JP2004084364A - Structure of pc steel wire anchoring part of composite bridge girder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a PC steel wire anchoring part of a composite bridge girder whereby reaction forces produced by PC steel wires disposed inside a steel box girder are evenly distributed to concrete placed in the box girder and to steel members near each end of the box girder. <P>SOLUTION: The composite bridge girder is obtained by stretching the PC steel wires 2 in a space inside the steel box girder 1 in span direction, placing concrete 7, and prestressing the PC steel wires. The PC steel wire anchoring parts 3 are arranged at predetermined intervals on a plurality of reaction steel plates 4 in such a manner as to close cross sections at each end of the box girder, with the ends of the PC steel wires passed through penetration holes 40 formed in lines through the reaction steel plates. A connecting steel plate 6 extending in the span direction connects and integrates the reaction steel plates, which are then arranged in a matrix when seen from the top face of the box girder. Further, a ribbed steel plate 5 extending in the span direction is disposed at the mounting part of each reaction steel plate on the inner surface of the box girder. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention belongs to the technical field of girder bridges, and particularly relates to a structure of a PC steel wire anchoring portion in a composite bridge girder including a steel box girder, concrete, and a PC steel wire.
[0002]
[Premise of the invention]
Generally, a girder bridge is constructed by constructing a bridge girder on an abutment and a pier, forming a floor slab thereon, and laying asphalt or the like thereon to form a floor slab.
[0003]
Conventional girder bridges include concrete girder bridges formed by formwork and steel girder bridges constructed only of steel materials (steel plates), which have been widely used.
[0004]
The bridge girder of such a concrete girder bridge is formed by casting concrete and compensating for the lack of tensile strength of the concrete material by introducing a prestress by enclosing a high-strength steel wire (hereinafter abbreviated as “PC steel wire”). Although the material itself is inexpensive, the operation costs of assembling / removing the formwork and arranging the formwork were inevitable.
[0005]
On the other hand, the bridge girder of the steel girder bridge is lighter than the bridge girder of the concrete girder bridge, and has the advantage of shortening the construction period by factory production.However, it has the disadvantage that the material cost and the transportation cost of large workpieces are expensive. there were.
[0006]
The applicant of the present application has previously filed a Japanese Patent Application No. 2001-333962 for a composite bridge girder that incorporates the advantages of both the bridge girder of the steel girder bridge and the bridge girder of the concrete girder bridge. Such a composite bridge girder has a structure in which prestressed concrete is cast in the internal space of a steel box girder made of steel instead of a concrete casting formwork.
[0007]
Problems to be solved by the prior art and the invention
Although the above composite bridge girder achieved the intended purpose and achieved excellent technical effects, the load on the composite bridge girder and the pre-stress (tension ) Introduces a large reaction force (compression force) from the PC steel wire, and most of the reaction force acts on concrete whose Young's modulus is about 1/7 that of steel (steel box girder). Met. Therefore, the inventor of the present application has made further improvements and developments to further enhance the function of the fixing section and improve the durability of the composite bridge girder, and as a result, has come to a new invention.
[0008]
【Purpose】
That is, the present invention has been made based on the above-described problem, and the reaction force of the PC steel wire of the box girder made of steel material is uniformly applied to the cast concrete and the steel materials near both ends of the box girder. An object of the present invention is to provide a structure of a PC steel wire anchoring portion in a novel composite bridge girder for distribution.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the structure of the PC steel wire anchoring portion in the composite bridge girder of the present invention is configured as follows.
That is, a PC steel wire (2) supported at both ends is stretched in the span direction into the inner space of the steel box girder (1), and concrete (7) is cast. Then, prestress is applied to the PC steel wire (2). In the composite bridge girder that is introduced, one or more anchoring portions (3) of the PC steel wire (2) are provided so as to close the cross sections near both ends of the box girder (1), or a plurality thereof at predetermined intervals in the span direction. Characterized in that the reaction steel plate (4) is penetrated, and the reaction steel plate (4) is penetrated to fix both ends of the PC steel wire (2).
[0010]
One or more through-holes (40) are formed in a matrix in the reaction steel plate (4), and the PC steel wire (2) is fixed by penetrating each of the through-holes (40). And
[0011]
Further, when a plurality of reaction steel plates (4) are arranged at predetermined intervals in the span direction, the respective reaction steel plates (4) are connected and integrated by a connection steel plate (6) extending in the span direction, The connection between the connection steel plate (6) and the reaction steel plate (4) is characterized in that the box girder (1) is arranged in a lattice shape when viewed from above.
[0012]
Still further, a rib steel plate (5) extending in the span direction is provided at an attachment portion of the reaction steel plate (4) on the inner surface of the box girder (1).
[0013]
Note that the reference numerals in parentheses described in the section of the claims and means for solving the problems are provided with reference numerals for reference in order to facilitate understanding of the structure of the invention. Of course, it is not limited to the form.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, specific embodiments of the structure of the PC steel wire anchoring portion in the composite bridge girder according to the present invention will be described in detail with reference to the drawings.
[0015]
FIG. 1 is a schematic view showing an example of building a girder bridge. FIG. 2 is a perspective view showing the embodiment, and an enlarged view showing a part of the embodiment, and a part of the embodiment is cut out. FIG. 3 is a view showing the embodiment. FIG. 4A is a longitudinal sectional view (A), and FIG. 4A is an enlarged sectional view taken along the line AA of FIG. 4A. FIG. FIG. 5 is an explanatory view showing the state of action of the force in the embodiment.
[0016]
First, a girder bridge B having a bridge girder structure was constructed such that a composite bridge girder Mb was juxtaposed with an abutment A or a pier P or connected with a cross girder C as shown in FIG. Later, it is constructed by laying asphalt or the like on the upper surface.
[0017]
As shown in FIG. 2, the structure of the PC steel wire anchoring portion in the composite bridge girder of the present invention mainly includes a box girder 1, a PC steel wire (high-strength steel wire) 2, a reaction steel plate 4, a connection steel plate 6, and It is composed of concrete 7.
[0018]
The box girder 1 is formed of a steel material such as a steel plate, and has an elongated rectangular bottom plate 10 extending in a span direction (or a bridge extension direction), and a web 11 formed on the both sides thereof so as to be opposed to both sides to form an upward open cross section. It has a substantially U-shaped long box shape. From each upper end of both webs 11, a long strip-like flange 12 for supporting the floor slab D is formed continuously in the outer horizontal direction and the span direction.
[0019]
The PC steel wire 2 is a wire made of a high-strength steel wire for introducing prestress into the filled concrete. The PC steel wire 2 is inserted through a sheath (cladding tube) 20 and stretched in the span direction of the internal space of the box girder 1. It is held in the fixing section 3 near both ends. In the present embodiment, the total number is 12 in 3 rows and 4 columns. As shown in FIG. 3 (A), the arrangement state of the PC steel wires 2 is via the racks 21 arranged opposite to each other with the central portion of the box girdle sandwiched therebetween, and between the racks 21 on the bottom plate 10 side. , And it is configured to be horizontal in a state where it converges and approaches. This takes into account the distribution of the section force due to the girder load.
[0020]
Next, as shown in FIGS. 2 and 3B, the fixing unit 3, which is the main feature of the present application, is characterized by comprising a reaction steel plate 4, a connection steel plate 6, and a rib steel plate 5.
[0021]
The reaction steel plate 4 is formed of a rigid plate, and a plurality (three in this embodiment) of the box girder 1 is formed so as to close the cross sections near both ends of the box girder 1 and at a predetermined separation distance in the span direction. It is integrated with the inner wall. A plurality of through-holes 40 having an opening shape (rectangular shape in the present embodiment) through which the sheath 20 into which the PC steel wire 2 is inserted can be penetrated with a sufficient gap in each plate surface of the reaction steel plate 4. Is formed. The through holes 40 are arranged in a matrix at substantially equal intervals (in this embodiment, a total of 12 in 4 rows and 3 columns), and the corresponding through holes 40 of each reaction steel plate 4 follow the arrangement of PC steel wires. They are arranged so as to be connected in a straight line. The number of the reaction steel plates 4 may be one or more.
[0022]
A strip-shaped rib steel plate 5 extending in the span direction perpendicular to the inner surface of the web 11 of the box girder 1 and perpendicular to the reaction steel plate 4 is attached. A semicircular notch 50 is formed in the rib steel plate 5 at a portion orthogonal to the reaction steel plate 4, and the upper and lower corresponding to the position of the through hole 40 of the reaction steel plate 4 (four places in this embodiment). And the reaction steel plates 4 are connected to each other. With this arrangement, the attachment of the reaction steel plate 4 to the web 11 is reinforced.
[0023]
Further, between the reaction steel plates 4 spaced apart in the span direction, there is provided a connection steel plate 6 arranged to be orthogonal to the plate surface of the reaction steel plate 4 and connected in parallel with the web 11. The connecting steel plate 6 is attached between the rows of the through holes 40 for forming the matrix (two locations in the present embodiment), and as shown in FIG. They are arranged so as to form a lattice in a positional relationship.
[0024]
Due to the lattice-like arrangement of the reaction steel plate 4 and the connection steel plate 6, the fixing part 3 has a so-called laminated structure of rectangular boxes, and exhibits a strong shape-retaining force in the span direction and the direction perpendicular thereto. Will be done.
[0025]
A large number of PC steel wires 2 penetrating through the sheath 20 in the box girder 1 are distributed for each wire, penetrate through the through-holes 40 of each reaction steel plate 4, and both ends are fixed in the fixing portion 3. Hold.
[0026]
With this configuration, concrete 7 is poured into the internal space of box girder 1 and hardened. After the hardening, a fixing tool 30 having a truncated right circular cone shape and having a fixed bottom plate 30a is attached to the tip of the PC steel wire 2, and is pulled and fixed with a predetermined tension. As shown in FIG. 5, the reaction force state of the fixing unit 3 is such that the reaction force of the residual tension of the PC steel wire 2 is pre-stressed (compressed) on the concrete 7 which has been poured and hardened via the bottom plate 30 a of the fixing tool 30. Force).
[0027]
As a result, the reaction force of the expanded bottom plate 30 a is dispersed and distributed in the concrete 7 in contact with the bottom plate 30 a and acts on the plate surface of the reaction steel plate 4. The acting force transmitted from the reaction steel plate 4 by this operation is further increased by the concrete 7 filled in the rectangular box-shaped laminated space formed by the lattice-like arrangement of the reaction steel plate 4 and the connecting steel plate 6. , And are transmitted in a three-dimensionally distributed manner and act more evenly. As a result, it is possible to prevent the concrete 7 and the box girder 1 from being broken due to stress concentration and to realize more durable shape retaining force and retaining force of the fixing portion 3.
[0028]
【effect】
Since the invention of the present application is configured as described above, more durable shape retention and holding power can be realized in the anchoring portion of the PC steel wire in the composite bridge girder, and the girder bridge using the composite bridge girder can be realized. It is possible to improve the overall strength and extend the life.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an example of building a girder bridge.
FIG. 2 is a perspective view showing the present embodiment and an enlarged view showing a part of the perspective view extracted and partially cut away.
FIG. 3 is a view showing the embodiment, and is a longitudinal sectional view (A) cut along the span direction and an enlarged sectional view (A) taken along the line AA in FIG. 3 (A).
FIG. 4 is a plan view showing the embodiment with a part cut away.
FIG. 5 is an explanatory diagram showing an action state of a force in the embodiment.
[Explanation of symbols]
1 Box girder 10 Bottom plate 11 Web 12 Flange 2 PC steel wire 20 Sheath (Clad tube)
21 Rack 3 Anchor 30 Anchor 30a Expanded bottom plate 4 Reaction steel plate 40 Through hole 5 Rib steel plate 50 Notch 6 Connecting steel plate 7 Concrete A Abutment B Girder bridge C Cross girder D Floor slab P Pier Mb Composite bridge girder

Claims (5)

After a PC steel wire (2) supported at both ends is stretched in the span direction into the internal space of the steel box girder (1) and concrete (7) is cast, prestress is introduced into the PC steel wire (2). Composite bridge girder
One or a plurality of reaction steel plates (4) are arranged at predetermined intervals in the span direction so as to close the cross sections near both ends of the box girder (1),
A PC steel wire anchoring portion in a composite bridge girder, wherein both ends of the PC steel wire (2) are anchored by penetrating the reaction steel plate (4). One or more through holes (40) are formed in a matrix in the reaction steel plate (4), and the PC steel wire (2) is fixed by penetrating each through hole (40). The structure of the PC steel wire anchoring part in the composite bridge girder according to claim 1. When a plurality of reaction steel plates (4) are arranged at predetermined intervals in the span direction,
The structure of the PC steel wire anchoring part in the composite bridge girder according to claim 1 or 2, wherein the reaction steel plates (4) are connected and integrated by a connection steel plate (6) extending in the span direction. . 4. The PC steel wire in a composite bridge girder according to claim 3, wherein the connecting steel plate (6) and the reaction steel plate (4) are arranged so as to form a lattice shape in a top view of the box girder. Structure of fixing unit. 5. The composite according to claim 1, wherein a rib steel plate (5) extending in the span direction is disposed at an attachment portion of the reaction steel plate (4) on the inner surface of the box girder (1). Structure of PC steel wire anchoring part in bridge girder.

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