JP2000073317A - Composite steel floor plate for continuous composite girder bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite steel floor plate applicable to a continuous girder bridge while having sufficient resistance to tensile stress of a support part and easily manufactured at a low cost. SOLUTION: A composite steel floor plate 30 is constituted by integrating a steel frame body 30A made of steel plates, and a concrete layer 30B. The steel frame body 30A is provided with rib members 32a in the cross direction of a bridge, erected on the upper face of a lower face plate 31 being welded and fixed at specified spaces in the axial direction of the bridge, and an upper face plate 33 is welded and fixed onto the upper faces of the rib members 32, near a supported part supported by a support 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite steel slab combined with a girder member to form a composite girder in a continuous composite girder bridge supported by a plurality of bearings.

[0002]

2. Description of the Related Art As a bridge structure constituting a bridge or an elevated road, there is a composite girder bridge formed by connecting a floor slab to a steel girder.

As a floor slab structure in such a composite girder bridge, as shown in a conceptual cross-sectional view in FIG. 4, an RC concrete layer 42 is formed on a steel plate substrate 41, and the steel slab and the RC slab are combined. A synthetic steel slab 40 utilizing the advantages of the slab is known. In this configuration, the steel plate substrate 41 constituting the lower surface functions not only as a formwork when the concrete is cast, but also as a strength member of the floor slab 40 itself after the concrete layer 42 is formed.

Recently, as shown in a perspective view of FIG.
A so-called sandwich in which a concrete layer 54 is formed by filling concrete into a slab steel shell 50 having a lower plate 51 and an upper plate 52 made of a steel plate joined at predetermined intervals via a joining member 53. A synthetic steel slab 60 called a slab has been proposed. In the illustrated configuration, a joining member 53 is erected on the upper surface of the lower plate 51 at predetermined intervals in the bridge axis direction, and a section in the bridge axis direction partitioned by the joining member 53 is provided on the upper edge of the joining member 53. Corresponding unit plate 52
Are welded and fixed, and these unit plates 52A constitute the upper surface plate 52 as a whole.

In such a sandwich slab (synthetic steel slab 60), the concrete layer 54 is composed of a lower plate 51 and an upper plate 5.
Since the closed space sandwiched between the two is filled, high rigidity can be obtained, and the structure can be made thin.

The synthetic steel slab girder using the synthetic steel slabs 40 and 60 as described above is a steel plate substrate 4 manufactured in a factory.
1 or the floor slab 50 is transported to the construction site and
After placing on the floor 61, concrete is cast to form concrete layers 42 and 54,
The connection between 0, 60 and the main girder 43, 61 is usually made with the main girder 43, 6
It is performed by a dowel erected on 1.

[0007]

FIG. 7 (A)
As shown in the conceptual diagram in FIG. 7, in a continuous girder bridge supporting a floor slab 70 continuous in the bridge axis direction by a plurality of bearings, FIG.
As shown in (1), a negative bending moment acts on the portion supported by the bearing 71, and a tensile stress in the bridge axis direction is generated on the upper surface side of the floor slab 70A at the portion where the negative bending moment acts.

For this reason, when a synthetic steel floor slab 40 formed by forming an RC concrete layer 42 on a steel plate substrate 41 shown in FIG.
Cracks occur on the upper surface of the two layers.

In the sandwich floor slab 60 shown in FIG. 5, the resistance to the tensile stress is increased by the upper plate 52 (the unit plate 5).
2A) depends on the bonding strength with the joining member 53,
Since the fillet welding as shown in FIG. 6 which is an enlarged front view of the part cannot provide a sufficient bonding strength, the upper surface plate 52 cannot be combined as a strength member. Further, since the floor slab 50 has a structure in which the upper and lower surfaces are closed by the lower surface plate 51 and the upper surface plate 52, the production is troublesome, and the concrete poured and filled into the inside thereof has a special fluidity. Therefore, there is a problem that the production cost is high.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has an adequate resistance to the tensile stress of a supporting portion, can be applied to a continuous girder bridge, and can be manufactured easily and at low cost. It is an object to provide a configurable composite steel slab.

[0011]

According to the present invention, there is provided a composite steel girder for a continuous composite girder bridge, which achieves the above object, in a continuous composite girder bridge supported by a plurality of bearings. A floor slab to be constructed, wherein plate-shaped steel plate rib members having a plurality of through holes formed on an upper surface of a lower plate member are erected at predetermined intervals in a bridge axis direction and near a portion supported by the bearing. A steel plate upper plate member is fixedly arranged on the upper edge of the rib member to form a steel frame, and concrete is poured between the upper surface of the lower plate member and the upper plate member of the steel frame.
It is characterized by being filled and forming a concrete layer.

The rib member has a T-shaped cross section having a flange at the upper edge of the belly plate, and is formed by welding a unit plate forming the upper surface plate member on the upper surface of the flange. It is characterized by the following.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 is a longitudinal sectional view of a bridge to which an example of a synthetic steel slab according to the present invention is applied, FIG. 2 is an enlarged view of a portion A, and FIG. 3 is a transverse sectional view.

The illustrated bridge 1 has a composite steel floor slab 10 in which a synthetic steel slab 30 is integrally joined on a girder set 20 composed of a main girder 21 and a horizontal girder 22 to a pier 2 via a bearing 3. It is supported and configured.

The girder set 20 includes a pair of main girder 21 on the left and right in the width direction.
(Only one is shown in FIGS. 1 and 4), and horizontal beams 22 are arranged at predetermined intervals between the main beams 21. The main girder 21 and the cross girder 22 are each formed of a steel plate and have a cross-sectional shape of an I-shape having a predetermined height, and the side girder 22 is fixed at its side edge to the web of the main girder 21 by welding. Reference numeral 20 denotes a cross joint portion between the main girder 21 and the cross girder 22 and is supported by the pier 2.

The synthetic steel slab 30 is a steel frame 30A made of a steel plate.
And the concrete layer 30B are integrally formed.

The steel frame 30A is provided with rib members 32 extending in the bridge width direction fixed at predetermined intervals in the bridge axis direction on the upper surface of a lower plate 31 as a lower plate member. An upper surface plate 33 as an upper surface member is welded and fixed to the upper surface of the rib member 32 in the vicinity of the support portion.
That is, the upper side of the lower surface plate 31 is divided in the bridge axis direction by the rib member 32, and only the upper side of the section near the supported portion is closed by the upper surface plate 33. The arrangement range of the upper plate 33 is set to a range in which a negative bending moment is generated in the synthetic steel slab 30 by the support by the bearing 3.

The rib member 32 has a cross section T in which a flange 32B having a predetermined width is integrally formed on the upper edge of the abdominal plate 32A in an orthogonal state.
And the height is the concrete layer 30B
The lower edge of the abdominal plate 32 </ b> A is welded and fixed to the upper surface of the lower surface plate 31 with the longitudinal direction being the direction orthogonal to the bridge axis. The abdominal plate 32A has a plurality of circular through holes 32C having a predetermined diameter. Although not shown, a reinforcing bar in the bridge axis direction is inserted and arranged in the through hole 32C as necessary. The shape of the through hole 32C is not limited to a circle, but may be any other shape.

The upper plate 33 is divided into unit plates 33A at intervals of the rib members 32. Each unit plate 33A is formed on the upper surface of the flange 32B of the rib member 32.
Is used as a backing metal and joined by butt welding to form a continuous flat plate and also joined to the rib member 32. In the present configuration example, three unit plates 33 </ b> A are joined and formed around the support site of the bearing 3. Therefore, the upper region of the three sections divided by the rib members 32 is covered with the upper surface plate 33. Is what it is.

The concrete layer 30B has a lower plate 31 in a section where the upper plate 33 of the steel frame 30A is not provided.
Is formed on the upper surface to a thickness equal to the height of the rib member 32,
In the division where the upper surface plate 33 is provided, the space between the upper surface plate 33 and the lower surface plate 31 is formed so as to be filled.

When the concrete layer 30B is formed, the concrete is poured from the upper side of the part where the upper surface is open, and the part closed by the upper surface plate 33 through the opening of the side edge. It can be performed from an adjacent open section through a through hole 32C formed in the rib member 32. Although not shown, a dedicated opening may be formed in the top plate 33 and the opening may be performed from the opening. For this reason, it is not necessary to use special concrete having good fluidity, and even if special concrete is used only for the portion closed by the upper surface plate 33, a small amount is sufficient and the cost can be reduced.

The concrete layer 30 thus formed
B indicates that the sections adjacent to each other across the rib member 32
In the section where the upper surface plate 33 is disposed integrally with the lower plate 31 and the upper plate 33, the partition is immovable in the closed space defined by the lower plate 31 and the upper plate 33, and is not provided with the upper plate 33. However, the flange 32C of the rib member 32 is in an engaged state and becomes immovable, and is firmly connected to and integrated with the steel frame 30A.

Here, the steps of casting concrete on the steel frame 30A to form the concrete layer 30B include a method performed at a manufacturing factory and a method performed at the site after the steel frame 30A is installed on the girder set 20. The above two methods are possible, and can be appropriately selected in consideration of the situation at the construction site, the heavy equipment used, and the like. In any case, the steel frame 30A functions as a mold.

The synthetic steel slab 30 and the girder set 20 (main girder 2)
The connection with 1) is performed by a dowel erected on the upper surface of the girder set 20 or by fastening with a bolt. That is, in the construction method in which concrete is poured in a manufacturing plant, the girder set 2 is formed by bolts penetrating the entire synthetic steel slab 30.
0, or by laying a dowel on the girder set 20 and casting concrete only at the corresponding joint site on site, etc. Also, after installing the steel frame 30A on the girder set 20 In the method of casting concrete on site, the steel frame 30A is fastened and fixed to the girder set 20 by bolts, or a dowel erected on the upper surface of the girder set 20 is made to penetrate through the lower plate 31 of the steel frame 30A to form a concrete layer. 30B.

In the construction method in which concrete is cast at the site after the steel frame is placed on the girder set 20, the blocks of the steel frame 30A divided in the bridge axis direction are connected with each other by B in FIG. This is performed by fastening a coupling flange 31A formed on the edge of the lower plate 31 as shown in the portion shown.

Thus, in the synthetic steel slab 30 constructed as described above, the steel frame body 30A and the concrete layer 30B are firmly bonded to each other and the strength is synthesized, so that high rigidity is obtained as a whole. Since the rib member 32 functions as a reinforcing member that resists the pulling force in the bridge width direction, the main girder interval can be set wide, and the reinforcing bar in that direction can be omitted, so that the cost can be easily reduced in a short time at low cost. Can be manufactured.

In addition, the concrete layer 30B is separated from the steel frame 30A (rib member 32) at the portion supported by the bearing 3 on which the negative moment acts, in order to resist the tensile force acting on the upper surface plate 33 located on the upper surface. No cracking occurs in the concrete layer 30B.

[0028]

As described above, according to the synthetic steel slab of the continuous girder bridge according to the present invention, the plate-shaped steel rib member having a plurality of through holes formed on the upper surface of the lower plate member is formed by the bridge. A steel plate upper plate member is fixedly arranged on the upper edge of the rib member in the vicinity of a portion supported by the bearing in the axial direction at a predetermined interval, and a steel frame is formed. Since the concrete layer is formed by casting and filling concrete between the upper surface of the face plate member and the upper surface plate member, the concrete layer separated by the rib member is continuously integrated through the through hole. Therefore, the steel frame and the concrete layer are firmly bonded to each other, and a lightweight and highly rigid synthetic steel slab can be obtained. Since the rib member functions as a reinforcing member that resists the pulling force in the bridge width direction, it is possible to set a wide main girder interval, and it is also possible to omit the reinforcing bar in the direction.
It can be easily manufactured at a low cost in a short time.

Further, at the portion supported by the bearing on which the negative moment acts, since the upper surface plate member located on the upper surface becomes a strength member resisting the tensile force, the concrete layer is separated from the steel frame or the concrete layer is cracked. In addition, since the top plate is not provided at the part between the bearings where the positive moment acting against the compressive stress acts only on the concrete layer without the occurrence of It is not necessary to use special concrete having good properties, and it can be constructed at low cost in combination with the simplification of the structure.

The rib member has a T-shaped cross section having a flange at the upper edge of the belly plate, and is formed by welding a unit plate forming an upper plate member on the upper surface of the flange. Since the unit plate can be firmly connected, the upper plate member as a whole can function as a strength member to resist tensile stress, and even in a portion where the upper plate member is not disposed, the concrete layer engages with the flange. Tightly bound,
It can prevent falling off.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a bridge to which an example of a synthetic steel slab according to the present invention is applied.

FIG. 2 is an enlarged view of a portion A of FIG.

FIG. 3 is a cross-sectional view of FIG.

FIG. 4 is a conceptual cross-sectional view of a synthetic steel slab as a conventional example.

FIG. 5 is a perspective view of a synthetic steel slab as a conventional example.

FIG. 6 is an enlarged front view of a portion X in FIG. 5;

7A is a conceptual diagram of a continuous girder bridge, and FIG. 7B is a moment diagram thereof.

[Explanation of symbols]

 Reference Signs List 1 bridge (continuous composite girder bridge) 3 bearing 10 synthetic steel deck slab (synthetic girder) 20 girder group (girder member) 21 main girder (girder member) 30 synthetic steel slab (floor slab) 30A steel frame 30B concrete layer 31 lower plate (lower plate member) 32 rib member 32A belly plate 32B flange 32C through hole 33 upper plate (upper plate member) 33A unit plate

Claims (2)

[Claims] 1. A floor slab combined with a girder member to form a composite girder in a continuous composite girder bridge supported by a plurality of bearings, wherein a plate having a plurality of through holes formed in an upper surface of a lower plate member. Steel plate rib members are erected at predetermined intervals in the bridge axis direction, and a steel plate upper plate member is fixedly arranged on the upper edge of the rib member in the vicinity of a portion supported by the bearing, thereby forming a steel frame. Wherein the concrete frame is formed by casting and filling concrete between the upper surface of the lower plate member and the upper plate member of the steel frame, thereby forming a continuous composite girder bridge. Steel deck. 2. The rib member has a T-shaped cross section having a flange on the upper edge of the abdominal plate, and is formed by welding a unit plate forming the upper plate member on the upper surface of the flange. The synthetic steel slab of the continuous composite girder bridge according to claim 1, wherein: