JP7219569B2 - composite deck slabs - Google Patents

Description

The present invention relates to composite deck slabs.

In recent years, in the design of joints between steel beams and floor slabs, composite beams have been designed by integrating steel beams and floor slab concrete using the shear resistance function of studs provided on the steel beam flanges. Another design is to transmit the horizontal force applied to the floor slab during an earthquake to the steel beam using the shear resistance function of the stud, and studs are often provided on the flange of the steel beam.
A typical example of a composite deck slab is shown in FIG. A composite deck slab is formed by arranging a wire mesh 13 on the upper surface of a deck plate (folded steel plate) placed on left and right beams such as a steel frame and placing concrete 12 thereon. Further, as proposed in Patent Literature 1, it is also proposed to provide studs 15 on the flange of the steel frame for reinforcement.
Conventionally, when joining a steel frame beam and a floor slab, a technique has been proposed in which a stud is provided on the flange of the steel frame beam and the concrete of the steel frame beam and the floor slab are integrated (for example, Patent Document 1 (Japanese Unexamined Patent Application Publication No. 2004-120000). 2012-012788))).
Patent Document 2 (Japanese Patent Application Laid-Open No. 2016-023440) provides a reinforcing member that is fixed to the concrete of the floor slab at the top of the upper flange of the steel beam by arranging a plurality of studs to reinforce the surroundings of the studs for the purpose of earthquake countermeasures. No. 5, 2003) and the like.

JP 2012-012788 A JP 2016-023440 A

As a result of examining the strength performance of the composite deck slab, the present inventor found that cracks extending from the top surface of the slab in the direction of the stud and cracks extending from the edge of the slab occur. An object of the present invention is to take measures to prevent this cracking.

The present invention has realized a composite deck slab that is reinforced at the ends by providing restraining members above the flanges of the steel beams or at the end faces of the slab concrete.
In particular, the members fastened to the studs provided on the top of the flange of the steel beam or placed near the studs disperse the shearing force and bearing pressure applied to the surrounding concrete, so in the event of a fire, the concrete around the studs will be affected. It suppresses the failure of concrete due to applied shear force and bearing pressure. And the floor slab can be enabled to support greater vertical loads.
The main configuration of the present invention is as follows.

1. In a composite deck slab consisting of a deck plate and slab concrete,
A composite deck slab using steel beams with studded flanges, the composite deck slab being provided with reinforcing means at least in the area of the flanges,
A composite deck slab, characterized in that the reinforcing means are U-shaped and are located on top of the flanges of the steel beams.
2. In a composite deck slab consisting of a deck plate and slab concrete,
A composite deck slab using steel beams with studded flanges, the composite deck slab being provided with reinforcing means at least in the area of the flanges,
A composite deck slab, characterized in that the reinforcement means are arranged by folding reinforcing bars downward from the top of the wire mesh at the slab ends.
3. In a composite deck slab consisting of a deck plate and slab concrete,
A composite deck slab using steel beams with studded flanges, the composite deck slab being provided with reinforcing means at least in the area of the flanges,
1. A synthetic deck slab, wherein the reinforcing means is arranged by extending a reinforcing steel bar arranged in a groove of the deck plate to the slab end side and bending it upward.
4. In a composite deck slab consisting of a deck plate and slab concrete,
A composite deck slab using steel beams with studded flanges, the composite deck slab being provided with reinforcing means at least in the area of the flanges,
1. A composite deck slab, wherein the reinforcing means is composed of a reinforcing bar extending from the groove of the deck plate toward the end of the slab and a steel plate joined to the end of the reinforcing bar.
5. In a composite deck slab consisting of a deck plate and slab concrete,
A composite deck slab using steel beams with studded flanges, the composite deck slab being provided with reinforcing means at least in the area of the flanges,
The reinforcing means is a reinforcing welded wire mesh having a narrower pitch than the mesh of the wire mesh, which is placed over the headed stud of the steel beam at the end of the slab and tied to the stud. Composite deck slabs.

1. The present invention can prevent cracking due to thermal exposure or the like by reinforcing the edges of the composite deck slab at the joint between the beam and the deck slab. Cracks can particularly be prevented from occurring on the upper side of steel beams towards the studs and cracks occurring at the slab ends.
2. A member tied to the stud provided on the upper part of the flange of the steel frame beam or arranged near the stud suppresses destruction of the concrete due to shear force and bearing pressure applied to the surrounding concrete. It also allows the floor slab to support greater vertical loads.
3. Since the slab ends, which are in the area of the upper flanges of the steel beams, are reinforced, the fixation of the slab ends of the composite deck slab to the steel beams can be improved.
4. The pull-out strength of the slab edge of the composite deck slab is improved, the degree of fixation to the steel frame beam is improved, and the expansion of cracks at the edge of the composite deck slab can be suppressed, increasing the permissible performance such as load capacity and span. can.

5. The present invention applies to composite deck slabs composed of deck plates and slab concrete, such as QL decks laid on steel beams, which are mainly applied to steel structures. Composite deck slabs collapse at the fulcrum position, which is the joint between the beam and the composite deck slab, in the event of a fire or the like. Therefore, by reinforcing the fulcrum position (joint position) of the composite deck slab, it is possible to improve the permissible performance such as the load and span, and improve the fire resistance performance.
In the present invention, as means for reinforcing the ends, (a) rebars are attached to both sides of the end studs, (b) the end studs are lengthened, (c) U-shaped rebars are inserted into the ends, ( d) Placing a reinforcing bar folded back from above the wire mesh, (e) Placing a reinforcing bar folded upward from the groove of the deck plate, (f) Placing a reinforcing bar with a steel plate joined to the end on the bottom surface of the wire mesh , (g) Reinforcing reinforcing bars with iron plates joined to their ends are placed in the grooves of the deck plate, (h) Reinforcing reinforcing bars arranged by sewing the studs, (i) Reinforcement welded wire mesh placed over the studs, (j ) Reinforcing bars are arranged by alternately stitching the studs so as to sandwich the studs.
6. For composite deck slabs, collapse of the fulcrum position (joint position) is one of the factors that determine the fire resistance time. The edge collapse of a composite deck slab during a fire is shown schematically in Figure 1. As shown in this figure, the stresses that develop concentrate around the studs, causing cracks in the concrete. Further, when the duration of heating is prolonged, the width of the generated cracks is increased rather than the number of cracks is increased, leading to collapse of the ends. Collapse of the composite deck slab is when it becomes 3-hinged. In a composite deck slab that does not have reinforcing means such as fire-resistant reinforcing bars, the collapse of the ends of the composite deck slab results in the collapse of the composite deck slab. can be made Also, if the beams that support the ends of the composite deck slabs are provided with a fire resistant coating, the reinforcement of the present invention will also be protected from the heat of the fire and will perform even better. In the present invention, reinforcement measures are taken to distribute the stress generated around the stud.

A diagram showing the edge collapse of a composite deck slab during a fire. (a) Schematic diagram Fig. 3 shows a composite deck slab with reinforcement measures according to the first embodiment; (a) (b) View of reinforcing steel bars provided on both sides of the stud, (c) (d) View of steel plates wider than the reinforcing bars provided along the direction of the stud FIG. 4 shows a composite deck slab with reinforcement measures according to the second embodiment; (a) Perspective view (b) Cross-sectional view Figure 3 shows a composite deck slab with reinforcement measures according to a third embodiment; (a) Perspective view (b) Cross-sectional view Figure 4 shows a composite deck slab with reinforcement measures according to a fourth embodiment; (a) Perspective view (b) Cross-sectional view (c) Perspective view of an example in which a reinforcing bar is added (d) Cross-sectional view of an example in which a reinforcing bar is added FIG. 5 shows a cross-section of a composite deck slab with reinforcing means according to a fifth embodiment; FIG. 6 shows a cross-section of a composite deck slab with reinforcement measures according to the sixth embodiment; FIG. 11 shows a cross-section of a composite deck slab with reinforcing means according to a seventh embodiment; FIG. 11 shows a composite deck slab with reinforcement measures according to an eighth embodiment; (a) Steel beam upper plan view (b) Steel beam perspective view FIG. 11 shows a composite deck slab with reinforcement measures according to the ninth embodiment; (a) Plan view (b) Perspective view Figure 10 shows a composite deck slab with reinforcement measures according to the tenth embodiment; (a) Steel beam upper plan view (b) Steel beam perspective view Diagram showing the construction of a typical composite deck slab.

The present invention is a composite deck slab with stiffening means at the ends.
The present invention applies to composite deck slabs composed of deck plates and slab concrete, such as QL decks laid on steel beams, which are mainly applied to steel structures. The basic structure of the composite deck slab is as shown in FIG. The QL deck is a deck plate that works together with concrete, and is a synthetic slab that conforms to Ministry of Land, Infrastructure, Transport and Tourism Notification No. 326 of 2002. Plays the role of a deck plate formwork when concrete is poured, and after the concrete hardens, the deck plate mainly resists tensile force and concrete resists compressive force, can withstand large loads, and can be spanned over a long span. . The composite slab of the QL deck can be designed as a composite slab for vertical and in-plane horizontal loads acting on the floor.
In addition, the steel beam can be designed as a composite beam by connecting the steel beam and the composite slab with headed studs.

Composite deck slabs collapse at the fulcrum position, which is the joint between the beam and the composite deck slab, in the event of a fire or the like. Therefore, the present invention reinforces the fulcrum position (joint position) of the composite deck slab to improve the permissible performance such as load and span, and to improve the fire resistance performance.
The main end reinforcing means of the present invention are (a) placing reinforcing bars on both sides of the end stud, (b) lengthening the end stud, and (c) inserting a U-shaped reinforcing bar into the end. (d) Placing reinforcing bars folded back from above the wire mesh, (e) Placing reinforcing bars folded upward from the grooves of the deck plate, (f) Reinforcing bars with iron plates joined to the ends on the bottom surface of the wire mesh Arrangement, (g) Reinforcing reinforcing bars with iron plates joined to the ends are placed in the grooves of the deck plate, (h) Reinforcing reinforcing bars arranged by sewing the studs, (i) Reinforcement welded wire mesh placed over the studs, ( j) Reinforcing bars in which a plurality of reinforcing bars are alternately arranged by stitching the stud so as to sandwich the stud.
By taking these reinforcement measures, the pull-out strength of the slab ends of the composite deck slab is improved, the degree of fixation to the steel frame beam is improved, and the spread of cracks at the ends of the composite deck slab can be suppressed, thereby reducing the load and the load. Allowable performance such as span can be increased.
The present invention prevents cracks that tend to occur on the end surface side and the end upper surface of the composite deck slab by improving the fixation of the composite deck slab end and dispersing the stress acting on the stud.
The strain caused by the load applied to the composite deck slab tends to concentrate on the studs installed on the flanges of the steel frame beams, which tends to induce cracks originating from the studs, but improves the fixation of the slab around the studs. Alternatively, by distributing the stresses to existing members such as adjacent studs, additional reinforcing bars, wire mesh, etc., cracking and pull-out at the edges of the composite deck slab can be reduced and yield strength improved.

Also, from the viewpoint of fire resistance, an improvement in fire resistance can be expected.
Composite deck slabs have fire endurance determined by collapse at the fulcrum location (joint location). The edge collapse of a composite deck slab during a fire is shown schematically in Figure 1, where the resulting stresses are concentrated around the studs, causing cracks in the concrete. In addition, when the heat exposure heating time is long, the width of the generated crack becomes large, leading to collapse of the edge.
Collapse of the composite deck slab is when it becomes 3-hinged. In deck slabs without reinforcing means such as refractory reinforcing bars, the collapse of the composite deck slab results in the collapse of the composite deck slab. Since the ends of the are reinforced, the fire resistance performance can be improved.

The inventors have found that when synthetic deck slabs are exposed to high temperatures, such as in fire, cracking develops as shown in FIG. 1, increasing edge weakness and reducing yield strength. Upon further analysis of the cracks, it was found that many of the cracks originate from the tips of the studs provided in rows on the upper surface of the flange of the steel beam.
FIG. 1 is a schematic diagram of a composite deck slab in which QL deck slabs are installed on left and right steel beams using H-shaped steel. To briefly show the cracks, from the upper end of the stud protruding from the upper surface of the flange of the steel beam (in this figure, an example of a stud with a head), the upper surface crack A1 on the slab upper surface and the end surface crack B1 on the end surface is.
Furthermore, as a result of examining crack countermeasures, it was determined that the main factor was the concentration of stress due to the strain generated in the composite deck slab at the studs, which are the joint points between the steel beams and the composite slab. Causes of distortion include, for example, tension and compression due to self weight and load, reduction in yield strength due to high temperature, and tension and compression due to elongation of members.
In the present invention, as a countermeasure for dispersing the stress concentrated around the stud and improving the degree of fixation of the synthetic slab edge, the occurrence and growth of cracks are suppressed by reinforcing the edge. Therefore, the composite deck slabs realized by the present invention can provide increased payload and improved fire resistance.

(First embodiment)
A composite deck slab according to a first embodiment of the present invention will be described below with reference to FIG.
The composite deck slab 1 includes a steel beam 14 made of H-shaped steel having a headed stud 15 on a flange 14F, a QL deck plate 11 passed between the steel beams 14, 14, and a wire mesh 13 on the QL deck plate. It is composed of concrete 12 that is reinforced and placed. As shown in FIG. 2, in the first embodiment, reinforcing bars and elongated steel plates (flat bars) are arranged along the rows of studs aligned in the axial direction of the steel beam.
2(a) and 2(b), an external reinforcing bar 21a and an internal reinforcing bar 21b are attached to both sides of the stud 15 as stud side reinforcing bars 21. As shown in FIGS.
FIGS. 2(c) and 2(d) are examples in which the flat bar 22 is laid along the outside of the stud 15. FIG.
The stud-side reinforcing bars 21 or the flat bar 22 are restrained from coming out upward because the stud has a head, but can be fixed to the stud 15 by means such as welding.

In this embodiment, the stud 15 is provided along with the stud reinforcing bars 21 or the flat bar 22, so that the deformation of the stud is suppressed and the stress generated in the stud is distributed to the stud both reinforcing bars 21 and the flat bar 22. can be made This prevents the generated stresses from concentrating around the individual studs and prevents the concrete from cracking. This reinforcement means improves the pull-out strength of the slab end of the composite deck slab, improves the degree of fixation to the steel frame beam, prevents cracks at the end of the composite deck slab, and suppresses the spread of cracks. Such allowable performance can be enhanced.
And since the composite deck slab ends are reinforced with reinforcing means for dispersing the stress generated around the studs, the fire resistance performance can be improved.

(Second embodiment)
A composite deck slab according to a second embodiment of the present invention will now be described with reference to FIG.
As shown in FIG. 3(a), the basic structure of the composite deck slab 1 is the same as in FIG. In Embodiment 2, a long stud 15l having a long stud length is used. The length of the long stud 15l is made equal to or greater than the height of the bar arrangement of the wire mesh 13.
By fixing the wire mesh to the long studs by binding or welding, it is possible to increase the degree of fixation, transfer the stress generated in the individual studs to the wire mesh, and increase the stress distribution to the wire mesh and other studs. . The length of the long stud is preferably "a stud whose tip is higher than the reinforcement position of the wire mesh".

Fig. 3(b) shows an example using a stud with a long wire mesh height, Fig. 3(c) shows an example where a wire mesh is fixed directly below the head of a long stud, and Fig. 3(d) shows an example using a long stud. FIG. 3(e) shows a perspective view of FIG. 3(c), showing an example of an intermediate beam in which the left and right wire meshes are stacked under the head and arranged.
By raising the stud height, the wire mesh can be arranged at the same height or below the stud, which reduces the stress generated in the stud, increases the integrity of the stud and the wire mesh, and reduces the stress on the individual stud. Concentration around the stud can be prevented, and the stress generated around the stud can be dispersed.
Therefore, the same effects as those of the first embodiment are obtained.

(Third embodiment)
The basic structure of the composite deck slab 1 is the same as in FIG. In Embodiment 3, the composite deck slab 1 is a composite deck slab in which U-shaped reinforcing bars 31 molded into a U-shape are inserted around the studs 15 to reinforce the ends of the composite deck slab 1 .
A composite deck slab according to a third embodiment of the present invention will now be described with reference to FIG. FIG. 4(a) schematically shows a state in which the U-shaped reinforcing bars 31 are inserted into the studs 15 provided on the beam flange 14F. FIG. 4(b) schematically shows a state in which the U-shaped reinforcing bar 31 is inserted into the end side (outside) of the stud 15 provided in the beam axial direction. A U-shaped reinforcing bar 31 is provided so as to straddle the upper portion of the stud 15 .
The U-shaped reinforcing bars 31 are arranged so that the horizontal members are above the height of the stud heads outside the flanges of the steel beams. Basically, the number of U-shaped reinforcing bars is equal to the number of studs.

By dropping the U-shaped reinforcing bars 31 onto the outside of the studs 15 provided on the flanges 14F of the steel beams 14, the degree of fixation of the ends can be enhanced. Cracks occurring near the stud 15 on the edge side of the deck slab and on the upper surface of the slab are suppressed by the U-shaped reinforcing bars 31 .

(Fourth embodiment)
A composite deck slab according to a fourth embodiment of the present invention will now be described with reference to FIG.
The basic structure of the composite deck slab 1 is the same as in FIG. In the present embodiment 4, the reinforcing reinforcing bars placed on the upper side of the wire mesh 13 are bent downward on the end side of the synthetic deck slab from the studs. The bend in the stiffening rebar can be further bent under the slab to extend past the proximal end of the stud and into a groove in a deck plate such as a QL deck. The figure shows a composite deck slab reinforced by arranging lower folding hook reinforcing bars 41 folded back at the slab end from the upper side of the wire mesh 13 to the base end side of the stud 15 . By providing the lower folding hook reinforcing bars 41, the pull-out resistance of the slab is improved, the degree of fixation is improved, cracks occurring on the upper surface of the slab can be suppressed from expanding, and cracks occurring at the ends of the slab can be suppressed. can also be suppressed from expanding. The lower folding hook reinforcing bar 41 is bent twice at 90 degrees to form a 180-degree hook. A 90-degree hook that is bent once by 90 degrees can also be used.
In the illustrated example, a reinforcing upper reinforcement 41a passing above the tip of the stud on the upper surface side of the wire mesh 13 passes between the left and right steel beams 14,14. The reinforcing reinforcing bar is bent at the end portion side of the wire mesh above the flange 14F of the steel frame beam 14 to become the end reinforcing bar 41b. It is preferable that the tip of the folded-back lower reinforcement 41c passes through the proximal end of the stud 15 and is housed in the groove of the QL deck 11 above the flange 14F on the right side of the steel beam 14.
The number of lower folding hook reinforcing bars 41 to be installed is basically the same as the number of studs, but it can be adjusted according to the necessity of design and the like.

In this embodiment, a bending portion reinforcing bar 42 consisting of an upper bending portion reinforcing bar 42a and a lower bending portion reinforcing bar 42b can be arranged in the axial direction of the steel frame inside the upper and lower folded portions. The bending portion reinforcing bar 42 is arranged in the axial direction of the steel frame beam 14, and does not need to be one piece extending over the entire length of the beam, and may be divided. The short ones are preferably longer than the spacing between adjacent studs.
By extending the wire mesh 13 as it is to the end portion side and folding it back, the wire mesh 13 can be used as a lower folding hook reinforcing bar. Alternatively, only the reinforcing bars in the direction between the steel frame beams 14 of the wire mesh 13 can be extended toward the end portion side and folded back to form the lower folding hook reinforcing bars.
In this embodiment, since the reinforcing bars are arranged from the top to the bottom of the end portion, the degree of fixation of the end portion is improved, and cracks occurring at the end portion and cracks occurring at the top of the slab are prevented and suppressed.

(Fifth embodiment)
A composite deck slab according to a fifth embodiment of the present invention will now be described with reference to FIG. The basic structure of the composite deck slab 1 is the same as in FIG. The reinforcing means are bent upwards at the slab ends from within the grooves of the deck plate to the top of the wire mesh. In addition, the embodiment relates to a composite deck slab in which the reinforcing bars can also be folded back over the ends.
In Embodiment 5, the reinforcing reinforcing bar passes through the groove of the QL deck 11, passes through the base end side of the stud 15, and is reinforced by arranging the upper folding hook reinforcing bar 51 that is folded back at the slab end. Composite deck slabs. By providing the upper folding hook reinforcing bars 51, the pull-out resistance of the slab is improved, the degree of fixation is improved, cracks occurring on the upper surface of the slab can be suppressed from expanding, and cracks occurring at the ends of the slab can be suppressed. can also be suppressed from expanding.
The upper folding hook reinforcing bar 51 is bent twice at 90 degrees to form a 180-degree hook. A 90-degree hook that is bent once by 90 degrees can also be used.
In the illustrated example, a lower reinforcing bar 51a extending from the groove of the QL deck 11 and passing through the proximal side of the stud passes between the steel beams 14,14. The upper folding hook reinforcing bar 51 for reinforcement is bent on the end side of the stud 15 above the flange 14F of the steel frame beam 14 to form an end bar 51b. The end reinforcement 51b is folded back above the stud 15 to form an upper reinforcement 51c, which extends upwardly of the wire mesh 13, and preferably extends above the right flange 14F of the steel beam 14. As shown in FIG.
The number of upper folding hook reinforcing bars 51 to be installed is basically the same as the number of studs, but it can be adjusted according to the necessity of design and the like.

In this embodiment, if a fireproof reinforcing bar is preliminarily installed in the groove of the QL deck 11 of the composite deck slab 1, the fireproof reinforcing bar can be extended and used as the upper folding hook reinforcing bar 51. can also
In this embodiment, a bending portion reinforcing bar 52 consisting of an upper bending portion reinforcing bar 52a and a lower bending portion reinforcing bar 52b can be arranged in the axial direction of the steel frame inside the upper and lower folded portions. The bending portion reinforcing bar 52 is arranged in the axial direction of the steel frame beam 14, and does not need to be one piece extending over the entire length of the beam, and may be divided. The short ones are preferably longer than the spacing between adjacent studs.
In this embodiment, since the reinforcing bars are arranged from the bottom to the top of the end portion, the degree of fixation of the end portion is improved, cracks occurring at the end portion can be prevented and suppressed, and furthermore, by folding back to the upper side of the stud Cracks occurring in the upper part of the slab can be prevented and suppressed.

(Sixth embodiment)
A composite deck slab according to a sixth embodiment of the present invention will now be described with reference to FIG.
The basic structure of the composite deck slab 1 is the same as in FIG. This embodiment relates to a composite deck slab in which the reinforcing means is provided with reinforcing bars placed on the underside of the wire mesh toward the ends of the slab and iron plates joined to the ends of the reinforcing bars.
A lower surface reinforcing bar 61 passing through the lower surface of the wire mesh 13 and an end surface reinforcing plate 62 joined to the lower surface reinforcing bar 61 at the end surface of the composite deck slab are provided. In this configuration, the degree of fixation of the end faces of the composite deck slab is particularly improved, and cracks occurring at the slab end portions can be suppressed from expanding. In particular, since the end surface reinforcing plate 62 is provided, the resistance to the extension of the lower surface reinforcing bar 61 is improved.
In the illustrated example, the lower surface reinforcing bar 61 for reinforcement passes below the height of the lower surface of the wire mesh 13 and the head of the stud 15 and higher than the QL deck 11 to reach the end of the composite deck slab. extends to The end surface reinforcing plate 62 and the lower surface reinforcing bar 61 arranged on the slab end surface are joined and fixed by welding or the like. Although the end face reinforcing plate 62 is provided on the surface of the slab concrete in the illustration of FIG. 7, it can also be embedded in the slab concrete.
The number of lower surface reinforcing bars 61 to be installed is basically the same as the number of studs, but it can be adjusted according to the necessity of design and the like.
The end face reinforcing plate 62 can also be provided continuously in the axial direction of the steel frame beam 14 . Alternatively, it is also possible to divide and provide a plurality of them. When splitting, a distance equal to or greater than the distance between adjacent studs is suitable.

The lower surface reinforcing bar 61 provided on the flange 14F of the steel frame beam 14 and the end surface reinforcing plate 62 provided at the end improve the fixation of the slab end, preventing cracks occurring at the end. Cracks occurring in the upper part of the slab can be prevented and suppressed.

(Seventh embodiment)
A composite deck slab according to a seventh embodiment of the present invention will be described with reference to FIG.
The basic structure of the composite deck slab 1 is the same as in FIG. This embodiment relates to a composite deck slab in which reinforcing steel bars, which are reinforcing means, are arranged from within grooves of the deck plate toward the slab ends, and iron plates are provided that are joined to the ends of the reinforcing steel bars.
A lower reinforcing bar 71 extending from the groove of the QL deck 11 and an end face reinforcing plate 72 joined to the lower reinforcing bar 71 at the end of the composite deck slab are provided. In this configuration, the degree of fixation of the end faces of the composite deck slab is particularly improved, and cracks occurring at the slab end portions can be suppressed from expanding. In particular, since the end surface reinforcing plate 72 is provided, the resistance to the extension of the lower surface reinforcing bar 71 is improved.
In the illustrated example, reinforcing lower reinforcing bars 71 extend through the interior of the QL deck 11 grooves to the ends of the composite deck slabs. The end face reinforcing plate 72 and the lower reinforcing bar 71 arranged in the concrete at the end of the slab are joined and fixed by welding or the like. Although the end face reinforcing plate 72 is embedded in the slab concrete in the illustration of FIG. 8, it can also be provided on the end surface of the slab concrete.
The number of lower reinforcing bars 71 to be installed is basically the same as the number of studs, but it can be adjusted according to the necessity of design and the like.
The end face reinforcing plate 62 can also be provided continuously in the axial direction of the steel frame beam 14 . Alternatively, it is also possible to divide and provide a plurality of them. When splitting, a distance equal to or greater than the distance between adjacent studs is suitable.

In this embodiment, if a fireproof reinforcing bar is preliminarily installed in the groove of the QL deck 11 of the composite deck slab 1, the fireproof reinforcing bar can be extended and used as the upper folding hook reinforcing bar 51. can also
The lower reinforcing bar 71 provided on the flange 14F of the steel beam 14 and the end surface reinforcing plate 72 provided at the end improve the fixation of the slab end, preventing cracks occurring at the end. It can be prevented and suppressed.

(Eighth embodiment)
A synthetic deck slab according to an eighth embodiment of the present invention will be described with reference to FIG.
The basic structure of the composite deck slab 1 is the same as in FIG. The embodiment relates to a composite deck slab in which the reinforcing bars of the reinforcing means are arranged alternately weaving adjacent studs.
Alternating refraction placement bars 81 are provided so as to alternately weave a plurality of studs 15 in which one or more reinforcing bars are provided in rows on the flange 14F of the steel beam 14 .
Since the alternating refraction placement bars 81 are present, the studs are prevented from deforming independently, and the stress acting on the studs is dispersed and is also borne by the alternating refraction placement bars 81 . If the stud 15 and the alternately refraction arrangement|positioning muscle 81 are connected by binding or welding, the fixation degree will be improved and deformation can be suppressed. Further, by using a stud with a head as the stud 15, the effect of preventing the alternating refraction arrangement muscle 81 from coming off is improved.
By arranging the alternating refraction placement muscle 81 on the lower side of the wire mesh, it is possible to transmit stress to the wire mesh as well, thereby dispersing the stress.
The alternating refraction placement bars 81 are preferably continuous in the axial direction of the steel frame beam, but they can exhibit their action and function even if they have a length between several studs.
FIG. 9(a) shows an example in which one reinforcing bar is used as the alternating refraction arrangement bar 81, and FIG. An example of arrangement is shown. Both (a) and (b) use headed studs. There may be three or more streaks for alternating refraction arrangement.

End face cracks and top face cracks leading from the end face or top surface of the composite deck slab to the vicinity of the stud head strengthen the restraint of the stud, and the stress applied to the stud is dispersed, suppressing the deformation of the stud and alternate bending arrangement By also bearing the stress on the streaks 81, cracks caused by concentration of strain do not grow, and cracks occurring on the end face and upper surface can be prevented and suppressed.

(Ninth embodiment)
A composite deck slab according to the ninth embodiment of the present invention will be described with reference to FIG.
The basic structure of the composite deck slab 1 is the same as in FIG. This embodiment relates to a composite deck slab in which a reinforcing welded wire mesh for reinforcement, which is a reinforcing means, is placed over the studs.
By arranging or fixing the reinforcing welded wire mesh around the stud, the stress acting on the stud can also be distributed to the reinforcing welded wire mesh.
The reinforcing welded wire mesh preferably has a narrower pitch than the wire mesh and is preferably welded or tied to the stud. In addition, by arranging the reinforcing welded wire mesh on the upper side or the lower side of the wire mesh, the stress can be transmitted to the wire mesh, and the stress due to the strain generated at the ends can be dispersed. .
The reinforcing welded wire mesh is preferably continuous in the axial direction of the steel frame beam, and the width of the steel frame in the flange direction is sufficient if it is within the width of the flange. It should be noted that the reinforcing welded wire mesh does not have to be a single piece, and may be divided.
FIG. 10 shows an example of a composite deck slab with reinforcing welded wire mesh 91 placed over studs 15 . (a) is a plan view, and (b) is a perspective view.
In this illustrated example, a reinforcing welded wire mesh 91 having a narrower pitch than the wire mesh 13 is placed on the headed stud 15 below the wire mesh 13 . The reinforcing welded wire mesh 91 used is in the shape of a ladder made up of two rebars extending in the axial direction of the steel beam 14 and cross bar-like rebars perpendicular to the two rebars. This reinforcing welded wire mesh 91 is coupled to the stud 15 by means such as binding. By fixing the narrow-pitch reinforcing welded wire mesh 91 to the stud 15, the stress concentrated on the stud 15 caused by distortion can be dispersed. By using the headed stud, the retaining function of the reinforcing welded wire mesh 91 is improved, and the pull-out resistance is improved. The reinforcing welded wire mesh may be configured by bundling reinforcing bars or the like.

End face cracks and top cracks that lead from the end face or top surface of the composite deck slab to the vicinity of the stud head are generated on the end face and top surface without the stress being dispersed by the reinforcing welded wire mesh, and the cracks that occur due to strain concentration do not grow. Cracks can be prevented and suppressed.

(Tenth embodiment)
A composite deck slab according to a tenth embodiment of the present invention will now be described with reference to FIG.
The embodiment relates to a composite deck slab in which the reinforcement means are arranged with a plurality of rebars alternately stitching adjacent studs in different orientations.
A pair of mutually alternately refracted facing reinforcements 86 are provided so as to alternately weave a plurality of studs 15 in which two reinforcing bars are provided in rows on the flange 14F of the steel beam 14 .
Since the mutually alternating refraction opposing arrangement|strand 86 exists, it is pressed from both sides of a stud, and the stress which acts on a stud is transmitted to the mutually alternating refraction opposing arrangement|positioning muscle 86, and it bears it. When the stud 15 and the mutually alternating refraction opposed reinforcement 86 are connected by binding or welding, the degree of fixation is increased and the stress is dispersed. Further, by using a stud with a head as the stud 15, the effect of preventing the alternating refraction arrangement muscle 81 from coming off is improved.
By arranging the mutually alternating refraction opposing arrangement muscle 86 on the lower side of the wire mesh, it is possible to transmit stress to the wire mesh as well, thereby dispersing the stress.
Although it is preferable that the mutually alternating refraction opposing arrangement bars 86 are continuous in the axial direction of the steel frame beam, even a length between several studs can exhibit its action and function.
FIG. 11(a) is a plan view schematically showing a mutually alternately refraction opposing arrangement reinforcement 86 in which two rebars provided above and below are alternately bent to adjacent studs in different directions. A perspective view is shown in (b).

End face cracks and top face cracks leading from the end face or top surface of the composite deck slab to the vicinity of the stud head strengthen the restraint of the stud, and the stress applied to the stud is dispersed, suppressing the deformation of the stud and mutual alternating refraction. By also bearing the stress on the opposed reinforcement 86, cracks caused by concentration of strain do not grow, and cracks occurring on the end face and upper surface can be prevented and suppressed.

A1, A2 Cracks on top surface B1, B2 Cracks on end surface

1 composite deck slab 11 deck plate (QL deck)
12 Concrete 13 Wire mesh 14 Steel beam 14b Intermediate steel beam 14F Flange 15 Stud 15l Long stud

21 stud both sides reinforcing bar 21a outer reinforcing bar 21b inner reinforcing bar 22 steel plate (flat bar)
31 U-shaped reinforcing bar 41 Lower hook reinforcing bar 41a Top bar 41b End bar 41c Lower bar 42 Bending part reinforcing bar 42a Upper bending part reinforcing bar 42b Lower bending part reinforcing bar 51 Upper bending hook reinforcing bar 51a Lower bar 51b End reinforcement 51c Upper reinforcement 52 Bending reinforcement 52a Upper bending reinforcement 52b Lower bending reinforcement

61 lower surface reinforcing bar 62 end face reinforcing plate 71 lower reinforcing bar 72 end face reinforcing plate 81 (adjacent stud) alternating refraction arrangement bar 81a upper alternating refraction arrangement bar 81b lower alternating refraction arrangement bar 86 mutually alternating refraction opposing arrangement bar 91 reinforcing welding wire mesh

Claims (5)

In a composite deck slab consisting of a deck plate and slab concrete,
A composite deck slab using steel beams with studded flanges, the composite deck slab being provided with reinforcing means at least in the area of the flanges,
A composite deck slab, characterized in that the reinforcing means are U-shaped and are located on top of the flanges of the steel beams. In a composite deck slab consisting of a deck plate and slab concrete,
A composite deck slab using steel beams with studded flanges, the composite deck slab being provided with reinforcing means at least in the area of the flanges,
A composite deck slab, characterized in that the reinforcement means are arranged by folding reinforcing bars downward from the top of the wire mesh at the slab ends. In a composite deck slab consisting of a deck plate and slab concrete,
A composite deck slab using steel beams with studded flanges, the composite deck slab being provided with reinforcing means at least in the area of the flanges,
1. A synthetic deck slab, wherein the reinforcing means is arranged by extending a reinforcing steel bar arranged in a groove of the deck plate to the slab end side and bending it upward. In a composite deck slab consisting of a deck plate and slab concrete,
A composite deck slab using steel beams with studded flanges, the composite deck slab being provided with reinforcing means at least in the area of the flanges,
1. A composite deck slab, wherein the reinforcing means is composed of a reinforcing bar extending from the groove of the deck plate toward the end of the slab and a steel plate joined to the end of the reinforcing bar. In a composite deck slab consisting of a deck plate and slab concrete,
A composite deck slab using steel beams with studded flanges, the composite deck slab being provided with reinforcing means at least in the area of the flanges,
The reinforcing means is a reinforcing welded wire mesh having a narrower pitch than the mesh of the wire mesh, which is placed over the headed stud of the steel beam at the end of the slab and tied to the stud. Composite deck slabs.

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