JPH041832B2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Technical Field of the Invention The present invention relates to a welding anchor installation method for a shear wall that is added to an existing SRC building that does not have an earthquake-resistant structure (design) for the purpose of earthquake reinforcement.

(b) Background of the technology As a measure to provide seismic reinforcement to existing SRC buildings that do not have an earthquake-resistant structure, earthquake-resistant walls may be added. Such shear walls are constructed using existing SRC reinforcing bars.
It can be structurally integrated with the existing SRC building by connecting it to an anchor installed on the side of the built building. There are two types of anchors: those installed on concrete parts and those installed on steel flanges. Anchors installed in concrete parts include carved anchors a shown in FIG. 9 and chemical anchors b shown in FIG. 10. Moreover, FIG. 11 shows a welding anchor d installed on a steel flange c.

(C) Prior Art and Problems By the way, in the case of the above-mentioned carved anchor a and chemical anchor b, since they are installed in the existing concrete e section, the anchor strength is affected by the strength of the concrete e. Therefore, the quality, properties, etc. of concrete e must be thoroughly investigated during construction. If the concrete e does not have a predetermined strength, or if cracks, jitters, etc. are found after the finishing material is removed, repairs must be made. Also, for this reason, you may not be able to use the anchor you had planned.

On the other hand, in the case of welding anchor d installed on steel flange c, there is no problem like the above-mentioned carved anchor a or chemical anchor b, but concrete e
As a result, there were some areas that could not be covered, resulting in a decrease in corrosion resistance and a risk that the specified seismic strength could not be obtained. That is, in order to weld the anchor d to the steel flange c, it is necessary to remove a predetermined portion of the concrete e so that the outer surface of the steel flange c is exposed. Conventionally, the anchor hole f formed in this way is left as it is after welding the anchor d and concrete g for the shear wall is poured, so the anchor hole f is filled with concrete g as shown in the figure. The gap h is left as is. Therefore, the anchor d is not covered in the gap h and is in an oxidizing environment. Before pouring the concrete g, it is possible to fill the anchor holes f with mortar to prevent the formation of voids h, but in such a case, filling the mortar requires considerable effort and may cause drying shrinkage or sagging of the mortar. etc., so it is not a desirable solution. Figure 12 shows welding anchor d installed on the column wall side.
A similar problem occurs in this case as well.

(d) Purpose of the Invention In view of the above-mentioned circumstances, the present invention provides a welding anchor installation method that reliably covers the welding anchor without forming any voids.

(e) Structure of the invention In order to achieve the above object, this invention
After boring a predetermined concrete part of an SRC building with a core drill so that the outer surface of the steel flange is exposed and welding an anchor to the steel flange in the bored part, the bored part has a compressive strength comparable to that of concrete. I filled it with a molded core.

(F) Embodiments of the invention The following are figures 1 to 5 showing embodiments of the invention.
This will be explained in detail based on the drawings.

In the figure, 1 is the concrete part of the beam of the existing SRC building, and 2 is the added shear wall that is structurally integrated with the concrete part of the beam by anchors 3.

When welding the anchor 3 to the steel flange 4, first, as shown in FIG. Clean the outer surface 5 with a brush. Next, as shown in FIG. 3, the anchor 3 is welded to the steel frame flange 4 by stud welding or resistance welding. After that, Figures 4 and 5
As shown in the figure, a straight-shaped molding core 7 as shown in FIG. 6 or a cone-shaped molding core 7 as shown in FIG. 7 is embedded in the boring part 6 to close the boring part 6. Molded core 7
A through hole 8 is bored in the shaft center, and the anchor 3 is passed through the through hole 8 from the lower end to the boring part 6.
Press fit. In this case, early-strengthening mortar 11 is applied to the inner end 9, outer circumferential surface 10, and through hole 8 of the molding core 7, so that no voids are formed in the boring portion 6. After the boring portion 6 is closed with the molded core 7 in this manner, the reinforcing bars 12 of the additional shear wall 2 are connected to the anchors 3, and concrete 13 is poured as shown in FIG. 1, as in the conventional case. Since the concrete 13 cannot be placed up to the bottom end 14 of the concrete 1 section of the beam, the concrete 1
The gap between the upper end 15 and the lower end 14 of 3 is filled with grout material 16. In addition, the boring section 6
The molded core 7 embedded in the molded core 7 is fixed by a wedge 17 driven into the through hole 8 portion.

The molded core 7 preferably has a compressive strength comparable to that of the concrete 1 and is noncombustible, and is therefore usually made of a cement-based material, such as mortar. Furthermore, the molding core 7 may be composed of a plurality of divided pieces 18 as shown in FIG.

(g) Effects of the Invention In summary, in the welding anchor installation method for an extension shear wall according to the present invention, a predetermined concrete part of an existing SRC building is bored with a core drill so that the outer surface of the steel flange is exposed. After welding the anchor to the steel flange,
Since the boring part is filled with a molded core that has a compressive strength comparable to that of concrete,
The shaped core makes it possible to completely cover the welding anchor without forming voids in the boring. Therefore, there is no longer a problem that the corrosion resistance of the welded anchor deteriorates and seismic strength cannot be obtained as in the conventional case.

[Brief explanation of drawings]

FIGS. 1 to 5 are sectional views showing embodiments of the present invention, FIGS. 6 and 7 are perspective views of the molded core, and FIG. 8 is a plan view showing a deformed structure of the molded core. Figure 9 is a sectional view showing a carved anchor, Figure 10 is a sectional view showing a chemical anchor, and Figure 11 is a sectional view showing a chemical anchor.
1 and 12 are cross-sectional views showing conventional welding anchors, respectively. In the figure, 1 is the concrete part of the beam of the existing SRC building, 2 is the added shear wall, 3 is the welding anchor, 4 is the steel flange, 5 is the outer surface of the steel flange, 6 is the boring part, 7 is the formed core, 12 is reinforced steel, and 13 is concrete.

Claims (1)

[Claims] 1. Boring a specified concrete part of an existing SRC building with a core drill so that the outer surface of the steel flange is exposed, and after welding an anchor to the steel flange of the bored part, the bored part is constructed to have a compressive strength comparable to that of concrete. A method for installing welded anchors for extension shear walls, which is characterized by filling them with molded cores.