JP3703760B2 - Girder bridge - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a girder bridge.
[0002]
[Prior art]
As shown in FIG. 5, in the conventional girder bridge 23, a bridge girder 25 formed by bundling 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 concrete girder members 28 in the length direction, and is prestressed by an inner cable 29.
[0003]
[Problems to be solved by the invention]
However, the span of the girder bridge as described above is limited to 30 to 40 m because the bending moment due to the weight of the bridge girder increases. In addition, since the limit of the girder height span ratio (girder height: lateral width) is 1 / 17.5, it is difficult to construct in places where the girder height is limited.
[0004]
The present invention has been made in view of the above problems, and an object of the present invention 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 of the bridge girder of the present invention for solving the above problems is that a plurality of main girders installed between abutments are bundled in the width direction to form a bridge girder , and the main girder is formed of steel and concrete. and both end portions joined plates on both sides prestressing is applied by the cable inner stringer which projects are embedded continuously joined by concrete in the length direction of the continuous each steel of the main beam is The outer cables wired along the both side surfaces of the main girder are fixed to both ends of the steel frame that is continuously joined to form a single piece. It is characterized by prestressing the steel frame by a cable. In addition, the girders are I-shaped in cross section, including that the joining plate is formed to have the same width as the flange at the flanges protruding on both sides of the web . Further, the plurality of main girders are bundled in the width direction by a horizontal cable wired on the joining plate, and the in-place concrete is placed between the main girders wired with the horizontal cable .
[0006]
The live load is mainly canceled by applying the lifting load 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 peer can be omitted. Further, the limit of the girder height span ratio (girder height: lateral width) can be reduced to 1/30, and the girder height can be reduced. A horizontal cable is routed on the joint plate formed at the flange with the same width as the flange, and on-site cast concrete is placed between the main girders where the horizontal cable is routed. The given cross beam can be formed into a bridge beam. Moreover, since the collar part which the outer cable penetrated becomes a bundle material, the main girder can be a stringed beam. The steel beam of the main girder, which is a stringed beam, is integrated with the concrete so that it does not buckle.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a girder bridge according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, this girder bridge 1 is configured by applying a lifting load to a bridge girder 3 between abutments 2 by an external cable 4 such as a PC steel wire or a PC twisted wire.
[0008]
As shown in FIGS. 2 to 4, the bridge girder 3 is configured by bundling six main girders 5 in the width direction with horizontal cables 6 such as PC steel wires and PC stranded wires. The main girder 5 is formed by joining a girder material 9 having an I-shaped cross section with a steel frame 13 and concrete 18 with a joining plate 10, and prestress is applied by an inner cable 12. The joint plate 10 is formed to have the same width as the flange 20 by the flanges 11 projecting on both sides of the web of the beam 9 in order to prevent damage to the joint due to repeated loads. In addition, a cast-in-place concrete 8 is placed between adjacent joining plates 7 to form a cross beam 21, and pre-stress is applied to the cross beam 21 by a horizontal cable 6.
[0009]
On the other hand, the steel frame 13 embedded in the flange 20 of the girder 9 is formed of two L-shaped steel plates 17 joined by a connecting plate 16 and is concreted by stud bolts 19 protruding from the lower surface of the L-shaped steel plate 17. 18 is integrated. A fixing plate 14 to which the end portion of the outer cable 4 is fixed is provided at one end portion of the steel frame 13, and a joining plate 15 is provided at the other end portion, which are overlapped and joined by a shear key 22. Therefore, the steel frames 13 of each girder are joined together to form a single steel frame. The steel frame 13 can be embedded not only at the upper flange but also over the entire beam 9, that is, the upper and lower flanges 20.
[0010]
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, so that the main girder 5 bundles the flanges 11. Suspension load is applied to the entire bridge girder 1 as a stringed string beam.
[0011]
【The invention's effect】
The live load can be canceled mainly by applying the lifting load to the bridge girder by the prestress applied to the steel frame of the main girder.
[0012]
Since the weight of the bridge girder is reduced, the span can be increased (50 to 70 m) and the conventional peer can be omitted.
[0013]
The limit of the digit height span ratio (digit height: width) can be reduced to 1/30, and the digit height can be reduced.
[0014]
A cross girder prestressed by a joining plate can be formed as a bridge girder.
[0015]
Since the collar portion through which the outer cable penetrates becomes a bundle material, the main girder can be a stringed beam.
[0016]
The steel beam of the main girder, which is a stringed beam, is united with concrete and will not buckle.
[Brief description of the drawings]
FIG. 1 (1) is a front view of a girder bridge, and (2) is a side view with the same part omitted.
2A is a conceptual diagram of a girder bridge, FIG. 2B is a cross-sectional view of a girder bridge, and FIG.
3 is a cross-sectional view of the main girder end, (2) is a cross-sectional view taken along line AA of (1), (3) is a side view of the main girder at the end, and (4) is an end view. It is the other side view of the main girder of a section.
4A is a cross-sectional view of the central part of the main beam, FIG. 4B is a cross-sectional view taken along the line BB of FIG. 1, and FIG. 4C is a cross-sectional view taken along the line CC of FIG.
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 cable 7 Between main girder 8 On-site concrete 9, 28 Girder 10 Joint plate 11 Saddle 12, 29 Inside cable 13 Steel frame 14 Fixing Plate 15 Joining Plate 16 Connecting Plate 17 Steel Plate 18 Concrete 19 Stud Bolt 20 Flange 21 Hook 22 Shear Key 27 Pier

Claims (3)

The installed plurality of main beam over between abutment is bundled in the width direction girders are formed, the main spar, stringer bonding plate on both sides of the steel is formed with the concrete and both ends projecting is continuously bonded to the longitudinal prestress is applied by a cable inner embedded in concrete, the steel of the main beam is continuously joined, as one is the continuously joined digit on both ends of it were steel outer cable is wired along the both sides of the main girder through each junction plate are fixed, characterized in that the prestress imparted to the steel by the cable sheath bridge. 2. The girder bridge according to claim 1, wherein the girder has an I-shaped cross section, and the joining plate is formed with flanges protruding on both sides of the web so as to have the same width as the flange. The plurality of main girder is joined in the width direction in the transverse cables wired to the junction board, to claim 1 or 2, characterized in that poured concrete is pouring in between the main girder of the transverse cable is wired The girder bridge described.

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