JPH0988353A - Mass constructing method using earth anchor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish reutilization of an underground concrete mass, suppressing the costs to a great extent, and shorten the construction term in dismantling an existing building having center column and replacing with a new building having no center column, by adjusting the stress condition in the underground portion and/or foundation of the existing building by the use of an earth anchor. SOLUTION: By this method according to present invention, an existing building consisting of underground floors and over-ground floor each equipped with center colmns 13, 23 is dismantled, and a building having no center column is to be built anew, wherein an earth anchor is furnished in the foundation part of the underground concrete mass of the existing building in such an a way as mating with the position of the center column 13 to be removed, and the over-ground structural mass 1 is dismantled and removed. Unnecessary center column 13 of the ground floor is removed while the underground mass 1 is left, and over-ground mass 2 having no center column 13 is built anew upon the underground mass 1, and introduction and adjustment of the axial force to each earth anchor are made from during works for the new building till its completion so that the stress shares of different places of the foundation are approached to the condition before the works.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a skeleton construction method using an earth anchor in rebuilding existing buildings.

[0002]

2. Description of the Related Art Recently, the number of building rebuilding works (renewal works) has increased, and the scale has been further increased. In addition, with the economic stagnation, price competition in the construction industry has become more severe. Now, in this kind of conventional rebuilding work, in general,
It is newly built after dismantling all the above-ground and underground parts, and even if it is reused, it is limited to the use of mountain retaining on the outer wall of the underground and the reuse of existing foundation piles, so the area of the underground structure is reduced and dismantled. There were many problems such as an increase in construction costs and an increase in waste such as dismantled concrete.

On the other hand, in a building constructed on a sloping ground, it has been proposed to reduce the stress generated in the underground portion which is subjected to uneven earth pressure by an oblique earth anchor (Japanese Patent Laid-Open No. 5-247935). In this case, the diagonal earth anchor is effective in reducing the horizontal force generated in the basement, particularly the horizontal force generated by the seismic force.

[0004]

By the way, in the basement,
There are many walls, and even buildings with the old seismic design method have surplus capacity for seismic force, so it is conceivable that the underground structure will be left as appropriate for reuse. There are few structural problems in the reuse of such underground structures if the pillars of the newly built aboveground part are compatible with the pillar layout of the existing part, but in general, there are many points that are impossible in terms of construction planning. . For example, in the case where the middle pillar cannot be placed on the above-ground structure, the stress sharing of the foundation and the pillar is significantly different between the existing building and the new building, which makes reuse difficult. But,
If long-term stress can be dealt with, it is likely that a technical solution for reuse can be created. Therefore, the present invention adjusts the stress state of the underground or foundation of the existing building by using an earth anchor when the existing building having the center pillar is dismantled and is rebuilt to a new building without the center pillar. By
The purpose is to make it possible to reuse the underground structure and to significantly reduce costs and shorten the construction period.

[0005]

According to the invention of claim 1, in a rebuilding work for dismantling an existing building to newly construct a building having various structures, the underground structure of the existing building is reused and the foundation of the underground structure is reused. It is characterized in that an earth anchor is attached to an appropriate place of the part, and the axial force of the earth anchor brings the stress sharing of the underground and each part of the foundation close to the state before the rebuilding.

According to the invention of claim 2, in the rebuilding work for dismantling an existing building consisting of a basement floor and a ground floor having a middle pillar on each floor to newly construct a building without a middle pillar, unnecessary middle pillars are removed. The underground skeleton of the existing building was removed and reused, and the ground anchor was attached to the foundation of the underground skeleton corresponding to the position of the removed middle pillar. The feature is that the stress distribution at each place is brought closer to the state before rebuilding.

The invention according to claim 3 is a substructure of an existing building in a rebuilding work for dismantling an existing building having a basement floor and a ground floor having a middle pillar on each floor and newly building a building having no middle pillar. In the foundation of the, the ground anchor is deployed corresponding to the position of the middle pillar to be removed, the ground structure is dismantled and removed, the unnecessary middle pillar on the basement floor is removed and the underground structure is left, and it is placed on the underground structure. A new ground structure without a center pillar is newly constructed, and axial forces are introduced / adjusted to each of the above-mentioned earth anchors from the time of construction to completion of the new construction work so that stress is shared between the underground and various parts of the foundation before rebuilding. It is characterized by approaching to.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings show an embodiment of a method for constructing a skeleton using an earth anchor according to the inventions of claims 1 to 3. 1 to 5 show the following (1) to (6)
This is a procedure of construction, and will be described below one by one. In addition, in the figure, A shows the vertical side surface of the building, B shows the transverse plane of the first basement of the underground structure, and B ′ shows the transverse plane of the second basement of the underground structure. . Further, in the following description, a building made of steel-framed reinforced concrete is targeted, but a building made of reinforced concrete or another building may be used.

(1) Existing Building (FIG. 1) FIG. 1 shows an existing building of steel reinforced concrete structure to be rebuilt. This existing building is one in which the ground floor 2 with 5 floors above ground is built on the basement 1 with 2 basement floors, and each floor has 10 columns (outer columns) on the outer walls 11 and 21. )
12 and 22 are arranged, and two middle pillars are provided in each middle part.
13,23 are arranged. The basement floor and the ground floor are not limited to the above-mentioned number of floors, and can be applied even when there is no basement floor. (same as below). In this case, the ground reaction force distribution b1 occurs in the foundation of the existing building, that is, the foundation beam 14, and
A long-term bending moment a1 is added, which becomes negative in the part of 13,23. The foundation part may be an independent foundation or a continuous foundation, and other than the foundation beam 14, footing, mat slab, and the like are appropriate (the same applies hereinafter).

(2) Anchor set (Fig. 2) Ground anchors 15 are set vertically on the foundation beams 14 on both sides of each middle pillar 13 in the second basement. This earth anchor 15
May be an existing one, but for example, a sheathed unbonded PC steel stranded wire having a fixed bearing plate and a load bearing body at the lower end and a movable bearing plate and a fixing wedge at the upper end is used. In this case, a vertical excavation hole is drilled from the foundation beam 14 to the support ground, the injection material is filled in the excavation hole, and immediately after that, the earth anchor is inserted, and the sheath, the fixed bearing plate and the load bearing body are inserted. Establish in the borehole. However, here, the movable support plate at the upper end is left in a free state, but with respect to the engagement with the foundation beam 14, it may be in a state of being projected onto the foundation beam or slab, or may be in a depressed state, Also,
Finally, it may be embedded.

(3) Demolition (Fig. 2) Based on the construction plan, the entire above-ground building 2 of the existing building is demolished and removed, and the middle pillars 13 on the first basement floor are removed and the pillars 12 with walls are also removed. Part of the inner side of the basement is cut off,
Most of underground structure 1 including 11 is left. Further, while the demolishing and removing the existing building, a part of the tension is introduced into the anchor 15 to adjust the stress of the foundation and the like.

(4) New construction work (Fig. 3) On a part of the underground and above ground, a ground structure 3 without a middle pillar is newly constructed on the existing base structure with 5 floors above ground.

(5) Completion of new construction (Fig. 4) Completion of new construction of the above-mentioned ground frame 3. At this point,
If anchors are not used, the minimum ground reaction force distribution b2 will occur in the central columns 13 and 23.
A long-term bending moment a2 that maximizes around 13,23 is added.

(6) Anchor axial force introduction / adjustment (FIG. 5) The axial force is introduced to each earth anchor 15 set so as not to give stress to the foundation portion of FIG.
Adjust so that the long-term bending moment a3 at is close to the long-term bending moment a1 of the existing building before demolition,
As a result, the ground reaction force distribution b3 is the same as the ground reaction force distribution b1 of the existing building before demolition. That is, in the above unbonded PC stranded wire, external tension is applied to the upper end,
After adjusting the external tension to an appropriate value corresponding to the required long-term bending moment in the foundation beam 14, the axial force of the earth anchor 15 is transmitted to the foundation beam 14 to generate the required long-term bending moment in the foundation beam 14. Of.

[0015]

According to the inventions of claim 1, claim 2 and claim 3, the underground building of the existing building is reused to reconstruct the required building, and the ground anchor is placed at the proper position of the foundation beam of the underground building. By attaching, the stress sharing of each part of the foundation beam can be made closer to the state before rebuilding by the axial force of the earth anchor,
Even if the pillar layout of the new building is different from the pillar layout of the existing building, the underground structure can be used under the same long-term stress condition as the building before rebuilding without any trouble. Therefore, dismantling work can be significantly reduced. The dismantling and removal period can be greatly shortened. The amount of dismantled waste materials can be greatly reduced. The cost of dismantling and removal can be greatly reduced. The construction period for new construction can be greatly shortened. There is no earthwork and it can be installed safely. The construction cost of new construction can be reduced significantly. Overall, the total construction cost can be reduced by about 15 to 20% in a steel frame reinforced concrete building with a total area of about 2,400 square meters.

In addition, according to the inventions of claims 2 and 3, when rebuilding an existing building having a middle pillar on each floor to a new building having no middle pillar, the unnecessary middle pillar is removed and the existing building is removed. Since the underground structure of the building is reused and the ground anchor is attached to the foundation of the underground structure so as to correspond to the position of the removed middle pillar, even if the new building does not have the middle pillar, the earth anchor By introducing and adjusting the axial force in, the long-term stress sharing in the underground and various parts of the foundation can be easily approached to the state before rebuilding, and the underground structure of the existing building can be reused without any trouble.

Further, according to the third aspect of the invention, since a specific procedure is performed such as introducing and adjusting the axial force to each earth anchor from the completion of the new construction to the completion of the new construction, rework work is required. It is possible to perform work smoothly and accurately in a procedural manner with little occurrence, and it is possible to further improve workability, quality, safety, economical efficiency, and the like.

[Brief description of drawings]

FIG. 1 is a procedure (1) showing an embodiment relating to a method of constructing a frame using the earth anchor of the invention of claims 1 to 3;
FIG.

FIG. 2 is an explanatory diagram of steps (2) and (3).

FIG. 3 is an explanatory diagram of the same procedure (4).

FIG. 4 is an explanatory diagram of the same procedure (5).

FIG. 5 is an explanatory diagram of the same procedure (6).

[Explanation of symbols] 1 ... Underground structure 2 ... Ground structure 3 ... Ground structure 11,21 ... Outer wall 12,22 ... Pillar 13,23 ... Middle pillar 14 ... Foundation beam 15 ... Earth anchor a1, a2, a3 ... Long-term bending Moment b1, b2, b3 ... Ground reaction force distribution

Claims (3)

[Claims] 1. In a rebuilding work for dismantling an existing building to newly construct a structure of various structures, the underground structure of the existing building is reused, and an earth anchor is attached to an appropriate place of the foundation of the underground structure, A method for constructing a skeleton using an earth anchor, characterized in that an axial force of the earth anchor causes stress distribution in various parts of the underground or foundation to be close to a state before rebuilding. 2. In a rebuilding work for dismantling an existing building consisting of a basement floor and a ground floor having a middle pillar on each floor to newly construct a building without a middle pillar, the unnecessary middle pillar is removed to remove the existing building. The underground skeleton of is used for reuse, the ground anchor is attached to the foundation of the underground skeleton in correspondence with the position of the removed pillar, and the axial force of the earth anchor contributes to the stress sharing of the underground and various parts of the foundation. A structure construction method using an earth anchor, which is characterized by bringing it closer to the state before rebuilding. 3. In a rebuilding work for dismantling an existing building consisting of a basement floor and a ground floor having a middle pillar on each floor to newly construct a building without a middle pillar, at the foundation portion of the underground structure of the existing building, A ground anchor is deployed corresponding to the position of the center pillar to be removed, the ground structure is dismantled and removed, unnecessary middle pillars on the basement floor are removed, leaving an underground structure, and there is no center pillar above the base structure. Characterized by newly constructing a skeleton and introducing / adjusting axial force to each of the earth anchors during construction and completion of the new construction work so that the stress distribution in the underground and various parts of the foundation is close to the state before rebuilding. Building method using earth anchors.