JP2003027591A - Connection structure between column and bottom plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively use an existing hardpan even when its bearing capacity and soil bearing capacity of the present ground cannot be secured sufficiently. SOLUTION: When the existing structural body is demolished and a new structural body is constructed in the site of the demolished structural body and the hardpan for the existing structural body is not demolished but left for building a newly installed column 2 on the existing hardpan 1, the existing hardpan and the column base of the newly installed column are connected together via a shear head 3 for dispersing a load applied to the newly installed column and transmitting it to the existing hardpan. The shear head and the column base part of the newly installed column are buried in the newly constructed hardpan 4 formed by placing concrete on the existing hardpan. The shear head is formed by crossing steel products 3 each other into a cross shape and fixed to the existing hardpan by means of an anchor 7, and the column base of the newly installed column is fastened to the upper face center part of the shear head by means of a bolt 8. A through hole 9 for passing a reinforcement arranged in the newly constructed hardpan is arranged in the shear head.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pillar to be applied when a new structure is dismantled and a new structure is built on the site of the existing structure by using the foundation bottom of the existing structure to erect a new structure pillar. It relates to the joint structure between the bottom plate and the bottom plate.

[0002]

2. Description of the Related Art Conventionally, when an existing structure such as a building is dismantled and a new structure is constructed on the site, generally, the existing structure is completely dismantled and vacated, and then the new structure is constructed. However, recently there is a tendency to use some of existing structures as much as possible, for example, leaving underground walls of existing buildings without dismantling them. It is becoming more and more popular to use it as an underground wall of a new building or a part of it.

By the way, it is not easy to dismantle the foundation of the structure, especially the bottom plate, since it is a sturdy concrete structure having a considerable thickness, and after dismantling, the same bottom plate is troublesome and costly. Since it is usual to build a new base structure, it is rational without waste if the existing base plate is left without being dismantled and can be used as it is as the base plate of the new structure or a part thereof.

[0004]

However, when the bottom plate of the existing structure is left and used as a new bottom plate, a new column is erected on the existing bottom plate, which is possible. In order to achieve this, it is premised that the existing base has sufficient bearing capacity against the load applied to the new pillar and the ground below the existing base has sufficient bearing capacity. It was not possible to use the existing bottom plate effectively.

In view of the above circumstances, it is an object of the present invention to provide means for enabling effective use of the existing bottom plate and the ground even when the ground strength cannot be sufficiently secured.

[0006]

According to the invention of claim 1, when the existing structure is dismantled and a new structure is constructed on the site, the bottom plate of the existing structure is left without being dismantled and the existing base plate is left. It is a joint structure of a pillar and a bottom board that is applied when a new pillar is erected on the top, and the existing bottom board and the new pillar through a shear head that distributes the load applied to the new pillar to the existing bottom board. It is characterized in that the shear head and the column base of the new column are buried in the new bottom plate which is joined to the column base of the above and the concrete is cast on the existing bottom plate.

According to a second aspect of the present invention, in the first aspect of the invention, the shear head is a steel material assembled in a cross shape, and the shear head is fixed to an existing bottom plate by an anchor, and the upper surface of the shear head is fixed. It is characterized in that a column base of a new column is fastened at the center.

The invention of claim 3 is characterized in that, in the invention of claim 1 or 2, the shear head is provided with a through hole for passing a reinforcing bar arranged in a new bottom plate.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an embodiment of the present invention.
In the figure, reference numeral 1 is an existing bottom plate left when the existing structure is dismantled, 2 is a new column standing on the existing bottom plate 1, and 3 is interposed between the existing bottom plate 1 and the column base of the steel column 2. The installed shear heads 4 are new bottom plates formed on the existing bottom plate 1.

The new pillar 2 in this embodiment is a steel frame pillar made of H-shaped steel or the like, which is a main pillar of a new structure and is a so-called true pillar that functions as a temporary pillar during construction of an underground structure. The pillar base of the new pillar 2 is the shear head 3
By connecting to the existing bottom plate 1 via the
The load (load at the time of construction and load after completion) applied to the existing bottom plate 1 and the ground 5 therebelow via the shear head 3.
Is dispersed and transmitted to the ground 5, and is stably supported by the ground 5 in a wide range as shown by an arrow in the figure. The new column 2 is not necessarily a true column, and may be a simple column, or may be a steel reinforced concrete column instead of a steel frame column.

The shear head 3 in this embodiment is
As shown in (b), the steel material 3a is assembled in a cross shape,
It is installed horizontally on the existing bottom plate 1 via the mortar 6 and fixed by the anchor 7, and the base plate 2a is fastened with the bolt 8 at the center of the upper surface of the shear head 3 so that the new pillar 2 is erected. It has become so.
Each steel material 3a of the shear head 3 is provided with a through hole 9 for passing a basic reinforcing bar (not shown) arranged when the new bottom plate 4 is constructed. Steel material 3 that constitutes the shear head 3
For example, H-section steel can be preferably used as a, and the cross-sectional dimension thereof is 300 × 300 mm to 400 × 400.
It may be about mm, and the planar size may be appropriately set so that the load can be dispersed in a desired range. The plane shape and dimensions of the shear head 3 are so long as the load can be effectively dispersed in consideration of the cross section of the new column 2, the load applied to it, the proof stress of the existing bottom plate 1, the proof stress of the ground 5, and the like. It is optional.

The procedure for constructing the new column 2 is as follows. The shear head 3 is positioned on the existing foundation 1 left when the existing structure is dismantled and fixed by the anchor 7, and the new column 2 is mounted on the shear head 3. Are positioned and fastened by bolts 8 to stand. Also, by arranging the basic rebar on the existing bottom plate 1,
At that time, the reinforcing bars arranged on the column bases are passed through the through holes 9 provided in the shear head 3. Then, concrete is cast on the existing bottom plate 1 to form a new bottom plate 4, and the shear head 3 and the column bases of the new column 2 are buried in the new bottom plate 4 to a predetermined height. When the new column 2 is an SRC column, the column reinforcing bars are laid around the steel frame erected as described above and concrete is placed.

As described above, by joining the new post 2 to the existing bottom plate 1 via the shear head 3, the load applied to the new post 2 is widely dispersed, and the existing bottom plate 1 and the ground 5 below it. Therefore, the stress of the existing bottom 1 and the ground 5 is relieved. Therefore, even if the strength of the existing bottom 1 or the ground 5 is not sufficient, the new pillar 2 is installed on the existing bottom 1 without any trouble. As a result, even the existing bottom plate 1 having insufficient proof stress can be effectively used without dismantling and removing it.

In particular, as the shear head 3, a steel material 3a such as an H-shaped steel is assembled in a cross shape, and when the new column 2 is constructed, the shear head 3 is fixed to the existing bottom plate 1 by the anchor 7. Since the steel frame as the new post 2 is simply fastened on the shear head 3 by the bolts 8, the construction is not troublesome and the shear head 3 has a through hole 9
Since it is provided, it does not interfere with the work of arranging the basic rebar.

It should be noted that it is realistic that the newly installed column 2 is erected by bolting it to the shear head 3 as in the above-mentioned embodiment because the workability is the most excellent, but the present invention is not limited to this. Alternatively, the new column 2 may be welded to the shear head 3 in the field, or the shear head 3 may be pre-welded by welding or bolting at the stage of factory manufacturing the new column 2.

[0016]

According to the joint structure of the pillar and the bottom board of the invention of claim 1, the existing bottom board and the column base of the new pillar are joined through the shear head, and the concrete is placed on the existing bottom board. Since the shear head and the column base of the new column are embedded in the newly formed bottom plate, not only can the new column be firmly and firmly joined to the existing bottom plate, but the load applied to the new column is dispersed by the shear head. Therefore, even if the existing bottom and the existing ground below it are transmitted to the existing bottom, and even if the bearing capacity of the existing bottom or the ground bearing capacity of the ground is not sufficient, it is possible to install new columns on the existing bottom without any problems, and as a result,
Even the existing base plate with insufficient proof stress can be effectively used without dismantling and removing it.

According to the invention of claim 2, as the shear head in the invention of claim 1, a steel head in a cross shape is adopted, and the shear head is fixed to the existing bottom plate by an anchor, Since the column base of the new column is fastened to the center of the upper surface of the head, the construction can be performed easily and at a sufficiently low cost.

According to the third aspect of the present invention, the shear head in the first or second aspect of the present invention is provided with the through hole for passing the reinforcing bar to be laid in the new bottom plate, which hinders the basic reinforcing work. Never come.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a column base portion showing an embodiment of the present invention.

[Explanation of symbols]

1 Existing base 2 new columns 2a Base plate 3 sheer head 3a steel 4 New base 5 ground 6 spread mortar 7 anchor 8 volt 9 through holes

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 2D046 AA15 AA16                 2E125 AA04 AA45 AB01 AC15 AG12                       AG13 AG41 BA12 BA22 BA32                       BB08 BB22 BD01 BE08 BF06                       BF08 CA03                 2E176 AA01 BB34

Claims (3)

[Claims] 1. When dismantling an existing structure and constructing a new structure on the site, it is applied when the bottom plate of the existing structure is left undisassembled and a new column is erected on the existing base plate. It is a joint structure of the pillar and the bottom plate, and the existing bottom plate and the column base of the new column are joined via the shear head for distributing the load applied to the new column to the existing bottom plate, A joint structure between a column and a bottom plate, in which a shear head and a column base of a new column are buried in a new bottom plate formed by concrete being cast into the ground. 2. The shear head is made of steel material assembled in a cross shape, the shear head is fixed to an existing bottom plate by an anchor, and a column base of a new column is fastened to the center of the upper surface of the shear head. The column-bottom joint structure according to claim 1, wherein 3. The column-bottom joint structure according to claim 1, wherein the shear head is provided with a through hole for passing a reinforcing bar arranged in a new bottom plate.