JP2002309511A - Main girder structure of truss bridge and method of erecting main girder - Google Patents

Abstract

(57) [Summary] [Problem] To obtain a main girder structure of a truss bridge capable of assembling members in an assembly plant, shortening a construction period and improving processing accuracy. A main girder supporting a floor slab is fixed to a lower surface of the floor slab at a predetermined interval in a width direction of the floor slab, and a pair of upper chord members connected by a horizontal chord connecting member. , 3b
And a pair of lower chord members 5a arranged below the pair of upper chord members 3a, 3b so that the interval is smaller than the interval between the pair of upper chord members 3a, 3b, and connected by the lower chord horizontal connecting member 4. , 5b and a plurality of diagonal members connecting the upper and lower chord members
The main girder structure of a truss bridge with a three-dimensional truss structure composed of 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a main girder structure and a method for erection of a main girder of a truss bridge applied to bridges, viaducts and the like.

[0002]

2. Description of the Related Art A number of structural members are joined to each other at ends.
A three-dimensional truss with a three-dimensional frame structure can make a girder that is taller than a girder with a rigid abdominal plate without increasing the weight, so die by increasing the span It is economical if applied to bridges where increasing the load is a problem.

[0003] Such a space truss has been adopted as a main girder of a bridge, for example, in a railway bridge built in Switzerland.
There is a bridge (Reference: Dauner, H.-G .: De)
rViadukt von Lully -eine
Neuheit im Verbundruckenb
an. Stahlbau 67 (1998), Helt
1). In the bridge, a steel pipe is used as a structural member, which is three-dimensionally combined to form a main girder, so that effective stress transmission can be realized with a minimum necessary material.

FIG. 6 is a perspective view showing the main girder structure of the Ruri bridge. And a pair of steel pipe upper chords 2 connected by a steel pipe horizontal structure 22.
2a and 22b and the pair of upper chords 22a and 2b
2b, the upper chord 22a and the upper chord 2
2b, one steel tube lower chord 23, upper chords 22a and 22b, and lower chord 2
3 has a three-dimensional truss structure composed of a plurality of diagonal members 24 made of steel pipes.

[0005]

However, the three-dimensional truss applied to the main girder of the above-mentioned Ruri bridge has the following problems.

Even in the case of a relatively small road bridge having two lanes in the upper and lower directions, the length of one side of the truss in the width direction of the road bridge is required to be 6 m or more. The truss cannot be loaded onto the truck in a state, and the three-dimensional truss is assembled by welding at the erection site, so the construction period is longer and the cost required for erection is increased compared to when assembling at the assembly factory, and the truss processing Accuracy cannot be guaranteed.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and some of the members can be assembled in an assembly factory in advance. It is an object of the present invention to provide a main girder structure of a truss bridge and a method of erection of the main girder, which can shorten the construction period and improve the processing accuracy.

[0008]

According to the main girder structure of a truss bridge according to the present invention, a main girder for supporting a floor slab is fixed to a lower surface of the floor slab at a predetermined interval in a width direction of the floor slab. A pair of upper chords connected by the upper chord connecting material, and arranged below the pair of upper chords so that the interval is smaller than the interval between the pair of upper chords, and connected by the lower chord connecting material. It has a three-dimensional truss structure composed of a pair of lower chord members and a plurality of diagonal members connecting the upper chord members and the lower chord members.

Further, the lower chord horizontal connecting member for connecting the pair of lower chord materials is an I-shaped cross-section girder material.

[0010] A method of erection of a truss bridge main girder according to the present invention is the method of erection of a truss bridge main girder described above,
At a place other than the truss bridge construction site, a plurality of panels in which the upper chord and the lower chord are connected by diagonal members are assembled in advance, and the plurality of panels, the upper chord lateral connecting material and the lower chord lateral connecting material are transported to the truss bridge construction site. After arranging the two sets of panels so that the upper chord members and the lower chord members face each other,
After connecting the upper chord members of the set of panels with upper chord horizontal connecting members and connecting the lower chord members with lower chord horizontal connecting members to complete the main girder, the main girder is arranged on the pier of the truss bridge. .

In the main girder structure of the truss bridge according to the present invention, the upper chord material and the lower chord material are each composed of two pieces, so that one upper chord material and one lower chord material, and the other upper chord material and the other lower chord are used. Each pair of materials can be processed into two sets of panels in which the upper chord material and the lower chord material are combined with a plurality of diagonal members at a factory.

The distance between the upper chord and the lower chord in the height direction is
Since the distance between the upper chords is shorter than the interval between the upper chords, the panel in which the upper chords and the lower chords are joined by a plurality of diagonals can be easily transported by truck.

[0013] Then, the panel, the upper string horizontal connecting material and the lower string horizontal connecting material are carried by truck to an assembling place near the construction site, and the two sets of panels are arranged so that the upper and lower chord materials face each other. After connecting the upper chord members of the two sets of panels with the upper chord horizontal connecting members and connecting the lower chord members of the two panels with the lower chord horizontal connecting members to complete the main girder, the main girder is placed on the pier of the truss bridge. .

As described above, the work of connecting the upper chord material and the lower chord material with diagonal members can be omitted at the construction site, so that the work of assembling the main girder can be performed in a short time and the assembling accuracy can be improved. it can.

Since the interval between the lower chords is narrow, even if the horizontal connecting member for connecting the lower chords is connected to one of the two sets of panels at a factory in advance, the panels are transported by truck. In this case, the work of assembling the main girder at the construction site can be further shortened, and the assembling accuracy can be further improved.

In this case, if the structure connecting the lower chord members is a gusset structure, the welding work can be minimized.

[0017]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the main girder structure of the truss bridge of the present invention, FIG. 2A is a front view of the main girder of the truss bridge of the present invention, and FIG. Plan view,
FIG. 2C is a side view of the main girder of the truss bridge of the present invention.

The structure of the main girder of the truss bridge according to the present invention is fixed to the lower surface of the PC slab 1 at regular intervals in the width direction of the PC slab 1 and connected by a plurality of first chord horizontal connecting members 2. A pair of steel pipe upper chords 3a and 3b, and a pair of upper chords 3a and 3b disposed below the pair of upper chords 3a and 3b so as to have a smaller interval than the pair of upper chords 3a and 3b;
A pair of lower chord members 5 connected by a plurality of lower chord lateral connecting members 4
a and 5b, an upper chord 3a and a lower chord 5a, and a plurality of diagonal members 6 connecting the upper chord 3b and the lower chord 5b to form a three-dimensional truss structure.

Next, a method of erection of the main girder of the truss bridge on the pier will be described. As shown in FIG. 3, two sets of panels 17 in which the upper chord material 13 and the lower chord material 15 are joined by a plurality of diagonal members 16 are assembled in an assembly factory in advance. Since the distance between the upper chord material 13 and the lower chord material 15 of the panel 17 is about 3 m or less, the panel 17 can be transported by land on a truck. The two sets of panels 17 are transported by truck to the assembly site near the truss bridge erection site together with the required upper string lateral connecting member 12 and lower string lateral connecting member 14. And
As shown in FIG. 4, two sets of panels 17 are arranged at a predetermined distance such that the upper chord members 13 and the lower chord members 15 face each other.
The lower chord members 15 are welded to each other by the lower chord lateral connecting members 14.

In this way, by connecting the two sets of panels 17 with the required upper string horizontal connecting member 12 and lower string horizontal connecting member 14, the main girder of the truss bridge is completed. Then, the main girder is suspended by a crane and arranged so as to straddle two piers of the truss bridge, thereby completing the construction of the main girder.

In some cases, as shown in FIG. 5, the lower string horizontal connecting member 14 is previously connected to one of the panels 17 at the assembly factory, and the lower string horizontal connecting member 14 is not connected thereto. The panel 17 and the panel 17 may be arranged to face each other and assembled.

Since the main girder of the truss bridge according to the present invention can be erected as described above, the work of assembling the main girder at the erection site can be reduced, the construction period can be shortened, and the cost required for erection is reduced. In addition to being able to reduce the truss, the processing accuracy of the truss can be increased.

The acting force on the lower string lateral connecting member 14 is smaller than the acting force on the other components, and particularly, the axial force is found to be smaller than the acting force on the other components. Even if a material having an I-shaped cross section is used, there is no problem in strength.

If the floor slab 1 has a structure to bear the load in the width direction, the horizontal chord connecting member 2 may be removed after the slab is erected.

[0025]

According to the present invention, the truss bridge can be erected in a short construction period, the erection cost can be reduced, and the processing ratio of the main girder in the manufacturing factory can be increased, so that the processing accuracy can be improved. And the safety of the truss bridge is improved.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a main girder structure of a truss bridge according to the present invention.

FIG. 2 is an explanatory view of a main girder structure of a truss bridge according to the present invention;
(A) is a front view of the main girder, (b) is a plan view of the main girder, and (c) is a side view of the main girder.

FIG. 3 is a view showing a main girder constituting material including a panel.

FIG. 4 is an explanatory view of a method of erection of a main girder.

FIG. 5 is an explanatory view of another method of erection of a main girder.

FIG. 6 is a perspective view of a conventional truss bridge.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 PC floor slab 2 Upper chord horizontal connecting material 3a, 3b Upper chord material 4 Lower chord horizontal connecting material 5a, 5b Lower chord material 6 Diagonal material 12 Upper chord horizontal connecting material 13 Upper chord material 14 Lower chord horizontal connecting material 15 Lower chord material 16 Diagonal material 17 Panel

Claims (3)

[Claims] 1. A pair of upper chords fixed to a lower surface of a floor slab at a predetermined interval in a width direction of the floor slab and connected by an upper chord horizontal connecting member; Below the upper chord material, the interval is arranged so as to be smaller than the interval between the pair of upper chord materials, a pair of lower chord materials connected by the lower chord horizontal connecting material, and a plurality of connecting the upper chord material and the lower chord material. The main girder structure of a truss bridge characterized by a three-dimensional truss structure composed of diagonal materials. 2. The main girder structure of a truss bridge according to claim 1, wherein the lower chord horizontal connecting member for connecting the pair of lower chord members is a girder member having an I-shaped cross section. 3. A method for erection of a main girder of a truss bridge according to claim 1 or 2, wherein a panel in which an upper chord material and a lower chord material are connected by a diagonal material at a place other than a truss bridge erection site. Plural assembly, the plurality of panels, upper string horizontal connecting material and lower string horizontal connecting material to the truss bridge erection site,
After arranging the two sets of panels so that the upper chords and the lower chords face each other, the upper chords of the two sets of panels are connected with the upper chord horizontal connecting material, and the lower chords are connected with the lower chord horizontal connecting material,
A method of erection of a main girder of a truss bridge, wherein after the main girder is completed, the main girder is disposed on a pier of the truss bridge.