Frost damage proofed pile

• US 4,818,148 A
• Filed: 03/07/1988
• Issued: 04/04/1989
• Est. Priority Date: 05/14/1985
• Status: Expired due to Term

• Current Assignee: Nippon Kokan K.K
• Original Assignee: Nippon Kokan K.K
• Inventors: Kidera, Kenji, Omori, Katsumi, Ohkuma, Toshiyuki, Hirose, Tetsuzo, Takeda, Takashi, Nakagawa, Shigeru
• Primary Examiner(s): Taylor, Dennis L.
• Application Number:
  US07/164,967
• Time in Patent Office: 393 Days
• Field of Search: 405/231, 405/232, 405/234, 405/216, 52/728, 52/515
• US Class Current: 405/234
• CPC Class Codes: E02D 5/60 Piles with protecting cases

Abstract

A covering is applied onto the outer surface of a pile including a steel pipe or the like to surround a predetermined length thereof so as to reduce a frost heaving force or negative friction acting on the pile in a frigid area. The covering is closely adhered by an adhesion layer the like to the pile over a given length thereof. This given length is between 0.5 and 5 m. The covering member includes a smooth-surfaced plastic covering or elastic covering. A rugged surface covering may be provided below the smooth surfaced covering.

Claims

1. A frost damage proofed pile comprising:

a pile member,

a smooth-surfaced plastic covering member having a low coefficient of friction and being formed on an outer surface of said pile member, integral with said pile member, to surround a predetermined length of said pile member for reducing a frost heaving force or negative friction acting on said pile member when said covering member is in contact with frozen soil in a frigid area, and

adhesion means for closely adhering said covering member to said pile outer surface within said predetermined length to a degree greater than a shear stress generated on said outer surface by said frozen soil.

2. A frost damage proofed pile according to claim 1, wherein said predetermined length is between 0.5 and 5 m.

3. A frost damage proofed pile according to claim 1, wherein said covering member has a relatively low coefficient of friction containing one percent by weight or more of polytrifluoroethylene or polytetrafluoroethylene.

4. A frost damage proofed pile according to claim 1, wherein said covering member has a glass transition temperature of 0°

C. or over.

5. A frost damage proofed pile according to claim 1, wherein said covering member comprises an elastic material.

6. A frost damage proofed pile according to claim 5, wherein the molecular chain of said elastic material has a net structure.

7. A frost damage proofed pile according to claim 5, wherein said elastic material essentially consists of a high molecular elastic material whose main chain comprises hard and soft segments.

8. A frost damage proofed pile according to claim 1, further comprising an adhered covering member having a rugged surface and arranged below said smooth-surfaced covering member.

9. A frost damage proofed pile according to claim 8, said rugged-surface covering member is made integral with said smooth-surfaced covering member.

10. A frost damage proofed pile according to claim 8, wherein a separate pile member having said rugged-surface covering member thereon is connected to said pile below said smooth-surfaced covering.

11. A frost damage proofed pile according to claim 8, wherein said rugged-surface covering member is formed on the surface of a portion of said smooth-surfaced covering.