JP2711724B2 - Column base metal fittings and crimp joining method for steel column bases using the metal fittings - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a column base metal used when a steel column of a civil engineering building structure is built on a concrete base, and a column base using the column base metal. The present invention relates to a column-base crimping joining method for crimping and joining on top.

(Prior art) Conventionally, when a steel column of a civil engineering building structure is built on a concrete base, the column is joined to the concrete base via column base hardware, and an axial compressive force, bending moment and shear force generated in the column are generated. Is transmitted to the concrete base. Conventionally, as a pillar base metal for such a construction method, for example, one having a projection on a bottom plate corresponding to a cross-sectional shape of a pillar, a projection provided on a bottom surface, and integrally molded by casting (Japanese Patent Publication No. 52-1982)
No. 4413). The pillar base metal has a protrusion on the bottom surface, thereby increasing the horizontal resistance of the bottom surface,
It was intended to increase the transmission force of the shear force acting on the column to the concrete base. Further, as another pillar base metal, a pedestal partly protruding from the bottom plate is provided around the anchor bolt fitting holes formed at the four corners of the bottom plate, and the bottom surface of the pedestal is provided above the bottom plate, and If an attempt is made to increase the resistance of the anchor bolt to the acting bending moment, and if the diameter of the anchor bolt fitting hole is increased and the axis of the hole is misaligned with the anchor bolt embedded in the concrete foundation, There is a known one in which a mating hole is adjusted with an eccentric washer or the like (Japanese Patent Application Laid-Open No. 62-296035).

(Problems to be Solved by the Invention) The connection of the column pedestal to the concrete base by the above-mentioned conventional foot casting is performed by bolt connection using anchor bolts. However, if the joint is simply bolted, sufficient surface contact between the base of the column base and the concrete base surface cannot be obtained, and the shearing force acting on the column may cause the joint surface to slip or act on the column There is a drawback that a sufficient connection between the column base and the concrete base cannot be obtained, for example, the bottom plate is bent by the bending moment. In order to eliminate the drawback, in each of the above conventional examples, resistance to shear force,
Alternatively, an attempt is made to improve the resistance to the bending moment by the above means, but it has been difficult to simultaneously increase the resistance to the shearing force and the bending moment. The most reliable way to increase the resistance to shear force and bending moment is to increase the weight of the column base metal and increase the rigidity, but the material cost of the column base metal increases and the cost increases. There is a problem that construction is difficult. In addition, conventional column base hardware has a small tolerance for the installation position of anchor bolts fixed to a concrete foundation, and the anchor bolt positions are slightly out of alignment with the bolt holes of the column base hardware, making it difficult to install the column base hardware. Met. The above-mentioned Japanese patent
In order to solve the problem, Japanese Unexamined Patent Publication No. 62-296035 discloses a method in which a bolt hole is enlarged and adjusted with a washer fitted into the bolt hole, but a plurality of types of washers having different hole positions are provided. And there is a problem that construction is troublesome.

The present invention has been made in view of the above circumstances,
A large surface area can be obtained by spreading the load, and a strong surface contact can be obtained. The rigidity can be increased without increasing the weight, the weight of the column base can be reduced, and the installation tolerance of the anchor bolt is increased. It is an object of the present invention to provide a column base metal fitting that can be easily assembled on site and a method of manufacturing the same.

(Means for Solving the Problems) The stress corresponding to the column is mainly a compressive force, a bending moment and a shear force in the axial direction. In order to support the column base metal on the concrete base by resisting these stresses, it is ideal that the column base metal and the concrete base are in a rigidly joined state. From this viewpoint, it is extremely effective to apply tension to the anchor bolts and press-join the column base metal and concrete by prestressing, but the rigidity of the column base metal is sufficiently high to exert its effect sufficiently. In addition, it is desirable that the tension of the anchor bolt be transmitted to the concrete bearing surface by being widely dispersed.

The present invention solves the above-mentioned problem by finding the following means that can reduce the weight of the column base metal as compared with the related art and satisfy the above conditions.

That is, the column base metal of the present invention for solving the above problems has a bottom plate having an anchor bolt hole formed therein, a projecting portion to which a steel column base provided on the upper surface of the bottom plate is fixed. A column base metal body integrally formed of cast steel in a hollow box shape having an upper portion opened with ribs protruding from the upper surface of the bottom plate so as to be located around the protruding portion, and an upper portion having an anchor bolt hole It has a configuration characterized by being composed of a combination with a steel plate.

Also, the crimp joining method of the steel column pedestal by the column base hardware,
A bottom plate provided with an anchor bolt hole, a protrusion provided on an upper surface of the bottom plate to which a steel column leg is fixed, and a rib protruding from the upper surface of the bottom plate so as to be located around the protrusion. A steel column base was butt-welded to the projecting portion of a column base hardware body integrally formed of cast steel having a hollow box shape having an open upper portion, and was mounted on a concrete base in an anchor bolt hole of the bottom plate. Penetrate the anchor bolt,
An upper steel plate having an anchor bolt hole is fitted to the anchor bolt and supported on the upper end of the rib, tension is introduced into the anchor bolt, and the tension is applied to the concrete base via the upper steel plate, the rib and the bottom plate. This method is characterized in that the steel column pedestal is crimped to the concrete base by transmitting it to the bearing surface in a distributed manner.

(Operation) Since the column base hardware of the present invention has a box-shaped structure with ribs, the transmission of the tension introduced into the anchor bolt to the concrete surface is performed by a nut, as schematically shown in FIG. (Washer) Applied to upper steel plate 3 as compression force from 11,
It is transmitted to the bottom plate 5 through the entire cross-section of the ribs 6 and 8, and is transmitted from the cross-section to the concrete base with spreading.
A compressive stress is generated between the cocrete base and a strong surface contact. In the figure, hatched portions S ₁ is represents the stress transmission area. On the other hand, since the above-mentioned conventional column base metal members have a thick plate structure of cast steel, even if tension is introduced into the column base metal members by the anchor bolts 21, stress transmission to the concrete base is performed as shown in FIG. the not transmitted only in part S ₂ extending from the surface of the plank 20 the nut 22 contacts the conical. Therefore, compared with the conventional thick plate structure, the column base metal of the present invention is lightweight, and more efficiently transmits the tension of the anchor bolt to the concrete bearing surface via the column base metal, and is close to a rigid joint. Bonding is obtained, frictional resistance is improved, and resistance to shear force is dramatically improved.

Further, since the column base metal has a box-shaped cross-sectional shape, the rigidity per weight is increased as compared with the case of a single thick plate structure. Therefore, the deformation due to the bending moment can be suppressed without increasing the thickness of the bottom plate.

In terms of construction, the upper steel plate is independent of the metal body, so it can be freely fitted to the anchor bolts, the crossing of the anchor bolts can be set to some extent, the number of assembly steps is small, and the column base hardware is lightweight. Therefore, construction is easy.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of a column base hardware according to the present invention. In the figure, reference numeral 1 denotes a column base metal, which is a combination of a column base metal main body 2 integrally formed of cast steel and a plurality of upper steel plates 3. The pillar base metal body 2 has a flat bottom plate 5, a peripheral wall rib 6 erected from the top four circumferences of the bottom plate and an open upper part, and a protruding portion for butt-welding a steel column 15 standing in the peripheral wall rib. 7 and an internal rib 8 provided between the projecting portion and the peripheral wall rib. Anchor bolt holes 9 are formed in the bottom plate 5 so as to be located at the centers of the squares defined by the ribs (see FIG. 2).
Is formed, but the hole diameter is sufficiently larger than the diameter of the anchor bolt (about +20 mm), so that even if the installation position of the anchor bolt is slightly shifted, the column base metal can be easily fitted. ing. The projecting portion 7 has a steel column 15
Has a box-shaped cross section for the box-shaped column in the illustrated example, but in the case of an I-type steel frame, the cross section of the protruding portion is also an I-type. To

The main pillar base has the above structure.
At the factory or construction site, a steel column 15 is butt-welded to the tip of the protruding portion 7 and joined, and the steel column 15 is erected on the concrete base through an anchor bolt 17 installed on the concrete base 16 in the bolt hole 9 of the bottom plate 5. And leveling. Then, the upper steel plate 3 is fitted to the anchor bolt 17 and supported on the tops of the ribs 6 and 8, and temporarily tightened with the nut 11 via the washer 10, and grout 18 is injected between the cement foundation 16 and the bottom plate. I do. Thereafter, tension is applied to the anchor bolt by an appropriate means such as a hydraulic jack, and the column base metal 1 and the concrete foundation are pressed and joined to be integrated. The column base hardware after construction may be left exposed from the concrete base, or if necessary, earth concrete or protection concrete may be cast so as to be buried in the concrete. An anchor bolt of PC steel rod is used to introduce tension.

In this embodiment, as described above, when the anchor bolt 17 is fitted, the bolt hole 9 of the bottom plate 5 has a large diameter and is a loose hole. be able to. And although the bolt hole of the upper steel plate has no play, the upper steel plate is in a state of being freely fitted to one anchor bolt one by one.
It can be fitted easily regardless of the position of the anchor bolt. In particular, since this method is a crimping method using pre-stress, the shearing force acting on the column is treated by the frictional force between the bottom surface of the column base metal and the concrete surface, and the fitting of the anchor bolt and the bolt hole is strictly required. There is no need to perform this operation, and the positioning accuracy of the anchor bolt can be reduced as described above.

(Effects) The present invention is configured as described above, and has the following special effects.

Since the column base metal has a box-type structure with ribs, the transmission of the tension introduced into the anchor bolt to the concrete base is transmitted to the bottom plate through the entire cross section of the rib. As a result, the column base metal of the present invention has a wider stress diffusion area than the conventional one having a single thick plate structure, improves frictional resistance, and dramatically improves resistance to shearing force.

Further, the rigidity per weight is drastically increased as compared with the conventional one, and deformation due to bending moment can be suppressed. Therefore, the weight of the column base fitting can be reduced.

In terms of construction, the upper steel plate is independent of the metal body, so it can be freely fitted to the anchor bolt, and the mounting crossing of the anchor bolt can be made somewhat large, and it is integrally formed with cast steel with ribs Since there is no need to weld ribs on site, the number of assembly steps is small. Moreover, since the column base hardware is also lightweight, construction is easy.

[Brief description of the drawings]

FIG. 1 is a perspective view of an embodiment of a column base metal according to the present invention, and FIG.
Fig. 3 is a side view including a partial cross section in the construction state, Figs. 3 (a) and 3 (b) are explanatory views showing a tension transmission mechanism by a crimping joining method of a steel column base of the present invention, and Figs. (B) is an explanatory view showing a tension transmission mechanism when a tension is introduced into a conventional column base hardware. 1: Pillar base, 2: Pillar base, 3: Top steel plate, 5: Bottom plate, 6:
Peripheral rib, 7: Projection, 8: Internal rib, 9: Anchor bolt hole, 15: Steel column, 16: Concrete base, 17: Anchor bolt

Claims (2)

(57) [Claims] 1. A bottom plate having an anchor bolt hole, a projection provided on an upper surface of the bottom plate, to which a steel column leg is joined, and an upper surface of the bottom plate located around the projection. A column base comprising a combination of a column base hardware body integrally formed of cast steel in a hollow box shape having an upper opening with ribs protruding into the upper part, and an upper steel plate having an anchor bolt hole. hardware. 2. A bottom plate having an anchor bolt hole formed therein, a projection provided on an upper surface of the bottom plate to which a steel column leg is fixed, and an upper surface of the bottom plate positioned around the projection. A steel column base is butt-welded to the protruding portion of the column base metal body integrally formed of cast steel by forming a hollow box shape having an upper part opening with ribs protruding into the bottom plate, and concrete is inserted into an anchor bolt hole of the bottom plate. An anchor bolt mounted on a base is penetrated, an upper steel plate having an anchor bolt hole is fitted into the anchor bolt and supported on the upper end of the rib, tension is introduced into the anchor bolt, and the tension is introduced. A crimping method for a steel column base, wherein the steel column base is crimped to a concrete base by dispersively transmitting to a concrete base supporting surface via an upper steel plate, a rib, and a bottom plate.