JP2003184029A - Girder bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a girder bridge which has an extended span and a reduced height. <P>SOLUTION: According to the girder bridge 1, a bridge girder 3 is formed by binding together main girders 5 which span an interval between bridge abutments 2, in a lateral direction. Each main girder 5 is obtained by connecting together concrete girder members 9 each with a built-in steel frame 13 in a lengthwise direction, applying prestress to the concrete girder members by inner cables 12, and applying prestress to the steel frames 13 by outer cables 4. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a girder bridge.

[0002]

2. Description of the Related Art As shown in FIG.
A bridge girder 25 formed by bundling the main girders 24 in the width direction is installed between abutments 26, and a central portion thereof is supported by a pier 27. The main girder 24 is formed by connecting girder materials 28 made of concrete in the length direction, and is prestressed by the inner cable 29.

[0003]

However, the span of the above-mentioned girder bridge is limited to 30 to 40 m because the bending moment due to the weight of the girder increases. In addition, since the limit of the girder height span ratio (height of girder: width) is 1 / 17.5, it was difficult to construct in a place where the girder height was restricted.

The present invention has been made in view of the above problems, and an object thereof is to provide a girder bridge capable of increasing the span of the bridge girder while reducing the girder height.

[0005]

Means for Solving the Problems The gist bridge of the present invention for solving the above problems is summarized as follows: main girders installed between abutments are bundled in the width direction to form a bridge girder, and the main girder is It is characterized in that a concrete girder material having a built-in steel frame is continuously joined in the longitudinal direction to be prestressed by the inner cable, and the steel frame is prestressed by the outer cable. Further, the girder material has an I-shaped cross section, and includes that the joint plate having the same width as the flange is formed at the end portion by the flange portions protruding on both sides of the web. Further, the outer cable includes that it is wired through the flange portion of the girder material. In addition, the main girders shall be joined by the horizontal cables that are wired to the joint plate, and the cast-in-place concrete shall be placed between the main girders that have the horizontal cables.

[0006] The live load is mainly canceled by the suspension load being applied to the bridge girder by the prestress applied to the steel frame of the main girder. Further, since the weight of the bridge girder is reduced, the span can be increased (50 to 70 m) and the conventional pier can be omitted. Further, the limit of the girder height span ratio (height of girder: width) can be set to 1/30, and the girder height can be reduced. A horizontal cable is laid on the joint plate formed at the flange with the same width as the flange,
Since the cast-in-place concrete is placed between the main girders on which the lateral cables are laid, the lateral girders prestressed by the joining plate can be formed on the bridge girders.
Further, since the flange portion through which the outer cable penetrates serves as a bundle, the main girder can be a string beam. In addition, the steel frame of the main girder, which has become a string beam, does not buckle because it is integrated with concrete.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a girder bridge of the present invention will be described below with reference to the drawings. As shown in FIG. 1, the girder bridge 1 is constructed by applying a hoisting load to the bridge girder 3 between the abutments 2 by an outer cable 4 such as a PC steel wire or a PC twisted wire.

As shown in FIGS. 2 to 4, the bridge girder 3 is constructed by binding six main girders 5 in the width direction with a horizontal cable 6 such as PC steel wire or PC twisted wire. The main girder 5 is formed by joining a girder material 9 formed in an I-shaped cross section by a steel frame 13 and concrete 18 with a joining plate 10, and prestressed by an inner cable 12. The joint plate 10 is formed to have the same width as the flange 20 by the flange portions 11 protruding on both sides of the web of the girder material 9 in order to prevent the joint portion from being damaged by repeated loads. In-situ concrete 8 is placed between the adjoining joint plates 7 to form lateral girders 21, and the lateral girders 21 are prestressed by the lateral cables 6.

On the other hand, the steel frame 13 embedded in the flange 20 of the girder member 10 has two L-shaped members joined by a connecting plate 16.
The L-shaped steel plate 17 is formed of a steel plate 17, and is integrated with the concrete 18 by a stud bolt 19 projecting from the lower surface of the L-shaped steel plate 17. A fixing plate 14 to which the end of the outer cable 4 is fixed is provided at one end of the steel frame 13, and a joining plate 15 is provided at the other end of the steel frame 13, which are superposed and joined by a shear key 22. Therefore, the steel frames 13 of the respective girder members are integrally joined to form one steel frame. The steel frame 13 can be embedded not only in the upper flange but also in the entire girder material 9, that is, the upper and lower flanges 20.

The outer cable 4 is wired through the flanges 11 on both sides of the main girder 5, and both ends are tensioned and fixed to the fixing plate 14 of the steel frame 13.
A suspension load is applied to the entire bridge girder 1 as a stringed beam using the collar portion 11 as a bundle.

[0011]

[Effect of the Invention] Since the suspension load is applied to the bridge girder by the prestress applied to the steel frame of the main girder, the live load can be canceled mainly.

Since the weight of the bridge girder is reduced, the span can be increased (50 to 70 m) and the conventional pier can be omitted.

The limit of the girder height span ratio (height of girder: width) can be set to 1/30, and the girder height can be reduced.

A cross girder prestressed with a joining plate can be formed in the bridge girder.

Since the flange portion through which the outer cable penetrates serves as a bundle, the main girder can be a string beam.

Since the steel frame of the main girder, which is a tension string beam, is integrated with concrete, it does not buckle.

[Brief description of drawings]

FIG. 1 (1) is a front view of a girder bridge, and FIG. 1 (2) is a side view with the same portion omitted.

2 (1) is a conceptual view of a girder bridge, (2) is a sectional view of the girder bridge, and (3) is a sectional view of essential parts.

3 (1) is a cross-sectional view of an end portion of the main girder, (2) is a cross-sectional view taken along the line AA of (1), (3) is a side view of the main girder at the end portion, FIG.
(4) is another side view of the main girder at the end.

4 (1) is a sectional view of a central portion of a main girder, (2) is a sectional view taken along line BB of (1), and (3) is a sectional view taken along line CC of (1).

FIG. 5 is a front view of a conventional girder bridge.

[Explanation of symbols]

1,23 girder bridge 2,26 abutment 3,25 bridge girder 4 outer cable 5, 24 main girder 6 horizontal cables Between 7 main digits 8 Cast-in-place concrete 9,28 girder material 10 Bonding plate 11 Tsuba Cable inside 12, 29 13 steel frame 14 Fixing plate 15 Bonding plate 16 Connection plate 17 Steel plate 18 concrete 19 Stud bolt 20 flange 21 Collar 22 shear key 27 peers

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Keizo Tanabe             1-36-7 Wakaba-cho, Chofu-shi, Tokyo Kurosawa construction             Within the corporation (72) Inventor Fumio Yamada             4-47 Hinodemachi, Kasuga City, Fukuoka Prefecture F term (reference) 2D059 AA07 BB39

Claims (4)

[Claims] 1. A main girder installed between abutments is bundled in the width direction to form a bridge girder, and the main girder is made of concrete girder material containing steel frames continuously joined in the length direction. A girder bridge characterized in that the inner cable is prestressed, and the steel frame is prestressed by the outer cable. 2. The girder bridge according to claim 1, wherein the girder material has an I-shaped cross section, and a joint plate having the same width as that of the flange is formed at the end portion by the flange portions protruding on both sides of the web. .. 3. The girder bridge according to claim 1, wherein the outer cable is wired so as to pass through the collar portion of the girder material. 4. The main girder is joined by a horizontal cable wired on a joining plate, and cast-in-place concrete is placed between the main girders on which the horizontal cable is wired.
The girder bridge according to any one of to 3.