JPS6160941B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a method of constructing a composite structure in which steel members such as columns or beams and reinforced concrete members such as wall plates or floor slabs are integrated using stud connectors. This is a construction method that aims to improve the composite effect of stud connectors by introducing prestressing of the concrete used.

Generally, the reason for a composite structure is that when in-plane and out-of-plane forces act on a concrete slab, mechanical cooperation with the supporting steel members is required, so the two are integrated. This synthetic integration is required for mechanical behavior, and by proactively using a synthetic structure from a design perspective, the steel frame structure as a whole becomes stronger and safety is improved.

Previous experiments have shown that when stud connectors are used to prevent shear between steel members and concrete floors, the bearing pressure of the concrete first breaks, and ultimately the shear strength of the stud material is not the deciding factor, but rather that the stud connectors are used to prevent shearing and deformation. Determined by the tensile strength of the material,
It is known that bending and tensile failure occurs as the ultimate state. The Architectural Institute of Japan's synthetic beam structure design and construction guidelines provide an experimentally obtained design formula for the bearing capacity of stud connectors.

Therefore, by increasing the strength of the concrete or by increasing the restraining force on the stud material, bearing pressure failure can be prevented, and the yield strength of each stud connector constituting the composite structure will be increased, and the composite effect will also be improved.

This invention was made under the above-mentioned circumstances, and is intended to achieve the restraint of the stud connector by the surrounding concrete by introducing prestress into the concrete, thereby enhancing the synthesis effect. Prestressing can be introduced using high-strength steel wires such as PC steel wires or PC stranded wires wired inside the concrete, but it is sufficient to apply stress that compresses the stud connector from the side.

The following description will be made based on the illustrated embodiment.

FIG. 1 shows an example of a composite beam floor slab in a conventional cast-in-place slab. A stud connector 3 with a head is previously provided protrudingly on the steel beam 1 by welding or the like, and is intended to be integrated with the concrete floor slab 2. When placing the concrete, high-strength steel wires 4 are wired in advance to this concrete slab 2, and after the concrete has hardened, high-strength steel wire tension is introduced and fixed to prestress the concrete. to restrain the stud bolt 3 from its surroundings. The tensioned end of the high-strength steel wire 4 is fixed to a slab or beam by a screw method, a wedge method, or the like.

In addition, to introduce prestress into concrete using high-strength steel wire 4, unbonded PC stranded wires can also be used, and these unbonded PC stranded wires can be arranged in a catenary shape between columns or beams so that they are convex on the tension side. By installing this, it is possible to reduce long-term deflection of the slab and increase the span.

FIG. 2 shows an embodiment of a slab with a deck plate, in which high-strength steel wires 4 are arranged in the concrete of the concrete slab 2 cast on the deck plate 5, similar to the embodiment described above. The stud connector 3 is restrained by introducing prestress into the concrete.

The examples of composite structures using steel beams and concrete slabs have been described above, but the steel columns and concrete wall slabs are integrated using stud connectors, and tension is introduced into the high-strength steel wires 4 arranged along the direction of the columns. It is possible to obtain a column wall structure with high synthesis effect.

This invention has the above-mentioned configuration, and since the stud connector is restrained from the surroundings by prestress introduced into the concrete by the post-tension method, a high synthesis effect can be expected. In addition, since the displacement between the steel frame member and the concrete slab is suppressed, bearing stress failure can be prevented and the proof strength of the stud connector can be effectively utilized.

[Brief explanation of the drawing]

FIGS. 1 and 2 are longitudinal cross-sectional views showing different embodiments of the present invention. 1... Steel beam, 2... Concrete floor slab, 3...
... Stud connector, 4... High strength steel wire, 5...
...Detsuki plate.

Claims (1)

[Claims] 1. When constructing a composite structure that integrates the steel members of a steel frame and a concrete slab, stud connectors are installed in advance on the steel members, and the concrete of the concrete slab is poured so as to bury the stud connectors. After the concrete has hardened, prestress is introduced into the concrete to restrain the concrete around the stud connector, and the high-strength steel wire wired inside the concrete is fixed under tension, and the reinforcing steel members and concrete slab are integrated. Construction method of composite structure of steel frame members and concrete slab.