JP2004225290A - Composite floor-slab girder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rational and costless composite floor-slab girder, in which the space of cross beams is adopted between floor-slab supports and the increase of weight and the long terms of works are not required. <P>SOLUTION: A bridge 1 is constituted by supporting the section between the floor slab supports at the space of the cross beams by a girder framing 10 composed of main girders 11 and the cross beam 12 in a synthetic floor slab 20, in which a concrete layer 21 is formed integrally on the upper side of a steel skeleton 30. The skeleton 30 consists of a central-section steel skeleton 30A between the main girders 11 in the direction orthogonal to a bridge axis and a side-section steel skeleton 30B forming a projecting section on the side, a vertical reinforcing beam 32A parallel with the bridge axis is fixed onto the top face of a bottom steel plate 31A in the central-section steel skeleton 30A and the side-section steel skeleton 30B is constituted by fixing a horizontal reinforcing beam 32B orthogonal to the bridge axis on the top face of the bottom steel plate 32B. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
TECHNICAL FIELD The present invention relates to a composite slab girder composed of a steel slab and a steel concrete composite slab in which a concrete layer is integrated with a steel skeleton and the strength is synthesized.
[0002]
[Prior art]
As one of the structures of bridges and elevated roads, there is known a composite slab slab in which a steel slab and a concrete layer are integrated and strength composited and supported by a steel girder.
[0003]
As a composite floor slab used for such a composite floor slab, a steel skeleton formed by arranging and fixing a large number of reinforcing members made of shaped steel or the like at predetermined intervals in a direction orthogonal to the extending direction on the upper surface of a steel plate substrate member. A structure in which an RC concrete layer is integrally formed on the upper side is proposed. According to this, a base member functions as a form when the concrete forming the concrete layer is cast. Is not required, and since the shape can be maintained on the girder set by the high rigidity, it is not necessary to provide a support, and the construction is facilitated.
[0004]
By the way, when the main girder span length is 10 m or more, as shown in Non-Patent Document 1, by adopting the horizontal girder spacing instead of the main girder spacing between the deck girder which determines the floor slab cross section, the thickness of the floor slab is increased. Can be made thinner. In other words, the horizontal girder spacing is set to be smaller than the main girder spacing, the floor girder is supported by the horizontal girder, and the load is transmitted to the main girder via the horizontal girder.
[0005]
In the case of adopting the horizontal girder spacing between the floor slabs, the main reinforcement in the floor slab must be disposed in parallel with the bridge axis, so that the upper surface of the steel plate base member as described above is reinforced by a shaped steel or the like. In a composite floor slab using a steel skeleton in which members are disposed and fixed, the reinforcing members are disposed with the longitudinal direction as the bridge axis direction.
[0006]
[Non-patent document 1]
"1st Steel Bridge Slab Symposium Proceedings"
November 1998 (Nov. 1998)
Japan Society of Civil Engineers Steel Structure Committee Steel Bridge Slab Investigation and Research Subcommittee P107-112
[0007]
[Problems to be solved by the invention]
By the way, in the composite slab of the steel skeleton in which the reinforcing members are arranged in the bridge axis direction by adopting the cross beams between the slab supports as described above, the support rigidity of the overhang portion on the side of the main slab of the slab is increased. A structure is required.
[0008]
For example, as shown conceptually in FIG. 6, when the floor slab 60 is supported by the girder set including the main girder 61 and the horizontal girder 62 at the horizontal girder spacing, brackets 63 are provided outside the main girder 61. The bracket 63 supports the overhanging portion and transmits the load of the overhanging portion to the main girder 61. Further, in the configuration disclosed in Non-Patent Document 1, only the overhanging portion is an RC slab in which the main reinforcing bar has a direction perpendicular to the bridge axis.
[0009]
However, the configuration in which the overhanging portion is supported by the bracket causes an increase in dead load, and the configuration in which only the overhanging portion is made of RC floor slabs requires support during construction, which increases the construction period. There was a problem that the cost was high and rational.
[0010]
The present invention has been made in view of the above problems, and provides a reasonable and low-cost composite slab girder that employs cross beams between floor slabs and does not require weight increase or a long construction period. The purpose is to:
[0011]
[Means for solving the problem]
The composite slab girder of the present invention that achieves the above object is a composite slab girder that supports a steel-concrete composite slab in which a concrete layer is integrated with a steel skeleton and strength-combined, and is supported by a girder combination of steel girders. The girder set supports the floor slab by a main girder in the direction orthogonal to the bridge axis and a horizontal girder bridged between the main girder, and the steel skeleton is provided on the upper surface of the substrate member between the main girder diameters. While a longitudinal reinforcing member in the bridge axis direction is arranged and fixed, a lateral reinforcing member in a direction orthogonal to the bridge axis is arranged and fixed on the upper surface of the substrate member at the overhang portion, and the lateral reinforcing member is attached to the longitudinal reinforcing member. It is characterized by being combined.
[0012]
This allows the vertical reinforcing members extending in the bridge axis direction to transmit the load to the horizontal girder in the span of the main girder, thereby making the floor slab span the horizontal girder spacing, and at the overhanging portion, perpendicular to the bridge axle. High rigidity can be obtained in the direction orthogonal to the bridge axis by the lateral reinforcing member extending in the direction in which the bridge extends.
[0013]
Further, the steel skeleton comprises a central steel skeleton provided with the vertical reinforcing member and constituting the main girder span, and a side steel skeleton provided with the lateral reinforcing member and constituting the overhang portion. A member is fastened to a connecting plate welded and fixed to the longitudinal reinforcing member, and the central steel skeleton and the side steel skeleton are connected to each other.
[0014]
Thereby, the center steel skeleton and the side steel skeleton can be easily and firmly joined on the girder set.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0016]
FIG. 1 is a cross-sectional view orthogonal to the bridge axis of a main girder portion of a bridge to which an example of a composite floor slab according to the present invention is applied, FIG. 2 is a cross-sectional view taken along line AA of FIG. 1, and FIG. 4 is a plan view of the steel skeleton corresponding to the plan view of FIG.
[0017]
The illustrated bridge 1 is configured by integrally supporting a slab 20 which is a steel-concrete composite slab by a girder set 10 including a main girder 11 and a horizontal girder 12 which are steel girders.
[0018]
The girder set 10 has a configuration in which a horizontal girder 12 is erected at a predetermined interval in the bridge axis direction between a pair of main girder 11 (only one is shown in FIG. 2) arranged on the left and right in the width direction of the bridge 1. Have been. The arrangement interval of the cross beams 12 is set to be narrower than the main girder interval, and the floor slab 20 is designed such that the horizontal slab interval is a floor slab span.
[0019]
The main girder 11 and the cross girder 12 are each formed of a steel plate into an I-shaped cross-section having a predetermined height, and the cross girder 12 is connected to an abdominal plate of the main girder 11 at an end thereof. A large number of stud dowels 13 are erected on the upper surfaces of the upper flanges 11A and 12A of the main girder 11 and the horizontal girder 12. The stud dowels 13 are immersed in a concrete layer 21 of the floor slab 20, which will be described later. 11 (that is, the girder set 10) and the floor slab 20 are connected.
[0020]
The floor slab 20 is configured such that a concrete layer 21 having a predetermined thickness is integrally formed above a steel skeleton 30. The part to be supported by the girder set 10 is thicker than other parts, and both sides thereof are haunch parts 22 having a predetermined angle. In addition, 23 in a figure is a reinforcing bar.
[0021]
The steel skeleton 30 has a plurality of reinforcing beams 32 functioning as main reinforcing bars arranged and fixed at predetermined intervals in a direction orthogonal to the extending direction thereof on the upper surface of a bottom steel plate 31 as a substrate member made of a steel plate having a predetermined thickness. The stud dove 33 is provided upright.
[0022]
The bottom steel plate 31 forms the entire lower surface of the floor slab 20 except for the portion supported by the girder set 10 (the portion corresponding to the upper flanges 11A and 12A of the main girder 11 and the horizontal girder 12). Is mounted on the upper flanges 11A and 12A of the main girder 11 or the horizontal girder 12.
[0023]
The reinforcing beam 32 is a U-shaped channel steel having a side plate portion 32b erected on both sides of the substrate portion 32a, and is welded to the upper surface of the bottom steel plate 31 by one of the side plate portions 32b in a side-down state. Fixed.
[0024]
The steel skeleton 30 is divided and manufactured in a manufacturing factory into unit blocks of an appropriate size in consideration of transportation means and the like, and the unit blocks are combined on the girder set 10 to be integrally constructed. In the illustrated configuration example, in the direction orthogonal to the bridge axis, the central steel skeleton 30A between the main girders 11 and the side steel skeleton 30B forming a lateral overhang are divided. Further, in the bridge axis direction, the central steel skeleton 30A is divided by the arrangement pitch of the cross beams 12, and the lateral steel skeleton 30B is divided by a predetermined length. A portion indicated by 50 in FIG. 3 is a connecting portion in the bridge axis direction of the side steel skeleton 30B, and is connected by a fastening mechanism 40 'similar to a fastening mechanism 40 described later. The central steel frame 30A is further divided in the direction perpendicular to the bridge axis according to the width of the bridge 1.
[0025]
Here, the arrangement direction of the reinforcing beams 32 is different between the central steel skeleton 30A between the main girders 11 and the side steel skeleton 30B forming the lateral overhang.
[0026]
That is, the reinforcing beam 32 of the central steel skeleton 30A is disposed and fixed in parallel with the bridge axis to form a vertical reinforcing beam 32A as a vertical reinforcing member, while the reinforcing beam 32 of the side steel skeleton 30B is connected to the bridge axis. And a transverse reinforcing beam 32B as a transverse reinforcing member. As described above, in the central steel skeleton 30A, the main reinforcement is the bridge reinforcing beam 32A in the bridge axis direction orthogonal to the cross beam 12, so that the rigidity in the bridge axis direction is secured and the space between the floor slabs is set as the cross beam interval. On the other hand, in the side steel skeleton 30B forming the overhang portion, the main reinforcement is a lateral reinforcing beam 32B in a direction orthogonal to the bridge axis, so that rigidity that cantilever support by the girder set 10 can be secured. .
[0027]
Further, the portion supported by the cross beam 12 of the central steel skeleton 30A and the portion supported by the main girder 11 of the side steel skeleton 30B form the reinforcing beam 32 (32A, 32B) and the lower surface of the haunch portion 22. The portion of the bottom steel plate 31 is connected by a connecting support plate 34, whereby the steel frame 30 can be placed on the girder set 10 at the portion where the haunch portion 22 of the bottom steel plate 31 is formed. I have.
[0028]
In addition, the connecting position of the central steel skeleton 30A and the side steel skeleton 30B avoids a position directly below the wheels of the vehicle passing through the bridge 1 where the dynamic load changes significantly, and further, in a cross section orthogonal to the bridge axis. It is preferable that the bending moment of the dead load is set at a position where the bending moment becomes substantially zero.
[0029]
The central steel skeleton 30A and the side steel skeleton 30B are an enlarged view of an X part in FIG. 4, FIG. 5 (A), which is a YY sectional view thereof, and FIG. 5 (B) and a ZZ sectional view of FIG. As shown in (C), the lateral reinforcing beam 32B of the side steel skeleton 30B is coupled to the longitudinal reinforcing beam 32A of the central steel skeleton 30A, and the bottom steel plate 31A of the central steel skeleton 30A and the side steel 31B. The bottom steel plate 31B of the skeleton 30B is joined to the bottom steel plate 31B by a fastening mechanism 40 provided at a predetermined interval along the joining line.
[0030]
The horizontal reinforcing beam 32B of the side steel skeleton 30B and the vertical reinforcing beam 32A of the central steel skeleton 30A are connected to a connecting plate 35 welded and fixed to the vertical reinforcing beam 32A with its plate surface orthogonal to the base plate of the reinforcing beam 32B. The portions 32a are connected by being fastened by bolts and nuts 36.
[0031]
The fastening mechanism 40 includes a flat U-shaped coupling metal 41 formed by extending a supporting rib 41B having a predetermined length from both edges of a fastening plate portion 41A having a predetermined height and a predetermined width. The fastening plates 41A are welded and fixed in a state where they face each other, and the fastening plates 41A of the coupling fittings 41 are fastened by bolts and nuts 42.
[0032]
In a coupling structure in which such a fastening mechanism 40 is intermittently provided at predetermined intervals along a coupling line between the bottom steel plates 31A and 32B of the central steel skeleton 30A and the side steel skeletons 30B, coupling is performed along the coupling line. Since the ribs are not erected, the thickness of the concrete layer 21 at the joint is not reduced so much that cracks due to stress concentration can be suppressed.
[0033]
Note that the above configuration example is an example in which the divided central steel skeleton 30A and the side steel skeleton 30B are joined on a girder set. In the present invention, the central steel skeleton and the side steel skeleton are integrally formed. It is also possible to apply to those that have. Further, the reinforcing member provided on the substrate member is not limited to the channel steel, and may have another cross-sectional shape, and may have a different cross-sectional shape between the central portion and the side portion.
[0034]
【The invention's effect】
As described above, according to the composite slab girder according to the present invention, the girder set supports the slab by the main girder in the direction orthogonal to the bridge axis and the horizontal girder erected between the main girder. In the steel skeleton, a longitudinal reinforcing member in the bridge axis direction is disposed and fixed on the upper surface of the base member between the main girder diameters, while a lateral reinforcing member in a direction orthogonal to the bridge axis is provided on the upper surface of the base member on the overhang portion. Is arranged and fixed, and the horizontal reinforcing member is connected to the vertical reinforcing member, so that the vertical reinforcing member extending in the bridge axis direction between the main girder diameters transmits a load to the horizontal girder. In this manner, the space between the slab supports can be set to the horizontal girder spacing, and high rigidity in the direction perpendicular to the bridge axis can be obtained at the overhanging portion by the horizontal reinforcing member extending in the direction perpendicular to the bridge axis. As a result, a support member such as a bracket for supporting the overhang portion is not required, and the span of the main girder and the overhang portion can be constructed by the same method without the need for a support work. The present invention can provide a reasonable and low-cost synthetic floor slab without adopting a weight and without requiring a long construction period.
[0035]
The steel skeleton comprises a central steel skeleton provided with the vertical reinforcing member and constituting the main girder span, and a side steel skeleton provided with the lateral reinforcing member and constituting the overhang portion. Are fastened to a connecting plate welded and fixed to the longitudinal reinforcing member, and the central steel skeleton and the side steel skeleton are connected to each other, so that the central steel skeleton and the side steel skeleton The above structure can be easily and firmly connected, and can be a rational structure with good workability.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view orthogonal to a bridge axis of a main girder portion of a bridge to which an example of a composite floor slab according to the present invention is applied.
FIG. 2 is a sectional view taken along line AA of FIG.
FIG. 3 is a sectional view taken along line BB of FIG. 1;
FIG. 4 is a plan view of a steel skeleton corresponding to the plan view of FIG. 1;
5A is an enlarged view of a portion X in FIG. 4, FIG. 5B is a cross-sectional view taken along the line YY of FIG. 4A, and FIG.
FIG. 6 is a cross-sectional view of a floor slab as a conventional example.
[Explanation of symbols]
1 bridge 10 girder set 11 main girder 12 horizontal girder 20 floor slab (steel concrete composite floor slab)
21 Concrete layer 30 Steel frame 30A Central steel frame 30B Side steel frame 31 (31A, 31B) Bottom steel plate (substrate member)
32 Reinforcement beam (reinforcement member)
32A vertical reinforcing beam (vertical reinforcing member)
32B Lateral reinforcement beam (lateral reinforcement member)
35 Coupling plate

Claims (2)

In a composite slab girder supported by a steel girder, a steel-concrete composite slab in which the concrete layer is integrated with the steel skeleton and the strength is synthesized,
The girder set supports the floor slab by a main girder in a direction orthogonal to the bridge axis and a horizontal girder bridged between the main girder,
In the steel frame, a longitudinal reinforcing member in the bridge axis direction is disposed and fixed on the upper surface of the substrate member between the main girder diameters, and a lateral reinforcing member in a direction orthogonal to the bridge axis on the upper surface of the substrate member on the overhang portion. Wherein the horizontal reinforcing member is connected to the vertical reinforcing member. The steel skeleton includes a central steel skeleton that includes the longitudinal reinforcing member and configures the main girder span, and a side steel skeleton that includes the lateral reinforcing member and configures the overhang portion. The composite floor slab according to claim 1, wherein the central steel skeleton and the side steel skeleton are connected to each other by being fastened to a connecting plate welded and fixed to the vertical reinforcing member. digit.

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