Precast foundation structure

Abstract

To provide a precast foundation structure which enables a column portion and a beam portion to be firmly connected together on a job site without the use of special work in field construction.SOLUTION: A precast foundation structure comprising a column foundation portion and a foundation beam portion, wherein the column foundation portion and the foundation beam portion are connected by a pin joint structure without being connected via a rigid joint member, wherein one of the column foundation portion and the foundation beam portion is provided with at least one recess, and the other is provided with a charging cavity for charging a connecting member connected to the recess, and wherein the connecting member is charged into the charging cavity to fill the recess with the connecting member, thereby connecting the column foundation portion and the foundation beam portion.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a precast foundation structure, and more particularly to a precast foundation structure that allows column portions and beam portions to be firmly connected on site with ease of on-site construction. [Background technology]

[0002] Foundation work for buildings usually involves tightening rebar before pouring concrete. This requires specialized work for rebar, formwork, etc., but there is currently a shortage of specialized workers, and precast foundations are attracting attention to address this labor shortage and simplify on-site construction. Various proposals have been made for precast foundations, and for example, Patent Document 1 proposes a joint device for precast foundation beams that is able to maintain sufficient shear strength. Specifically, the proposed joint device has a cotter recess formed on each end face of adjacent precast foundation beams, and a joint locking means such as a cotter recess or a protruding reinforcing bar is provided near the side faces that form the corners of the adjacent end faces, with joint concrete poured to cover the end faces and the locking means. Furthermore, Patent Document 2 proposes a precast concrete foundation and construction method that can be used on ground that has a certain level of bearing capacity but is low in bearing capacity, and that is easy to construct, can be completed in a short time, and is low in cost. Specifically, the proposed foundation structure includes a precast concrete fabric base of a predetermined length that is placed continuously in the foundation construction part of the building, and precast concrete fabric beams of a predetermined length that are erected on the fabric base, the fabric base covering the lower parts of the fabric beams and the surrounding ground above, and having a hollow interior that is open at the bottom. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 5-55656 [Patent Document 2] Patent No. 3027498 Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the above proposals have localized the scope of special work by using precast concrete, it is still necessary to tighten the reinforcing bars at joints, which are important for stress transmission, and to install formwork, so they have not yet gone so far as to eliminate the need for special work. Therefore, there is a demand for the development of precast foundation structures that do not require special construction and can be constructed more easily.

[0005] Therefore, an object of the present invention is to provide a precast foundation structure that can firmly connect column portions and beam portions on site without using special construction work at the site. [Means for solving the problem]

[0006] As a result of intensive research into solving the above problems, the inventors discovered that the above object could be achieved by preparing a column foundation structure and a beam foundation structure and installing cavities in each of them in advance, and thus completed the present invention. That is, the present invention provides the following inventions. 1. Equipped with a column base and a foundation beam, The column foundation portion and the foundation beam portion are connected by a pin joint structure without being connected via a rigid joint member, A precast foundation structure in which one of the column foundation section and the foundation beam section has one or more recesses, and the other has an input cavity into which connecting material connected to the recesses is input, and by inputting the connecting material into the input cavity, the connecting material fills the recesses, connecting the two sections. 2. A precast foundation structure as described in 1, wherein the column foundation portion is fixed to the ground by an earth anchor, and the input cavity consists of a main body into which the anchor rebar is inserted and a communication portion provided to connect the main body to the recess. [Effects of the Invention]

[0007] The precast foundation structure of the present invention allows the column and beam portions to be firmly connected on-site without the need for special construction work. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view showing a schematic view of the entire precast structure, with some parts being seen through. [Figure 2] FIG. 2 is a cross-sectional view taken along line aa in FIG. 1, where (a) is a view showing the entire cross section, and (b) is an enlarged view of part c in (a). [Figure 3] FIG. 3 is a cross-sectional view taken along line bb in FIG. 2(b). [Explanation of symbols]

[0009] 1 Precast foundation structure, 10 Column foundation, 11 Insertion cavity, 20 Foundation beam, 21 Recess, 30 Earth anchor, 31 Anchor foundation, 33 Anchor rebar, 40 Connecting material DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. As shown in Figures 1 to 3, the precast foundation structure 1 of this embodiment includes a column foundation portion 10 and a foundation beam portion 20. The column foundation portion 10 and the foundation beam portion 20 are connected by a pin joint structure, without being connected via rigid joint members such as bent reinforcing bars. Specifically, a recess 21 is provided in the foundation beam section 20, and an input cavity 11 is provided in the column base section 10 for inputting connecting material connected to the recess 21. By inputting the connecting material into the input cavity 11, the connecting material is filled into the recess 21, forming a pin joint structure and connecting the two. In the precast foundation structure 1 of this embodiment, column foundations 10 and foundation beams 20 are arranged in a grid pattern, and an anchor foundation 31 is provided at the bottom of each column foundation 10. The anchor foundation 31 is made by pouring mortar or the like into a steel pipe and has an anchor rebar 33 (see Figures 2 and 3) installed in the center. Although not specifically shown, the anchor foundation 31 is buried in the ground. Although not specifically shown, bolt sections for installing columns or foundations can be exposed at the top of the column base section 20, and the precast foundation structure 1 is configured so that an architectural structure can be installed on top of it. As shown in Figures 2 and 3, the column foundation 10 and the foundation beam 20 are not connected by rigid connecting members such as bent reinforcing bars, but are connected so that the column foundation 10 supports the foundation beam 20 by a pin structure 3 that ensures only the transmission of shear force, formed by the hardening of connecting material that is poured from the pouring cavity 11 to the recess 21. This will be explained in more detail below.

[0011] [Column foundation] The column base 10 has a rectangular column-like appearance. The earth anchor 30 is cylindrical, and although not shown in the figure, its lower part is buried in the ground. Although not shown in Figure 1 for clarity, the column base 10 rests on a spacer 39 installed on the earth anchor 30. The column base 10 has an input cavity 11 formed therein, spanning the entire height of the column base 10. The input cavity 11 consists of a cylindrical main body 13 and a communication section 15 formed on the side of the main body 13. As shown in Figures 2 and 3, each communication section 15 has a cross-sectional shape that is the same as the opening shape of a recess 21, which will be described later, and two communication sections 15 are provided, one above the other and one below the other, so as to form an opening on the side of the column base 10. In this embodiment, the upper opening of the main body 13 of the input cavity 11 is configured to be wide-mouthed, as shown in Figure 2, to improve ease of input of connecting material. The earth anchor 30 has an earth anchor 33 made of a linear steel material installed in its center, and the anchor reinforcing bar 33 is arranged with a length that is exposed above the column base 10. The column base 10 is configured so that the anchor rebar 33 is inserted into the main body 13 of the input cavity 11. Therefore, the main body 13 may be cylindrical and penetrate all the way to the bottom (earth anchor side) as described above, or may be configured to have an insertion hole (not shown) into which the anchor rebar 33 is inserted. In either case, however, it is preferable to provide an opening at the bottom. This is because the anchor rebar 33 can be inserted without drilling holes on site, making on-site construction easier. As described above, in this embodiment, the column base 10 includes the anchor reinforcing bar 33 of the earth anchor 30 therein, and is thereby fixed to the ground via the earth anchor 30 .

[0012] [Foundation beam section] The foundation beam portion 20 has a rectangular parallelepiped shape, and two recesses 21, each having the same rectangular parallelepiped opening shape, are provided on both longitudinal end faces of the foundation beam portion 20, one above the other. The recess 21 is formed to have the same size as the opening shape, and the entire recess 21 forms a cavity in the shape of a rectangular parallelepiped. The total size of the opening surfaces of the recesses 21 must be such that the area required for design is secured with a margin, but it is preferable that the total area is 20 to 30% of the area of ​​the end faces 25 of the foundation beam portions 20. From the same viewpoint, the depth of the recesses 21 is also preferably 5 to 10 cm. Reinforcing bars 23 are embedded in the foundation beam section 20 to ensure the bending and shear performance of the foundation beam section 20.

[0013] [Pin joint structure] As shown in Figures 1 to 3, the column foundation 10 and the foundation beam 20 are pin-joined by a connecting member 40 formed by filling the input cavity 11 and the recess 21 of the column foundation 10 with a connecting material and hardening the connecting material. That is, in the precast foundation structure 1 of this embodiment, the column foundation 10 and the foundation beam 20 are connected by the connecting member 40 formed by hardening the connecting material. The pin-joint structure formed in this way allows the column foundation 10 to support the foundation beam 20. Furthermore, in the pin joint structure of this embodiment, the foundation beam 20 is connected and supported by the connecting member 40 filled and hardened in the recess 21, and no other rigid connecting members such as bent reinforcing bars are used. In other words, in the precast foundation structure of the present invention, the column foundation 10 and the foundation beam 20 are connected without any rigid connecting members. Although not all are shown, recesses are formed on the end faces of all foundation beam sections 20, and communication sections 15 are provided on all surfaces of column foundation sections 10 that come into contact with foundation beam sections 20.

[0014] 〔material〕 The materials forming each component of the precast foundation structure of this embodiment are as follows. Pillar base: concrete, etc. Foundation beam: concrete, etc. Anchors for foundation beams: rebars, etc. Earth anchor: concrete, etc. Anchor rebar: Reinforced bars, etc. Connecting materials: mortar, concrete, etc. [Construction] In this embodiment, the precast foundation structure is fabricated in a factory with column bases and foundation beams of a predetermined shape. At the construction site, earth anchors are first installed in their predetermined locations, and then the column bases are installed by inserting them into the earth anchors' anchor rebar insertion cavities. After the column bases are installed, the foundation beams are placed between the column bases, and the spacers on the top of the earth anchors align the connecting portions with the recesses. Next, the connecting material is inserted into the insertion cavities, and it is preferable to temporarily fasten the tops of the connecting materials to prevent gaps from forming between the column bases and the foundation beams.

[0015] [Action and effect] The precast foundation structure 1 of this embodiment can be easily installed on-site without the need for laborious positioning, and the structure can be formed by fixing the column foundation parts 10 and the foundation beam parts 20. Therefore, construction is simple, and a foundation structure can be constructed with sufficient joint strength for a pin joint structure. Furthermore, since the column base 10 is fixed via the earth anchor 30 and supports the foundation beam 20 using a pin joint structure, the column base 10 has sufficient strength to withstand both upward and downward tensile forces, and the foundation has sufficient strength and rigidity to withstand both vertical and horizontal loads on the entire structure.

[0016] The precast foundation structure of the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, if the pull-out force acting on the column base is offset by the weight of the foundation structure, the earth anchor may be omitted. Furthermore, by incorporating the column foundation section into the foundation beam section in one direction in advance, the number of joints required on-site can be reduced, making construction easier. In addition, when the upper structure is a steel frame rigid frame structure including the foundation, the column foundation is treated as an independent precast foundation, and part of the foundation beam can be omitted.

Claims

1. The structure includes a column foundation and a foundation beam, The column foundation portion and the foundation beam portion are connected by a pin joint structure without being connected via a rigid joint member, and the precast foundation structure, One or more recesses are provided in either the column foundation or the foundation beam, and an input cavity is provided in the other to input connecting material connected to the recesses. By inputting the connecting material into the input cavity, the connecting material is filled into the recesses, and the two are connected. Precast foundation structure.

2. The column base is fixed to the ground by an earth anchor, and the input cavity comprises a main body into which the anchor rebar is inserted and a communication part provided so as to communicate from the main body to the recess. The precast foundation structure according to claim 1.

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