JP2007198055A - Bridge structure made of synthetic floor plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bridge structure constructed of a synthetic floor plate which can simplify molding processing and attaching work, and can reduce construction cost by omitting a haunch structure since the processing of a haunch plate and a foor steel plate and their attachment at a work site become complicated, and makes impossible sufficinet reduction in cost when conducting the streamlining of the bridge structure made of the synthetic floor plate. <P>SOLUTION: The center of the floor plate 12 composed of the synthetic floor plate in the direction at right angles with respect to a bridge shaft is supported by a main girder 13 composed of a box girder of a small width. Then a bracket 14 is projected from the lower end of the main girder 13 in a slanting upward direction, and the tip of the bracket 14 is jointed to the end of the floor plate 12 in the direction at right angles with respect to the bridge shaft. By this, since the floor plate 12 is supported at its center and its end and not cantilevered, becomes possible to keep the thickness of the floor plate constant by reducing bending moment by a dead load and a unit load of the floor plate, and thus the haunch part can be omitted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a bridge structure made of a composite floor slab for rationalizing a steel bridge structure using a composite floor slab of steel and concrete.

  Of the structures that make up the bridge, the floor slab supports the wheel load and transmits the load to the floor assembly or main structure. This type of floor slab does not require formwork for floor slab construction. In order to save labor and shorten the construction period, there is a composite floor slab that integrates a bottom steel plate and concrete. On the other hand, as a bridge structure that aims to rationalize with steel bridges, such as reducing materials and shortening the construction period, for example, a conventional 4-main girder bridge consisting of 4 main girders is a 2-main girder bridge with 2 main girder. Or the box girder bridge is an open section girder bridge or narrow box girder bridge.

  FIG. 7 shows a bridge 1, which is a four-main girder bridge structure in which a floor slab 2 is supported by four main girders 3. As shown in FIG. 8, the bridge having this structure has a structure in which the floor slab 2 is supported by two main girders 4 and a horizontal girder 5 is spanned over the two main girders 4. Thereby, rationalization can be achieved by reducing the number of members to reduce the construction period and shortening the construction period.

  By the way, in order to obtain a rational bridge structure, if the number of main girders is reduced, the negative bending moment applied to the support portion of the floor slab increases, so it is necessary to have a structure that can resist this negative bending moment. As this structure, for example, it is conceivable to increase the cross-sectional area by increasing the thickness of the floor slab. However, the cross-sectional shape of the floor slab will be determined by the cross-sectional shape in the support part, the dead load will increase and the girder cross section will increase, the amount of steel will increase, hindering the reduction of material, It becomes a bridge with a structure that cannot be fully rationalized.

  Normally, a haunch structure is adopted at the joint between the floor slab and the main girder, and a floor slab thickness that resists the negative bending moment of the support portion is provided. For example, Patent Document 1 discloses a structure in which a stud for preventing slippage is welded on a flange of a main girder having a two-main girder structure, and a concrete is driven by providing a hole for fitting the stud in a bottom steel plate. A structure in which the flange of the main girder is continuous with the haunch plate is disclosed. Patent Document 2 and Patent Document 3 disclose a bridge structure in which a haunch structure is adopted at a joint portion between a main girder having a two-main girder structure and a floor slab.

  3 and 4 show the haunch structure of the composite floor slab. A flange plate 6 is welded to the upper end portion of the main girder 4, and a stud dowel 6 a is implanted in the flange plate 6. A haunch plate 8 is stretched between the end of the flange plate 6 in the direction perpendicular to the bridge axis and the bottom steel plate 7a of the floor slab 7. A stud bolt 9 is used for joining the end portion of the haunch plate 8 to the flange plate 6 and the bottom steel plate 7a. As shown in FIG. 4, an opening 7b is formed in a part of the bottom steel plate 7a facing the flange plate 6, and the end of the stud gibber 6a is bottomed from the opening 7b. It protrudes to the upper side of the steel plate 7a. Further, a gibber material 10 made of mold steel is welded at an appropriate position of the haunch plate 8 and in the vicinity of the joint between the haunch plate 8 and the bottom steel plate 7a. Then, when concrete is driven in, it reaches the haunch plate 8 from the opening 7b, and the stud plate 6a and the gibber material 10 ensure that the bottom steel plate 7 and the haunch plate 8 are joined to the concrete. is there.

  5 and 6 show a distribution curve L of the negative bending moment in the bridge. FIG. 5 shows a case where the haunch structure is adopted, and FIG. 6 shows a case where the haunch structure is not adopted. In any structure, the negative bending moment generated in the support portion is maximized, and the negative bending moment is reduced at the end portion protruding from the support portion. In the case where the haunch portion is provided, the cross-sectional area of the haunch structure can also contribute to the structural design by having a function of resisting the negative bending moment. In the case where the haunch structure shown in FIG. 6 is not adopted, in order to resist the negative bending moment as in the case where the haunch structure is adopted, it is necessary to increase the cross-sectional area of the support portion, that is, increase the thickness of the floor slab. is there.

JP 2002-13108 A JP 2002-81018 A Japanese Patent No. 3611510

  With the above-described haunch structure, the haunch portion can resist the negative bending moment as an effective cross section, and the thickness of the floor slab 2 is not increased, and the members can be reduced. However, in the case of a structure in which the haunch plate 8 is combined with a composite floor slab, the end portion of the haunch plate 8 is connected to the flange plate 6 and the haul plate 8 in order to ensure the joining of the bottom steel plate 7 and the haunch plate 8. It is necessary to bend and form so as to match the bottom steel plate 7. Further, it is necessary to perform the installation work of the haunch plate 8 on site. For this reason, by adopting the haunch structure, the number of man-hours due to the production of the haunch plate 8 and the number of on-site work processes increase and the construction period increases, which may increase the construction cost of the bridge.

  On the other hand, when the haunch structure is simply omitted, as described above, it is necessary to increase the cross-sectional area of the support portion by the main girder 4 to resist the bending moment. Since the negative bending moment is small in the portion protruding outward from the main girder 4 of 2, the thickness of the floor slab 2 of the portion can be reduced. In this case, since the position of the upper surface of the floor slab 2 constitutes the road surface, the height position cannot be changed, and the bottom steel plate 7 located outside the main girder 4 is biased upward. The bottom steel plate 7 needs to be bent. Therefore, even if the haunch structure is omitted, there is a possibility that the processing steps of the bottom steel plate 7 will increase and the work steps at the site will increase, and the construction cost of the bridge will not be reduced.

  Accordingly, an object of the present invention is to provide a bridge structure made of a composite floor slab without providing a haunch structure and without increasing the cross-sectional area of the floor slab and inhibiting the reduction.

  As a technical means for achieving the above object, a composite floor slab bridge structure according to the present invention comprises a bottom steel plate, and a composite floor slab bridge structure using a composite floor slab made of steel and concrete, The main girder is arranged in the central portion of the synthetic floor slab in the direction perpendicular to the bridge axis, and supports the synthetic floor slab, and the bracket is extended from the main girder and connected to the end of the synthetic floor slab. It is characterized by that.

  The composite floor slab is supported by the main girder at the center in the direction perpendicular to the bridge axis, and the end is supported by the bracket. The end portion of the composite slab is supported without being cantilevered from the main girder to the side, and the negative bending moment generated at the support portion can be reduced. As the bracket, a steel pipe, a shaped steel, a concrete-filled steel pipe, reinforced concrete, prestressed concrete, or the like can be used.

  The bridge structure made of a composite floor slab according to the invention of claim 2 is characterized in that the main girder is a narrow box girder and the bracket is projected from the lower end of the narrow box girder.

  Although the structure of the main beam can be various, it is a narrow box beam which is the most rational structure.

  The bridge structure made of a composite floor slab according to the invention of claim 3 is a bridge structure made of a composite floor slab comprising a bottom steel plate and using a composite floor slab made of steel and concrete. A main girder that supports the composite floor slab by being arranged at both ends in a right angle direction, and a vertical girder that is arranged to be connected to the main girder and supports the central part in the direction perpendicular to the bridge axis of the composite floor slab. It is a feature.

  The ends of the composite floor slab in the direction perpendicular to the bridge axis are supported by the main girder, and the end of the composite floor slab is supported without being cantilevered laterally from the main girder. It is possible to prevent the negative bending moment from being generated. Further, by supporting the center portion of the composite slab with a vertical girder, an increase in the slab thickness can be prevented by reducing the positive bending moment at the center of the floor slab support. In order to link the vertical girder to the main girder, for example, a structure in which a horizontal girder is spanned over the main girder and supported by the horizontal girder can be employed.

  According to the bridge structure made of composite floor slab according to the present invention, since the end portion of the composite floor slab does not have a cantilever structure, the negative bending moment generated at the joint with the main girder can be reduced, and a haunch structure is provided. Even if not, a synthetic floor slab that does not increase the cross-sectional area can be used. By omitting the haunch part, it is not necessary to form the haunch plate or bottom steel plate. Even if the bracket is formed and the installation work is performed on site, the workability and assemblability of the members for bridge construction are improved. Thus, the construction cost can be reduced.

  Further, according to the bridge structure made of a composite floor slab according to the invention of claim 2, the bracket can be easily attached and the attachment workability can be improved.

  Further, according to the composite floor slab bridge structure according to the invention of claim 3, by omitting the haunch structure, it is not necessary to form a haunch plate or a bottom steel plate, thereby improving workability and assemblability. Construction costs can be reduced.

  Hereinafter, based on the illustrated preferred embodiment, the bridge structure made of a composite floor slab according to the present invention will be specifically described.

  FIG. 1 shows a first embodiment, in which a composite floor slab bridge 11 having this structure is cut along a plane perpendicular to the bridge axis. The floor slab 12 is a composite slab of steel and concrete in which concrete is driven into the upper surface of the bottom steel plate 12a. The center portion of the floor slab 12 in the direction perpendicular to the bridge axis is supported by a main girder 13 by a narrow box girder via a flange plate 13a. A base end portion of the bracket 14 is attached to the lower end portion of the main girder 13 so as to project obliquely upward in a direction perpendicular to the bridge axis. The front ends of the brackets 14 are joined to both ends of the floor slab 12 in the direction perpendicular to the bridge axis. Therefore, the floor slab 12 is supported by the main girder 13 and the bracket 14 at the center and both ends in the direction perpendicular to the bridge axis.

  As the bracket 14, a structure or material having good workability and mounting workability may be selected. For example, an appropriate one such as a steel pipe, a shape steel, a concrete-filled steel pipe, reinforced concrete, or prestressed concrete is used. In addition, the mounting structure of the bracket 14 is a structure according to workability, such as a welded one or a stud bolt.

  In the bridge structure made of the composite floor slab of the first embodiment, even when the central portion is supported by the main girder 13, the end portion side of the floor slab 12 does not have a cantilever structure, so a negative bending moment generated in the support portion is not generated. It becomes small and can prevent increase in floor slab thickness. Moreover, since the cross-sectional area of the floor slab 12 is uniform, there is no need to bend the bottom steel plate 12a. Further, the work of attaching the haunch plate can be omitted.

  FIG. 2 shows a second embodiment of the composite floor slab bridge 21 having the structure according to the present invention, and is a cross-sectional view cut in a direction perpendicular to the bridge axis. As the floor slab 22 of the second embodiment, a synthetic floor slab made of steel and concrete is used. Both ends of the floor slab 22 in the direction perpendicular to the bridge axis are supported by a main girder 23 of I-girder through a flange plate 23a. A horizontal girder 24 is stretched over the main girder 23, and a central portion of the floor slab 22 in the direction perpendicular to the bridge axis is supported by a vertical girder 25 by an I-girder supported by the cross girder 24.

  In the bridge structure made of a composite floor slab according to the second embodiment, both ends are supported by the main girder 23 and the floor slab 22 is not cantilevered, and is supported by the vertical girder 25 in the center part. Negative bending moment generated in the support portion of the floor slab 22 can be suppressed. Therefore, the floor slab 22 can be made uniform without increasing the cross-sectional area. Therefore, as compared with the case where the haunch structure is adopted, the forming work and the assembling workability at the site are improved, the number of members can be reduced, and a bridge having a structure with reduced construction cost can be obtained.

  In the embodiment described above, the narrow box girder is used as the main girder 13 and the I girder is used as the main girder 23. However, the girder according to conditions such as terrain on which the bridge is constructed and traffic volume is used. It can be a structure.

  In the composite floor slab bridge structure according to the present invention, the bending moment can be resisted without increasing the cross-sectional area of the floor slab without providing a haunch structure. For this reason, it is possible to contribute to constructing an economically advantageous bridge by improving the workability of installation on the site, reducing the cost and construction period, without requiring the forming process of the haunch plate or the bottom steel plate.

It is a figure explaining the bridge made from synthetic floor slab provided with the structure concerning a 1st embodiment of this invention, and is a sectional view cut in the direction perpendicular to the bridge axis. It is a figure explaining the bridge made from synthetic floor slab provided with the structure concerning a 2nd embodiment of this invention, and is a sectional view cut in the direction perpendicular to the bridge axis. It is a figure explaining the haunch part provided in the support part of the floor slab by a main girder, and it is a sectional view cut away in the direction perpendicular to the bridge axis, and omitting a part. It is a top view of the haunch part in FIG. This shows the distribution of negative bending moment generated in the floor slab. When a haunch structure is adopted, the cross-sectional area of the haunch part functions as a resistance part of the negative bending moment. This shows the distribution of the negative bending moment generated in the slab, and indicates that when the haunch structure is not adopted, it is necessary to increase the cross-sectional area at the support portion of the slab, that is, the thickness of the slab. It is sectional drawing cut | disconnected in the bridge axis orthogonal direction which shows 4 main girder bridges. It is sectional drawing cut | disconnected in the direction orthogonal to the axis | shaft which shows the 2 main girder bridge which aimed at rationalization of the structure of the 4 main girder bridge shown in FIG.

Explanation of symbols

11 Composite floor slab bridge
12 Floor slab
12a Bottom steel plate
13 Main digits
13a Flange plate
14 Bracket
21 Composite floor slab bridge structure
22 Floor slab
23 Main digits
23a Flange plate
24 horizontal girder
25 column

Claims (3)

In the bridge structure made of composite floor slab using a composite floor slab made of steel and concrete, equipped with a bottom steel plate,
A main girder that supports the composite floor slab arranged in the central portion of the composite floor slab perpendicular to the bridge axis;
A bridge structure made of a composite floor slab, characterized by comprising brackets projecting from the main girder and respectively connected to end portions of the composite floor slab.   The bridge structure made of a composite floor slab according to claim 1, wherein the main girder is a narrow box girder, and the bracket is projected from a lower end portion of the narrow box girder. In the bridge structure made of composite floor slab using a composite floor slab made of steel and concrete, equipped with a bottom steel plate,
A main girder that supports the composite floor slab arranged at both ends of the composite floor slab perpendicular to the bridge axis;
A bridge structure made of a composite floor slab which is arranged to be connected to the main girder and serves as a vertical girder which supports a central portion of the composite floor slab in a direction perpendicular to the bridge axis.

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