JPH04250246A - Structural member consisting of pipe body and tendon - Google Patents

Abstract

PURPOSE:To enable a pipe body not to be bent even if a tensile force is introduced into a tendon, and form the pipe body and the tendon integrally to be deflectively deformed. CONSTITUTION:In a structural member consisting of a pipe body 12 and a tendon 14 inserted into the pipe body over the full length, on the tendon 14, a plurality of spacers 15 are fixed at intervals L in the longitudinal direction. By the spacers 15, a central axial line in the longitudinal direction of the pipe body and a central axial line in the longitudinal direction of the tendon 14 are retained to coincide with each other roughly. The tendon 14 together with the spacers 15 fixed on it is moved in the pipe body and in the longitudinal direction. Even if a tensile force is introduced into the tendon, applied deflection is not generated, and the tensile force can be uniformed. Even if camber is generated on the pipe body 12, prestress can be uniformly introduced along the axial line of the pipe body 12.

Description

[Detailed description of the invention]

0001

[Industrial Field of Application] This invention relates to a structural member consisting of a tubular body and a tendon inserted into the tubular body. It relates to a structural member that is held so that the central axes of the structural members substantially coincide with each other.

0002

[Prior Art] The upper chord member and the lower chord member are constructed from a conventional metal tube body, the upper chord member and the lower chord member are connected by a diagonal member, and P
In a truss in which C steel rods, etc. have been inserted, (1) insert a PC steel rod into the chord material of the pipe body, and attach the end of the PC steel rod to the string using an anchor plate, etc. attached to the end of the chord material; (2) A PC steel rod is inserted into the chord of the pipe body and an anchor plate is attached to the end of the chord. The end of the PC steel bar was fixed to the end of the chord material, tensile force was introduced into the PC steel bar, and concrete was filled between the inner circumferential surface of the chord material and the outer circumferential surface of the PC steel bar. There are things etc.

0003

[Problem to be solved by the invention] (1) and (2) above
) The chord material of the tube body bends due to the weight of the chord tube body and the PC steel rod before tensile force is applied, and due to this initial bending, misalignment of the hole center of the anchor plate, etc. The central axis in the longitudinal direction of the tube body and the central axis in the longitudinal direction of the PC steel rod do not match. Therefore, when a tensile force is introduced into the PC steel bar, eccentric bending and additional deflection occur in the chord pipe body. As in (2) above, when filling concrete inside the chord tube, the PC steel rod is held eccentrically within the chord tube. However, when a short-term load acts on the structural members in the above state,
When compressive force is applied to the string material, the yield strength decreases significantly. In other words, when bending occurs in a chord whose pipe is not filled with concrete, the bending stiffness of the chord is P.
Until the C steel rod comes into contact with the inner wall of the chord tube, the tube only has bending rigidity, and the chord and PC steel bars of the tube do not behave as one against deflection, ensuring sufficient rigidity of the PC steel rod. I can't perform well. In the case of a so-called filled-type structural member in which concrete is filled inside the chord pipe, the concrete filled inside the pipe and the PC steel bar should not be combined in order to introduce tensile force into the PC steel bar. When this filled-type structural member is made into a long piece for use in a large-span structure, it becomes heavy and difficult to transport and cure during construction, making it uneconomical. The problem to be solved by this invention is to provide a structural member that does not have the above-mentioned drawbacks. In other words, it is an object of the present invention to provide a structural member that does not have the above-mentioned drawbacks. Another object of the present invention is to provide a structural member in which the tube body does not bend and the tube body and tendon can be bent and deformed as one.

0004

[Means for Solving the Problems] The present invention employs the following configuration as a means for solving the above problems. The structure of the present invention is a structural member consisting of a metal tube and a tendon inserted over its entire length into the tube.
A large number of spacers are fixed to the tendon at intervals in the longitudinal direction thereof, and the spacers hold the longitudinal center axis of the tube body and the longitudinal center axis of the tendon so that they substantially coincide with each other, and the tendon is The structural member is characterized in that it is movable in the longitudinal direction of the tube together with the fixed spacer. In a preferred embodiment of the structural member of the present invention, at least one of the upper chord member and the lower chord member is constituted by a metal pipe body, and the entire length of the structural member is in a truss in which the upper chord member and the lower chord member are connected by a diagonal member. It is applied to the upper or lower chord of the tube into which the tendon is inserted.

[0005] In this preferred embodiment, a steel rod, steel cable, or the like made of high-strength steel is used as the tendon (that is, a tensile member for reinforcing the tube body). For example, PC steel rods, PC steel wires, PC steel cables, etc. used as tendons for prestressed concrete are used. As the tube, a closed metal tube with a cross section, such as a steel tube with a circular cross section or a steel tube with a square cross section, is used. As a spacer, the outer diameter is slightly smaller than the inner diameter of the tube body, and the through hole of the tendon formed in the center is the same as or slightly larger than the diameter of the tendon, and is formed integrally or as two or more divided pieces. Use the one formed by combining. Those spacers are
For example, it is fixed to the tendon using a suitable fixing means such as screws or adhesive. The gap between the outer circumferential surface of the spacer and the inner circumferential surface of the tubular body is created when the longitudinal central axis of the tubular body and the longitudinal central axis of the tendon are approximately aligned. Make it large enough to move without much resistance. The portion of the outer circumferential surface of the spacer that is in contact with the inner circumferential surface of the tube is shaped to reduce sliding friction.

[0006]

[Embodiment] The first embodiment is an example in which the structural member of the present invention is applied to the lower chord member 12 of a truss 10. As shown in FIG. 1, the truss 10 includes an upper chord member 11 made of a steel tube, a lower chord member 12 in which a PC steel rod 14 is inserted over the entire length of the steel tube, and the ends of these members are connected to the upper chord. It is composed of a large number of diagonal members 13 made of steel plates or pipes welded to a member 11 and a lower chord member 12. As shown in FIGS. 2 and 3, before the PC steel rod 14 is inserted into the tubular body of the lower chord 12, the outer diameter of the PC steel rod 14 is slightly smaller than the inner diameter of the lower chord 12. A large number of annular spacers 15 whose inner diameter is slightly larger than the outer diameter of the PC steel rod 14 are fitted into the hole 15a through which the PC steel rod 14 is inserted.
are fixed at a predetermined interval L in the longitudinal direction. In this case, as shown in FIGS. 4 and 5, a plurality of screw holes 15b are bored in the spacer 15, and setscrews 15c are screwed into the screw holes to fix the spacer 15 to the PC steel rod 14, or as shown in FIG. As shown in FIG. 2, adhesive 16 is injected into the gap between the outer peripheral surface of the PC steel rod 14 and the inner peripheral surface of the through hole 15a of the spacer 15 to fix the spacer 15 to the PC steel rod 14.

[0007] Also, the outer peripheral surface of the spacer 15 and the lower chord member 12
In order to reduce the sliding friction between the tube and the inner peripheral surface of the tube,
As shown in FIG. 6, the outer circumferential surface of the spacer 15 facing the inner circumferential surface of the tube body of the lower chord member 12 is made into a circular arc surface 15d to reduce the contact area, or the inner circumferential surface of the tube body of the lower chord member 12 is As shown in FIG. 7, recesses 15e are formed at equal intervals on the outer circumferential surface of the spacer 15 facing the surface of the spacer 15 to reduce the contact area. The difference between the outer diameter of the spacer 15 and the inner diameter of the lower chord member 12 of the tube is P
With the central axis of the C steel rod 14 and the central axis of the tube of the lower chord 12 substantially aligned, the PC steel rod 14 can be moved in the longitudinal direction within the tube of the lower chord 12 without significant resistance. Make it bigger. The lower chord member 12 is connected by a large number of spacers 15.
In other words, the gap between the inner circumferential surface of the tube of the lower chord member 12 and the outer circumferential surface of the PC steel rod 14 is maintained substantially constant, in other words, the gap between the longitudinal center axis of the tube of the lower chord member 12 and the longitudinal direction of the PC steel rod 14 is maintained substantially constant. Anchor plate 1 in which the end of the PC steel rod 14 is attached to the end of the tubular body of the lower chord member 12 in a state in which the central axis of the direction substantially coincides with that of the anchor plate 1
7 through the through hole so that the end of the PC steel bar can be fixed to the end of the lower chord member 12 with an appropriate fixing means such as a nut,
Introduce initial tensile force to the PC steel bar using a jack etc., and
The state in which a tensile force is introduced into the C steel bar is fixed by the fixing means. As shown in FIG. 1, support parts 18 and 1 are provided with both ends of the upper chord member 11 on opposing surfaces of supports A1 and B1.
The truss 10 is supported by support bodies 18a and 19a of 9 in the form of a simple beam. The PC steel rod 14 to which the spacer 15 is fixed is inserted into the tubular body of the lower chord member 12, and the outer circumferential surface of the spacer 15 contacts the inner circumferential surface of the tubular body of the lower chord member 12. Since the bar 14 is movable in its longitudinal direction, when a vertical load is applied to the truss 10, there is a gap between the outer circumferential surface of the PC steel bar 14 and the inner circumferential surface of the tubular body of the lower chord member 12. Even if there is a gap, the PC steel rod 14 and the lower chord member 12 of the tubular body will bend and flex together, and the rigidity of the PC steel rod 14 can be fully demonstrated.

The second embodiment is an example in which the structural member of the present invention is applied to the upper chord member 21 of a truss 20. As shown in FIG. 8, the truss 20 includes an upper chord member 21 in which a PC steel cable 24 is inserted over its entire length into a steel pipe body, a lower chord member 22 made of a steel pipe body, and an upper chord member at the end thereof. 21 and a diagonal member 23 made of a large number of steel plates or tubes welded to the lower chord member 22. As shown in FIGS. 9 and 10, before inserting the PC steel cable 24 into the tubular body of the upper chord member 22, a spacer 25 consisting of two divided pieces 25A and 25B is attached to the PC steel cable 24 in the longitudinal direction of the PC steel cable 24. Fix a large number at intervals. When the spacer 25 is connected to the two divided pieces 25A and 25B, the spacer 25
5 is slightly smaller than the inner diameter of the upper chord member 21, and the inner diameter of the through hole 25a of the PC steel cable 24 at the center of the spacer 25 is configured to approximately match the outer diameter of the PC steel cable 24. The two divided pieces 25A and 25B each pass a bolt 25c through a bolt through hole 25b drilled at both ends thereof, and a nut 25d is screwed into the threaded portion of the bolt 25.
They are connected to each other and fixed to the PC steel cables 24. If the sliding friction of the spacer 25 is also desired to be reduced, as shown in FIGS. 6 and 8, the outer periphery of the spacer 25 is made into an arcuate surface, or a plurality of recesses are formed at intervals on the outer periphery of the spacer 25.

The difference between the outer diameter of the spacer 25 and the inner diameter of the tube of the upper chord member 21 is the same as in the first embodiment. The spacer 25 keeps the gap between the inner circumferential surface of the upper chord member 21 and the outer circumferential surface of the PC steel cable 24 substantially constant, and the longitudinal center axis of the tube body of the upper chord member 21 and the longitudinal direction of the PC steel cable 24 Initial tension is introduced into the PC steel cable 24 in a state where the central axis line substantially coincides with the PC steel cable 24. As shown in FIG.
Support part 26 with the end of 1 provided on the opposing surfaces of buildings A2 and B2
, 27 in the form of a simple beam to hold the truss 20. At the same time, the end of the steel cable 24 passed through the tubular body of the upper chord member 21 is attached to the holding part 28 of buildings A2 and B2.
, 29 so that the end of the steel cable 24 can be adjusted with a suitable fixing means 30 such as a nut.
Fixed at 9. Without introducing an initial compressive force into the upper chord member 21 itself, an initial tensile force is introduced into the steel cable 24 using a jack or the like, and the steel cable 24 is fixed using the fixing means 30 so that the initial tensile force is maintained. Holding parts 28, 2 of buildings A2, B2
Fixed at 9. The steel cable 24 to which the spacer 25 is fixed is inserted into the tubular body of the upper chord member 21, and the outer circumferential surface of the spacer 25 contacts the inner circumferential surface of the tubular body, and the steel cable 24 is inserted into the tubular body of the upper chord member 21.
4 can move in the longitudinal direction, so when a vertical load is applied to the truss 20, even if there is a gap between the outer circumferential surface of the steel cable 24 and the inner circumferential surface of the pipe body of the upper chord member 21. ,
Both the steel cable 24 and the upper chord member 21 of the tube body are deformed in a direction perpendicular to their longitudinal direction, and the compressive force acting on the upper chord member 21 of the tube body can be relaxed.

0010

Effects of the Invention In the structural member of the present invention, a large number of spacers are fixed to the tendon at intervals in the longitudinal direction, and the spacers allow the longitudinal center axis of the tube body to be aligned with the longitudinal center axis of the tendon. Since the tendons are held substantially in agreement, no additional deflection occurs even if a tensile force is introduced to the tendon. In addition, since the tendon can be moved in the longitudinal direction within the tube together with the spacer fixed to it, a constant tensile force can be introduced to the tendon.
Furthermore, even if the tubular body is bulged, prestress can be uniformly introduced along the axis of the tubular body. When a PC steel bar is used as a tendon, the tube body and the PC steel bar deform as one, so that the bending rigidity of the PC steel bar can be fully exhibited. If the structural member of this invention is used as the upper chord of a truss, and tensile force is introduced only to the tendons without introducing an initial compressive force to the pipe of the upper chord, when a vertical load is applied to the truss, The compressive force acting on the upper chord member can be alleviated. In addition, if this structural member is used as the bottom chord of a truss, and tensile force is introduced into the tendon, and initial compressive force is introduced into the bottom chord tube, the stress generated in the bottom chord tube can be alleviated. . When the structural member of the present invention is used as the lower chord member or upper chord member of a truss, these chord members can be made elongated and lighter, so that a truss with a large span can be provided at a low cost.

[Brief explanation of the drawing]

[Fig. 1] Front view of the truss of the first embodiment

[Fig. 2] A side view of the lower chord of the truss shown in Fig. 1, taken along line a-a.

[Fig. 3] A front view of the lower chord material etc. in Fig. 2 taken along line b-b.

[Fig. 4] The spacer fixed with bolts is shown in Fig. 5 c-c.
Side view cut along the line

[Figure 5] Front view of the one in Figure 4 taken along the dd line

[
Figure 6: Front view showing a partial cross-section of a spacer etc. fixed with adhesive

[Figure 7] Side view of a spacer with multiple recesses formed on the outer periphery

[Fig. 8] Front view of the truss of the second embodiment

[Fig. 9] The PC steel cable with the spacer fixed is shown in Fig. 10.
Side view cut along the line

[Figure 10] Plan view of the one in Figure 9

[Explanation of symbols]

10 Truss 11 Top chord material 12 Lower chord material 13 Diagonal material 14 PC steel bar 15 Spacer 15a Through hole 16 Adhesive 20 Truss 21 Top chord material 22 Lower chord material 23 Diagonal material 24 PC steel cable 25 Spacer 25a Through hole

Claims (6)

[Claims] Claims: 1. A structural member comprising a metal tube and a tendon inserted over its entire length into the tube, in which a number of spacers are fixed to the tendon at intervals in the longitudinal direction, and the spacer The longitudinal center axis of the tube body and the longitudinal center axis of the tendon are held so as to substantially coincide with each other, and the tendon can be moved in the longitudinal direction within the tube body together with the spacer fixed thereto. Characteristic structural members. 2. The structural member according to claim 1, wherein the structural member is an upper chord member or a lower chord member of a truss. 3. The structural member according to claim 1 or 2, wherein the tendons are composed of a prestressed steel rod or a prestressed steel cable. 4. The structural member according to claim 1, wherein the tube body is made of a steel tube with a circular or square cross section. 5. The outer diameter of the tube is slightly smaller than the inner diameter of the tube, the through hole of the tendon at the center thereof is slightly larger than the diameter of the tendon, and the tube is fixed to the tendon with screws or adhesive. spacer. [Claim 6] It is constructed by joining at least two divided pieces, and when the divided pieces are joined, the outer diameter is slightly smaller than the inner diameter of the tube body, and the inner diameter of the through hole of the tendon at the center thereof is the outer diameter of the tendon. 1. A spacer having a diameter that is approximately the same as or slightly larger than the diameter of the spacer, and each divided piece is connected to each other by screws, adhesive, etc., and is fixed to a tendon.