe pile by way of the connecting element, the first pipe pile comprising: a cylindrical pipe body extending longitudinally between two opposite ends, the cylindrical pipe body being formed of a plurality of pipe sections arranged along a common central longitudinal axis between the two opposite ends, wherein all of the pipe sections have substantially the same constant outside diameter along the central longitudinal axis of the pipe body between the two opposite ends, the outside diameter measured at an exterior surface of the pipe body, the exterior surface of the pipe body being directly exposed to at least one of water, air, or earth; and a first pipe section of the plurality of pipe sections having a first constant inside diameter along the central longitudinal axis of the pipe body measured at an innermost portion of the first pipe section; a second pipe section of the plurality of pipe sections, having a second constant inside diameter along the central longitudinal axis of the second pipe section measured at an innermost portion of the second pipe section, the second constant inside diameter being different from the first constant inside diameter; the innermost portions of the first and second pipe sections being directly exposed to at least one of water, air, or earth.

2. The retaining wall of claim 1, wherein an end of the first pipe section abuts an end of the second pipe section; wherein the first pipe pile is made of a steel which corrodes when exposed to water and air.

3. The retaining wall of claim 1, wherein the second pipe pile is connected to the first pipe pile such that the central longitudinal axis of the first pipe pile and the central longitudinal axis of the second pipe pile are arranged substantially in parallel.

4. The retaining wall of claim 3, wherein the first pipe pile and the second pipe pile are disposed in a body of water, and wherein the first pipe pile and the second pipe pile extend downward through the water into the earth below.

5. The retaining wall of claim 4, wherein the retaining wall supports an ocean platform.

6. The retaining wall of claim 4, wherein the body of water is an ocean and the water is sea water.

7. The retaining wall of claim 4, wherein the first pipe section of the first pipe pile is located in a splash zone of the retaining wall; wherein the second pipe section of the first pipe pile is location in a permanent immersion zone; and wherein a material thickness of the first pipe section is greater than a material thickness of the second pipe section.

8. The retaining wall of claim 4, wherein the first pipe section of the first pipe pile is location in a low water zone of the retaining wall; wherein the second pipe section of the first pipe pile is located in a permanent immersion zone of the retaining wall; wherein a material thickness of the first pipe section is greater than a material thickness of the second pipe section.

9. The retaining wall of claim 4, wherein the first pipe section of the first pipe pile is located in an intertidal zone of the retaining wall; wherein the second pipe section of the first pipe pile is located in a permanent immersion zone; wherein a material thickness of the first pipe section is greater than a material thickness of the second pipe section.

10. The retaining wall of claim 4, wherein the first pipe section of the first pipe pile is located in a permanent immersion zone of the retaining wall; wherein the second pipe section of the first pipe pile is located in a buried zone of the retaining wall; wherein a material thickness of the first pipe section is greater than a material thickness of the second pipe section.

11. A retaining wall that separates earth from sea, comprising: a first pipe pile; a connecting element; and a second pipe pile connecting the first pipe pile by way of the connecting element, the first pipe pile comprising: a substantially cylindrical pipe body extending longitudinally between two opposite ends, the cylindrical pipe body being formed of a plurality of pipe sections arranged along a common central longitudinal axis between the two opposite ends; wherein the cylindrical pipe body is hollow, the cylindrical pipe body comprising an inner surface and an exterior surface; wherein the plurality of pipe sections have the same constant outside diameter along the central longitudinal axis of the pipe body between the two opposite ends, the outside diameter measures at the exterior surface of the pipe body; wherein a first pipe section of the first pipe pile has a first material thickness defined by a difference between the outside diameter and a first inside diameter, wherein the first inside diameter is measured at the inner surface of the first pipe section; wherein a second pipe section of the first pipe pile has a second material thickness defined by a difference between the outside diameter and a second inside diameter, wherein the second inside diameter is measured at the inner surface of the second pipe section.

12. The retaining wall of claim 11, wherein the first material thickness and the second material thickness varies in accordance with an expected rate of corrosion, wherein the first material thickness of the first pipe section is greater than the second material thickness of the second pipe section.

13. The retaining wall of claim 11, wherein the first material thickness and the second material thickness varies in accordance with an expected bending stress, wherein the first material thickness of the first pipe section is greater than the second material thickness of the second pipe section.

14. The retaining wall of claim 11, disposed along a coast of a body of water, with earth retained on one side of the wall against air and water on an opposite side.

15. The retaining wall of claim 14, wherein the body of water is an ocean and the water is sea water.

16. The retaining wall of claim 15, wherein the first pipe section of the first pipe pile is located in a splash zone of the retaining wall; wherein the second pipe section of the first pipe pile is located in a permanent immersion zone of the retaining wall; wherein the first material thickness is greater than the second material thickness.

17. The retaining wall of claim 15, wherein the first pipe section of the first pipe pile is located in a low water zone of the retaining wall; wherein the second pipe section of the first pipe pile is located in a permanent immersion zone of the retaining wall; wherein the first material thickness is greater than the second material thickness.

18. The retaining wall of claim 15, wherein the first pipe section of the first pipe pile is located in an intertidal zone of the retaining wall; wherein the second pipe section of the first pipe pile is located in a permanent immersion zone of the wall; wherein the first material thickness is greater than the second material thickness.

19. The retaining wall of claim 15, wherein the first pipe section of the first pipe pile is located in a permanent immersion zone of the retaining wall, wherein the second pipe section of the first pipe pile is located in a buried zone of the retaining wall; wherein the first material thickness of the first pipe section is greater than the second material thickness.

20. A retaining wall comprising: a plurality of pipe piles, each of the plurality of pipe piles comprising connecting elements welded to an exterior of the pipe pile, wherein each pipe pile of the plurality of pipe piles comprises: a substantially cylindrical pipe body extending longitudinally between two opposite ends, the pipe body being formed of a plurality of pipe sections with differing pipe thicknesses, the pipe sections welded together end to end, arranged along a common central longitudinal axis between the two opposite ends, an outside diameter of the pipe body being substantially constant along the central longitudinal axis of the pipe body, the outside diameter being substantially constant between the two opposite ends, the outside diameter measured at an exterior surface of the pipe body; wherein the retaining wall is configured to be driven into the earth with respective longitudinal axes of the plurality of pipe piles arranged substantially in parallel and along a common, substantially horizontal line, the plurality of pipe piles connected together by the connecting elements interlocked between adjacent pipe piles of the plurality of pipe piles, wherein the exterior surface of the pipe body is exposed to at least one of water, air, or earth and an innermost portion of the pipe body is exposed to at least one of water, air, or earth.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 is a representational diagram of a pipe pile retaining wall with accompanying graphs showing the approximate rate of corrosion and a typical bending moment distribution along the length of the pipe piles.

[0026] FIG. 2 is an illustration of a row of pipe piles of the type to which the present invention relates.

[0027] FIG. 3 is a plan view showing two pipe piles linked together by male and female connecting elements, welded to the exterior pipe pile surfaces.

[0028] FIG. 4 is a detailed plan view of the male and female connecting elements shown in FIG. 3.

[0029] FIG. 5 is a detailed plan view showing another embodiment of male and female connecting elements that may be used to connect pipe piles.

[0030] FIG. 6 is a plan view of two pipe piles linked by two Z-shaped sheet piles.

[0031] FIG. 7 is a plan view of two pipe piles linked by a U-shaped sheet pile.

[0032] FIG. 8 is a cross-sectional view of a retaining wall (not to scale) of the type to which the present invention relates.

[0033] FIG. 9 is a cross-sectional view of a pier (not to scale) of the type to which the present invention relates.

[0034] FIG. 10a is a cross-sectional view (not to scale) showing a single pipe pile comprised of three sections, welded together end-to-end along a common longitudinal axis, with each section having the same outer diameter but a differing internal diameter.

[0035] FIG. 10b is a lateral cross-sectional view (not to scale) of each pipe pile section of FIG. 10a.

[0036] FIG. 11 is a cross-sectional, detailed view (not to scale) of the abutting ends of two pipe piles of differing wall thickness, welded together along their seam;

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] The preferred embodiments of the present invention will now be described with reference to FIGS. 1-11 of the drawings. Identical elements in the various figures are designated with the same reference numerals.

[0038] FIG. 1 shows a retaining wall 10 formed of steel pile piles which retains and separates the earth 12, on one side, from the sea 14 on the other. As explained in the Background of the Invention section above, the pipe piles in this wall are subjected to continuous stress and to the continuous effects of corrosion due to the action of air and water.

[0039] The pipe piles of the retaining wall are driven into the earth below the sea bed with their longitudinal axes arranged substantially in parallel and along a common, substantially horizontal, line. FIG. 2 shows such a series of pipe piles 32, arranged along a horizontal line 33 and connected together by intermediate connecting elements 34, which are affixed to the external, curved surfaces of the piles by welding.

[0040] FIG. 3 illustrates how two such pipe piles 32 are joined by such connecting elements 34, the details of which are presented in FIG. 4. Prior to ramming, a “male” connecting element 36 is welded to one side of each pipe 32 and a “female” connecting element 38 is welded to the opposite side, over the entire length (or nearly the entire length) of the pipe. The pipes are then driven into the earth, one at a time, with the male connecting element 36, welded to one pipe, inserted in and interlocked with the female connecting element 38 that is welded to the next, adjacent pipe.

[0041] FIG. 5 shows another type of connecting element 40 that may be used between adjacent pipes 32 to connect the pipes closely together. This connecting element, which is similar to the connecting elements described in detail in the U.S. Pat. No. 7,168,214, comprises a short male element 42 with an interlocking head strip 44 and a female element formed by a claw.

[0042] FIGS. 6 and 7 each show two pipe piles 32, also arranged side by side and longitudinally in parallel, which are separated by sheet piles instead of connectors only. In FIG. 6 the adjacent pipe piles are connected together by two Z-shaped sheet piles 50 and 52; in FIG. 7 the pipe piles are connected by an intervening U-shaped sheet pile 54.

[0043] FIG. 8 is a cross-sectional side view of a pipe pile 32, one of many in a seaside retaining wall 60. The wall supports the earth 62, on one side, from eroding and falling into to the sea 64, on the other. The pipes of the wall, represented by pipe 32, pass through the sandy earth 66 beneath the sea floor and are preferably of sufficient length to reach the bedrock 68 below. Although the average level of the sea varies with the tides within a certain range, indicated by the double arrow 70, and waves splash against the wall within a certain average range, indicated by the double arrow 72, the wall of pipes is constructed considerably higher so as to protect against storms and other contingencies, To achieve the total length of pipe required, the pipes are transported to the construction site in convenient (e.g. 20 foot) lengths and welded end-to-end when they are installed. Depending on the total length of the pipe piles required, and upon the preferences of the contractor, the pipe sections can either be rammed, section by section, and welded together during the ramming process, or they can be welded first, end to end, and rammed as a single lengthy unit.

[0044] The useful life of a pipe pile and sheet pile wall depends entirely upon the rate of corrosion of the material (e.g. steel) caused by the elements, particularly the exposure to water and/or air. The water—particularly salt water, brackish water or polluted water—causes a steel pile wall to corrode at an accelerated rate, particularly in the regions 70 and 72. Outside of these regions, where the sheet pile wall is either continuously immersed in the water or in the ground, or where the pipe pile wall meets primarily air, except on rainy days, the corrosion is somewhat, or even substantially, less,

[0045] To increase the life of pipe pile walls, it is known to cover at least a portion of the pipe surfaces with a coat of paint or epoxy, for example in the region 74 which is most vulnerable to corrosion. The application of such a protective coating allows the construction engineer to specify thinner-walled pipes for the sheet pile wall than would otherwise be required, resulting in a considerable cost saving in the total amount of material (e.g., steel).

[0046] FIG. 9 is a diagram, similar to FIG. 8, which shows the use of steel pipe piles 32 to support an ocean pier 76. Like FIG. 8, this diagram shows an intertidal zone 70 and a splash zone 72. As compared to the pipes of the retaining wall of FIG. 8, the steel pipe piles 32 are subjected to a substantially less bending moment. However, they are subjected to corrosion, especially in the splash zone, intertidal zone, low water zone and permanent immersion zone, as explained above in connection with FIG. 1.

[0047] According to the present invention, as illustrated in FIGS. 10a and 10b, the pipe piles 32 of FIGS. 8 and 9 are of differing wall thickness at different places along their length, so as to take into consideration the differing rates of corrosion during their useful life. FIG. 10a shows a length of pipe 32 in three sections: a lower section 86 (intended to remain continuously beneath the water level); a middle section 88 (intended for location in the tide zone and splash zone of the wall) and an upper section 90 (intended to remain continuously in the open air). As indicated in FIG. 10b the pipe in section 88, which corrodes at a much faster rate has a considerably thicker wall than the pipe in sections 86 and 90. The pipe section 86, which must withstand a greater bending stress, has a somewhat greater wall thickness than the pipe section 90.

[0048] However, all three sections of pipe have the same external (outside) diameter.

[0049] The seams 92 and 94 between the sections of pipe are welded together with the sections abutting end-to-end.

[0050] FIG. 11 shows in detail the welded seam between the pipe sections 86 and 88. As may be seen, the ends of the pipe sections are chamfered at an angel of about 30 to 35°, leaving a “land” of at least 1/16 inches to make abutting contact with the adjacent section. The weld material 96 fills the space afforded by the chamfer.

[0051] When designing port or a pier, the civil engineer should specify the chamfer for each pipe section, for example 35° with a 1/16 inch land. The engineer should also specify the following parameters:

[0052] 1. The number, the lengths and the wall thicknesses of all the pipes; more specifically, all the pipe sections that make up the pipes to be used in a project.

[0053] 2. The outer diameter of all the pipes. Different pipes in the project may have different outer diameters, but all the pipe sections making up an individual pipe must have the same outer diameter.

[0054] 3. The inner and outer tolerance of the outer diameter; for example, an OD of 36 inches from minus 0 to plus ¼ inch.

[0055] 4. The tolerance of the out of roundness of the pipes; for example, equal to or less than 1%.

[0056] 5. The type and grade of material; for example, the steel base grade ASTM A572, Grade 50.

[0057] 6. The type of pipe; for example, spiral wound and welded for thinner pipe having a wall thickness of less than 1 inch, or rolled and longitudinally welded for thicker pipe.

[0058] The invention has the advantage of supplanting the need for coating the pipes in regions susceptible to increased corrosion (the tidal zone and splash zone, for example), while at the same time allowing for reduced pipe thickness in the regions which are less susceptible to corrosion (the region beneath the earth for example).

[0059] There has thus been shown and described an improved steel pipe pile, and pipe pile structures incorporating a plurality of this type of pipe pile, which fulfill all the objects and advantages sought therefor. Many changes, modifications, variations and other uses and applications of the subject invention will, however, become apparent to those skilled in the art after considering this specification and accompanying drawings which disclose the preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is to be limited only by the claims which follow.