JP2004044143A - Fixing structure between steel pipe and concrete - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fixing structure between a steel pipe having sufficient proof strength against tension and compression and a concrete though it is a simple structure without requiring a work such as a welding and a bolting. <P>SOLUTION: A fixed section of the steel pipe 1 to concrete C is constituted of a steel pipe with ribs 1 providing a plurality of flange-shaped ribs 2 on the outer circumference and, at the same time, an outer pipe 3 formed of a steel pipe having a diameter larger than the outer circumference is coaxially placed in a double pipe-shape on the outer circumference section of the rib attached pipe steel at a predetermined space. The steel pipe 1 is constrained to the concrete C of the outer pipe 3 successively through the concrete C and the steel pipe between the steel pipe and the outer pipe 3. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fixing structure between a steel pipe and concrete.
[0002]
[Prior art]
In order to fix steel members such as steel pipes in concrete, an anchoring structure provided with members serving as anchors has been adopted.Conventionally, the end face of the steel pipe is covered with an end plate, and an anchor reinforcing bar or an anchor steel rod is attached to this. There are two main types: a mounting structure (type 1) and a gusset structure or a structure using steel members such as cast iron (type 2).
[0003]
[Problems to be solved by the invention]
However, regardless of the structure, work such as welding and bolting is required, and the construction takes time.
[0004]
In particular, in the type 1 structure, since it is a structure that is weak against tension, and it is necessary to apply a compressive force in advance using a PC steel material or the like, the case where a compressive stress is applied to a member and the case where a tensile stress is applied are different. There was a disadvantage that the behavior was different.
[0005]
On the other hand, in the type 2 structure, since all of the force transmission is performed between steel members, the number of components constituting the anchoring structure is large, and the structure of the joint to concrete is large. Had become high.
[0006]
The present invention has been made to solve the above problems, and has an object of providing a sufficient strength against tension and compression even with a simple structure without work such as welding or bolting. An object of the present invention is to provide a fixing structure between steel pipe and concrete.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a fixing structure between a steel pipe and concrete, wherein the steel pipe is concentrically provided with a predetermined gap between the steel pipe and an outer periphery of a fixing portion of the steel pipe with the concrete. The steel pipe has a plurality of ribs at an outer peripheral portion of a fixing portion with the concrete, and the outer pipe has a plurality of ribs at an inner peripheral portion thereof. And concrete is cast between the steel pipe and the outer pipe and on the outer periphery of the outer pipe. Therefore, according to the present invention, it is possible to omit the work by welding or bolting as in the related art, and to provide a fixing structure having a sufficient resistance to tension and compression in the axial direction of the steel pipe.
[0008]
In the present invention, the anchoring end of the steel pipe is opened, and the concrete can be filled inside the steel pipe as the concrete is poured, thereby further improving the anchoring effect. it can.
[0009]
Further, since the outer pipe is provided with a plurality of ribs on its outer periphery, good adhesion performance to concrete can be ensured, and particularly, the inner rib is formed by a strut effect acting between the ribs of the steel pipe. The effect of fixing the inner steel pipe to concrete is greatly improved.
[0010]
Further, since the outer pipe has a plurality of through holes penetrating inside and outside thereof, it is possible to obtain a bearing effect and a composite effect of concrete and a filling property of concrete.
[0011]
In the present invention, by arranging reinforcing steel around the outer tube, the outer tube can be prevented from coming off, and the fixing effect can be further improved.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0013]
1 and 2 show a structure for fixing a steel pipe to concrete according to the present invention.
In the figure, a plurality of flange-shaped ribs 2 are provided at a predetermined pitch on the outer periphery of a fixing portion of a hollow steel pipe 1 for concrete C. The ribs 2 are for ensuring good adhesion performance to the concrete C cast on the outer periphery of the steel pipe 1, and the formation pitch thereof, the amount of projection to the steel pipe 1, the width, and the like are set as appropriate. Further, the rib 2 may have a structure in which the ribs 2 are integrated at a predetermined pitch into the ordinary steel pipe 1 at least for the fixing length to the concrete C.
[0014]
Further, the anchoring end of the steel pipe 1 is open, and when the concrete C is poured, a part of the concrete C is wrapped around the opening 1a to be filled, and is integrated with the surrounding concrete C as the filling concrete C1. Thus, the fixing effect is improved, and the depth of the opening is appropriately set according to the fixing length to the concrete C.
[0015]
An outer pipe 3 made of a steel pipe having a larger diameter and a shorter length is disposed on the outer periphery of the steel pipe 1. As shown in the cross section of FIG. 2, the steel pipe 1 is provided by simple temporary fixing means 4 such as a pin or a binding wire. Are arranged concentrically (may be slightly displaced) with a predetermined gap between them. The temporary fixing means 4 does not firmly connect the steel pipe 1 and the outer pipe 3 but merely acts as a stopper for the concrete C when the concrete C is poured.
[0016]
The diameter of the outer pipe 3 is, for example, about 600 cm when the diameter of the steel pipe 1 is, for example, about 450 cm, and the length thereof is set to about 1 to 1.5 times the diameter. The concrete C filled in the gap 3 is restrained.
[0017]
A plurality of flange-shaped ribs 5 and 6 are formed on the inside and outside of the outer tube 3 at a predetermined pitch, a projecting amount, and a width, and a plurality of through holes 7 penetrating inside and outside are formed in a staggered manner. ing. The ribs 5 and 6 ensure good adhesion performance to the concrete C in the same manner as described above. In particular, the inner rib 5 has a strut effect acting between the steel pipe 1 and the rib 2 so that the concrete C can adhere to the concrete pipe 1. This is provided to greatly improve the fixing effect on the toner. The through holes 7 are provided for the purpose of supporting and synthesizing the concrete C and for filling the concrete C.
[0018]
Further, reinforcing steel bars 8 formed, for example, around the outer tube 3 and formed in a reinforcing bar cage around the outer tube 3 are arranged, and are arranged concentrically around the outer tube 3 with a predetermined gap therebetween (the outer tube). It may be fixed to the tube 3). The reinforcing steel bars 8 are provided for restraining the concrete C cast in the gap with the outer pipe 3 and for preventing the outer pipe 3 from coming off, and for improving the fixing effect of the steel pipe 1. Therefore, in the above fixing structure, the steel pipe 1 can be fixed in the concrete without welding or bolting.
[0019]
Then, in a state where the concrete C is cast, the concrete C wraps around the outer periphery of the steel pipe 1, the inside and outside of the outer pipe 3, and the inside and outside of the reinforcing bar 8, as shown particularly in a cross section in FIG. 2. Then, since the inside of the concrete C is integrated through the through hole 7 of the outer pipe 3, the outer pipe 3 is firmly embedded in the concrete C. Further, a part of the concrete C flows into the opening 1a of the steel pipe 1 and becomes a filling concrete C1 integrated with the surrounding concrete C.
[0020]
After the concrete C is solidified, as shown in the enlarged view of FIG. 3, in a state where a pulling force is applied in the axial direction of the steel pipe 1 indicated by an arrow, the concrete C located between the steel pipe 1 and the outer pipe 3 becomes an oblique arrow. As shown in the drawing, the steel pipe 1 receives the compressive stress and acts on the outer pipe 3 through the concrete C and the outer pipe 3 between the steel pipe 1 and the outer pipe 3 in this order by the strut effect acting between the ribs 2 and 5. Restrained by concrete C. Similarly, when the opposite compressive stress is applied to the steel pipe 1, the steel pipe 1 receives the compressive stress in the opposite direction, and is constrained by the concrete C.
[0021]
By the above operation, at the fixing position of the steel pipe 1, a sufficient strength can be secured in both the pulling and pressing directions. Also, between the outer tube 3 and the reinforcing bar 8, by substantially the same operation, the strength against both pressing and pulling can be obtained.
[0022]
FIG. 4 shows a case where the present invention is applied to molding of a PC bridge unit constituting a steel truss web PC bridge. In the figure, a PC bridge unit 10 includes a concrete PC bridge ceiling 11 in which upper and lower lanes 11a are provided symmetrically in a front view, and a concrete PC bridge narrower than the ceiling 11 below the ceiling 11. It is composed of a main body portion 12 and four steel pipes 1 each having a cross section that constitute a steel truss web disposed therebetween, and are integrally formed in a form support device 13.
[0023]
The upper end of each steel pipe 1 is located inside the formwork forming the ceiling portion 11 of the PC bridge, and is inclined inward toward the lower side at the median strip position and the road side zone position in the upper and lower lane portions 11a of the ceiling portion 11. The lower end is arranged together with the outer tube 3, and the lower end is also arranged in a mold forming the main body 12 together with the outer tube 3, and is supported in an angular state by a steel tube supporting means (not shown) provided in the form supporting device 13. . The angle of inward inclination and the supporting height of each steel pipe 1 are measured by measuring means or the like, and can be changed by adjusting the supporting means.
[0024]
Then, after the reinforcement including the necessary reinforcing steel bars 8 in each formwork is performed, concrete C is poured into each formwork, so that the upper and lower end portions of each steel pipe 1 become the ceiling portion 11 and the main body portion. 12, and the PC bridge unit 10 is completed by hardening the concrete C and integrating each part. The PC truss web PC bridge is completed by sequentially connecting the PC bridge units 10 molded as described above in a direction orthogonal to the plane of the drawing at the construction site.
[0025]
In addition, bridges are erected by methods such as cantilever erection and all erection erection, according to the type of construction.However, when concrete is poured in, the formwork and shoring supporting it are sunk by the weight of concrete. I do. Therefore, this subsidence is to be performed in advance (overtaking is performed), and fine adjustment of this overtaking can be easily performed during the molding.
[0026]
The fixing structure of the present invention can be applied not only to the unit of the steel truss web PC bridge but also to the unit of the PC box girder bridge with struts. In any case, since a large number of steel pipes 1 are arranged at predetermined intervals along the longitudinal direction of the PC bridge, in manufacturing these units, welding such as conventional fixing portions or bolting is used. The fixing structure can be omitted, and a simple and reliable fixing structure can be obtained, which is suitable for shortening the construction period.
[0027]
Furthermore, the above anchoring structure is generally applicable to the structure that anchors the lower part of steel pipe to concrete, such as the foundation anchoring structure of a bridge pier using steel pipe columns, the foundation anchoring structure of lighting columns, and the anchoring structure of steel pipe piles. Of course.
[0028]
【The invention's effect】
As is clear from the above description, in the anchoring structure between steel pipe and concrete according to the present invention, sufficient strength against tension and compression can be obtained even with a simple structure. Further, since the structure is simple, the construction is also simplified, and the construction period can be shortened.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional exploded perspective view illustrating a member configuration of a fixing structure according to the present invention.
FIG. 2 is a front sectional view and a plan sectional view showing an identification attachment structure.
FIG. 3 is an enlarged partial cross-sectional view showing a portion A in FIG. 2;
FIG. 4 is a front view showing a case where the identification attachment structure is applied to molding of a PC bridge unit constituting a steel truss web PC bridge.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hollow steel pipe 1a Opening 2 Rib 3 Outer pipe 5 Inner rib 6 Outer rib 7 Through hole 8 Reinforcing steel bar C Concrete C1 Filling concrete 10 PC bridge unit

Claims (5)

An anchoring structure between steel pipe and concrete,
On the outer periphery of the fixing portion of the steel pipe with the concrete, concentrically disposed with a predetermined gap between the steel pipe and the outer circumference of the steel pipe, a shorter outer pipe having a larger diameter than the steel pipe,
The steel pipe has a plurality of ribs on an outer peripheral portion in a fixing portion with the concrete, and the outer pipe has a plurality of ribs on an inner peripheral portion,
A fixing structure between a steel pipe and a concrete, wherein concrete is cast between the steel pipe and the outer pipe and on an outer periphery of the outer pipe. 2. The anchoring structure for steel pipe and concrete according to claim 1, wherein an anchoring end of the steel pipe is opened, and concrete is also filled inside the steel pipe as the concrete is poured. The fixing structure of a steel pipe and concrete according to claim 1 or 2, wherein the outer pipe has a plurality of ribs provided on an outer periphery thereof. The fixing structure of steel pipe and concrete according to any one of claims 1 to 3, wherein the outer pipe is formed with a plurality of through holes penetrating inside and outside thereof. The anchoring structure between a steel pipe and concrete according to any one of claims 1 to 4, wherein a reinforcing reinforcing bar is arranged around the outer pipe.

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