Construction method for direct foundation structures, and direct foundation structures

Abstract

To improve workability when fixing a base plate of a steel column to a spread foundation via an anchor bolt.SOLUTION: A construction method of a spread foundation structure comprises: a steel column erection process of erecting a steel column 40 which has a base plate 50 at its lower end and to which a steel foundation beam 60 is joined on an upper surface 20U of leveling concrete 20 via an erection column 30; and a spread foundation construction process of installing concrete around the erection column 30 with anchor bolts 52 attached to the base plate 50 to form a footing 70 in which the erection column 30 and the anchor bolts 52 are embedded.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for constructing a direct foundation structure and a direct foundation structure.

Background Art

[0002] There is disclosed a steel column to which a base plate is joined to a temporary column protruding upward from the head of a cast-in-place concrete pile (see, for example, Patent Document 1).

[0003] Also, anchor bolts for fixing the column foot of a steel column to a foundation are known (see, for example, Patent Documents 2 and 3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, when fixing a base plate provided at the lower end of a steel column to an anchor bolt protruding upward from a direct foundation such as a footing with a nut, there may be a case where, if there is a construction error in the anchor bolt, it is difficult to attach the base plate to the anchor bolt, and the workability may decrease.

[0006] In consideration of the above facts, an object of the present invention is to improve the workability when fixing a base plate of a steel column to a direct foundation via an anchor bolt.

Means for Solving the Problems

[0007] Regarding the first aspect The construction method for a direct foundation structure comprises a steel column erection step, in which a steel column having a base plate at its lower end and to which a steel foundation beam is joined is erected on the installation surface via erection columns, and a direct foundation construction step, in which concrete is poured around the erection columns with anchor bolts attached to the base plate, thereby forming a direct foundation in which the erection columns and the anchor bolts are embedded.

[0008] First aspect According to the construction method for the direct foundation structure, in the steel column erection process, a steel column having a base plate at its lower end and to which a steel foundation beam is joined is erected on the installation surface via an erection column.

[0009] Next, in the direct foundation construction process, with anchor bolts attached to the base plate, concrete is poured around the erection columns to form a direct foundation in which the erection columns and anchor bolts are embedded.

[0010] As a result, the present invention improves workability compared to the case where the base plate is positioned relative to anchor bolts that protrude directly upward from the foundation.

[0011] Furthermore, by erecting steel columns on the installation surface via erection columns, it is possible to connect, for example, steel foundation beams to the steel columns in parallel with the construction of the direct foundation. Therefore, the present invention can shorten the construction period compared to the case in which steel foundation beams are connected to steel columns after the construction of the direct foundation.

[0012] Regarding the second aspect The construction method for direct foundation structures is: Regarding the first aspect In the construction method for a direct foundation structure, in the steel column erection process, the steel column is erected on the upper surface of the lean concrete, which is constructed on the ground as the installation surface, via the erection column.

[0013] According to the construction method for a direct foundation structure of claim 2, after laying lean concrete on the ground, steel columns can be erected on the top surface of the lean concrete via erection columns without waiting for the direct foundation to be constructed. Therefore, the construction period can be shortened.

[0014] Regarding the third aspect The direct foundation structure comprises a construction column erected on the installation surface, a steel column having a base plate at its lower end that is joined to the upper end of the construction column and to which a steel foundation beam is joined, anchor bolts attached to the base plate and extending from the base plate around the construction column, and a direct foundation in which the construction column and the anchor bolts are embedded.

[0015] Third aspect In the direct foundation structure described herein, the erection columns are erected on the installation surface. The base plate at the lower end of the steel column is joined to the upper end of the erection column. The steel foundation beam is then joined to this steel column.

[0016] Furthermore, anchor bolts are attached to the base plate at the lower end of the steel column. The anchor bolts extend from the base plate around the erection column. These erection columns and anchor bolts are directly embedded in the foundation.

[0017] Thus, in this invention, by supporting the steel column with erection columns set up on the installation surface, concrete can be poured around the erection columns with anchor bolts attached to the base plate, allowing for the direct construction of the foundation. Therefore, in this invention, the constructability is improved compared to the case where the base plate is positioned relative to anchor bolts protruding upward from the direct foundation.

[0018] Furthermore, by supporting the steel columns with erection columns placed on the installation surface, it is possible to connect, for example, the steel foundation beams to the steel columns in parallel with the construction of the direct foundation. Therefore, the present invention can shorten the construction period compared to the case in which the steel foundation beams are connected to the steel columns after the construction of the direct foundation.

Advantages of the Invention

[0019] As described above, according to the present invention, the workability when fixing the base plate of the steel column directly to the foundation via anchor bolts can be improved.

Brief Description of the Drawings

[0020] [Figure 1] It is an elevation view showing a building column, a steel column, anchor bolts, and a direct foundation to which a direct foundation structure according to an embodiment is applied. [Figure 2] It is an elevation view showing the construction process of the direct foundation structure shown in FIG. 1. [Figure 3] It is an elevation view showing the construction process of the direct foundation structure shown in FIG. 1.

Modes for Carrying Out the Invention

[0021] Hereinafter, an embodiment will be described with reference to the drawings.

[0022] (Direct Foundation Structure) As shown in FIG. 1, the direct foundation structure according to this embodiment is, as an example, an independent foundation structure. This direct foundation structure shows a building column 30, a steel column 40, a plurality of anchor bolts 52, and a footing 70. The footing 70 is an example of a direct foundation (independent foundation).

[0023] (Building Column) The building column 30 is a column that temporarily supports the steel column 40 before the construction of the footing 70, and has a smaller cross-sectional area than the steel column 40. Also, the height of the building column 30 is the same as the height of the footing 70. This building column (steel building column) 30 is formed of H-shaped steel.

[0024] The cross-sectional area and height of the building column 30 can be changed as appropriate. Also, the building column 30 is not limited to H-shaped steel, and may be, for example, C-shaped steel or steel pipe steel.

[0025] A base plate 32 is provided at the lower end of the erection column 30. This erection column 30 is erected on lean concrete 20 that has been constructed on the ground 10.

[0026] Specifically, a recess 12 is formed in the ground surface (ground) of the ground 10. The lower ends of multiple anchor bolts 22 are placed in the recess 12. In this state, lean concrete 20 is formed by pouring concrete onto the ground 10 including the recess 12. The lean concrete 20 is provided in the construction area of ​​the footing 70. In addition, the upper ends of multiple anchor bolts 22 protrude from the upper surface 20U of the lean concrete 20.

[0027] The upper surface 20U of the lean concrete 20 is an example of an installation surface. The recess 12 may be provided as needed and can be omitted as appropriate. The ground 10 may also be improved as needed.

[0028] Multiple mounting holes (not shown) are formed on the outer circumference of the base plate 32. The upper ends of multiple anchor bolts 22, which protrude upward from the upper surface 20U of the lean concrete 20, pass through these mounting holes. The base plate 32 is fixed to the lean concrete 20 via the multiple anchor bolts 22 by tightening nuts 24 onto the upper ends of these anchor bolts 22.

[0029] Furthermore, the space between the upper surface 20U of the lean concrete 20 and the lower surface of the base plate 32 (the gap) is filled with a cement-based filler material 34 such as mortar or grout. This cement-based filler material 34 allows for level adjustment of the erection column 30 and absorbs construction errors. In addition, the fixing structure of the column base of the erection column 30 is not limited to anchor bolts, etc., and can be changed as appropriate.

[0030] (Steel column) The steel column 40 is a permanent column and has a larger cross-sectional area than the erection column 30 mentioned above. The steel column 40 is also formed from H-shaped steel. This steel column 40 has a pair of flange portions 42 that face each other in the horizontal direction and a web portion 44 that connects the pair of flange portions 42.

[0031] The steel column 40 has a column-beam joint 40S to which the steel foundation beam 60 is joined. A pair of diaphragms 46 are provided in the column-beam joint 40S. The pair of diaphragms 46 are through diaphragms and are arranged facing each other in the vertical direction.

[0032] The pair of diaphragms 46 are not limited to through diaphragms; they may also be external or internal diaphragms.

[0033] The steel foundation beam 60 is erected on the steel column 40 and another steel column 40 (not shown). The steel foundation beam 60 is, as an example, a bracket-type steel beam. This steel foundation beam 60 has a pair of brackets 60A that form both ends of the steel foundation beam 60, and a beam body 60B that forms the middle section of the steel foundation beam 60 and connects the pair of brackets 60A.

[0034] The bracket 60A and the beam body 60B are formed from H-shaped steel. These brackets 60A and beam body 60B have a pair of flange portions 62 that face each other in the vertical direction, and a web portion 64 that connects the pair of flange portions 62.

[0035] The bracket 60A is joined to the column-beam joint portion 40S of the steel column 40 by welding or other means in a factory or other facility. Specifically, the ends of a pair of flange portions 62 on the bracket 60A are joined to the ends of a pair of diaphragms 46 on the column-beam joint portion 40S by welding or other means. In addition, the end of the web portion 64 on the bracket 60A is joined to the outer surface of the flange portion 62 on the column-beam joint portion 40S by welding or other means.

[0036] The flange portions 62 of bracket 60A and beam body 60B are bolted together on site via splice plates 66. Similarly, the web portions 64 of bracket 60A and beam body 60B are bolted together on site via splice plates 68.

[0037] The number of steel foundation beams 60 connected to the column-beam joint 40S of the steel column 40 can be changed as appropriate. Furthermore, the steel foundation beams 60 are not limited to bracket type; non-bracket type beams are also acceptable.

[0038] A base plate 50 is provided at the lower end of the steel column 40. The base plate 50 is made of steel plate or the like and is positioned with its thickness in the vertical direction. The lower end of the steel column 40 is joined to the upper surface of the base plate 50 by welding or the like, with the column abutting against it. On the other hand, the upper end of the erection column 30 is joined to the lower surface of the base plate 50 by welding or the like, with the column abutting against it.

[0039] Furthermore, the base plate 50 of the steel column 40 and the upper end of the erection column 30 may be joined on-site, or they may be joined in a factory or site yard.

[0040] The outer periphery of the base plate 50 protrudes outward from the steel column 40. Multiple mounting holes (not shown) are formed on the outer periphery of the base plate 50. These mounting holes are circular through-holes that penetrate the base plate 50 in the thickness direction. The upper ends of anchor bolts 52 are attached to these mounting holes.

[0041] (Anchor bolts) The anchor bolt 52 serves as an anchor member for fixing the steel column 40 to the footing 70. The anchor bolt 52 is made of, for example, a steel rod. The upper end of the anchor bolt 52 is inserted into the mounting hole from the lower side of the base plate 50. The upper end of the anchor bolt 52 is also provided with a male threaded portion. The anchor bolt 52 is fixed to the base plate 50 by tightening a nut 54 onto the upper end of the anchor bolt 52.

[0042] The anchor bolts 52 are attached to the base plate 50, extending downward from the base plate 50 and positioned around the erection column 30. The lower end of the base plate 50 is located at the height of the column base of the erection column 30. A mechanical anchoring body 56 is provided at the lower end of the base plate 50.

[0043] The mechanical anchoring body 56 may be provided as needed and can be omitted as appropriate. Furthermore, the anchor bolts 52 may be, for example, J-shaped or L-shaped anchor bolts.

[0044] (Hooching) The footing 70 serves as an independent foundation supporting the steel columns 40. The footing 70 is made of reinforced concrete, with multiple reinforcing bars 72 embedded within it. The footing 70 is shaped like a rectangular parallelepiped, with its upper surface in contact with the lower surface of the base plate 50. Furthermore, the erection columns 30 and multiple anchor bolts 52 are embedded within the footing 70.

[0045] Furthermore, a concrete slab 16 is laid on the ground 10 surrounding the footing 70, with gravel 14 in between.

[0046] (Construction method for direct foundation structures) Next, an example of a construction method for the direct foundation structure according to this embodiment will be described.

[0047] (Steel column erection process) First, let's explain the steel column erection process. Figure 2 shows the state after lean concrete 20 and multiple anchor bolts 22 have been installed on the ground 10. From this state, as shown in Figure 3, the steel column 40 is erected on the upper surface 20U of the lean concrete 20 via erection columns 30.

[0048] Specifically, the steel column 40 to which the erection column 30 is attached is lifted by a lifting machine (not shown) and placed on the upper surface 20U of the lean concrete 20 via spacers (not shown). At this time, the upper ends of multiple anchor bolts 22 that protrude upward from the upper surface 20U of the lean concrete 20 are inserted into mounting holes formed on the outer circumference of the base plate 32 of the erection column 30, and the level of the base plate 32 is adjusted.

[0049] Next, a cement-based filler 34 is filled between the upper surface 20U of the lean concrete 20 and the lower surface of the base plate 32 and allowed to harden. Then, nuts 24 are tightened onto the upper ends of each anchor bolt 22 that protrudes upward from the base plate 32. This fixes the base plate 32 to the lean concrete 20.

[0050] In this embodiment, the base plate 50 of the steel column 40 is pre-attached to the upper end of the erection column 30 in the factory or site yard. However, after the erection column 30 is installed on the upper surface 20U of the lean concrete 20, the base plate 50 of the steel column 40 may be attached to the upper end of the erection column 30 by welding or other means.

[0051] (Direct foundation construction process) Next, we will explain the direct foundation construction process. In the direct foundation construction process, first, reinforcing bars 72 for the footing 70 are appropriately placed around the erection columns 30.

[0052] Next, the upper ends of multiple anchor bolts 52 are attached to the base plate 50 of the steel column 40. Specifically, the upper ends of the anchor bolts 52 are inserted from below into mounting holes formed on the outer circumference of the base plate 50 of the steel column 40. Then, nuts 54 are tightened onto the upper ends of the anchor bolts 52 that protrude upward from the base plate 50. This supports the anchor bolts 52 in a suspended state from the base plate 50.

[0053] The anchor bolts 52 may also be attached to the base plate 50 of the steel column 40 in factories, site yards, etc.

[0054] Next, temporary formwork (not shown) is erected around the erection column 30, and concrete is poured inside the formwork. In other words, concrete is poured around the erection column 30 and allowed to harden. After that, the formwork is removed, forming a footing 70 in which the erection column 30 and multiple anchor bolts 52 are embedded, as shown in Figure 1.

[0055] Furthermore, before or after the construction of the footing 70, or in parallel with the construction of the footing 70, the beam body 60B is joined to the bracket 60A of the steel foundation beam 60 which is connected to the column-beam joint portion 40S of the steel column 40. Similarly, the floor concrete 16 is constructed before or after the construction of the footing 70, or in parallel with the construction of the footing 70.

[0056] (Mechanism of Action and Effects) Next, the operation and effects of this embodiment will be described.

[0057] As described above, according to this embodiment, first, in the steel column erection process, the steel column 40 is erected on the upper surface 20U of the lean concrete 20 via the erection column 30. As a result, the steel column 40 is supported on the upper surface 20U of the lean concrete 20 via the erection column 30.

[0058] Next, in the direct foundation construction process, with anchor bolts 52 attached to the base plate 50 of the steel column 40, concrete is poured around the erection column 30 to form a footing 70 in which the erection column 30 and anchor bolts 52 are embedded.

[0059] As a result, in this embodiment, the constructability is improved compared to the case in which the base plate 50 of the steel column 40 is positioned relative to the anchor bolts 52 that protrude upward from the footing 70.

[0060] Furthermore, in this embodiment, after laying the lean concrete 20 on the ground 10, the steel columns 40 can be erected on the upper surface 20U of the lean concrete 20 via the erection columns 30 without waiting for the footing 70 to be constructed. Therefore, the construction period can be shortened.

[0061] Furthermore, in this embodiment, by erecting the steel column 40 on the upper surface 20U of the lean concrete 20 via the erection column 30, the beam body 60B can be joined to the bracket 60A of the steel foundation beam 60, which is joined to the column-beam joint portion 40S of the steel column 40, in parallel with the construction of the footing 70. Therefore, this embodiment can shorten the construction period compared to the case where the beam body 60B is joined to the bracket 60A of the steel foundation beam 60 after the construction of the footing 70.

[0062] (modified version) Next, a modified example of the above embodiment will be described.

[0063] In the above embodiment, the erection column 30 is a steel column (steel frame construction). However, the erection column is not limited to a steel column; for example, it may be a concrete column. This concrete column may be made of reinforced concrete, steel-reinforced concrete, precast concrete, etc.

[0064] Furthermore, in the above embodiment, the steel column 40 is erected on the upper surface 20U of the lean concrete 20, which serves as the installation surface, via the erection column 30. However, the installation surface is not limited to the upper surface 20U of the lean concrete 20, but may be, for example, the upper surface of another simple foundation.

[0065] Furthermore, in the above embodiment, the direct foundation is a footing 70 (isolated foundation). However, the direct foundation is not limited to a footing 70; for example, it could be a strip foundation or a raft foundation.

[0066] Although one embodiment of the present invention has been described above, the present invention is not limited to these embodiments, and various modifications may be used in appropriate combinations with one embodiment, and of course, the invention can be implemented in various forms without departing from the spirit of the present invention. [Explanation of symbols]

[0067] 10 Ground 20 Lean concrete 20U top surface (installation surface) 30 Columns for erection 40 Steel columns 50 base plate 52 Anchor bolts 60 Steel foundation beam 70 Footing (direct foundation)

Claims

1. A steel column erection process involves erecting a steel column, which has a base plate at its lower end and to which a steel foundation beam is joined, on the installation surface via erection columns, A direct foundation construction process involves attaching anchor bolts, separate from the erection columns, to the base plate, pouring concrete around the erection columns, and forming a direct foundation in which the erection columns and the anchor bolts are embedded. A construction method for a direct foundation structure that includes [a specific feature / feature].

2. In the steel column erection process described above, the steel column is erected on the upper surface of the lean concrete, which serves as the installation surface, constructed on the ground, via the erection column. A method for constructing a direct foundation structure according to claim 1.

3. A support column for erection is placed on the installation surface, A steel column to which a steel foundation beam is joined has a base plate at its lower end that is joined to the upper end of the aforementioned erection column, An anchor bolt attached to the base plate and extending from the base plate to the periphery of the erection column, The direct foundation in which the erection columns and anchor bolts are embedded, A direct foundation structure equipped with a foundation.

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