JP2747816B2 - Fixed structure such as steel column base - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an object to be fixed such as a steel column base, a reinforced concrete column base, or an iron mounting base (hereinafter referred to as a steel column base) fixed to a concrete foundation body using anchor bolts or the like. More specifically, the present invention relates to a fixed structure such as a steel column base having a shear key embedded in a concrete foundation projecting from a lower end thereof.

[0002]

2. Description of the Related Art As a structure for fixing a steel column base of this type, there is, for example, an invention described in Japanese Patent Application Laid-Open No. 4-289349. In the structure according to the present invention, a steel column base is connected by a flange thereof to an anchor bolt fixed to the concrete foundation, and the concrete foundation is connected via a connection metal having a shear key protruding along the flange of the steel column base. It is connected to the body, and transmits shearing force to the concrete foundation as supporting pressure, especially by a shear key.

[0003]

According to the structure described in the above-mentioned publication, the shear force is borne by the shear key, so that the burden of the shear force by the anchor bolt is reduced. However, the head of the anchor bolt is protruded upward by penetrating the fixing portion extending horizontally from the metal joint, and a nut is screwed to the head (screwed portion) and tightened. The bolts are buried in the concrete foundation except for the head. Therefore, a part of the shearing force of the steel column base acts near the head of the anchor bolt.

In a steel column base having a shear key as described above, when designing fixing means such as an anchor bolt for a concrete foundation, the shear force is different from the shear key, and the vertical force (pulling force) is different from the anchor bolt. In general, design is performed as a burden on the user. However, actually, since the shearing force also acts on the anchor bolt as described above, it is necessary to make the strength of the anchor bolt larger than the numerical value required in the design in consideration of the shearing force, and only the vertical force is required. Cannot be strictly designed on the premise that the anchor bolt bears the load.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and a steel column pedestal in which only a vertical force (pull-out force) acts on an anchor bolt as much as possible, so that the anchor bolt can be designed accurately and easily. It is an object to provide a fixing structure such as

[0006]

In order to solve the above-mentioned problems, a fixing structure for a steel column base or the like according to the present invention comprises a shear key protruding from a lower end of an object to be fixed such as a steel column base attached to the concrete foundation. At the same time, the head of the anchor bolt buried in the concrete foundation is passed through a base plate integrally fixed to the lower end of the object to be fixed, and tightened by a nut screwed into the anchor bolt head. A structure for fixing a fixed object to a concrete foundation, wherein a space is formed around the anchor bolt in the concrete foundation within a predetermined range of the anchor bolt below the base plate. Here, the predetermined range refers to an axial length necessary to allow the upper portion to bend to the extent that the shearing force of the fixed object does not act on the anchor bolt.

[0007] With this configuration, the shearing force of the object is transmitted to the concrete foundation by the shear key. At the same time, the shearing force tends to act on the head of the anchor bolt via the base plate, but the vicinity of the head is curved in the direction of the shearing force within the space above the anchor bolt. Has almost no shearing force. On the other hand, the vertical force (pulling direction force) of the fixed object
Is transmitted to the concrete foundation via the anchor bolts. Therefore, when designing the anchor bolt, it is possible to take into account only the pulling force (vertical force) to be applied to the anchor bolt, in other words, it is possible to design without considering the shearing force.

In a state where the lower part of the anchor bolt is buried in a concrete foundation in advance, a through hole formed in a base plate of an object to be fixed is inserted into the head of the anchor bolt and tightened with a nut. And the position of the anchor bolt head may be slightly shifted. In such a case, since the space is provided above the anchor bolt, the upper part of the anchor bolt is curved in a predetermined direction, so that the position of the head of the anchor bolt at the position of the through hole of the base plate can be simplified. Can be adjusted to

According to a second aspect of the present invention, the upper portion of the anchor bolt can be inserted into a center hole of a bottom plate of a cylindrical body having an open upper end, and the space can be formed by the cylindrical body.

With this configuration, a space can be easily and reliably formed between the upper portion of the anchor bolt and the concrete foundation.

According to a third aspect of the present invention, the space may be formed by surrounding an upper portion of the anchor bolt with an elastic material such as sponge.

According to this structure, a space can be easily and reliably formed between the upper portion of the anchor bolt and the concrete foundation.

According to a fourth aspect of the present invention, two washers are superposed and arranged under a nut screwed into a head side screw portion of the anchor bolt, and a low friction material is interposed between the washers. In addition, it is desirable that the anchor bolt through hole of the base plate be formed larger than the outer diameter of the anchor bolt.

According to this configuration, even when the fixed object such as the steel column base is fixed on the concrete foundation by fastening the nut screwed to the head of the anchor bolt on the base plate, the fixed object is sheared. The force is not transmitted to the anchor bolt by the low friction material interposed between the washers, and the base plate smoothly slides in the direction of the shearing force with respect to the anchor bolt, so that the shearing force is reliably applied to the anchor bolt. Is prevented.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a fixing structure for a steel column base and the like according to the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a fixing structure of a lower end portion of a steel column base, FIG. 2 is a sectional view taken along the line II-II of FIG.
FIG. 2 is an enlarged front view showing the anchor bolts and accessories shown in FIG. FIG. 4 is an enlarged sectional view showing an anchor bolt having a fixing structure according to another embodiment and its attached parts.

As shown in FIG.
A steel column base 1 of a building is fixed to a top surface of a frame-shaped concrete foundation A projecting upward from the ceiling. This steel column base 1 is, as shown in FIG.
a is provided on the lower surface, and a column 1b having a cross section in this example is integrally fixed on the base plate 1a, and the center in the width direction of the flat plate 1c is orthogonally welded to each end of the column 1b. Have been. Also, as shown in FIG. 1, a shear key 1d is integrally provided downward from the central lower surface of the base plate 1a. In the present embodiment, the shear key 1d has a structure in which an iron plate having a constant thickness is formed in a box shape having an open upper end by welding, and the box-shaped shear key 1d is integrally fixed to the center of the lower surface of the base plate 1a by welding. Further, a through hole 1e for inserting a head (also referred to as a base end) of an anchor bolt (main body) 2 described later is formed in each corner of the base plate 1a. These through holes 1e are
The outer diameter of the anchor bolt (main body) 2 is slightly larger.

The anchor bolt used to fix the steel column base 1 on the concrete foundation A has the following characteristic structure. That is, as shown in FIG. 3, the anchor bolt main body 2 has male screw portions 2a and 2b at its distal end (lower end) and proximal end (upper end), respectively.
Is cut, and the washer 3 is inserted into the tip screw portion 2a,
A nut 4 in which the washer 3 is screwed to the tip screw portion 2a
On top. A cylindrical body 5 formed by welding a circular plate 5b having a central hole 5c formed at the lower end opening of a cylindrical pipe member 5a is fixed to the upper part of the anchor bolt main body 2 by welding, and the anchor bolt main body 2 is fixed to the central hole 5c. It is inserted and fixed at a predetermined position by welding. That is, in FIG. 1, the cylindrical body 5 is fixed by welding or the like to the axial direction (length direction) of the anchor bolt main body 2 where the upper end of the cylindrical body 5 contacts the lower surface of the base plate 1a. In this example, this position is substantially at the center of the anchor bolt body 2 in the axial direction. Also, the head side screw portion 2b of the anchor bolt body 2
, Two washers 6.6 and two nuts 7.7 are arranged. A low-friction material, in this example, a Teflon plate 6a, is adhered to the surfaces of the washers 6, 6 which come into contact with each other. The hole 6b of each washer 6, 6 is larger than the outer diameter of the anchor bolt main body 2, similarly to the through hole 1e of the base plate 1a.

Next, a procedure for fixing the steel column base 1 on the concrete foundation A using the anchor bolt 2 having the above-described configuration will be described.

As shown in FIG. 1, the anchor bolt 2 is embedded in the concrete foundation A in advance with the head side projecting upward with the nut 4 and the washer 3 attached to the lower end screw portion 2a. The embedding positions of the four anchor bolts 2 correspond to the positions of the through holes 1e of the base plate 1a shown in FIG. An inverted trapezoidal hole C is provided near the upper center of the concrete foundation A.

In the above state, a loading surface E is formed by appropriately installing a level adjusting member made of an iron plate or the like on the concrete foundation A so that the lower surface of the base plate 1a of the steel column base 1 is at a predetermined level. Pillar 1 is erected. At this time,
The shear key 1d is inserted into the grout D in the hole C, and the through hole 1e of the base plate 1a is inserted into the head of the anchor bolt body 2. This insertion work is performed through the through hole 1
e is larger than the outer diameter of the anchor bolt main body 2, and the head side of the anchor bolt main body 2 can be bent within a certain range (space between the pipe member 5a and the anchor bolt main body 2) in the horizontal direction. Can be done very easily from Thereafter, grout D is packed into a space below loading surface E including hole C, and steel column base 1 is fixed.

Then, in a state where the grout D is completely solidified, as shown in FIG. 1, two washers 6.6 are overlapped and inserted into the head side screw portion 2b of the anchor bolt body 2, and then the two bolts are inserted. Then, the fixing work of the steel column base 1 is completed by screwing the nuts 7 into the screw portion 2b in order.

As described above, the fixing structure of the steel column base 1 according to the present embodiment is configured. According to this fixing structure, a horizontal force acts on the steel column base 1 due to, for example, a typhoon or an earthquake. In this case, it is transmitted to the concrete foundation A by the shear key 1d at the lower end of the base plate 1a.
At this time, when the base plate 1a moves to the side where the horizontal force acts on the anchor bolt 2, the lower washer 6 moves together with the base plate 1a. The interposed Teflon plates 6a slide with each other, and no shearing force acts on the head of the anchor bolt main body 2. Also, even if the moving distance of the base plate 1a is large and moves beyond the diameter of the through hole 1e, and the inner wall of the through hole 1e of the base plate 1a abuts on the head of the anchor bolt body 2, the anchor bolt body 2 Is curved within the range of the space S in the pipe member 5a, so that the shearing force is prevented from acting on the anchor bolt body 2.
On the other hand, when an upward force is applied to the steel column base 1 or a bending moment is applied, a pulling force is applied to the head of the anchor bolt main body 2 via the washers 6.6, so that the concrete foundation A is Is transmitted.

As a result, the anchor bolt 2 can be designed faithfully and strictly based on the pull-out force that must be borne without considering the shearing force.

Although the embodiment of the fixing structure of the steel column base 1 according to the present invention has been described above, the present invention can be implemented as follows.

Instead of the rigid cylindrical body 5, for example, a columnar sponge body (not shown) is mounted on the upper part of the anchor bolt main body 2, or a prismatic soft rubber body (not shown) is mounted on the anchor bolt main body. Even when it is mounted on the upper part of the anchor bolt 2, the space part S in which the upper part of the anchor bolt 2 can bend within a predetermined range can be similarly formed in the concrete foundation A.

The low friction material such as the Teflon plate 6 a
Instead of providing them on the phase contact surfaces of the two washers 6,6,
As shown in FIG. 4, only one washer 6 is used, and a Teflon plate 6a, 1f is attached to the lower surface of the washer 6 and the periphery of the through hole 1e on the upper surface of the base plate 1a, or a low friction material is used. It may be coated. In addition, even when such a low friction material is not used by being attached to the washer 6 or the like, the effect of the present invention is produced, but it goes without saying that the use of the low friction material is more effective.

The steel column base 1 is not limited to the above-described cross-shaped cross section, and may have any shape such as a cross-section H shape. The fixed object to be fixed is the steel column base 1 and an iron machine mounting table. Can be similarly implemented.

The tip (lower end) of the anchor bolt 2
Since the washer 3 is provided to prevent slipping, a washer-shaped radially projecting member is integrally formed at the distal end of the anchor bolt 2 instead of being attached with the nut 4 screwed to the distal end screw portion 2a. You may.

[0030]

As is apparent from the above description, the fixing structure of the steel column base and the like according to the present invention has the following excellent effects.

(1) Since only the vertical force (pulling force) acts on the anchor bolt as much as possible, the pulling force (vertical force) to be applied to the anchor bolt when designing the anchor bolt A strict design can be made without considering only the shear force. Also, with the lower part of the anchor bolt buried in the concrete foundation in advance, when inserting the through hole drilled in the base plate of the fixed object into the anchor bolt head, the position of the through hole of the base plate and Even if the position of the anchor bolt head is slightly misaligned, the position of the anchor bolt head can be easily adjusted to the position of the through hole in the base plate by bending the upper part of the anchor bolt in the space around it. .

(2) According to the second aspect, a space can be easily and reliably formed between the upper portion of the anchor bolt and the concrete foundation.

(3) According to the third aspect, a space can be easily and reliably formed between the upper portion of the anchor bolt and the concrete foundation.

(4) According to the structure of the fourth aspect, the nut screwed to the head of the anchor bolt is tightened on the base plate to fix the object such as the steel column base on the concrete foundation. However, the shear force of the anchor bolt is not transmitted to the anchor bolt because the low friction material interposed between the washers causes the base plate to slide in the shear force direction with respect to the anchor bolt. Can be prevented more reliably.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a fixing structure of a lower end portion of a steel column base according to the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

FIG. 3 is an enlarged front view showing the anchor bolts and accessories of FIG. 1, and a part is shown in a cross section.

FIG. 4 is an enlarged sectional view showing an anchor bolt and accessories of a fixing structure according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 steel column base 1a base plate 1d shear key 1e through hole 1f, 6a Teflon plate (low friction material) 2 anchor bolt (main body) 3,6 washer 4,7 nut 5 cylinder 5a pipe member A concrete foundation D grout S space

Claims (4)

(57) [Claims] 1. A shear key protruding from a lower end of an object to be fixed such as a steel column base is embedded in the concrete foundation,
The head of the anchor bolt buried in the concrete foundation is passed through a base plate integrally fixed to the lower end of the object to be fixed, and tightened by a nut screwed to the head of the anchor bolt. A fixing structure for a steel column base or the like, characterized in that a space is formed around the anchor bolt in the concrete foundation in a predetermined range below the base plate of the anchor bolt. . 2. The fixing structure for a steel column base or the like according to claim 1, wherein an upper portion of said anchor bolt is inserted into a central hole of a bottom plate of a cylindrical body having an open upper end, and said cylindrical portion forms said space. 3. The fixing structure for a steel column base or the like according to claim 1, wherein an upper portion of said anchor bolt is surrounded by an elastic material such as sponge to form said space. 4. A low friction material is interposed between the washers under a nut screwed into a head side screw portion of the anchor bolt, and a low friction material is interposed between the washers. The fixing structure for a steel column base or the like according to any one of claims 1 to 3, wherein the anchor bolt through hole is formed to be larger than the outer diameter of the anchor bolt.