Methods for rebuilding buildings with underground structures

Abstract

To provide a reconstruction method of a building having an underground structure, reduced in a construction period and cost, and improved in construction accuracy.SOLUTION: In a reconstruction method of a building having an underground structure, a floor slab of an existing underground structure is dismantled and concrete is placed, a temporary floor slab 18 is constructed by reinforcing an existing foundation skeleton formed of an existing bottom and existing foundation beams, a pedestal 40 is constructed on the temporary floor slab 18, and underground pile columns 4 are constructed by installing lower columns 41 and upper columns 42 on the pedestal 40. A diameter of a lower end part 41a of the underground pile column 4 is expanded.SELECTED DRAWING: Figure 2

Description

Technical Field

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[0001] The present invention relates to a method for rebuilding a building having an underground structure part.

Background Art

[0002] Conventionally, when constructing the underground structure of a building, a reverse construction method is known in which the original floor beam is used as a retaining support work, and the construction of the underground structure is advanced from the upper floor to the lower floor. Generally, when constructing a building with a deep basement, by adopting this reverse construction method and simultaneously constructing the above-ground structure while constructing the underground structure, the construction period can be shortened. <00,000,10>

[0003] In the case of rebuilding an existing building having an underground structure part, since the demolition of the existing underground structure is involved, it may take a long time to construct the new underground structure. In this case, the reverse construction method that can simultaneously construct the underground structure and the above-ground structure is effective in terms of shortening the construction period.

[0004] <0,000,015>The column for supporting the existing floor and the above-ground structure, which serves as a retaining support work during construction, is called a structural true column. In the case of the reverse construction method, it is necessary to first construct the structural true column (see, for example, Patent Documents 1 and 2). The structural true column in the reverse construction method is constructed by inserting a steel column into a cast-in-place concrete pile.

[0005] In the case of rebuilding an existing building having an underground structure part, the cast-in-place concrete pile work and the steel structural true column work are carried out after the completion of the demolition of the existing above-ground structure and the construction of the construction ground for constructing the cast-in-place concrete pile. The construction ground often involves backfilling with fluidized treated soil of the existing underground structure or reinforcement work of the existing underground structure.

Prior Art Documents

Patent Documents

[0006] Japanese Patent Laid-Open No. 11-050480

Patent Document 2

[0007] However, constructing structural columns using the inverted construction method requires the time and cost associated with driving cast-in-place concrete piles. Furthermore, inserting steel columns into cast-in-place concrete piles is a difficult task and requires considerable effort to ensure accuracy. Even when direct foundation construction is possible in terms of design, there is a construction problem in that cast-in-place concrete piles must be constructed to erect the structural columns.

[0008] In the case of rebuilding an existing building with an underground structure, it is necessary to complete the demolition of the existing building's above-ground structure, construct the ground for the construction of cast-in-place concrete piles, and then carry out the cast-in-place concrete pile construction. This presents the problem of a long construction period before the construction of the above-ground structure can begin.

[0009] In view of the above circumstances, the present invention provides a method for rebuilding a building having an underground structure that can reduce construction time and costs, and improve construction accuracy. [Means for solving the problem]

[0010] To achieve the above objective, the present invention employs the following means. In other words, the method for rebuilding a building having an underground structure according to the present invention is a method for rebuilding a building having an underground structure, wherein the existing foundation structure consisting of the existing base slab and existing foundation beams of the existing underground structure is reinforced to construct a temporary floor slab, a base is constructed on the temporary floor slab, and structural columns are constructed on the base.

[0011] In this method of rebuilding a building with an underground structure, cast-in-place concrete piles for erecting structural columns become unnecessary, reducing construction time and costs. Furthermore, in the construction of the structural columns, the insertion of steel frames into cast-in-place concrete piles is eliminated, and the work is handled by standard steel frame erection methods, thereby improving the construction accuracy of the structural columns. Furthermore, the work of reinforcing the existing foundation structure, which consists of the existing base slab and existing foundation beams, to construct a temporary floor slab, as well as the construction of the base, can be carried out during the demolition of the existing above-ground structure. By carrying out these tasks in parallel with the demolition of the above-ground structure, it is possible to further shorten the construction period.

[0012] Furthermore, in the method for rebuilding a building having an underground structure according to the present invention, the lower end of the structural column may be enlarged in diameter.

[0013] In this method of rebuilding a building with an underground structure, the lower end of the structural column is widened in diameter, so the axial force acting on the base is distributed over a wide area, and the stress generated in the temporary floor slab can be kept even smaller. [Effects of the Invention]

[0014] According to the present invention, a method for rebuilding a building having an underground structure can reduce construction time and costs, and improve construction accuracy. [Brief explanation of the drawing]

[0015] [Figure 1] This diagram shows the basement portion of the existing building before reconstruction. [Figure 2] This figure shows the underground portion of a newly constructed building that has been rebuilt using a method for rebuilding a building with an underground structure according to one embodiment of the present invention. [Figure 3] This diagram shows the rebuilding procedure. [Figure 4] This diagram shows the rebuilding procedure and represents the subsequent steps after Figure 3. [Figure 5] This diagram shows the rebuilding procedure, specifically the steps following those shown in Figure 4. [Figure 6] It is a diagram showing the rebuilding procedure and shows the subsequent process of FIG. 5. [Figure 7] It is a diagram showing the rebuilding procedure and shows the subsequent process of FIG. 6. [Figure 8] It is a diagram showing the rebuilding procedure and shows the subsequent process of FIG. 7. [Figure 9] It is a diagram showing the rebuilding procedure and shows the subsequent process of FIG. 8. [Figure 10] It is a diagram showing the rebuilding procedure and shows the subsequent process of FIG. 9. [Figure 11] It is a diagram showing the rebuilding procedure and shows the subsequent process of FIG. 10. [Figure 12] It is a diagram showing the difference bars of the foundation slab.

Mode for Carrying Out the Invention

[0016] Hereinafter, a method for rebuilding a building having an underground structure according to an embodiment of the present invention will be described based on the drawings. FIG. 1 shows an existing building (hereinafter referred to as the "existing building") 1 before rebuilding, and FIG. 2 shows a newly constructed building (hereinafter referred to as the "new building") 2 after rebuilding. Note that the plans of the existing building 1 and the new building 2 are examples.

[0017] As shown in FIG. 1, the existing building 1 has an underground structure part 10 and a ground structure part (not shown). The underground structure part 10 has an underground floor part 11 composed of a plurality of floors and an underground pit 13. In the present embodiment, the underground floor part 11 is composed of four floors, but the number of floors can be set as appropriate.

[0018] An underground outer wall 14 is arranged on the outer periphery of the underground structure part 10. The underground outer wall 14 receives lateral earth pressure. An existing bottom plate 15 is arranged at the bottom of an existing foundation beam 12 of the existing foundation body. The existing bottom plate 15 receives earth pressure from below. <0​As shown in Figure 2, the newly constructed building 2 has an underground structure 20 and an above-ground structure (not shown). The underground structure 20 has an underground floor section 21 consisting of multiple levels and a foundation slab 22. As will be described in detail later, the foundation slab 22 is provided on top of the existing foundation beam 12 from which the floor slab 16 has been removed and the concrete 17 filled in the underground pit 13. In this embodiment, the underground floor section 21 has floor structures 45, 47, 49, floor slabs 46, 48, 50 and newly constructed columns 5. The newly constructed columns 5 are columns that utilize the temporary structural columns 4. The underground floor section 21 consists of three levels, but the number of levels can be set as appropriate.

[0020] Next, we will explain the method for rebuilding from existing building 1 to new building 2. As shown in Figure 3, demolition begins with the underground structure 10 of the existing building 1. The floor slab 16 of the fourth basement level is demolished using demolition machinery 91. The existing foundation structure, consisting of the existing base slab 15 and existing foundation beams 13, is reinforced to construct a temporary floor slab 18. Specifically, concrete is sent from a ready-mix concrete truck 92 and a pump truck 93 installed above ground and poured into the underground pit 13. The temporary floor slab 18 is constructed when the underground pit 13 is filled with concrete 17. The temporary floor slab 18 has sufficient strength and load-bearing capacity to support the load applied to the structural columns 4 which will be constructed in a later step.

[0021] Concrete is delivered from the ready-mix concrete truck 92 and the concrete pump truck 93 and poured onto the inner perimeter of the underground outer wall 14. A reinforced wall section 25 made of concrete is constructed.

[0022] On the first and second basement floors, the spaces between the upper and lower floor slabs, and between the floor slabs and beams, are supported by multiple supports 23 extending in the vertical direction. The multiple supports 23 are connected to each other by connecting members 24 extending in the horizontal direction.

[0023] As shown in Figure 4, a base 40 is constructed on the temporary floor slab 18. The base 40 is provided at the lower end of the structural column 4, which will be constructed in a later step. By providing the base 40, the axial force of the structural column 4 is distributed. In this embodiment, the base 40 is made of concrete, composed of concrete delivered from the ready-mix concrete truck 92 and the pump truck 93.

[0024] As shown in Figure 12, connecting bars 43, which will be connected to the lower reinforcement bars 52 of the foundation slab 51 to be constructed in a later step, may be pre-inserted into the base 40. A mechanical joint 44 is provided on the end face side of the base 40.

[0025] As shown in Figure 5, the support 23 and connecting members 24 are removed from the existing basement floor, and the structural elements such as the floor slab 28, columns 29 and beams 30 of the first floor are demolished. In the existing second basement floor, the support 23 and connecting members 24 are removed at the points where they interfere with the structural column 4, and the structural elements such as the floor slab 32 and beams 33 are dismantled. At the points where the floor slab 32 has been dismantled, reinforcing members 37 are erected around the dismantled areas to provide reinforcement. In the existing third basement floor, the structural elements such as the floor slab 34 and beams 35 will be demolished at the points where they interfere with the main structural column 4. At the points where the floor slab 32 has been demolished, reinforcing members 37 will be erected around the demolished areas to provide reinforcement. Furthermore, the demolition of the above-ground structures will proceed.

[0026] As shown in Figure 6, the floor slab 38 is demolished at the point where it interferes with the structural column 4 on the existing first basement floor. Reinforcement is provided by installing reinforcing members 37 around the demolished area of ​​the floor slab 38. In the existing second and third basement floors, the columns 39 (see Figure 5) that interfere with the structural columns 4 will be dismantled. In the areas where the columns 39 have been dismantled, reinforcing members 37 will be installed on the floor slab 32 to provide reinforcement. In the existing fourth basement floor, column 39 (see Figure 5) will be dismantled at the point where it interferes with the structural column 4 to be constructed in a later stage.

[0027] As shown in Figure 7, the floor structure 45 and floor slab 46 are installed on the second basement floor of the new building. In the newly constructed third basement floor, the lower column 41 is installed on the base 40. In this embodiment, the lower end portion 41a of the lower column 41 is enlarged in diameter, but it does not have to be enlarged.

[0028] As shown in Figures 8 and 9, the floor structure 47 and floor slab 48 are installed on the first floor of the new building. In the newly constructed second and first basement floors, an upper column 42 is joined to the upper part of the lower column 41. The lower column 41 and the upper column 42 constitute the structural column 4.

[0029] As shown in Figures 10 and 11, the existing basement floor slab 38, the existing basement floor slab 32 and columns 39, the existing basement floor slab 34 and columns 39, and the existing basement floor columns 39 are demolished in sequence. As shown in Figure 2, the floor structure 49 and floor slab 50 are installed on the new basement floor 1. The foundation slab 51 is installed on the new basement floor 3. As shown in Figure 12 (the concrete portion of the foundation slab 51 is shown by a dashed line), the lower reinforcement bars 52 of the foundation slab 51 are connected to the mechanical joints 44 of the base 40. In this way, the lower reinforcement bars 52 of the foundation slab 51 and the connecting bars 43 of the base 40 are connected via the mechanical joints 44. Concrete is poured to construct the foundation slab 51. The lower part of the structural column 4 is embedded in the foundation slab 51.

[0030] In the newly constructed building 2, the base 40 on which the structural column 4 is installed diffuses the axial force of the structural column 4 within the range of its thickness, thereby minimizing the stress generated in the temporary floor slab 18.

[0031] A new column 5 is constructed using the existing steel-framed structural column 4. In this embodiment, the new column 5 is made of steel-reinforced concrete and is constructed, for example, by arranging main reinforcement and stirrups around the steel frame of the structural column 4 and then pouring concrete.

[0032] In this method of rebuilding a building with an underground structure, cast-in-place concrete piles for erecting the structural columns 4 are unnecessary, thus reducing construction time and costs. Furthermore, in the construction of the structural columns 4, the insertion of steel frames into the cast-in-place concrete piles is eliminated, and the work can be handled using normal steel frame erection methods, thereby improving the construction accuracy of the structural columns 4.

[0033] Furthermore, the concrete filling work in the underground pit 13 of the existing underground structure 10 and the construction work of the base 40 can be carried out during the demolition work of the existing above-ground structure. By carrying out these works in parallel with the demolition work of the above-ground structure, it is possible to further shorten the construction period.

[0034] Furthermore, the concrete base 40 distributes the axial force applied to the structural column 4 in a planar manner, reducing the stress generated in the temporary floor slab 18. By making the concrete strength of the base 40 higher than that of the existing structure, it becomes possible to support a larger axial force. In addition, the connecting bars 43, which will become the reinforcement for the foundation slab 51, can be pre-placed in the base 40, and the lower reinforcement bars 52 of the foundation slab 51 and the connecting bars 43 of the base 40 can be joined during the reinforcement work for the foundation slab 51.

[0035] Furthermore, because the lower end portion 41a of the structural column 4 is enlarged in diameter, the axial force acting on the base 40 is distributed over a wide area, and the stress generated in the temporary floor slab 18 can be kept even smaller.

[0036] Furthermore, if the main structural column 4 is installed on the temporary floor slab 18 without providing the base 40, the steel frame of the main structural column 4 will prevent the lower reinforcement of the foundation slab 51 from passing through the main structural column 4. In this embodiment, by pre-inserting the lower reinforcement of the foundation slab 51 into the base 40, the reinforcement arrangement problem is solved, and the foundation slab 51, base 40, and main structural column 4 can be integrated.

[0037] Although one embodiment of the method for rebuilding a building having an underground structure according to the present invention has been described above, the present invention is not limited to the above embodiment and can be modified as appropriate without departing from the spirit of the invention.

[0038] In the embodiment described above, the procedure for constructing the floor structure from the middle section of the underground floor was explained, but the procedure for constructing the floor structure can be set as appropriate.

[0039] Furthermore, in the embodiment described above, concrete 17 is filled into the underground pit 13, but the present invention is not limited to this. Fluidized soil may be filled into the underground pit 13 instead of concrete 17. [Explanation of Symbols]

[0040] 1 Existing building 2. Newly constructed buildings 4 Structure pillar 10 Existing underground structure 18 Temporary floor slab 20 New underground structure 40 base 41a Lower end

Claims

1. A method for rebuilding a building that has an underground structure, The existing foundation structure, consisting of the existing base slab and existing foundation beams of the existing underground structure, is reinforced to construct a temporary floor slab. A concrete base is constructed on the aforementioned temporary deck, A structural column is constructed on the aforementioned base, The aforementioned base is a block shape provided directly below each of the structural columns, A method for rebuilding a building having an underground structure in which the concrete of the base is stronger than the concrete of the existing foundation frame.

2. A method for rebuilding a building having an underground structure as described in claim 1, wherein the lower end of the main structural column is widened in diameter.

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