JP2001107317A - Floor slab and joint structure therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sandwich floor slab allowing the use of not only highly flowable concrete but also general concrete in placing of concrete and the compaction, and a floor stab joint structure excellent in fatigue durability. SOLUTION: This sandwich floor slab form is formed of a bottom steel plate 1, a U-shaped rib 20 fixed onto the bottom steel plate 1 so as to have substantially reverse U-shape, and upper steel plates 23, 231, 23b laid between the upper surfaces of the U-shaped rib and fixed thereto. A plurality of holes 21, 22 is formed on the upper surface of the U-shaped rib 20, and a plurality of holes 24 is formed on the upper steel plate 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sandwich floor slab form used for a bridge or the like, a floor slab, and a joint structure for a floor slab.

[0002]

2. Description of the Related Art In recent years, sandwich slabs have been developed and used for the purpose of supporting formwork required for reinforced concrete slabs of bridges and the like, saving labor on site work, and improving fatigue durability of the slabs. ing. (Public Works 38 Vol. 13 No. 199
See 7.12). As shown in FIG. 5, this sandwich floor slab welds a T-section steel 2 on a bottom steel sheet 1 at intervals.
A slab for the floor slab is manufactured by welding the upper steel plate 3 between the upper surfaces of the flanges of the adjacent T-shaped steels 2 and 2, and the interior space of the slab is filled with a high-fluid concrete 4 at the site to form a slab. Things.
For filling of the high-fluid concrete, an inlet 5 is provided at one end of the section and an air vent 6 is provided at the other end for each section V of the inner space of the formwork. The injection is performed while the air in the compartment is exhausted from the air vent 6 while the fluid concrete 4 is injected. (See FIG. 6).

As a joint structure between molds, the following is generally employed. That is, the distribution reinforcing bar 7 (I
The reinforcing bars are arranged on the flange of the section steel rib 2a).
As shown in FIG. 7, a lap joint in which a distribution joint bar 8 having a predetermined length is overlapped at the end of the distribution bars 7, 7 is employed. As shown in FIG. 8, the bottom steel plates 1 are connected to each other.
Is attached to the end of the base plate, and the base plate 9 and the bottom steel plates 1 and 1 are fastened with high tension bolts 10. In addition, there is a method in which a stud bolt is welded to a bottom steel plate to fasten an attachment plate.

[0004]

Since the conventional sandwich slab is sealed by the upper steel plate and the bottom steel plate, it is difficult to confirm the filling property of the concrete after the concrete is cast. For this reason, it is necessary to use a special concrete having a high fluidity such as a high fluidity concrete.

[0005] Since no holes are formed in the section steel ribs, space sections are formed between the section steel ribs and the section steel ribs, so that a concrete must be cast in each space section. (FIG. 6
reference). Further, since the upper and lower steel plates are hermetically sealed, the concrete cannot be compacted, and a defect may occur in the quality of the concrete.

[0008] When a method of superposing the contact plate on the bottom steel plate and fastening with a high tension bolt (the method of FIG. 8) is adopted, it is necessary to insert the bolt from the back of the bottom steel plate. is there. Further, a joint in which a stud is welded to a bottom steel plate and the bottom steel plate and the contact plate are fastened has a defect in fatigue durability because of a welded portion. Also, lap joints used as joints between distribution steel bars have a defect in fatigue durability because the joint bars are fixed by concrete having a less restrictive force.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to use not only a high-fluid concrete but also a normal concrete at the time of placing the concrete, and the sandwich can be compacted. An object of the present invention is to provide a slab and a joint structure for a slab excellent in fatigue durability.

[0008]

The object of the present invention is attained by the following slab formwork, slab and joint structure for the slab.

[0009] The formwork of the first aspect includes a bottom steel plate, and a U-shaped rib fixed on the bottom steel plate so as to be substantially inverted U-shaped.
A sandwich floor slab form spanning between the upper surfaces of the U-shaped ribs and comprising a fixed upper steel plate, wherein a plurality of holes are formed in the upper surface and side surfaces of the U-shaped ribs, and This is a floor slab form having a plurality of holes.

[0010] The floor slab of claim 2 is a floor slab obtained by casting concrete in the form of claim 1.

In the formwork according to the first aspect and the floor slab according to the second aspect, a plurality of holes are formed in the upper surface of the upper steel plate and the U-shaped rib, and these holes are used as a concrete inlet or an air vent. Can be used as mouth. It can also be used to check the filling condition of the concrete.
Further, a compacting tool can be inserted from these holes to sufficiently compact the filled concrete.

Further, since a plurality of holes are formed in the side surface of the U-shaped rib, the space from the U-shaped rib to the space between the U-shaped ribs or the space between the U-shaped ribs to the U-shaped rib is formed. Since the concrete can flow through the inner space of the mold rib, the filling property of the concrete is improved.

Therefore, not only high-fluid concrete but also ordinary concrete can be poured into the mold, and a sandwich floor slab filled with concrete having few defects can be obtained.

The joint structure according to claim 3 is adjacent to claim 1.
Between the bottom steel plate ends of the formwork for floor slabs by means of an attachment plate attached to one bottom steel plate and stud bolts attached to the other bottom steel plate, and having side holes adjacent to each other across the joint.
This is a joint structure for floor slabs in which a reinforcing bar is penetrated into the side surface of a mold rib to form a joint reinforcing bar, and the joint reinforcing bar is fixed by concrete in the U-shaped rib.

In this joint structure, the joining between the bottom steel plates is performed by the attachment plate attached to one bottom steel plate and the stud bolt attached to the other bottom steel plate.
Compared with the method shown in FIG. 8, the workability on site is significantly improved.

In addition, since a reinforcing bar is penetrated into the side surface of the U-shaped rib adjacent to the joint portion so as to form a joint reinforcing bar, the joint reinforcing bar has a strong binding force filled inside the U-shaped rib welded to the bottom steel plate. It is fixed by concrete. This allows
The fatigue durability of the joint part of the sandwich floor slab is improved.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of the joint of the sandwich floor slab according to the present invention, and FIG. 2 is a cross-sectional view in the bridge axis direction of the joint of the sandwich floor slab according to the present invention.

First, the floor slab form will be described. The formwork for the floor slab is mounted on the bottom steel plate 1 by welding at predetermined intervals in the bridge axis direction such that the U-shaped ribs 20 to 20 are inverted U-shaped. Each U-shaped rib 20 is provided with a plurality of holes 21 to 21 at predetermined intervals in a length direction of the upper surface (a direction perpendicular to the bridge axis direction). Also, a plurality of holes 22 to 22 are formed on both side surfaces of each U-shaped rib 20 at predetermined intervals in the length direction. The height of the hole 22 from the bottom steel plate 1 is the same for each U-shaped rib.

An upper steel plate 23 is attached between the upper surfaces of the adjacent U-shaped ribs 20, 20 by welding. Note that the upper steel plate 23a on the end side of the U-shaped rib 20 at the end of the floor slab form is attached after the floor slab forms are fastened and joined together on site without being installed at the factory. When the joint rebar 25 is to be attached to the U-shaped ribs 20, 20 at the ends of the formwork for floor slab to be joined, the upper steel plate 23a and the upper steel plate 23b adjacent thereto are not attached at the factory, and the joint rebar 25 And after attaching and joining the formwork for floor slabs. The upper steel plates 23, 23a and 23b have their length directions (perpendicular to the bridge axis direction).
Are provided with a plurality of holes 24 to 24 at predetermined intervals.

The holes 24 in the upper steel plates 23, 23a and 23b
The hole 21 on the upper surface of the U-shaped rib is used as an inlet for a concrete, an air vent, a hole for confirming a concrete filling condition, or an insertion hole for a concrete compacting tool. Further, the hole 22 on the side surface of the U-shaped rib is a flow hole for a concrete in the space between the U-shaped rib inner space and the U-shaped rib,
Alternatively, it is used as an insertion hole for the joint reinforcing bar 25.

Next, the joint structure between the floor slabs will be described. As shown in FIG. 3, an attachment plate 26 is attached to one end of the bottom steel plate of one floor slab by welding, and a plurality of slabs are attached to one end of the bottom steel plate of the other floor slab. Stud bolts 27 to 27 are attached at intervals. Then, the bottom steel plates are joined together by bolt holes 26
This is performed by inserting stud bolts 27 to 27 into a to 26a and fastening nuts.

When a joint reinforcing bar is to be attached to the joint of the formwork for floor slab, as shown in FIG. 4, the bottom steel plates are joined to each other by the attachment plates 27 and the stud bolts 27 to 27, and then the joint reinforcing bars 25 are attached. Through the hole 22 on the side of the U-shaped rib,
It penetrates from the mold rib to the other U-shaped rib and is temporarily attached to an appropriate portion of the U-shaped rib. This tacking is performed to prevent the joint reinforcing bar from moving due to the flow of the concrete when the concrete is filled. The number of joint rebars to be installed is determined according to the strength required for the joint.

The joining of the floor slabs is performed by one of two methods. The first method is a method in which the bottom steel plate is joined to the attachment plate 26 with the stud bolt 27, and then the upper steel plate 23a is welded to the upper surface of the U-shaped rib. Second
In the method of (1), the bottom steel plate is joined to the attachment plate 26 by the stud bolt 27, and the joint reinforcing bar 25 is penetrated and attached to the adjacent U-shaped rib across the joint, and then the upper steel plate 23a is attached to the upper surface of the U-shaped rib. And the two upper steel plates 23b, 23b are welded.

As described above, after the floor slab form is joined in place, the concrete 4 (high flow concrete or ordinary concrete) is inserted into the form space from the hole 24 of the upper steel plate and the hole 21 on the upper surface of the U-shaped rib. -G). During filling, the state of filling of the concrete 4 is confirmed from the hole, and compaction is appropriately performed with a compacting tool. In this way, if the concrete filled in the form space is hardened, the sandwich slab is completed.

As shown in FIG. 2, when the distribution reinforcing bar 7 is inserted through the U-shaped rib 20 through which the joint reinforcing bar is not inserted, the integration of the U-shaped rib 20 and the concrete 4 is further improved. I do.

[0026]

According to the first aspect of the present invention, since a plurality of holes are formed in the upper surface of the upper steel plate and the U-shaped rib, it is necessary to confirm the filling state of the concrete and compact the concrete at the time of placing the concrete. The quality of the concrete to be filled can be improved. Also, since a plurality of holes are formed in the side surface of the U-shaped rib, the concrete can be circulated between the spaces of the formwork, and the fillability of the concrete is improved.

The floor slab of the second aspect is obtained by casting concrete on the formwork of the first aspect, so that it becomes a sandwich slab filled with concrete having few defects.

According to the joint structure of the third aspect, since the bottom steel plate is joined to the attachment plate by the stud bolt, workability on site is remarkably improved as compared with the method of FIG. In addition, since the joint rebar is fixed by a strong binding concrete filled in the inside of the U-shaped rib welded to the bottom steel plate, the rebar and the concrete have high adhesiveness, and the sandwich slab is provided. The fatigue durability of the joint is improved. In addition, since the joint reinforcing bars are arranged using the holes on the side surfaces of the U-shaped ribs as guides, workability on site is good.

[Brief description of the drawings]

FIG. 1 is a perspective view of a joint of a sandwich floor slab according to the present invention.

FIG. 2 is a sectional view in the bridge axis direction of a joint portion of the sandwich floor slab according to the present invention.

FIG. 3 is an explanatory view of a method for joining a bottom steel plate of a floor slab form according to the present invention.

FIG. 4 is a view showing a state in which a joint reinforcing bar is arranged on a U-shaped rib of a floor slab form joint according to the present invention.

FIG. 5 is a perspective view of a conventional sandwich floor slab.

FIG. 6 is an explanatory view of a method for filling the internal space of a conventional sandwich floor slab form with high-fluid concrete.

FIG. 7 is a plan view of a conventional distribution reinforcement joint.

FIG. 8 is a front view of a conventional bottom steel plate joint.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Bottom steel plate 2 T-shaped steel 3 Upper steel plate 4 Concrete 5 Injection port 6 Air release port 7 Distributing reinforcing bar 8 Distributing reinforcing bar joint 9 Attached plate 10 High tension bolt 20 U-shaped rib 21,22 hole 23,23a, 23b Steel plate 24 hole 25 Joint reinforcing bar 26 Abutment plate 27 Stud bolt 27a Bolt hole

Claims (3)

[Claims] 1. A bottom steel plate, a U-shaped rib fixed on the bottom steel plate so as to have a substantially inverted U-shape, and an upper steel plate bridged and fixed between upper surfaces of the U-shaped rib. A sandwich slab formwork, wherein a plurality of holes are formed in an upper surface and a side surface of the U-shaped rib, and a plurality of holes are formed in an upper steel plate. 2. A concrete slab according to claim 1,
Floor slab. 3. The end portions of the bottom steel plates of the adjacent slab formwork according to claim 1 are joined by an attachment plate attached to one bottom steel plate and a stud bolt attached to the other bottom steel plate, and the joint portion is formed. A joint structure for a floor slab, characterized in that a reinforcing bar is penetrated into a side surface of a U-shaped rib having side holes adjacent to each other so as to form a joint reinforcing bar, and the joint reinforcing bar is fixed by concrete in the U-shaped rib.