JP2000129625A - Deck truss bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deck truss bridge capable of having simplified constitution with few constituent members and being constituted at a low cost. SOLUTION: A bridge 1 is so constituted that a floor slab 10 is borne on a main truss 20 assembled at the lower side thereof. The floor slab 10 is so constituted that a concrete layer 12 is formed on a sill substrate 11, and the main truss 20 is so constituted that one lower chord 22 extended in the direction of the bridge axis placed to the center at right angles to the bridge axis and a longitudinal beam 21S on the bridge side of a floor framing 21 provided by connecting to the floor slab 10 on the lower surface side of the floor slab 10 are connected with a diagonal member 23. Then, when the diagonal member 23 is projected in the direction of the bridge axis of the bridge 1, it is so placed that the oblique side of a triangle making the lower chord 22 as the vertex thereof is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an upper truss bridge used for a bridge or an elevated road and supporting a floor slab above a main truss.

[0002]

2. Description of the Related Art Conventionally, there is a bridge or an elevated road having a configuration called an upper truss bridge.

[0003] An upper truss bridge is constructed by supporting a reinforced concrete floor slab 4 above a main truss 5 as shown in a conceptual perspective view seen from below in FIG.

[0004] The illustrated main truss 5 is provided on a lower surface of a reinforced concrete floor slab 4 with a floor group 6 composed of a vertical beam 61 and a horizontal beam 62 made of steel.
The vertical beams 61 on both the left and right sides are used as upper chord members, and the vertical beams 61 and a pair of left and right lower chord members 51 arranged corresponding to the vertical beams 61 below the floor set 6 are vertical members. 52 and a diagonal member 53 indicated by a dashed line in the figure.

[0005]

However, in the above-mentioned conventional upper truss bridge, since many components such as a chord, a vertical, a diagonal, and a joint member thereof are combined and formed, each truss bridge has a different structure. There is a problem that it takes time to produce and assemble the constituent members, and the cost is high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide an upper truss bridge which can be configured at a low cost with a simplified configuration using a small number of components.

[0007]

According to the present invention, there is provided an upper truss bridge in which a main truss supports a floor slab above the main truss. A concrete layer is formed on the main truss, and the main structural truss is connected to the floor slab on the lower surface side of the floor chord and one lower chord extending in the bridge axis direction disposed at the center in the direction orthogonal to the bridge axis. The bridge-side portion of the provided floor set is joined by a plurality of diagonal members, and the diagonal members are arranged so as to form an oblique side of an inverted triangle having the lower chord as a vertex when projected in the bridge axis direction of the bridge. It is characterized by comprising.

[0008] Further, the steel plate substrate constituting the floor slab has a wavy shape which is continuously bent up and down in a trapezoidal shape, and is arranged so that a continuous direction of the unevenness is set as a bridge axis direction. Features.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a perspective view of a bridge which is an example of an upper truss bridge according to the present invention, FIG. 2 is a transverse sectional view thereof, and FIG. 3 is a longitudinal center sectional view.

The illustrated bridge 1 is constituted by a floor slab 10 supported by a main truss 20 assembled thereunder.

The floor slab 10 is a composite slab in which a concrete layer 12 having a predetermined thickness is integrally formed on a lower frame substrate 11 made of a steel plate.
Are connected to a floor set 21.

The lower frame substrate 11 is formed by continuously bending a steel plate having a predetermined thickness up and down in a trapezoidal shape so as to exhibit a waveform.
1A are formed at predetermined intervals, and the unevenness continuous direction is set as the bridge axis direction (that is, the direction of the concave streak 11A is set as the bridge axis orthogonal direction).

The concrete layer 12 is a reinforced concrete in which a reinforcing bar (not shown) is disposed. The reinforcing layer is provided on the upper side of the lower frame substrate 11, and is formed to a predetermined thickness by casting concrete. ing. That is, the lower frame substrate 11 functions as a mold and is integrated with the concrete layer 12 so that the strength can be synthesized as it is after the concrete is cast. A dowel or the like is erected so as to increase the bonding strength with the concrete layer 12.

Here, the floor slab 10 is constructed by mounting the floor slab 10 completed in a unit shape on the main truss 2 provided between the piers.
A unit construction method of juxtaposition on a lower frame substrate, a component construction method of fixing a frame (component) of a predetermined size in which a reinforcing bar is disposed on a lower frame substrate 11 onto a main truss 20 erected on a pier and then casting concrete. Any of these methods is possible, and the method may be appropriately selected in consideration of the conditions at the construction site, the heavy equipment used, and the like. In the case of the component construction method, by arranging concave ridges 11A formed at predetermined intervals as the bridge axis direction, as in the lower frame substrate 11 of the present configuration example, the bridge axis direction is provided. High rigidity can be obtained, and the component fixed to the main truss 20 (that is, the lower frame substrate 11) can function to stably maintain the shape of the main truss 20 before placing concrete.

The main truss 20 is a floor set 21 which is located on the lower surface of the floor slab 10 and is connected to the floor slab 10.
One lower chord member 22 disposed at the center of the bridge width direction on the lower side by one predetermined amount is connected by a plurality of diagonal members 23.

The floor set 21 is composed of three bridge beams 21S, 21C in the direction of the bridge axis arranged on both the left and right sides and the center, and bridges arranged at predetermined intervals in the bridge axis direction to connect the vertical beams 21S, 21C. The cross beam 21H in the direction perpendicular to the axis is joined and integrated by welding.

The vertical beams 21S, 21C and the horizontal beams 21H are H-shaped section steels having flanges at both edges of the abdominal plate, and are assembled with their flange surfaces horizontal. The lower frame substrate 11 of the floor slab 10 is connected to the flange of 21C by bolts and nuts.

The lower chord member 22 is a steel pipe having a predetermined thickness and a predetermined diameter, and is spaced apart from the floor set 21 by a predetermined amount as described above.
The central axis is arranged parallel to the bridge axis. Although the inside is hollow in the drawing, concrete may be filled inside the lower chord material 22 at a portion where a compressive force acts on the lower chord material 22 such as a bearing portion.

The diagonal members 23 (23L, 23R) are the lower chord members 2
2 is a steel pipe having a predetermined thickness smaller than 2 and a predetermined diameter.
The lower flange surface and lower chord material 22 of the longitudinal beams 21S on both sides of
When viewed in the direction of the bridge axis (as shown in FIG. 2 which is a cross section orthogonal to the bridge axis), the left and right diagonal members 23
L, 23R and the floor set 21 are set as sides, and the longitudinal beams 21S and the lower chord members 23 are arranged at the vertices to form an inverted triangle (in the illustrated example, an inverted regular triangle having an apex angle of 60 °), and from the side. When viewed, as shown in FIG. 3 which is a longitudinal center cross-sectional view, the diagonal members 23R... Adjacent to each other in the bridge axis direction and the vertical beams 21S of the floor group 21 are connected to the lower chord members 22 of the diagonal members 23 and the vertical direction. Beam 21S
It is arranged so as to form a triangle having the connection position with the triangle as a vertex. The connection of the diagonal member 23 with the vertical beam 21S and the lower chord member 22 is performed by welding.

The diagonal member 23 does not necessarily have to be arranged obliquely in the bridge axis direction when viewed from the side.
For example, in the present configuration example, additional arrangement may be made between the diagonal members 23 adjacent in the bridge axis direction so as to be vertical when viewed from the side (that is, at the center of the angle formed by the diagonal members 23), or the like. It can be changed as needed.

The bridge 1 having the above construction is supported and supported by piers at both ends and a predetermined position through a support. At the support position, the lower chord member 22 is installed so as to be unrotatable about its axis. For example, only the relevant portion of the main truss 20 may be formed in a rectangular shape as shown by an imaginary line in FIG.

Thus, in the bridge 1 configured as described above, the floor slab 10 and the main truss 20 are joined and integrated, and the strength is synthesized, so that a lightweight, highly rigid and rational configuration is possible.

Further, the main truss 20 can be composed of fewer components (floor set 21, lower chord 22, diagonal 23) than a general upper truss bridge having a pair of left and right lower chords. Thus, the time required for producing and assembling the constituent members can be reduced, and the construction cost can be reduced.

[0025]

As described above, according to the upper truss bridge according to the present invention, the floor slab has a concrete layer formed on a steel plate substrate, and the main truss is located at the center in the direction orthogonal to the bridge axis. A single lower chord extending in the direction of the bridge axis and a bridge-side portion of a floor set provided on the lower surface side of the floor slab and connected to the floor slab are connected by a plurality of diagonal members. When arranged in the direction of the bridge axis of the bridge, it is arranged to form the hypotenuse of an inverted triangle having the lower chord as a vertex, so that a lightweight, highly rigid and rational configuration is possible, The main truss can be composed of fewer components compared to a general upper truss bridge with a pair of left and right lower chords, so the time required for production and assembly of the components can be reduced, and construction costs can be reduced. It becomes possible.

Further, the steel plate substrate constituting the floor slab has a wavy shape which is continuously bent up and down in a trapezoidal shape, and the unevenness continuous direction is arranged as a bridge axis direction. Since high rigidity can be obtained in the direction perpendicular to the axis, when the lower frame substrate is fixed on the main truss and the concrete is cast, the shape of the main truss is stabilized before casting the concrete. Can keep the function.

[Brief description of the drawings]

FIG. 1 is a perspective view of a bridge which is one configuration example of an upper truss bridge according to the present invention.

FIG. 2 is a cross-sectional view of a bridge.

FIG. 3 is a vertical center sectional view of a bridge.

FIG. 4 is a conceptual perspective view of a conventional upper truss bridge viewed from below.

[Explanation of symbols]

 Reference Signs List 1 bridge (upper truss bridge) 10 floor slab 11 lower frame substrate (steel plate substrate) 12 concrete layer 20 main structure truss 21 floor group 22 lower chord material 23 diagonal material

Claims (2)

[Claims] 1. An upper truss bridge in which a main truss supports a floor slab on an upper side thereof, wherein the floor slab is formed by forming a concrete layer on a steel plate substrate, and the main truss is a bridge shaft. A single lower chord member extending in the bridge axis direction provided at the center in the orthogonal direction and a bridge-side portion of a floor set provided on the lower surface side of the floor slab and connected to the floor slab are connected by a plurality of diagonal members. An upper truss bridge, wherein the diagonal members are arranged so as to form an oblique side of an inverted triangle having a lower chord as a vertex when projected in the bridge axis direction of the bridge. 2. The steel plate substrate constituting the floor slab has a wavy shape which is continuously bent up and down in a trapezoidal shape, and is arranged so that a continuous direction of the unevenness is set as a bridge axis direction. The upper truss bridge according to claim 1, wherein: