JP5901675B2 - Steel / concrete composite floor slab - Google Patents

Description

  The present invention relates to a steel / concrete composite slab.

  Steel / concrete composite slab, which is a composite structure of steel material with tensile strength and concrete body with compressive strength, is applied as the structural type of bridge floor plates and floor plates installed in tunnels such as shield tunnels. There is a case.

  Here, in Patent Document 1, a plurality of hat-type rib members are laid on the bottom steel plate in parallel to the direction perpendicular to the bridge axis and at a predetermined interval in the bridge axis direction. A steel / concrete composite slab is disclosed in which the head stud studs are attached at predetermined intervals in the direction of the bridge axis and in the direction perpendicular to the bridge axis, and concrete is cast on the bottom steel plate.

  Further, Patent Document 2 discloses that a resin gap forming mold made of resin material such as foamed polystyrene or urethane foam, which is light and easy to cut, is installed on the bottom steel plate, and is placed on the bottom steel plate between the concrete gap forming molds. A steel / concrete composite slab is disclosed that is constructed by attaching a plurality of stud gibbles with heads and placing concrete on a bottom steel plate.

  As disclosed in Patent Documents 1 and 2, conventional steel / concrete composite floor slabs are intended to integrate the bottom steel plate and the concrete body with a number of stud gibber with heads, etc. It takes time and money to connect the attached stud gibber etc. to the bottom steel plate by welding or the like, which is one factor affecting the construction cost.

  Regarding the weight, the steel / concrete composite floor slab disclosed in Patent Document 1 has a hollow hat-shaped rib as a component for the purpose of reducing its weight, and the steel / concrete composite floor slab disclosed in Patent Document 2 is also the same. The concrete gap forming formwork is used as a component for the purpose of weight reduction, but since all the stud studs with heads are applied for all, it is economical to adopt hat type ribs and concrete gap forming formwork. The effect is reduced.

JP 2010-255196 A JP 2012-154124 A

  The present invention has been made in view of the above-mentioned problems, has a high unity between the bottom steel plate and the concrete material while eliminating the headed stud gibber and the like, and is significantly lighter than the conventional structure. The purpose is to provide the planned steel-concrete composite slab.

  In order to achieve the above object, a steel / concrete composite floor slab according to the present invention comprises a bottom steel plate, a skeleton body comprising a plurality of hollow block gibels fixed on the bottom steel plate, and a block gibel on the bottom steel plate. And a concrete body formed so as to be embedded.

  In the steel / concrete composite slab of the present invention, a plurality of hollow block dowels were attached on the bottom steel plate, and a concrete body was formed by embedding the block gibels on the bottom steel plate, and their integration was achieved. Is. Since the block diver has a hollow structure, the entire floor board can be reduced in weight.

  In addition, the hat-type rib material disclosed in Patent Document 1 and the concrete gap forming mold disclosed in Patent Document 2 are not expected to have a function of preventing slippage. Is what you expect. That is, while the techniques disclosed in Patent Documents 1 and 2 make a large number of stud gibels in addition to the hat-type rib material and the concrete gap forming mold, the floorboard of the present invention is a hollow block. Only the gibber realizes both integration and weight reduction of the entire floorboard.

  The block gibber is made of steel, and joining to the bottom steel plate is performed by an adhesive having high adhesive strength in addition to welding.

  Here, examples of the shape of the hollow block dowel include a prismatic shape, a cylindrical shape, and an elliptical prism shape, as well as a cone shape, a pyramid shape, a truncated cone shape, and a truncated pyramid shape.

  Among them, the truncated pyramid shape can be said to be a desirable shape because it can easily calculate the adhesion area between the concrete body and the concrete body and the block gibber in terms of design.

  In addition, the truncated pyramid type is such that when the worker joins the foot of the block gibel and the bottom steel plate by welding from above, the cross-sectional area becomes smaller as it goes upward, so that good welding workability can be secured. Can also be said to be a suitable shape.

  Of the truncated pyramids, a truncated quadrangular pyramid is desirable. Here, “squares” of “quadrangular pyramids” include squares, rectangles, rhombuses, parallelograms, and the like.

  When steel / concrete composite floor slabs are installed on the main girder extending in the direction of the bridge axis, two adjacent edges among the four edges where the block square of the truncated quadrangular pyramid contacts the bottom steel plate A truncated square pyramid block dowel is arranged so that one of the two faces in the direction of the bridge axis and the other in the direction perpendicular to the bridge axis.

  The area of each face of each truncated square pyramid block gibber, the bridge axis direction, and the bridge axis so as to satisfy the horizontal shear strength between the block diver and the concrete body required in the bridge axis direction and the direction perpendicular to the bridge axis Sets the radix of the block gibel to the right angle method. In addition, since each side surface constituting the truncated quadrangular pyramid is an inclined surface, when calculating the shear strength, the shear strength is calculated based on the area of the projection surface when each side surface is projected onto the vertical surface. . When the truncated quadrangular pyramid is installed on the bottom steel plate with the above arrangement, each of the two sides bears the shear strength in each of the two directions in the bridge axis direction, and each shear strength in the two directions in the direction perpendicular to the bridge axis. The remaining two sides will each bear.

  Furthermore, it is preferable that the height of the block jib is set to a height equal to or less than the neutral axis of the steel / concrete composite deck.

  Regarding the bending resistance due to the weight of the slab and the wheel load, concrete is poor in tensile resistance, so the design expects tensile resistance only for steel. Further, the punching shear force due to the wheel load is expected to have a proof strength depending on the thickness of the concrete in the compression region. Therefore, even if the concrete in the tensile region is replaced with a block diver, it does not affect the bending strength or punching shear strength of the slab.

  In addition, the size including the height of the block jib also affects the size of the hollow, and the larger the size of the hollow, the more the weight of the steel / concrete composite deck is reduced. On the other hand, when the width and length of the block jib are increased, the contact area with the concrete body is lowered, and there is a possibility that necessary horizontal shear strength cannot be ensured. In addition, if the height of the block jib is made higher than the neutral shaft, the effective cross section of the concrete body is reduced, so that there is a possibility that the compression resistance expected for the concrete body will be insufficient.

  As described above, the size of the block jib affects both the required horizontal shear strength and compression strength, and therefore is determined by comprehensively considering these factors.

  Further, a preferred embodiment of the steel / concrete composite slab according to the present invention is a form in which the concrete body is made of a precast manufactured in a factory.

  By applying precast steel / concrete composite floor slabs, it is possible to increase the construction efficiency during bridge construction and tunnel construction and shorten the construction period.

  Further, in another embodiment of the steel / concrete composite floor slab according to the present invention, steel vertical ribs are provided on the bottom steel plate at intervals, and a plurality of hollow block gibels are provided between the provided vertical ribs. It is arranged.

  The longitudinal ribs are necessary in this case, particularly when the concrete body is constructed on site. In this case, the dead weight of the concrete body becomes a dominant factor for determining the member cross section. Therefore, when placing concrete, it is common to deal with form support, but from the viewpoint of shortening the work period, if it is assumed that this form support will not be used, vertical ribs are formed on the bottom steel plate. By attaching it, it is possible to deal with bending moments and the like caused by the concrete body weight with this vertical rib. In addition, as a vertical rib, the form which combined these 2 types or more besides H type steel, I type steel, C type steel, a flat steel is applicable.

  Further, when welding the steel block dowel and the vertical rib to the bottom steel plate, the working efficiency can be improved by simultaneously welding both members to the bottom steel plate.

  As can be understood from the above description, according to the steel / concrete composite floor slab of the present invention, a hollow block dowel is attached on the bottom steel plate, and a concrete body is formed by winding the block dowel. Because it is possible to eliminate the mounting of the stud gibber, the integration of the concrete body and the bottom steel plate can be achieved and the displacement prevention effect can be achieved only by the block jib, and furthermore, the volume of the concrete body can be reduced as much as possible. The weight of the entire floorboard can be reduced.

It is a perspective view of Embodiment 1 of the frame which constitutes the steel and concrete composite floor slab of the present invention. 1 is a perspective view of Embodiment 1 of a steel / concrete composite deck according to the present invention. (A) is a perspective view of Embodiment 1 of a block dowel, (b) is a bb arrow line view of (a). (A), (b), (c), (d) is a perspective view of Embodiment 2-5 of a block dowel, respectively. It is a perspective view of Embodiment 2 of the frame which constitutes the steel and concrete composite slab of the present invention. It is a perspective view of Embodiment 2 of the steel and concrete composite floor slab of this invention. It is a VII-VII arrow line view of FIG. It is the figure which showed the result of having implemented weight comparison for every floor-plate span length regarding the steel and concrete composite floor slab concerning an Example and a comparative example.

  Hereinafter, embodiments of a steel / concrete composite deck according to the present invention will be described with reference to the drawings.

(Embodiment 1 of steel / concrete composite floor slab)
FIG. 1 is a perspective view of Embodiment 1 of a skeleton body constituting a steel / concrete composite floor slab of the present invention, and FIG. 2 is a perspective view of Embodiment 1 of a steel / concrete composite floor slab of the present invention. . FIG. 3A is a perspective view of the first embodiment of the block jib, and FIG. 3B is a view taken along the line bb in FIG. 3A.

  A skeleton body 10 shown in FIG. 1 is composed of a bottom steel pipe 1 and a plurality of block dowels 2 fixed on the bottom steel pipe 1 by welding.

  The X1 direction is, for example, the traveling direction of the vehicle. When a steel / concrete composite slab having a skeleton body 10 is applied to a bridge, it is bridged in a direction orthogonal to a main girder extending in the X1 direction. Installation is performed at. Moreover, when applied to the floor board in a shield tunnel, it is bridged to the right and left support parts in the tunnel.

  As shown in FIG. 2, a steel / concrete composite floor slab 100 is manufactured by constructing a concrete body 20 above the skeleton body 10.

  Here, as shown in FIG. 3, the block gibber 2 includes a hollow 2 a and has a truncated quadrangular pyramid shape (a square is a rectangle).

  As apparent from FIGS. 1 and 2, depending on the required shear strength, the block dowels 2 may be densely arranged on the bottom steel plate 1. In such a configuration, since the block diver 2 has a truncated pyramid shape, when a worker joins the foot of the block gibel 2 and the bottom steel plate 1 by welding from above, the cross-sectional area of the block diver 2 is Since it becomes small as it goes upwards, favorable welding workability | operativity can be ensured.

  Further, when the X1 direction of FIG. 1 is the bridge axis direction and the orthogonal direction is the bridge axis perpendicular direction, the two adjacent edges among the four edges where the block square 2 of the truncated quadrangular pyramid contacts the bottom steel plate 1 A truncated square pyramid block dowel 2 is arranged so that one of the sides faces the bridge axis direction and the other faces the bridge axis perpendicular direction. The area of each surface of each truncated quadrangular pyramid block gibel 2 so as to satisfy the horizontal shear strength between the block gibel 2 and the concrete body 20 required in the bridge axis direction and the direction perpendicular to the bridge axis, and the bridge axis direction Although the radix of the block dowel 2 to the bridge axis orthogonal method is designed, this ease of design can also be enjoyed when the truncated quadrangular block dowel 2 is applied. For example, when assuming a truncated cone block diver as a comparison object, it can be understood that it is easy to design a truncated quadrangular pyramid block dove by making a comparison with this.

  Further, the steel / concrete composite floor slab 100 does not use any stud gibber as in the conventional structure, and the skeleton body 10 and the concrete body 20 are integrated only by the block gibber 2 having the hollow 2a. Therefore, manufacture becomes easy.

  In addition to the forms shown in FIGS. 1 to 3, the block dowel has a truncated conical form as shown in FIG. 4a, a truncated elliptical cone form as shown in FIG. 4b, and as shown in FIG. 4c. It may be in the form of a truncated quadrangular pyramid (a square is a square) or a quadrangular prism shape as shown in FIG. 4d.

  The steel / concrete composite floor slab 100 may be made, for example, by precasting the skeleton body 10 in a factory and constructing the concrete body 20 on-site, but by making the entire steel / concrete composite floor slab 100 precast. The construction efficiency when the steel / concrete composite floor slab 100 is applied to the construction of a bridge or a tunnel can be improved, and the construction period can be shortened.

(Embodiment 2 of steel / concrete composite deck)
FIG. 5 is a perspective view of Embodiment 2 of a skeleton body constituting the steel / concrete composite floor slab of the present invention, and FIG. 6 is a perspective view of Embodiment 2 of the steel / concrete composite floor slab of the present invention. 7 is a view taken along arrow VII-VII in FIG.

  In the illustrated skeleton body 10A, steel vertical ribs 3 are provided on the bottom steel plate 1 at intervals, and a plurality of hollow block dowels 2 are disposed between the vertical ribs 3 provided. More specifically, a flat bar 4 is fixed to the end of the bottom steel plate 1, and a plurality of vertical ribs 3 are disposed therein.

  Here, as the vertical rib 3, H-shaped steel, I-shaped steel, C-shaped steel or the like can be applied.

  Further, it is possible to weld the vertical rib 3 and the block dowel 2 to the bottom steel plate 1 at the same time.

  The steel / concrete composite floor slab 100A provided with the longitudinal ribs 3 in this manner is particularly suitable when the concrete body 20 is constructed on site. In this case, since the weight of the concrete body 20 is a dominant factor for determining the cross section of the member, it is common to deal with placing the concrete with a formwork support, but from the viewpoint of shortening the work period, this formwork support work is performed. If the vertical rib 3 is attached to the bottom steel plate, it is possible to cope with a bending moment or the like caused by the weight of the concrete body 20 with the vertical rib 3.

  In addition, as shown in FIG. 7, it is preferable that the height of the block diver 2 is set to a height equal to or less than the neutral axis N of the steel / concrete composite floor slab 100A. Specifically, when the height of the steel / concrete composite floor slab 100A is t1, and the height of the neutral axis N is t1 / 2, the height t2 of the block gibber 2 is t1 / 2 or less. Adjust to.

[Estimation and results of verifying steel weight and concrete weight of composite floorboard]
The present inventors made a trial calculation to verify the weight of each steel material and the concrete weight for the synthetic floor boards according to the following two types of Examples 1 and 2 and Comparative Examples 1 and 2. Hereinafter, Example 1 and Comparative Example 1, and Example 2 and Comparative Example 2 are comparative objects, respectively.

(Example 1)
The synthetic floor board according to Example 1 is provided with a block gibber and a concrete body is constructed on site. Here, the width of the bottom steel plate is 2300mm, two large I-shaped steels are used, and the total weight is 3100kg.

(Comparative Example 1)
The synthetic floorboard according to Comparative Example 1 does not have a block jebel and is a concrete body constructed on site. Here, the width of the bottom steel plate is 2300 mm, three large I-shaped steels are used, the I-shaped steel web is punched, and the total weight is 3220 kg.

(Example 2)
The synthetic floor board according to Example 2 is a pre-cast floor board including a block body and including a concrete body. Here, the width of the bottom steel plate is 2420 mm and the total weight is 14506 kg.

(Comparative Example 2)
The synthetic floor board according to Comparative Example 2 is a floor board made of precast including a concrete body without including a block diver. Here, the width of the bottom steel plate is 2420 mm, and the total weight is 17466 kg.

(Comparison results)
When Example 1 and Comparative Example 1 were compared, since both used large I-shaped steel, no support work was required when placing concrete. Further, in Example 1, the concrete volume can be suppressed by arranging the hollow block dowel, and further, the total weight can be reduced as compared with Comparative Example 1 by reducing the number of I-shaped steels. I was able to.

  On the other hand, when Example 2 and Comparative Example 2 were compared, the amount of work on site was greatly reduced because both were made of precast. Further, in Example 2, the volume of the concrete could be suppressed by arranging the hollow block dowel, and the overall weight could be reduced as compared with Comparative Example 2.

  Furthermore, the present inventors made a trial calculation to compare the composite floor board weight for each floor board span length. Here, Comparative Example A is a floor board in which five flat steels are applied to the longitudinal ribs in the longitudinal section, Comparative Example B is a floor board in which three I-shaped steels are applied to the longitudinal ribs, and Example A is the longitudinal rib. It is a floor board using two I-shaped steels and a block jib. In addition, as shown in FIG. 5, each floor board has two flat steel separately in the both ends of a longitudinal cross section. Further, in both Comparative Example A, Comparative Example B, and Example A, the number of ribs and the like are determined so that the total value of the stress level of the bottom steel plate due to the dead load and the stress level of the bottom steel plate due to the live load is approximately the same. did. The trial calculation results are shown in FIG.

  From the figure, it was found that in Example A, compared to Comparative Examples A and B, a weight reduction of about 20% was achieved for each span length.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and there are design changes and the like without departing from the gist of the present invention. They are also included in the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Bottom steel plate, 2, 2A, 2B, 2C, 2D ... Block jib, 2a ... Hollow, 3 ... Vertical rib (I-shaped steel), 4 ... Vertical rib (flat steel), 10, 10A ... Skeleton, 20 ... Concrete Body, 100, 100A ... Steel / concrete composite floor slab

Claims (4)

A bottom steel plate, a plurality of hollow and truncated quadrangular pyramid block gibels fixed on the bottom steel plate, a skeleton body, and a concrete body formed so as to embed the block diver on the bottom steel plate, A steel-concrete composite floor slab formed from
When the steel / concrete composite floor slab is arranged on the main girder extending in the direction of the bridge axis, two adjacent edges out of the four edges where the block square of the truncated quadrangular pyramid contacts the bottom steel plate A steel / concrete composite slab with one side facing the bridge axis and the other facing the direction perpendicular to the bridge axis . The steel / concrete composite floor slab according to claim 1, wherein the height of the block gibel is set to a height equal to or less than the neutral axis of the steel / concrete composite floor slab. The steel / concrete composite floor slab according to claim 1, wherein the concrete body is made of a precast manufactured in a factory. The steel / concrete according to any one of claims 1 to 3 , wherein steel vertical ribs are provided at intervals on the bottom steel plate, and a plurality of hollow block dowels are disposed between the provided vertical ribs. Synthetic floor slab.

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