Precast concrete foundation beam structure

Abstract

To provide a foundation beam structure which facilitates carry-in to a site and facilitates joining to a pile head part and completion of a beam at the site in a precast concrete foundation beam.SOLUTION: There is provided a foundation beam structure 1 in which a foundation beam 5 and a pile head part foundation 8 are joined to each other, wherein a pair of precast concrete beam members 10 and 10 where a beam main reinforcement 14 projects in a long-axis direction of the foundation beam 5, and a part of a first stirrup reinforcement 15 projects in a beam width direction of the foundation beam 5 so as to surround the beam main reinforcement 14 are made to face each other so as to form a first joint space S1 in the beam width direction and are mounted on a bottom plate, a second stirrup reinforcement 21 is arranged so as to surround a pair of beam main reinforcements 15 in a second joint space S2 between the pair of precast concrete beam members 10 and 10 and the pile head part foundation 8, cast-in-place concrete is placed in the first joint space S1 and the second joint space S2, and the whole is integrated.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a precast concrete foundation beam structure, and more particularly to a foundation beam structure in which a precast concrete foundation beam is formed using a plurality of half-precast concrete members.

Background Art

[0002] The foundation beam structure of a building is often constructed by conventional methods. However, according to the conventional methods, since the construction labor and the construction period increase, precast concrete may be adopted not only for the upper structure but also for the foundation beam structure which is the lower structure.

[0003] When precast concrete is used for the foundation beam structure, in large buildings such as condominiums and buildings, since the beam formation and the beam span of the foundation beam become large, the precast concrete foundation beam becomes considerably heavier than the precast concrete column. For this reason, a large crane corresponding to the weight of the foundation beam is required at the site, which causes factors such as an increase in construction cost.

[0004] In order to address these problems, Patent Document 1 discloses a construction method of a foundation structure in which a foundation beam is formed by integrating two precast concrete beam members with in-situ concrete, thereby reducing the weight per precast concrete beam member.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the invention described in Patent Document 1, pre-assembled reinforcing bars are placed between the two precast concrete beam members that make up the foundation beam, and retaining members that maintain the distance between the two beam members are provided at the upper and lower ends of the foundation beam, which increases the labor and costs required to construct the foundation beam.

[0007] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a foundation beam structure that can be easily constructed using precast concrete. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides a foundation beam structure including a foundation beam and a pile head foundation. ,before A pair of precast concrete beam members, each having a beam main reinforcement protruding in the longitudinal direction of the foundation beam and a first stirrup reinforcement protruding in the beam width direction of the foundation beam so as to surround the beam main reinforcement, are placed on a base plate so as to face each other to form a first joint space in the beam width direction, and a second joint space between the pair of precast concrete beam members and the pile head foundation is filled with a 、 Second and the third The stirrup muscles of The third stirrup bar is offset from the second stirrup bar in the beam width direction so as to be in contact with the long axis direction and surround some of the beam main reinforcements. The present invention is characterized in that reinforcement is arranged and concrete is poured into the first joint space and the second joint space.

[0009] The concrete is poured into the first joint space without any gaps, It is preferable that the weight of the pair of precast concrete beam members is equal to or less than the weight of the precast concrete column members to be placed on the upper surface of the pile head foundation.

[0010] It is preferable that the beam width of each of the pair of precast concrete beam members is wider than the width in the beam width direction of the concrete poured in the first joint space.

[0011] The foundation beam is preferably placed and supported on a lightweight embankment material.

[0012] It is preferable that the pair of precast concrete beam members each consist of a pair of precast concrete beam members facing each other in the center of the longitudinal direction with a third joint space between them, and that the main beam reinforcement bars of the pair of precast concrete beam members protrude from each of the pair of precast concrete beam members into the third joint space into which concrete is poured. Effect of the Invention

[0013] According to the present invention, it is possible to provide a foundation beam structure that can be easily constructed using precast concrete. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1(a) is a front view of a foundation beam structure according to an embodiment of the present invention, FIG. 1(b) is a plan view of FIG. 1(a), and FIG. 1(c) is a cross-sectional view of a beam enlarging part A of FIG. 1(a). FIG. 1(d) is a cross-sectional view of a beam at a joint space S2 shown by a cross-sectional line 1d-1d. [Diagram 2] FIG. 2(a) is a side cross-sectional view of a half-precast concrete foundation beam member according to an embodiment of the present invention, and (b) is a rear view of (a). [Diagram 3] FIG. 2A is a front view of a foundation beam structure according to a modified example of the present invention, and FIG. 2B is a side cross-sectional view of the foundation beam of FIG. [Figure 4] FIG. 10(a) is a front view of a foundation beam structure according to another modified example of the present invention, and (b) is a plan view of (a). [Diagram 5] FIG. 2A is a rear view of a half-precast concrete foundation beam member according to a modified example of the present invention, and FIG. 2B is a side cross-sectional view taken along the Vb-Vb cross-sectional line in FIG. [Figure 6] 6A is a rear view of a half-precast concrete foundation beam member according to another modified example of the present invention, and FIG. 6B is a side cross-sectional view taken along the line VIb-VIb in FIG. 6A. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The foundation beam structure of the present invention will be described below with reference to the accompanying drawings. Note that the same components are designated by the same reference numerals.

[0016] 1(a), (b), and (c) show a foundation beam structure 1 of a foundation beam and a pile head foundation according to an embodiment of the present invention. The foundation beam structure 1 is configured by pouring cast-in-place concrete 20 between half precast concrete foundation beam members 10, 10 (hereinafter referred to as precast beam members 10) installed with their main surfaces facing each other at a predetermined interval, and integrating the half precast concrete 20 between the half precast concrete foundation beam members 10, 10 and the pile head foundation 8 connected to both ends of the half precast concrete foundation beam members 5 and the head of a precast pile P. In this embodiment, the column span S is 10 m, the weight of each precast concrete column member 7 (hereinafter referred to as precast column member 7) constituting the column 6 is about 10 t, and the cross section is 1200 mm x 1200 mm. In addition, as the precast pile P, for example, a shell steel pipe concrete pile (SC pile) having a diameter of φ=1000 mm is poured.

[0017] The foundation beam 5 is a beam with a beam width W=1000 mm, and includes precast beam members 10, 10 as components, each having a beam depth H=2000 mm, a length L=5250 mm, a beam width W1=370 mm, and a weight of approximately 9.7 t. As shown in Fig. 2(a) and (b), the precast beam member 10 is arranged so that the beam main reinforcement 14 protrudes from the end faces 12, 13 of the beam concrete 11 in the longitudinal direction. Inside and outside the beam concrete 11, the beam main reinforcement 14 is surrounded by stirrup reinforcement 15 arranged so that a part of the beam main reinforcement 14 protrudes from the inner surface 16 of the beam concrete 11 in the beam width direction. Some of the beam main reinforcement 14 is arranged by being tied to the protruding stirrup reinforcement 15, not inside the beam concrete 11. The inner surface 16 of one precast beam member 10 facing the other precast beam member 10 corresponds to the concrete pouring surface when the precast slab is manufactured, and the unevenness of the surface at the time of manufacture is left as it is, enhancing adhesion to the cast-in-place concrete 20.

[0018] (Beam width direction joint structure) The foundation beam 5 is formed by placing precast beam members 10, 10 at predetermined positions on the leveled concrete at the base of a trench (not shown) formed by excavating the ground, facing each other with their protruding stirrup bars 15 facing inward (towards the precast beam members 10) as shown in Figure 1(c), leaving a joint space S1 of 260 mm (W2 in Figure 1(c)) between them, and pouring cast-in-place concrete 20 into the joint space S1, so that the precast beam members 10, 10 and the cast-in-place concrete 20 are integrated together.

[0019] (Longitudinal beam joint structure) As shown in Figs. 1(a), (b), and (d), in the joint space S2, the beam main reinforcement 14 protruding from both axial end faces 12, 13 of the precast beam member 10 and the beam main reinforcement joint 9 arranged so as to protrude from the side of the pile head foundation 8 are joined via a mechanical joint 30. Furthermore, at the joint site, stirrup reinforcement 21 (Fig. 1(d)) arranged as a set of two pieces shifted in the beam cross section so as to surround the beam main reinforcement 14 and the beam main reinforcement joint 9 are arranged at a predetermined reinforcing pitch in the beam longitudinal direction. Cast-in-place concrete 20 is poured in the joint space S2, and the foundation beam 5 and the pile head foundation 8 are integrated. Also, the column main reinforcement (not shown) arranged so as to protrude from the top surface of the pile head foundation 8 is joined to the mechanical joint (not shown) at the lower end of the precast column member 7. In addition, the precast column members 7 and the pile head foundation 8 are provided with predetermined structural and assembly reinforcement bars (not shown) to ensure the necessary strength and durability.

[0020] As described above, the foundation beam 5 and the pile head foundation 8 are integrated together to form the foundation beam structure 1.

[0021] According to the foundation beam structure 1 of this embodiment, the weight of each precast beam member 10 constituting the foundation beam 5 can be kept below the weight of each precast column member 7 constituting the column 6, and even though a precast foundation beam is used in the foundation beam structure, it can be constructed with a small lifting machine with the same capacity as when the foundation beam structure is constructed by a conventional construction method. Furthermore, reinforcing bars are not required between the precast beam members 10, 10 (joint space S1). In addition, since the precast beam member 10 is heavier than the cast-in-place concrete 20 cast in the joint space S1, formwork support can be omitted on the back of the precast beam member 10, and separators and the like are also not required. Therefore, the construction labor and construction costs can be reduced, and the foundation beam structure 1 can be easily constructed.

[0022] (Modification) In the above embodiment, the foundation beams 5 were placed on leveled concrete, but on a site with soft ground, they may be placed and supported on lightweight embankment material constructed using large EPS (Expanded Poly-Styrol) blocks 40, as shown in Figures 3(a) and (b).

[0023] In addition, in the above embodiment, the foundation beam 5 has two precast beam members 10 as its components, but for example, depending on the weight of each precast beam member, as shown in Figures 4(a) and (b), the foundation beam 5A may have as its components a precast beam member 10A in which the main beam reinforcement bars 14, 14 are divided into four pieces and joined with cast-in-place concrete 20 within the joint space S3 in the middle of the column span, or it may be a foundation beam having four or more precast beam members as its components.

[0024] In the above embodiment, the inner surface 16 of the precast beam member 10 has an uneven surface. However, for example, as shown in Figures 5(a) and (b), a V-shaped groove 17 extending in the longitudinal direction may be formed, or as shown in Figures 6(a) and (b), a number of rectangular cotters 18 may be formed to increase adhesion to cast-in-place concrete.

[0025] In addition, in the above embodiment, the cast-in-place concrete 20 is poured between the precast beam members 10, 10 of the foundation beam 5, but the foundation beam may be formed by arranging two precast beam members, in which the stirrup reinforcement does not protrude from the precast beam member, side by side in the beam width direction. The thickness, length and spacing of the precast beam members are not limited to the values ​​in the above embodiment.

[0026] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the claims. In other words, embodiments obtained by combining technical means appropriately modified within the scope of the claims are also included in the technical scope of the present invention. [Explanation of symbols]

[0027] 1,2,3 Foundation beam structure 5,5A foundation beam 6 Pillars 7 Precast concrete column members (precast column members) 8 Pile head foundation 9 Beam main reinforcement connection reinforcement 10, 10A, 10B, 10C Half precast concrete foundation beam members (precast beam members) 11 Beam Concrete 12,12A,13,13A end face 14 Main beam reinforcement 15,21 Stirrup muscle 16 Inner Surface 17 V-shaped groove 18 Cotter 20 Cast-in-place concrete 30 Mechanical couplings 40 Lightweight embankment material (EPS block) P Prefabricated pile S1,S2,S3 joint space

Claims

1. A foundation beam structure consisting of a foundation beam and a pile head foundation, A pair of precast concrete beam members, each having a main beam reinforcement protruding in the longitudinal direction of the foundation beam and a first stirrup reinforcement protruding in the beam width direction of the foundation beam so as to surround the main beam reinforcement, are placed on a base plate so as to face each other to form a first joint space in the beam width direction, In the second joint space between the pair of precast concrete beam members and the pile head foundation, the second and third stirrup bars are in contact with each other in the longitudinal direction, and the third stirrup bars are arranged offset from the second stirrup bars in the beam width direction so as to surround a part of the beam main reinforcement together, Concrete is poured into the first joint space and the second joint space. A precast concrete foundation beam structure.

2. The concrete is poured into the first joint space without any gaps, The weight of the pair of precast concrete beam members is equal to or less than the weight of the precast concrete column member to be placed on the upper surface of the pile head foundation.

2. The precast concrete foundation beam structure according to claim 1.

3. The beam width of each of the pair of precast concrete beam members is wider than the width of the concrete poured in the first joint space in the beam width direction; 3. A precast concrete foundation beam structure according to claim 1 or 2.

4. The foundation beam is placed and supported on a lightweight embankment material. A precast concrete foundation beam structure according to any one of claims 1 to 3.

5. The pair of precast concrete beam members each include a pair of small precast concrete beam members facing each other at the center in the longitudinal direction with a third joint space therebetween, In the third joint space, beam main reinforcements protrude from the pair of small precast concrete beam members, and concrete is poured into the third joint space. A precast concrete foundation beam structure according to any one of claims 1 to 4.

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