Pin joint type structural member made of double steel pipe for restraining buckling thereof

Patent metadata

Field	Value
Publication number	US-9879412-B2
Application number	US-201314418177-A
Country	US
Kind code	B2
Filing date	Jul 30, 2013
Priority date	Jul 30, 2012
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

A pin joint type structural member, made of double steel pipe consisting of a main pipe and a stiffening pipe, restrains buckling so as to be stable under axial compressive force. A clearance between the stiffening pipe 2 and the reinforcing member is determined so that a ratio (P c2 /P c2 ) of the reinforcing member contact force with the stiffening pipe inner surface at the end 4 b of a counter-clevis side, to the reinforcing member contact force with the stiffening pipe inner surface at the end 4 a of the clevis side may be 0.40 to 0.65 when the reinforcing member 4 inclines to the main pipe 1 due to the axial force acting on the main pipe 1 . In addition, a length L in that the stiffening pipe 2 overlaps with the reinforcing member 4 is at least 1.1 times as large as the reinforcing member outer diameter at the overlapping portion.

First claim

The invention claimed is:

1. A pin joint type structural member made of a double steel pipe comprising:
a main pipe for sustaining an axial force, and a reinforcing member coaxially fixed to a first end of the main pipe to prevent the first end of the main pipe from deforming when an axial compressive force acts on the structural member;
a stiffening pipe for forming a double steel pipe with the main pipe, the stiffening pipe encircling the main pipe including the reinforcing member to prevent a bend of the main pipe from increasing and being displaceable in an axial direction relative to the main pipe; and
pin support type devises located at each end of the main pipe;
wherein a clearance between the stiffening pipe and the reinforcing member has a ratio of a contact force of the reinforcing member with an inner surface of the stiffening pipe at an end at a counter-clevis side thereof, to a contact force of the reinforcing member with the inner surface of stiffening pipe at an end at the clevis side thereof is between 0.40 to 0.65 when the reinforcing member inclines to the main pipe due to the axial force acting on the main pipe, and
a length that the stiffening pipe overlaps with the reinforcing member is 1.1 to 1.6 times as large as an outer diameter of the reinforcing member at an overlapping portion thereof.

2. The pin joint type structural member of claim 1 , wherein:
the reinforcing member is a reinforcing pipe fixed to an inner surface of the stiffening pipe of the double steel pipe as a cylindrical mouth piece, the stiffening pipe being a cylindrical outer pipe for encircling the reinforcing pipe.

3. The pin joint type structural member of claim 2 , wherein the stiffening pipe has a thickness between six to sixteen millimeters and the thickness of the cylindrical mouthpiece is greater than the thickness of the stiffening pipe.

4. The pin joint type structural member of claim 1 , wherein:
the reinforcing member is a core metal and extending axially at the counter-clevis side of a cylindrical mouth piece which is fixed to the main pipe that is configured as an outer pipe of the double steel pipe encircling the stiffening pipe, and the stiffening pipe is a cylindrical inner pipe encircling the core metal.

5. The pin joint type structural member of claim 1 , wherein:
the main pipe has an outer diameter of 100 to 500 millimeters, the overlap length being 1.2 to 1.6 times as large as the outer diameter of the reinforcing member at the overlapping portion.

6. The pin joint type structural member of claim 1 , wherein:
the main pipe has an outer diameter of 100 to 500 millimeters, the clearance ratio at the overlapping portion being between 0.01 to 0.02 when the main pipe is made of ordinary steel that comprises a non-negligible amount of carbon.

7. The pin joint type structural member of claim 1 , wherein:
the main pipe has an outer diameter of 100 to 500 millimeters, the clearance ratio being between 0.005 to 0.01 when the main pipe is made of a low yield point steel that is nearly pure iron in that the low yield point steel comprises no more than a negligible amount of carbon.

8. The pin joint type structural member of claim 1 , wherein:
at least a part of the overlapping portion of the stiffening pipe that overlaps with the reinforcing member is thicker than at least a portion of the stiffening pipe that is not overlapping the reinforcing member.

9. The pin joint type structural member of claim 1 , wherein the stiffening pipe is coaxially fixed and supported at only one point located at a second end of the main pipe and does not receive axial force exerted on the main pipe such that the stiffening pipe is axially displaceable relative to the main pipe.

10. A method of proportioning a pin joint type structural member made of a double steel pipe comprising:
a main pipe for sustaining an axial force, and a reinforcing member coaxially fixed to a first end of the main pipe to prevent the first end of the main pipe from deforming when an axial compressive force acts on the structural member;
a stiffening pipe for forming a double steel pipe with the main pipe, the stiffening pipe encircling the main pipe including the reinforcing member to prevent a bend of the main pipe from increasing wherein the stiffening pipe is displaceable in an axial direction relative to the reinforcing member; and
pin support type devises located at each end of the main pipe;
wherein the method comprises:
selecting a clearance between the stiffening pipe and the reinforcing member to have a ratio of
a contact force of the reinforcing member with an inner surface of the stiffening pipe at an end at a counter-clevis side thereof, to
a contact force of the reinforcing member with the inner surface of stiffening pipe at an end at the clevis side thereof between 0.40 to 0.65 when the reinforcing member inclines to the main pipe due to the axial force acting on the main pipe, and

selecting a length that the stiffening pipe overlaps with the reinforcing member that is 1.1 to 1.6 times as large as an outer diameter of the reinforcing member at an overlapping portion thereof.

11. The method of claim 10 , wherein the reinforcing member is a reinforcing pipe fixed to an inner surface of the stiffening pipe of the double steel pipe as a cylindrical mouth piece, the stiffening pipe being a cylindrical outer pipe for encircling the reinforcing pipe.

12. The method of claim 11 , wherein the stiffening pipe has a thickness between six to sixteen millimeters and the thickness of the cylindrical mouthpiece is greater than the thickness of the stiffening pipe.

13. The method of claim 10 , wherein the reinforcing member is a core metal and extending axially at the counter-clevis side of a cylindrical mouth piece which is fixed to the main pipe that is configured as an outer pipe of the double steel pipe encircling the stiffening pipe, and the stiffening pipe is a cylindrical inner pipe encircling the core metal.

14. The method of claim 10 , wherein the main pipe has an outer diameter of 100 to 500 millimeters, the overlap length being 1.2 to 1.6 times as large as the outer diameter of the reinforcing member at the overlapping portion.

15. The method of claim 10 , wherein the main pipe has an outer diameter of 100 to 500 millimeters, the clearance ratio at the overlapping portion being between 0.01 to 0.02 when the main pipe is made of ordinary steel that comprises a non-negligible amount of carbon.

16. The method of claim 10 , wherein the main pipe has an outer diameter of 100 to 500 millimeters, the clearance ratio being between 0.005 to 0.01 when the main pipe is made of a low yield point steel that is nearly pure iron in that the low yield point steel comprises no more than a negligible amount of carbon.

17. The method of claim 10 , wherein at least a part of the overlapping portion of the stiffening pipe that overlaps with the reinforcing member is thicker than at least a portion of the stiffening pipe that is not overlapping the reinforcing member.

18. The method of claim 10 , wherein the stiffening pipe is coaxially fixed and supported at only one point located at a second end of the main pipe and does not receive axial force exerted on the main pipe.

Assignees

• Jfe Civil Eng & Construction Corp
• Jfe Steel Corp
• Jfe Civil Eng & Construction Corporation

Inventors

• Miyagawa Kazuaki
• Kitamura Wataru
• Kinoshita Tomohiro
• Ishii Takumi

Classifications

• E04C2003/0413

  being built up from several parts · CPC title

• E04C3/04 Primary

  of metal (E04C3/29 takes precedence; as reinforcing elements E04C5/06; manufacture B21) · CPC title

• E04B2001/1927

  of essentially circular cross section · CPC title

• Y10T403/27

  Cross-Sectional Technologies · mapped topic

• E04B1/1903 Primary

  Connecting nodes specially adapted therefor · CPC title