JP2004316278A - Structure of steel pipe plinth part - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure of a steel pipe plinth part capable of further improving the strength, simplifying the construction, and shortening a construction time period. <P>SOLUTION: This steel pipe plinth part is constituted in such manner that anchor bolts 2 mounted on an outer periphery of a steel pipe column 11a and anchor bars mounted inside of the steel pipe column 11a and using deformed bars are buried in the foundation concrete 1 in a state that their head parts are projected from the foundation concrete 1. The head parts of the anchor bolts 2 and the head parts of the anchor bars 3 are inserted to a base plate 12 mounted on a lower end part of the steel pipe column 11a, and the inside of the steel pipe column 11a is filled with non-contractive mortar 4 or slight expandable mortar 4 of high strength and high fluidity to bury the anchor bars 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a structure of a steel pipe column base erected on a foundation concrete.
[0002]
[Prior art]
Generally, a column base of a steel pipe structure is connected to a lower foundation concrete portion by installing about four to eight anchor bolts on the outer periphery of the steel pipe column of a base plate provided at the lower end of the steel pipe column. . Improvements in the structure of such a column base have been advanced to withstand a large earthquake.
Therefore, as a method of firmly installing the steel pipe columns in the foundation concrete, anchor bolts and anchor bars are previously embedded in the foundation concrete with their respective heads left on the ground. Then, the heads of the anchor bolts and the anchor bars are inserted into the base plates welded to the legs of the steel pipe columns, and the heads of the anchor bolts are tightened with nuts. In this case, the anchor bolt is disposed on the outer periphery of the steel pipe column, and the anchor bar is disposed in the steel pipe column. After that, it is known that an anchor bar and a steel pipe pillar are integrated by casting concrete into the steel pipe pillar, and the steel pipe pillar is fixed on the foundation concrete (for example, see Patent Document 1). The concrete is poured into the steel pipe column through the concrete filling opening provided above the steel pipe column.
In this way, by arranging the anchor bar on the steel pipe column of the steel pipe column base, the amount of rebar is increased twice or more, and the tensile strength of the steel pipe column base is increased.
[0003]
[Patent Document 1]
JP 2000-297480 A
[Problems to be solved by the invention]
By the way, since concrete is cast in the steel pipe column of the above steel pipe column base, the bonding strength of the anchor bar can be increased to some extent by restraining the steel pipe column, but the bonding strength is further increased, and the steel pipe column base is improved. It is desired to further improve the performance.
In addition, the concrete filling opening provided in the steel pipe column is a relatively large opening (for example, a diameter of about 150 mm) because concrete is poured into the steel pipe column and a vibrator is inserted to compact the concrete after casting. Therefore, these openings must be closed by on-site welding after concrete placement is completed, and there has been a problem that the construction is troublesome.
Furthermore, since the concrete is typically cast into the steel pipe column at the time of slab casting, it is a work after the work of building the leg portion of the steel pipe column. For this reason, concrete is poured into the steel pipe column, and the steel pipe column base does not exhibit the performance until the strength of the concrete is developed.
[0005]
The present invention has been made in view of the above circumstances, and it is possible to further improve the strength of a steel pipe column pedestal, and to simplify the construction and shorten the construction period of a steel pipe column pedestal. The task is to provide a structure.
[0006]
[Means for Solving the Problems]
In order to solve the above problem, the invention of claim 1 is, for example, as shown in FIG. 1, a structure of a steel pipe column base 11 erected on a foundation concrete 1,
Anchor bolts 2,... Arranged on the outer periphery of the steel tube column 11a of the steel tube column base 11 and anchor bars 3,... Using deformed reinforcing bars arranged inside the steel tube column 11a are provided on the foundation concrete 1. Each head is buried protruding from the foundation concrete 1,
The heads of the anchor bolts 2,... And the heads of the anchor bars 3,... Are inserted into a base plate 12 provided at the lower end of the steel tube column 11a. Are filled with a high-strength, high-flowability, non-shrinkable mortar 4 or slightly expandable mortar 4 so as to be embedded.
[0007]
According to the first aspect of the present invention, the non-shrink mortar or the slightly expandable mortar is filled with high strength and high fluidity so that the anchor bar is buried inside the steel pipe column. As a result, the effect of restraining the mortar from the steel pipe column is further enhanced, and the integrity of the mortar and the steel pipe column and the adhesion strength of the anchor bar are significantly increased. Therefore, the strength of the steel pipe column base can be increased, and the structural performance of the steel pipe column base is more stable. Further, the anchoring length of the anchor streaks can be significantly reduced.
Further, since mortar is used instead of concrete, a large opening for inserting a vibrator is not required unlike the conventional case, so that a mortar filling hole for filling mortar can be reduced. In addition, it is not necessary to close the mortar filling hole, so that the construction can be simplified and the construction period can be shortened.
In addition, since the mortar is filled in the present invention, the mortar can be installed at the same time as filling the mortar between the lower surface of the base plate and the foundation concrete, instead of at the time of slab casting as in the related art. Can be shortened. Since the mortar filling operation can be performed at an early stage in this way, the temporary period until the steel pipe column base exhibits its performance is shortened, and safety can be improved.
[0008]
In the invention of claim 2, for example, as shown in FIG. 1, the steel pipe column 11a of the steel pipe column base 11 communicates with the inside of the steel pipe column 11a immediately above the base plate 12, and the mortar 4 is A mortar filling hole 11b to be filled is formed.
[0009]
According to the second aspect of the present invention, the mortar can be easily filled in the steel pipe column by the mortar filling hole.
[0010]
For example, as shown in FIG. 1, the steel pipe column 11a of the steel pipe column base 11 is provided above the mortar filling hole 11b and above the upper end position of the anchor streaks 3,. A hole 11c is formed to communicate with the inside of the steel pipe post 11a and to check the mortar 4 filled with air inside the steel pipe post 11a and to confirm the filling.
[0011]
According to the third aspect of the present invention, air can be removed from the steel pipe column filled with the holes for air release and filling confirmation, and the mortar can be reliably filled in the steel pipe column.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1A and 1B show the structure of a steel pipe column base according to the present invention, wherein FIG. 1A is a side sectional view, and FIG. 1B is an AA sectional view of FIG.
First, the structure of a steel pipe column base according to the present invention will be described with reference to FIGS. 1 (a) and 1 (b). In the basic concrete 1, eight anchor bolts 2,... And four anchor studs 3,.
The anchor bolts 3,... Have a bolt diameter of about 22 mm, and the length buried in the foundation concrete 1 is about 850 mm (about 40 times the bolt diameter). These anchor bolts 3,... Are provided at equal intervals as shown in FIG.
[0013]
For the anchor bars 2,..., Deformed bars having irregularities formed on the surface thereof are used. The diameter of the reinforcing bar is about 38 mm, and the length of the portion buried in the foundation concrete 1 is about 1500 mm (about 40 times the diameter of the reinforcing bar) in consideration of the tensile stress. The length is about 800 mm (about 20 times the rebar diameter). These anchor bars 2 are provided at equal intervals as shown in FIG.
[0014]
As shown in FIG. 1 (b), the steel pipe column base 11 has a steel pipe column 11a of a rectangular steel pipe, and a base plate 12 is welded to the lower end thereof to be integrally formed. A mortar filling hole 11b communicating with the inside of the steel pipe column 11a is formed directly above the base plate 12 in the steel pipe column 11a. Above the mortar filling hole 11b of the steel pipe column 11a, a hole 11c is formed which serves both to release air during filling of the mortar and to confirm the filling.
The diameter of the mortar filling hole 11b and the diameter of the hole 11c that also serves to confirm air release and filling are about 10 mm. That is, the mortar filling hole 11b can be made such a small hole because it is not necessary to insert a vibrator for compacting the concrete as in the related art.
[0015]
The base plate 12 has a substantially square plate shape, and the anchor bolts 2,..., Through which the anchor bolt openings 12a,. Are formed corresponding to the embedding positions. The opening diameter of the anchor bolt openings 12a,... Is formed larger than the diameter of the head of the anchor bolts 2,.
Further, on the center side of the base plate 12 with respect to the anchor bolt openings 12a,..., Anchor head openings 12b,. It is formed corresponding to. The opening diameter of the anchor streaks 12b,... Is formed to be about 10 to 20 mm larger than the diameter of the anchor streaks 3,.
[0016]
The heads of the anchor bolts 2,... And the heads of the anchor bars 3,... Are inserted through the anchor bolt openings 12a,. The washers 21 are inserted into the heads of the anchor bolts 2 and fastened with nuts 22.
The mortar 4 is filled from the mortar filling hole 11b formed in the steel pipe column 11a so that the heads of the anchor bars 3,... Are embedded in the inside of the steel pipe column 11a. Has been established. Further, the mortar 4 is also filled between the lower surface of the base plate 12 and the foundation concrete 1.
The mortar 4 to be used is a non-shrink mortar having high strength and high fluidity or a slightly expandable mortar having high strength and high fluidity.
[0017]
Here, the required anchoring length of the anchor streaks 3,... Differs between the case where concrete is cast inside the steel pipe column 11a as in the related art and the case where mortar 4 is filled as in the related art.
That is, Anchors 3, ... is rebar at D38, strength 5000 kg / cm ^2, when the intensity of the concrete is 240 kg / cm ^2, the adhesion strength of the Anchors 3, ... and, 0.5 × 240 kg / cm ² = 120 kg / cm ² , and the required fixing length is 5000 × 11.4 / (120 × 12) ≒ 400 mm.
On the other hand, when the strength of the mortar 4 is 360 kg / cm ² , the adhesion strength to the anchor streaks 3 is 0.5 × 360 kg / cm ² = 180 kg / cm ² and the required fixing length is 5000 × 11.4 / (180 × 12) ≒ 263 mm.
Therefore, as compared with the case of using concrete by using the high-strength mortar 4, the anchoring length of the anchor bars 3,... It can be seen that the length can be significantly shortened to less than about.
[0018]
Next, a procedure for constructing the above-described structure of the steel pipe column base 11 will be described.
First, the base plate 12 is fixed to the lower end portion of the steel pipe column 11a by welding in advance. On the other hand, when constructing the foundation concrete 1, the anchor bolts 2,... And the anchor bars 3,.
Next, the anchor bolts 2,... And the anchor bars 3,... Are inserted into the anchor bolt openings 12a,. I do. At this time, the base plate 12 is arranged at a predetermined distance from the foundation concrete 1.
Then, after filling the mortar 4 between the base plate 12 and the foundation concrete 1, the heads of the anchor bolts 2,... Are fastened with washers 21,.
Thereafter, the mortar 4 is filled into the inside of the steel pipe column 11a through the mortar filling hole 11b.
[0019]
As described above, according to the structure of the steel pipe column base 11 of the embodiment of the present invention, the heads of the anchor bolts 2,... And the anchor bars 3,. Since the non-shrink mortar 4 or the slightly expandable mortar 4 having high strength and high fluidity is filled in the inside of the steel pipe column 11a, the steel pipe of the mortar 4 is compared with the case where conventional concrete is cast. The binding effect from the column 11a is further enhanced, and the integrity of the mortar 4 and the steel tube column 11a and the adhesion strength at the anchoring length portion of the anchor bars 3,. It can be a reinforcing bar. .. Penetrate the base plate 12, the base plate 12 acts as a supporting plate against the tensile force of the anchor streaks 3,.
Therefore, by the synergistic effect of these two actions, it is possible to further shorten the anchoring length of the anchor bars 3, arranged in the steel pipe column 11a. In addition, since the anchoring length can be shortened, the work of inserting the anchor bars 3, buried in the foundation concrete 1 into the anchor bar openings 12b,. Things. Further, since the pulling force from the anchor bars 3 is transmitted by the above two actions, the thickness of the base plate 12 can be made very thin as long as it can cope with the force shared by the supporting pressure of the base plate 12. .
From the above, it is possible to greatly increase the tensile strength of the steel pipe column base 11 as compared with the case where conventional concrete is used, and it is possible to make the transmission of stress more reliable. The structural performance of the leg 11 is more stable.
[0020]
Further, the amount of reinforcing bars can be greatly increased by the anchor bars 3, arranged inside the steel pipe column 11a. Therefore, it is necessary to increase the number of the anchor bolts 2, arranged on the outer periphery of the steel pipe column 11a. Disappears. Therefore, it is not necessary to increase the size of the base plate 12, and the steel tube column base 11 can be accommodated well.
[0021]
Further, since the mortar 4 is used in the present invention, it is not necessary to insert a vibrator into the mortar filling hole 11b, so that the mortar filling hole 11b can be made smaller, and it is necessary to close the mortar filling hole 11b. Therefore, it is possible to simplify the construction and shorten the construction period.
Further, the work of filling the mortar 4 into the steel pipe column 11a can be performed at the same time as filling the mortar 4 between the lower surface of the base plate 12 and the foundation concrete 1, so that the construction period is shortened. be able to. In addition, the temporary period until the steel pipe column base 11 exhibits its performance is shortened, so that safety can be improved.
[0022]
Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist of the present invention.
For example, the anchor bolts 2,... And the anchor streaks 3,... Are not limited to the number described above, and can be changed as appropriate.
Although the steel pipe column 11a is a square steel pipe, it may be a circular steel pipe, for example.
[0023]
【The invention's effect】
According to the structure of the steel pipe column base according to the present invention, since high strength and high fluidity, non-shrink mortar or slightly expandable mortar is filled so that the anchor bar is embedded inside the steel pipe column, The integrity of the mortar and the steel tube column and the adhesion strength of the anchor bar become extremely high. Therefore, the strength of the steel pipe column base can be increased, and the structural performance of the steel pipe column base is more stable. Further, the anchoring length of the anchor streaks can be significantly reduced.
Further, the mortar filling hole for filling the mortar can be reduced. In addition, it is not necessary to close the opening, so that the construction can be simplified and the construction period can be shortened.
In addition, the filling of the mortar into the steel pipe column can be performed at the same time as the filling of the mortar between the lower surface of the base plate and the foundation concrete, and the construction period can be shortened. Moreover, since the temporary installation period until the steel pipe column base exhibits its performance is shortened, safety can be improved.
[Brief description of the drawings]
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view for showing the structure of a steel pipe column base according to the present invention, wherein (a) is a side sectional view, and (b) is an AA sectional view of (a).
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Foundation concrete 2 Anchor bolt 3 Anchor bar 4 Mortar 11 Steel pipe column base 11a Steel pipe column 11b Mortar filling hole 11c Hole for venting and confirming filling of mortar 12 Base plate

Claims (3)

The structure of a steel pipe column base standing on the foundation concrete,
In the foundation concrete, anchor bolts arranged around the outer periphery of the steel tube column of the steel tube column base and anchor bars using deformed reinforcing bars arranged inside the steel tube column are respectively buried with their heads protruding from the foundation concrete. Has been
A head plate of the anchor bolt and a head of the anchor bar are inserted into a base plate provided at a lower end portion of the steel pipe column, and high strength and fluidity are provided so that the anchor bar is embedded inside the steel pipe column. A high-strength, non-shrink mortar or a slightly expandable mortar is filled with the steel pipe column base structure. The mortar filling hole which communicates with the inside of the steel pipe column and which is filled with the mortar is formed in the steel pipe column of the steel pipe column base immediately above the base plate. Of steel pipe column base. The steel pipe pillar of the steel pipe pillar has an upper portion above the mortar filling hole and above an upper end position of the anchor bar, communicates with the inside of the steel pipe column, and vents the mortar filled inside the steel pipe column. 3. A steel pipe column base structure according to claim 2, wherein a hole for confirming the filling is formed.

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