JP7037472B2 - Structure Shinbashira support method - Google Patents

Description

The present invention is, for example, established in a new foundation to be constructed later in a rebuilding work in which an existing structure provided with an underground structure is dismantled and a new structure is constructed above an existing pressure plate left after the dismantling. It is related to the method of supporting the structure Shinbashira that temporarily supports the structure Shinbashira.

As the above-mentioned structural pillar support method, the structural pillar support method disclosed in the method for constructing the building frame of Patent Document 1 and the new pillar (structure) disclosed in the joint structure between the pillar and the bottom of Patent Document 2. Shinbashira) There is a support method.
In Patent Document 1, when the structure pillar 2 to be fixed to the foundation beam 6 is temporarily supported, the lower end portion of the structure pillar 2 is placed on the upper surface portion of the existing foundation slab 5 which is an existing pressure plate. A support method for directly transmitting the axial force of the true pillar 2 to the existing foundation slab 5 is disclosed.
In Patent Document 2, when the new pillar 2 to be fixed to the new bottom plate 4 is temporarily supported, a plane having a ground contact area wider than the cross-sectional area of the new pillar 2 at the lower end of the new pillar (construction pillar) 2. A cross-shaped shear head 3 is attached, the shear head 3 of the new pillar 2 is placed on the upper surface of the existing bottom plate 1, and the axial force of the new pillar 2 is directly applied to the existing bottom plate 1 via the shear head 3. Support methods for communication are disclosed.

Japanese Unexamined Patent Publication No. 11-062247 Japanese Patent Application Laid-Open No. 2003-027591

In the method of supporting the structural pillar of Patent Document 1, since a large axial force of the structural pillar 2 is directly transmitted to the existing foundation slab 5 which is an existing pressure plate, the existing foundation slab 5 may be destroyed. Further, in the method of supporting the new column (batholith) of Patent Document 2, the axial force of the new column 2 is somewhat planar via the shear head 3 having a ground contact area wider than the cross-sectional area of the new column 2. Although it is transmitted to the existing batholith 1 which is an existing pressure plate in a dispersed state, the large axial force of the new column 2 is directly transmitted to the existing batholith 1, so that the existing batholith 1 may be destroyed. .. Therefore, in any of the support methods, if the existing pressure plate (existing foundation slab 5 or existing foundation slab 5) is destroyed, for example, groundwater may be discharged when the groundwater level is higher than the existing pressure plate. Problems may occur.

Further, in the method of supporting the new pillar (construction pillar) of Patent Document 2, the shear head 3 having a cross shape in a plan view attached to the lower end portion of the new pillar 2 is embedded in the new batholith 4. Therefore, the shear head 3 causes a defect in the concrete of the new batholith 4, and the shear head 3 interferes with the reinforcement of the new batholith 4, so that the reinforcement of the new batholith 4 cannot be arranged appropriately and efficiently. be.

In view of this situation, the main problem of the present invention is to disperse the large axial force of the structural pillar in a plane by rational improvement utilizing the difference in the installation level between the new foundation to be constructed later and the existing pressure plate. The point is to provide a structural pillar support method that can be supported by a support portion below the existing pressure plate in the state.

In the first characteristic configuration of the present invention, the plurality of structural pillars to be fixed to the new foundation to be constructed later are arranged in a plurality of types of arrangement forms having different arrangement relationships with the existing foundation beam and the existing foundation pit space.
A structural pillar support method in which a plurality of the structural pillars are supported by a support portion below the existing pressure plate via an existing pressure plate below the planned installation location of the new foundation.
The existing foundation pit space between the upper surface portion of the existing pressure plate and the lower end portion of the structural pillar is filled with a filler, and the axial force of the structural pillar is dispersed in a plane through the filler. In the state of being transmitted to the existing pressure plate,
In the existing foundation pit space, in the first region where the axial force is transmitted from the structural pillar, the first one on the high strength side as the filler is used according to the arrangement form of each of the plurality of structural pillars. The second region in the existing foundation pit space where the filler is filled and the axial force is not transmitted from the structural pillar is filled with the second filler on the low strength side as the filler .

According to the above configuration, the existing pressure plate is obtained by planarly distributing the axial force of the existing pressure plate through the filler filled in the space between the upper surface portion of the existing pressure plate and the lower end portion of the structural pillar. It is possible to support the structural pillar on the lower support part of the existing pressure plate while avoiding the destruction of the structure. In addition, it is possible to secure the filling height of the filler for planarly dispersing the axial force of the structural pillar by utilizing the difference in the installation level between the new foundation to be constructed later and the existing pressure plate.
Furthermore, when filling the existing foundation pit space with the filler, by using the first filler on the high strength side in the first region where the axial force is transmitted from the structural pillar, the axial force from the structural pillar is used. Can be properly communicated. On the other hand, the material cost can be suppressed by using the second filler on the low strength side in the second region where the axial force is not transmitted from the structural pillar. Moreover, in the existing foundation pit space, not only the first region where the axial force is transmitted from the structural pillar but also the second region where the axial force is not transmitted from the structural pillar is filled with the filler, so that the existing foundation beam can be used. The filler can be restrained more appropriately, the collapse of the filler due to the axial force of the structural pillar can be further suppressed, and the effect of dispersing the axial force can be maintained more appropriately.

The second characteristic configuration of the present invention is that the filler is filled in the existing foundation pit space from the upper surface of the existing pressure plate to the top end of the existing foundation beam.

According to the above configuration, by filling the existing foundation pit space with the filler, the level of the upper surface of the filler can be easily and highly accurately aligned. As a result, the level of the upper surface of the filler can be set as the installation surface, and a large number of structural pillars can be installed easily and with high accuracy, and the level of the upper surface of the filler can be used as the work floor. Moreover, the filling height of the filler becomes a large height corresponding to the height of the existing foundation beam, and the effect of dispersing the axial force of the structural pillar can be satisfactorily obtained. Furthermore, since the filler filled in the existing foundation pit space can be restrained by the existing foundation beam, it is necessary to suppress the collapse of the filler due to the axial force of the structural pillar and appropriately maintain the effect of dispersing the axial force. Can be done.

A vertical sectional view at the time of building a structural pillar showing the method for supporting the structural pillar of the present invention. Perspective view when building the Shinbashira Vertical cross-sectional view at the time of building the structure Shinbashira Vertical cross-sectional view during the construction of the Shinbashira Explanatory drawing of the transmission of the axial force of the Shinbashira Vertical cross-sectional view showing the first case of the arrangement relationship between the existing foundation and the structural Shinbashira Vertical cross-sectional view showing the second case of the arrangement relationship between the existing foundation and the structural Shinbashira Vertical cross-sectional view of another embodiment showing the second case of the arrangement relationship between the existing foundation and the structural Shinbashira. Vertical cross-sectional view showing the third case of the arrangement relationship between the existing foundation and the structural Shinbashira Vertical cross-sectional view showing the fourth case of the arrangement relationship between the existing foundation and the structural Shinbashira

An embodiment of the present invention will be described with reference to the drawings.
1 and 2 show a state in the middle of rebuilding work in which an existing structure 1 having an underground structure portion 1A and an above-ground structure portion is dismantled and a new structure is constructed above the existing pressure plate 2 left after the dismantling. Is shown. The existing structure 1 shown in FIGS. 1 and 2 is a general building made of steel-framed reinforced concrete.
In FIG. 1, the existing underground structure 1A from the first basement floor B1 to the fifth basement floor B5, which is a part of the dismantled existing structure 1, is left. The existing underground skeleton of the existing underground structure portion 1A includes an existing pressure plate 2 which is the bottom of the existing foundation, an existing foundation beam 3 which is constructed in a grid pattern on the upper surface portion 2a side of the existing pressure plate 2 in a plan view. The outer peripheral portion of the existing pressure plate 2 is provided with an existing underground outer wall 4 having a height from B1 on the first basement floor to B5 on the fifth basement floor, and an existing floor slab 5 on the first floor above ground F1 to the fourth basement floor B4. ..

Next, as shown in FIGS. 3 and 5, the structural pillar 7 to be fixed to the new foundation 51 (see FIG. 5) to be constructed later in the rebuilding work in which the above-mentioned existing underground structure 1A is left is shown. A method of supporting a structural pillar to be supported by a ground improvement body 13 which is a support portion below the existing pressure plate 2 below the planned installation location of the new foundation 51 will be described. In this structural pillar support method, the space between the upper surface portion 2a of the existing pressure plate 2 and the lower end portion of the structural pillar 7 (hereinafter referred to as the existing foundation pit space 6) is a filler having curability and the like. Filling of 8, in other words, a filler filling step of filling the filler 8 in the existing foundation pit space 6 partitioned by the existing grid-shaped foundation beams 3, and a large number of structural pillars 7 at predetermined positions. It is equipped with a Shinbashira building process.

As shown in FIGS. 1 to 3, there are various arrangement relationships between the newly constructed Shinbashira 7 arranged based on the design of the new structure and the existing foundation beam 3 and the existing foundation pit space 6 of the existing structure 1. It is diverse. The axial force transmission state in which the axial force of the structural pillar 7 is transmitted to the existing pressure plate 2 differs depending on the difference in the arrangement relationship. Therefore, when the combination of the structural pillar 7 and the existing foundation beam 3 and the existing foundation pit space 6 of the existing structure 1 is divided into cases, it is divided into the following three cases shown in FIGS. 3 and 6 to 8.

[First case]
As shown in FIG. 6, the first case is a state in which the lower end portion of the structural pillar 7 is arranged on the center side in the existing foundation pit space 6. In this first case, the filler 8 in the existing foundation pit space 6 is filled to the same height as the top end 3a of the existing foundation beam 3, and the built-in portion of the structural pillar 7 on the upper surface of the filler 8 is filled. As shown in FIG. 4, a pre-laying mortar 12 that enhances the building accuracy of the structural pillar 7 is constructed. On the upper surface of the leading mortar 12, a base plate 7A at the lower end of the structural pillar 7 whose verticality and horizontal position are adjusted with high accuracy is arranged. The base plate 7A of the structural pillar 7 is fixed to an anchor bolt 11 (see FIG. 4) for construction, which is later installed on the filler 8 in the existing foundation pit space 6.

In the first case, as shown in FIG. 6, the axial force of the structural pillar 7 is dispersed in a plane toward the lower layer of the filler 8 in the existing foundation pit space 6, and in the figure, the upper surface of the existing pressure plate 2 is distributed. The axial force of the structure pillar 7 is transmitted toward the inner bottom corner portion where the surface of the existing foundation beam 3 and the inner surface of the existing foundation beam 3 intersect.
In this way, the axial force of the structural pillar 7 is dispersed in a plane through the filler 8, so that the structural pillar 7 is supported below the existing pressure plate 2 while avoiding the destruction of the existing pressure plate 2. It can be supported by the ground improvement body 13 which is a part. Further, as shown in FIG. 6, filling is performed to disperse the axial force of the structural pillar 7 in a plane by utilizing the installation level difference H between the new foundation 51 to be constructed later and the upper surface portion 2a of the existing pressure plate 2. The filling height of the material 8 can be secured.

In the first case, by filling the existing foundation pit space 6 with the filler 8, the level of the upper surface 8a of the filler 8 can be easily and highly accurately aligned. As a result, the upper surface 8a of the filler 8 can be used as an installation surface, and a large number of structural pillars 7 can be installed easily and with high accuracy, and the upper surface 8a of the filler 8 can be used as a work floor. Moreover, the filling height of the filler 8 becomes a large height corresponding to the height of the existing foundation beam 3, and the effect of dispersing the axial force can be satisfactorily obtained. Further, since the filler 8 filled in the existing foundation pit space 6 can be restrained by the existing foundation beam 3, the collapse of the filler 8 due to the axial force of the structural pillar 7 is suppressed and the effect of dispersing the axial force is enhanced. Can be maintained properly.

In the first case, the entire width of the filler filling region in the existing foundation pit space 6 becomes the first region T1 to which the axial force of the structural pillar 7 is transmitted, and the first region T1 is used as the filler 8 as the filler 8. The first filler 8A on the high strength side is used. Examples of the first filler 8A include high-standard fluidized soil and concrete having fluidity and high strength.
Then, the axial force can be appropriately transmitted from the structural pillar 7 by the first filler 8A on the high strength side filled in the existing foundation pit space 6.

[Second case]
As shown in FIG. 7, the second case is a state in which the lower end portion of the structural pillar 7 is arranged near the inner surface side of the existing foundation beam 3 in the existing foundation pit space 6. In this second case as well, the filler 8 in the existing foundation pit space 6 is filled to the same height as the top end 3a of the existing foundation beam 3, and the built-in portion of the structural pillar 7 on the upper surface of the filler 8 is filled. A pre-laying mortar 12 that enhances the building accuracy of the structure Shinbashira 7 is constructed. On the upper surface of the leading mortar 12 (see FIG. 4), a base plate 7A at the lower end of the structural pillar 7 whose verticality and horizontal position are adjusted with high accuracy is arranged. The base plate 7A of the structural pillar 7 is fixed to an anchor bolt 11 (see FIG. 4) for construction, which is later installed on the filler 8 of the existing foundation pit space 6.

In the second case, as shown in FIG. 7, since the structural pillar 7 is arranged at the time of the existing foundation beam 3, the transmission direction of the axial force of the structural pillar 7 is restricted by the existing foundation beam 3. Therefore, on the side of the existing foundation beam 3, as shown on the left side of the figure, the axial force of the structural pillar 7 is transmitted in the vertical direction along the inner surface side of the existing foundation beam 3. On the other hand, on the side away from the inner surface of the existing foundation beam 3, as shown on the right side of the figure, the axial force of the structural pillar 7 is dispersed in a plane toward the lower layer of the filler 8 in the existing foundation pit space 6. In the figure, the axial force of the structural pillar 7 is transmitted toward the center side of the existing foundation pit space 6 on the upper surface of the existing pressure plate 2.

Therefore, in the second case, although the transmission direction of the axial force of the structural pillar 7 is limited by the existing foundation beam 3, the effect is close to that of the first case. In particular, the axial force of the structural pillar 7 is dispersed in a plane through the filler 8, and the installation level difference H between the new foundation 51 to be constructed later and the existing pressure plate 2 is used to utilize the structural pillar 7. By ensuring the filling height of the filler 8 to disperse the axial force in a plane, the structural pillar 7 is a support portion below the existing pressure plate 2 while avoiding the destruction of the existing pressure plate 2. It can be supported by the ground improvement body 13.

Further, in the second case, the filler filling region in the existing foundation pit space 6 is a first region T1 in which the axial force is transmitted from the structural pillar 7, and a second region in which the axial force is not transmitted from the structural pillar 7. Divided into T2. In the first region T1, the first filler 8A on the high strength side is used as the filler 8 as in the first case. Further, the second region T2 is filled with the second filler 8B on the low strength side as the filler 8. Examples of the second filler 8B include low-standard fluidized soil having relatively high fluidity and low strength, a similar filler, and surplus cement material generated by ground improvement.

Then, when the existing foundation pit space 6 is filled with the filler 8 and the level of the upper surface is made uniform, the first filler 8A on the high strength side is placed in the first region T1 where the axial force is transmitted from the structural pillar 7. By using it, the axial force can be appropriately transmitted from the structural pillar 7. On the other hand, by using the second filler 8B on the low strength side in the second region T2 where the axial force is not transmitted from the structural pillar 7, the material cost can be suppressed. Moreover, in the existing foundation pit space 6, the second filler 8B is provided not only in the first region T1 where the axial force is transmitted from the structural pillar 7, but also in the second region T2 where the axial force is not transmitted from the structural pillar 7. Since the filler 8 is filled, the filler 8 can be more appropriately restrained by the existing foundation beam 3, the collapse of the filler 8 due to the axial force of the structural pillar 7 is further suppressed, and the effect of dispersing the axial force is more appropriate. Can be maintained.

In the second case, if the bearing capacity is insufficient only in the first region T1 in which the first filler 8A on the high strength side is used as the filler 8, the following measures can be considered.
(1) Increase the strength of the first filler 8A.
(2) By using a shear connector that enhances the joining force with the existing foundation beam 3, or by roughly roughening the skeleton surface 3b on the existing foundation pit space 6 side of the existing foundation beam 3 as shown in FIG. , Shear force can be transmitted to the existing foundation beam 3. Therefore, the first region T1 in which the axial force is transmitted from the structural pillar 7 can be expanded to the sum of the width of the existing foundation beam 3 and the filling width of the first filler 8A.

[Third case]
As shown in FIG. 9, the base plate 7A at the lower end of the structural pillar 7 is arranged at the top end 3a of the existing foundation beam 3 which is narrower than the width of the base plate 7A, and the base plate 7A of the structural pillar 7 is arranged. However, the state of protruding into both existing foundation pit spaces 6 adjacent to each other is defined as the third case. Also in this third case, the filler 8 in the existing foundation pit space 6 is filled to the same height as the top end 3a of the existing foundation beam 3, and the upper surface of the filler 8 in both adjacent existing foundation pit spaces 6 and the existing one. A pre-laying mortar 12 (see FIG. 4) that enhances the building accuracy of the structure pillar 7 is constructed at the site where the structure pillar 7 is built over the top end 3a of the foundation beam 3. On the upper surface of the leading mortar 12, a base plate 7A at the lower end of the structural pillar 7 whose verticality and horizontal position are adjusted with high accuracy is arranged. The base plate 7A of the structural pillar 7 is fixed to an anchor bolt 11 (see FIG. 4) for construction, which is later installed on the filler 8 of the existing foundation pit space 6.

In the third case, since the structural pillar 7 is arranged over the upper surface of the filler 8 in both adjacent existing foundation pit spaces 6 and the top end 3a of the existing foundation beam 3, the axis of the structural pillar 7 is provided. The force transmission system is the first axial force transmission system transmitted from the existing foundation beam 3 to the existing pressure plate 2 as shown in the center of FIG. 9, and the adjacent two as shown on both the left and right sides of FIG. It is divided into a second axial force transmission system that is transmitted to the existing pressure plate 2 via the filler 8 in the existing foundation pit space 6.
In the second axial force transmission system, the lower layer of the filler 8 in the existing foundation pit space 6 is dispersed in a plane, and the structure pillar 7 is directed toward the center side of the existing foundation pit space 6 on the upper surface of the existing pressure plate 2. Axial force is transmitted.
Therefore, the same effect as in the first case or the second case is obtained in the third case. In particular, the axial force of the structural pillar 7 is dispersed in a plane through the filler 8, and the installation level difference H between the new foundation 51 and the existing pressure plate 2 to be constructed later is used to utilize the structural pillar 7. By securing the filling height of the filler 8 to disperse the axial force in a plane, the ground improvement body 13 which is the lower support portion of the existing pressure plate 2 is constructed while avoiding the destruction of the existing pressure plate 2. The true pillar 7 can be supported.

Further, in the filler filling region in the existing foundation pit space 6 adjacent to each other, the first region T1 in which the axial force is transmitted from the structural pillar 7 and the second region T2 in which the axial force is not transmitted from the structural pillar 7. Divided into. In the first region T1, the first filler 8A on the high strength side is used as the filler 8 as in the second case. The second region T2 is filled with the second filler 8B on the low strength side as the filler 8.

[4th case]
As shown in FIG. 10, the base plate 7A at the lower end of the structural pillar 7 is arranged at the top end 3a of the existing foundation beam 3 which is wider than the width of the base plate 7A, and the base plate 7A of the structural pillar 7 is provided. The fourth case is a state in which the two existing foundation pit spaces 6 adjacent to each other do not protrude. In this fourth case as well, a pre-laying mortar 12 (see FIG. 4) that enhances the building accuracy of the structural pillar 7 is constructed at the construction site of the structural pillar 7 at the top end 3a of the existing foundation beam 3. .. On the upper surface of the leading mortar 12, a base plate 7A at the lower end of the structural pillar 7 whose verticality and horizontal position are adjusted with high accuracy is arranged. The base plate 7A of the structural Shinbashira 7 is fixed to an anchor bolt 11 (see FIG. 4) for construction, which is later constructed on the existing foundation beam 3. Therefore, the axial force of the structural pillar 7 is transmitted from the existing foundation beam 3 to the existing pressure plate 2. The first region T1 to which the axial force is transmitted from the structural pillar 7 is wider than the width of the existing foundation beam 3.
Since the axial force is not transmitted from the structural pillar 7 to the filler 8 in the existing foundation pit space 6, the first filler 8A on the high strength side is unnecessary, and only the second filler 8B on the low strength side is filled. Will be done.
If the bearing capacity is insufficient only in the first region T1 of the existing foundation beam 3, the above-mentioned third case is adopted.

As shown in FIGS. 1 to 3, in the above-mentioned first to third cases, the existing floor slabs 5 on the first floor above ground F1 to the fourth floor below ground B4 are used before the construction of the structural pillar 7. A column insertion opening 15 is formed so that the structural pillar 7 can be inserted from above.

Further, in B5 on the 5th basement floor, a new foundation 51 of the new underground skeleton 50 is constructed in a state of being integrated with the upper surface 8a of the filler 8 in the existing foundation pit space 6 and the top end 3a of the existing foundation beam 3. To. Therefore, each of the structural Shinbashira 7 is fixed to the new foundation 51 of the new underground skeleton 50, and is attached to the ground improvement body 13 which is the lower support portion of the existing pressure plate 2 via the new foundation 51 and the existing pressure plate 2. Be supported.

Further, among the many existing foundation pit spaces 6 partitioned by the existing foundation beams 3, the existing foundation pit space 6 in which the structural pillar 7 is not installed is also filled to the same height as the top end 3a of the existing foundation beams 3. The material 8 is filled. In this case, the second filler 8B on the low strength side is filled as the filler 8.

2 Existing pressure plate 3 Existing foundation beam 3a Top end 6 Space (existing foundation pit space)
7 Structure Shinbashira 8 Filler 8A 1st filler 8B 2nd filler 13 Support part (ground improvement body)
51 New foundation T1 1st area T2 2nd area

Claims (2)

The multiple structural pillars that will be fixed to the new foundation to be constructed later are arranged in multiple types of arrangements that have different arrangement relationships with the existing foundation beams and the existing foundation pit space.
A structural pillar support method in which a plurality of the structural pillars are supported by a support portion below the existing pressure plate via an existing pressure plate below the planned installation location of the new foundation.
The existing foundation pit space between the upper surface portion of the existing pressure plate and the lower end portion of the structural pillar is filled with a filler, and the axial force of the structural pillar is dispersed in a plane through the filler. In the state of being transmitted to the existing pressure plate,
In the existing foundation pit space, in the first region where the axial force is transmitted from the structural pillar, the first one on the high strength side as the filler is used according to the arrangement form of each of the plurality of structural pillars. In the existing foundation pit space where the filler is filled, the second region where the axial force is not transmitted from the structural pillar is filled with the second filler on the low strength side as the filler. Method. The structural pillar support method according to claim 1, wherein the filler is filled in the existing foundation pit space from the upper surface of the existing pressure plate to the top end of the existing foundation beam.

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