Claims
- 1. A string of joints of metal thick-walled pipe extending through and being restrained by earth material, the string being subject to change in axial load subsequent to installation, the string comprising:at least one such joint having a side wall which has been formed along at least part of its length into sinusoidal corrugations; the corrugated joint having a diameter to wall thickness ratio (D/t) less than 100; the corrugations having a corrugation radius of curvature to thickness ratio (R/t) less than 10; and the corrugations varying in wall thickness along their length, as a result of having been formed.
- 2. The string as set forth in claim 1, wherein:the corrugated joint side wall has been hydroformed to create the corrugations.
- 3. The string as set forth in claim 1 wherein:the corrugated joint side wall has been hydroformed while maintaining the length of the joint substantially constant.
- 4. The string as set forth in claim 1 wherein:the corrugations have a D/t less than 50 and an R/t less than 5.
- 5. The string as set forth in claim 2 wherein:the corrugations have a D/t less than 50 and an R/t less than 5.
- 6. The string as set forth in claim 3 wherein:the corrugations have a D/t less than 50 and an R/t less than 5.
- 7. The string as set forth in claim 1 wherein:the corrugations have webs and peaks and the webs have a web angle of at least 20° with respect to the axis of the corrugated joint.
- 8. The string as set forth in claim 3 wherein:the corrugations have webs and peaks and the webs have a web angle of at least 20° with respect to the axis of the corrugated joint.
- 9. The string as set forth in claim 4 wherein:the corrugations have webs and peaks and the webs have a web angle of at least 20° with respect to the axis of the corrugated joint.
- 10. The string as set forth in claim 5 wherein:the corrugations have webs and peaks and the webs have a web angle of at least 20° with respect to the axis of the corrugated joint.
- 11. The string as set forth in claim 6 wherein:the corrugations have webs and peaks and the webs have a web angle of at least 20° with respect to the axis of the corrugated joint.
- 12. A joint of steel pipe having a longitudinal axis, comprising:a tubular body having a side wall, the body side wall having been formed along at least part of its length into sinusoidal corrugations; the side wall having a diameter to wall thickness ratio (D/t) less than 100; the corrugations having a corrugation radius of curvature to thickness ratio (R/t) less than 10; and the corrugations varying in wall thickness along their length, as a result of having been formed.
- 13. The joint as set forth in claim 12 wherein:the corrugated side wall has been hydroformed, while maintaining the length of the joint substantially constant, to create the corrugations.
- 14. The joint as set forth in claim 12 wherein:the corrugations have a D/t less than 50 and an R/t less than 5.
- 15. The joint as set forth in claim 13 wherein:the corrugations have a D/t less than 50 and an R/t less than 5.
- 16. The joint as set forth in claim 13 wherein the corrugations have webs and peaks and the webs have a web angle of at least 20° with respect to the axis of the joint.
- 17. The joint as set forth in claim 15 wherein the corrugations have webs and peaks and the webs have a web angle of at least 20° with respect to the axis of the joint.
Parent Case Info
This application claims benefit of Prov. No. 60/132,632 filed May 5, 1999.
US Referenced Citations (9)
Provisional Applications (1)
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Number |
Date |
Country |
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60/132632 |
May 1999 |
US |