JP2002309706A - Stud of composite girder or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance shearing strength and shearing rigidity. SOLUTION: A stud body 1 is welded to a steel girder G. A reinforcing cylinder body 2 held in a rising state till then is lowered blow. A female screw 2a is threadedly engaged with a male screw 1c, a lower end surface 2c of the cylinder body 2 is allowed to firmly get in contact with an upper surface of the steel beam G. The outer periphery of a welding part w is covered with a covering part 2b. Since an effective diameter of a stud becomes substantially large by the reinforcing cylinder body 2 in this state, the shearing strength, bending strength, and the shearing rigidity of the stud are heightened. Thus, after fixing the stud to the steel girder G, a reinforcement and a form for a concrete floor slab are arranged, concrete is placed, and the concrete floor slab P is integrally fixed to the steel girder G via the stud.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stud suitable for fixing a concrete slab to a steel girder.

[0002]

2. Description of the Related Art In the case of constructing a steel bridge (composite girder) in which a steel girder and a concrete slab are integrally fixed, as shown in FIG. After the reinforcing bars 10 are planted by welding, reinforcing bars for the concrete slab, formwork, and the like are installed, concrete is cast and the concrete slab P is integrally fixed to the steel girder G.

[0003]

The shear strength and shear stiffness of the stud 10 welded to the steel girder G are determined by the cross-sectional area of the welded portion w at the root of the stud and the bearing stress degree generated in the concrete in front of the root of the stud. Depends on Therefore, a stud having a large diameter is effective in increasing the shear strength and shear rigidity of the stud. However, simply increasing the diameter of the conventional headed stud 10 increases the cost of the stud itself, increases the size of the stud welding machine, and significantly increases the overall cost.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide a stud such as a composite girder which has high shear strength and high shear rigidity and does not impair workability. Another object of the present invention is to provide a stud such as a composite girder which can reduce the cost comprehensively.

[0005]

In order to achieve at least one of the above-mentioned objects, according to the first aspect of the present invention, a head is formed at an upper end, a male screw is formed at a lower end, and a steel girder is formed at a lower end. A stud body welded to the upper surface of the steel girder and planted on the steel girder, and a female screw is formed on the upper part and a cover part is formed on the lower part, and a female screw is formed on the male screw of the stud body planted on the steel girder or the like And a reinforcing cylinder attached to the stud body by covering the welded portion between the steel girder and the stud body with a cover, and contacting the lower end surface with the upper surface of the steel girder etc. The configuration was adopted.

In this means, the lower end of the stud main body is welded to the upper surface of a steel girder or the like, and then the reinforcing cylinder previously mounted on the stud main body is rotated by screwing its female screw to the male screw of the stud main body. This causes the lower end surface to contact the upper surface of a steel girder or the like. In the above-described mounting state of the stud, since the reinforcing cylinder substantially increases the diameter of the stud, the shear strength, the bending strength and the shear rigidity of the stud are improved. The welding work of the stud main body to the steel girder or the like can be performed with a small welding machine like the conventional one because the diameter of the stud main body does not increase as before with respect to the thickness.

[0007] The cost per stud increases by processing the male thread on the stud body and by adding the reinforcing cylinder, but the reinforcement of the shear strength and the shearing rigidity by the reinforcing cylinder increases the stud cost. Since the required number can be reduced, the cost is reduced overall.

[0008] In the stud such as the composite girder according to the first aspect, it is preferable that the reinforcing cylinder is configured to be movable along the stud main body from the lower end to the vicinity of the upper end of the stud main body. . With this configuration, when the stud body is welded to the upper surface of the steel girder or the like, the reinforcing cylinder body previously fitted to the stud body is retracted upward from the upper surface of the steel girder or the like, so that the welding operation can be performed smoothly. it can.

[0009]

Embodiments of the present invention will be described with reference to the accompanying drawings. 1 and 2 show an embodiment of a stud such as a composite girder according to the present invention. A stud A such as a composite girder includes a stud body 1 and a reinforcing cylinder 2.

The stud body 1 has a head 1a at the upper end and a male screw 1c at the lower end, which is larger in diameter than the upper end 1b, and is made of steel or the like with a circular cross section.

The reinforcing cylinder 2 is formed of steel or the like, with a female screw 2a formed on the upper part and a cover part 2b formed on the lower part. The female screw 2a is the male screw 1c of the stud body 1.
And the inside diameter is made smaller than the outside diameter of the head 1a. The cover 2b is made of a steel girder G (FIG. 3).
The inner diameter is sufficiently larger than the inner diameter of the female screw 2a (the outer diameter of the male screw 1c of the stud body 1). For this reason, the welding portion w is covered with a margin by the covering portion 2b, and the reinforcing cylinder 2
Can be raised along the stud body 1 to the vicinity of its head 1a through the male screw 1c of the stud body 1 (see the two-dot chain line in FIG. 1). The outer shape of the reinforcing cylinder 2 is hexagonal so that the reinforcing cylinder 2 can be rotated with a wrench, but may have other shapes.

FIG. 3 shows a composite girder B in which a concrete floor slab P is integrally fixed to a steel girder G by a stud A having the above-described structure. An example of a method of constructing the composite girder B will be described. First, the reinforcing tubular body 2 is mounted on the stud body 1 and moved near the head 1a of the stud body 1, and the state is maintained by any means. The lower end of the stud main body 1 is welded to the upper surface of the steel girder G, and the stud main body 1 is vertically implanted on the steel girder G.

In the above welding operation, since the reinforcing cylinder 2 is retracted upward from the portion of the male screw 1c and does not become an obstacle,
It can be done smoothly. Further, the stud body 1 does not need to be made larger in diameter than the conventional stud for the reason described later, so that it can be performed efficiently with a small stud welding machine as in the conventional case.

After the welding operation is completed, the reinforcing cylinder 2 held up to that point is lowered, the female screw 2a is screwed into the male screw 1c, and the rotation of the reinforcing cylinder 2 is continued to reinforce. The lower end surface 2c of the tubular member 2 is firmly brought into contact with the upper surface of the steel girder G, and the outer periphery of the welded portion w of the steel girder G and the stud body 1 is covered with a cover 2b. In this case, since the inner diameter of the cover portion 2b is sufficiently larger than the outer diameter of the male screw 1c as described above, the lower end surface 2c of the reinforcing cylinder 2 does not come into contact with the welded portion w having severe irregularities. Therefore, the entire lower end surface 2c of the reinforcing cylinder 2 comes into close contact with the upper surface of the steel girder G.

In the above-described state where the reinforcing cylinder 2 is fastened to the male screw 1c of the stud body 1 with its lower end surface 2c abutting against the steel girder G, the effective diameter of the stud A is substantially reduced by the reinforcing cylinder 2. The stud A has high shear strength, bending strength and shear rigidity.

After the stud A is fixed to the steel girder G as described above, a reinforcing bar and a formwork for the concrete floor slab are installed, concrete is poured, and the steel girder G and the concrete floor slab P are integrated. To

The stud A of the present invention is widely used not only for newly-constructed composite girder B but also for repair work of an existing composite girder such as floor slab replacement performed by cutting a stud, or for a structure other than a composite girder. be able to. In the case of composite girder B, since a large number of studs are generally used, the stud shear strength, bending strength and shear rigidity per stud are large, and the stud A, which can reduce the number of used studs, reduces material costs. In addition, since the construction is easy, it greatly contributes to cost reduction.

[0018]

As described above, according to the first aspect of the present invention, the concrete slab and the like are fixed to the steel girder or the like at low cost by enhancing the shear strength, the bending strength and the shear rigidity. And a stud such as a composite girder that can be obtained.

In the stud such as the composite girder according to the first aspect, if the reinforcing cylinder is configured to be movable along the stud main body from the lower end portion of the stud main body to near the head of the upper end thereof,
Welding work can be performed smoothly, and workability is improved.

[Brief description of the drawings]

FIG. 1 is a partially sectional view showing an embodiment of a stud such as a composite girder according to the present invention.

FIG. 2 is a partially sectional view showing a threaded state of a reinforcing cylinder to a stud body.

FIG. 3 is a sectional view showing an embodiment of a composite girder according to the present invention.

FIG. 4 is a cross-sectional view of a conventional composite girder in which a concrete slab is fixed to a steel girder with a conventional stud.

[Explanation of symbols]

 A Stud B Composite girder P Concrete floor slab G Steel girder w Welded part 1 Stud body 1a Head 1b Upper end 1c Male screw 2 Reinforcing cylinder 2a Female screw 2b Cover 2c Lower end face

Claims (2)

[Claims] 1. A stud body having a head formed at an upper end and a male screw formed at a lower end, and a lower end welded to an upper surface of a steel girder and the like, and a female screw formed at an upper part. A cover portion is formed at the lower portion, and a welded portion between the steel girder and the stud body is covered with a cover portion in a state in which a female screw is screwed to a male screw of the stud body implanted in a steel girder, and A stud for a composite girder or the like, comprising: a reinforcing cylinder attached to the stud body with its lower end surface in contact with an upper surface of a steel girder or the like. 2. The stud according to claim 1, wherein the reinforcing cylinder is movable along the stud main body from a lower end portion of the stud main body to near an upper end head.