Precast concrete footing beam structure

Abstract

To provide a footing beam structure corresponding to the position of a through-hole and having excellent construction efficiency in a footing beam using a precast concrete member.SOLUTION: A foundation beam structure 1 is a foundation beam structure of a pile head foundation 8 and a foundation beam 5 in which a man hole 50 and a through hole 60,70 are formed in a beam width direction. A pair of precast concrete girder members 1010, which are opposed to each other in the beam-width direction of the footing girder 5 and in which a preceding open hole is formed at a position where the through-hole 50 is to be formed, are placed on the batholith so as to have a joining space S1 between the pile head footing 8, a pipe member for forming the through-hole 6070 is provided in the joining space S1, the cast-in-place concrete 20 is placed in the joining space S1 excluding the pipe member, and the through-hole 6070 is formed in the beam-width direction of the footing girder 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a precast concrete foundation beam structure, and more particularly to a reinforced concrete foundation beam structure having a through hole in the beam width direction, which is efficiently constructed using a plurality of precast concrete members. [Background technology]

[0002] The foundation beam structure of a building is often constructed using conventional construction methods. However, because conventional construction methods increase the amount of work and construction time required, precast construction methods are sometimes used not only for the superstructure but also for the substructure, which is the foundation beam structure.

[0003] When using precast construction methods for foundation beam structures, in large buildings such as condominiums and office buildings, the beam depth and beam span of the foundation beams become large, so the precast concrete foundation beams become significantly heavier than precast concrete columns. As a result, the lifting equipment used on site must be large enough to handle the weight of the foundation beams, which increases construction costs.

[0004] To address these problems, Patent Document 1 discloses a method for constructing half-precast reinforced concrete foundation beams in which main reinforcement bars protrude from the end faces. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 11-350501 Summary of the Invention [Problem to be solved by the invention]

[0006] In the case of the foundation beams described in Patent Document 1, there were problems such as the fact that manufacturing precast reinforced concrete foundation beams in a factory required waiting for the determination of the positions of through holes for equipment piping, etc., which resulted in a longer construction period, or that taking into account the longer construction period meant that precast construction methods could not (or could not) be selected for the foundation beams.

[0007] Therefore, an object of the present invention is to provide a foundation beam structure using precast concrete members that is efficient in construction and corresponds to the position of the through holes. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the precast concrete foundation beam structure of the present invention is a foundation beam structure consisting of a foundation beam having a manhole and a through hole formed in the beam width direction and a pile head foundation, in which a pair of pre-openings are formed at the position where the manhole is planned to be formed, facing each other in the beam width direction of the foundation beam, are placed on a base so as to have a first joint space between them and the pile head foundation, a first pipe member for forming the through hole is provided in the first joint space, cast-in-place concrete is poured into the first joint space excluding the first pipe member, and the through hole is formed in the beam width direction of the foundation beam.

[0009] A second joint space is formed between the pair of precast concrete beam members in the beam width direction of the foundation beam, and a second pipe member communicating between the advance openings is provided in the second joint space, and cast-in-place concrete is poured into the second joint space excluding the second pipe member, and the through hole is formed in the beam width direction of the foundation beam.

[0010] The weight of each of the pair of precast concrete beam members may be equal to or less than the weight of the precast concrete column member placed on the top surface of the pile head foundation.

[0011] It is preferable that opening reinforcement bars be arranged to surround the manhole and the through hole in the circumferential direction.

[0012] Above and below the manhole and the through hole, upper and lower opening reinforcement bars may be arranged to surround the main beam reinforcement arranged at the upper or lower part of the beam and the horizontal reinforcement arranged at the upper or lower part of the opening.

[0013] It is preferable that stirrups are arranged in the first joint space so as to avoid the top and bottom of the through-hole.

[0014] The opening reinforcement bars may be arranged so that the positions of the through holes can be changed in the beam depth direction.

[0015] The first pipe member may be a void pipe that is removed after the foundation beam is constructed.

[0016] In the first joint space, the stirrups may surround the main beam reinforcement protruding from one of the pair of precast concrete beam members and the main beam reinforcement at the outer periphery of the main beam reinforcement protruding from the other precast concrete beam member.

[0017] The pair of precast concrete beam members are placed on the base plate so as to be adjacent to each other with a gap in the beam width direction of the foundation beam, and the gap is preferably filled with grout material. [Effects of the Invention]

[0018] According to the present invention, a foundation beam structure that uses precast concrete members and that is construction efficient and corresponds to the position of the through holes can be provided. [Brief explanation of the drawings]

[0019] [Figure 1] (a) is a front view showing the structure of a precast concrete foundation beam according to the first embodiment of the present invention, (b) is a plan view of (a), and (c) is an enlarged view of part Ic of (a). [Figure 2](a) is a cross-sectional view of a beam at the joint space including the manhole shown by the IIa-IIa cross-sectional line in Figure 1(a), (b) is a cross-sectional view of a beam at the joint space shown by the IIb-IIb cross-sectional line in Figure 1(a), (c) is a cross-sectional view of a beam at the joint space including the through hole shown by the IIc-IIc cross-sectional line in Figure 1(a), and (d) is a cross-sectional view of a beam at the joint space shown by the IId-IId cross-sectional line in Figure 1(a). [Figure 3] (a) is a rear view of a half-precast concrete beam member according to the first embodiment, (b) is a cross-sectional view taken along the IIIb-IIIb cross-sectional line in (a), (c) is a cross-sectional view at the precast hole taken along the IIIc-IIIc cross-sectional line in (a), and (d) is a rear view of (a) without the beam concrete. [Figure 4] FIG. 2 is a front view showing an example of an opening reinforcing bar unit used in the foundation beam structure according to the first embodiment. [Figure 5] FIG. 1 is a cross-sectional view of a beam in which a void pipe is provided in the foundation beam structure according to the first embodiment. [Figure 6] (a) is a front view showing the structure of a precast concrete foundation beam according to the second embodiment of the present invention, (b) is a plan view of (a), and (c) is an enlarged view of part VIc of (a). [Figure 7] (a) is a cross-sectional view of a beam in the joint space including the manhole shown by the VIIa-VIIa cross-sectional line in Figure 6(a), (b) is a cross-sectional view of a beam in the joint space shown by the VIIb-VIIb cross-sectional line in Figure 6(a), (c) is a cross-sectional view of a beam in the joint space including the through hole shown by the VIIc-VIIc cross-sectional line in Figure 6(a), and (d) is a cross-sectional view of a beam in the joint space shown by the VIId-VIId cross-sectional line in Figure 6(a). [Figure 8] FIG. 10 is a front view showing an example of reinforcement for reinforcing an opening used in a foundation beam structure according to a modified example. [Figure 9] A front view showing an example of the shape of a precast hole used in a modified foundation beam structure. DETAILED DESCRIPTION OF THE INVENTION

[0020] A foundation beam structure according to an embodiment 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.

[0021] [First embodiment] 1(a)-(c) and 2(a)-(d) show a foundation beam structure of a foundation beam and a pile head foundation according to a first embodiment of the present invention. In the foundation beam structure 1, the foundation beam 5 and the pile head foundation 8 are integrated by pouring cast-in-place concrete 20 into the joint space S1 between the foundation beam 5 and the pile head foundation 8 and into the joint space S2 between half-precast concrete foundation beam members 10, 10 (hereinafter referred to as precast beam members 10) installed at a predetermined distance with their main surfaces facing each other. Furthermore, a manhole 50 and through holes 60, 70 are formed in the width direction of the foundation beam 5. The foundation beam structure 1, for example, constitutes the foundation beam structure of a large logistics warehouse. The column span S is 10 m, and each precast concrete column member 7 (hereinafter referred to as precast column member 7) constituting the column 6 weighs approximately 10 t, has a cross section of 1000 mm × 1000 mm, and is 4000 mm long. In addition, as precast piles P, outer shell steel pipe concrete piles (SC piles) with a diameter of 1000 mm have been cast.

[0022] The foundation beam 5 is a beam with a beam width of 1000 mm, and is composed of precast beam members 10, 10, each of which has a beam height of 2000 mm, a length of 7000 mm, a beam width of 250 mm, a beam width of 500 mm, and a weight of approximately 8.8 t. As shown in Figures 3(a)-(d), the precast beam members 10 are reinforced so that the beam main reinforcement 14 protrudes from the longitudinal end faces 12, 13 of the beam concrete 11. An opening 51 in the precast member penetrates the beam width direction as a preliminary opening at the planned location for the manway 50. In the joint space S1, stirrups 21, 22 are arranged to surround the beam main reinforcement 14 (or the beam main reinforcement joint 9, described later) that are partially different from each other. A void pipe (pipe member) 40 is installed at the planned location for the formation of through holes 60, 70 for facility piping, electrical wiring, etc.

[0023] The beam main reinforcement bars 14 are surrounded by stirrups 15, which are arranged inside and outside the beam concrete 11 so that some of them protrude from the inner surface 16 of the beam concrete 11 in the beam width direction. Some of the beam main reinforcement bars 14 are arranged by being tied to the protruding stirrups 15, rather than being 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 panel is manufactured, and the unevenness of the surface at the time of manufacturing is left as it is, improving adhesion to the cast-in-place concrete 20.

[0024] The opening 51 in the precast member is a through hole (pre-opening) with a diameter of 600 mm to form the manhole 50 in the foundation beam 5, and is surrounded by an opening reinforcement unit 53 (see Figure 4). No stirrups 15 are arranged above or below the opening 51 in the precast member. Instead, upper opening reinforcement 58 is arranged above the opening to surround the main beam reinforcement 14 and upper horizontal reinforcement 56, and lower opening reinforcement 59 is arranged below the opening to surround the main beam reinforcement 14 and lower horizontal reinforcement 57. As shown in Figure 4, the opening reinforcement unit 53 has a substantially octagonal outer periphery reinforcement 54 and a substantially square inner periphery reinforcement 55 arranged inside it. The upper opening reinforcement 58 and the lower opening reinforcement 59 are arranged at pitches equal to or narrower than the stirrups 15. The center distance D1 between the manhole 50 shown in FIG. 1(a) and the through-hole 60 that needs reinforcement is set to be three times or more the average diameter of the two holes.

[0025] The through hole 60 is a 250 mm diameter through hole formed in the joint space S1 for the equipment piping of the foundation beam 5. As shown in FIG. 1(c), no stirrups 21, 22 are arranged above or below the through hole 60. Instead, an upper opening reinforcement 68 is arranged above the hole to surround the main beam reinforcement 14 and upper horizontal reinforcement 66, and a lower opening reinforcement 69 is arranged below the hole to surround the main beam reinforcement 14 and lower horizontal reinforcement 67. The opening reinforcement unit 63 surrounding the circumferential direction of the through hole 60 has a substantially octagonal outer peripheral reinforcement 64 and a substantially square inner peripheral reinforcement 65 bundled and arranged inside it, similar to the opening reinforcement unit 53 shown in FIG. 4. The upper opening reinforcement 68 and the lower opening reinforcement 69 are arranged at pitches equal to or narrower than the stirrups 21, 22. Since the through hole 60 is formed within the joint space S1, the position of the equipment piping only needs to be determined by the time of reinforcement work in the joint space S1, rather than during the manufacture of the precast beam member 10, and a foundation beam structure with high construction efficiency that corresponds to the position of the through hole can be provided.

[0026] The through hole 70 is a through hole with a diameter of 100 mm for electrical wiring in the foundation beam 5. The through hole 70 is arranged between the stirrups 21, 22. No opening reinforcement units or other reinforcing bars are arranged in the through hole 70. Because the through hole 70 is formed in the joint space S1, the position of the electrical wiring only needs to be determined before the reinforcement work in the joint space S1 is performed, not during the manufacture of the precast beam member 10, and a foundation beam structure with high construction efficiency corresponding to the position of the through hole can be provided.

[0027] (Longitudinal beam joint structure) As shown in Figures 1(a) and 1(b), in the joint space S1, the beam main reinforcement bars 14 protruding from both end faces 12, 13 of the precast beam member 10 in the beam longitudinal direction (axial direction) are joined to the beam main reinforcement connector bars 9 arranged to protrude from the side of the pile head foundation 8 via known mechanical joints 80. Furthermore, at the joint site, two stirrups 21, 22 of different widths are arranged as a set (see Figure 2(d)) surrounding the beam main reinforcement bars 14 and the beam main reinforcement connector bars 9 in the beam longitudinal direction (axial direction) at a predetermined reinforcing pitch. Cast-in-place concrete 20 is poured into the joint space S1 to integrate the foundation beam 5 and the pile head foundation 8. Furthermore, as mentioned above, through holes 60, 70 are formed in the joint space S1 at positions that take into consideration the installation piping and electrical wiring. In addition, main column reinforcement (not shown) arranged to protrude from the top surface of the pile head foundation 8 is connected to a mechanical joint (not shown) at the lower end of the precast column member 7. The precast column member 7 and the pile head foundation 8 are also provided with predetermined structural reinforcement and assembly reinforcement (not shown) to maintain the required strength and bearing capacity.

[0028] (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 bottom of a trench (not shown) formed by excavating the ground, with the protruding stirrups 15 facing the inner surface 16 (the precast beam member 10 side) and leaving a joint space S2 of 500 mm (W2 in FIG. 2(a)) as shown in FIG. 2(d), and pouring cast-in-place concrete 20 into the joint space S2, thereby integrating the precast beam members 10, 10 and the cast-in-place concrete 20. When pouring the cast-in-place concrete 20, as shown in FIG. 5, a void pipe 40 is installed in the joint space S2 so as to connect the opening hole 51 of one precast member with the opening hole 51 of the other precast member, and the cast-in-place concrete 20 is poured into the joint space S2. By removing the void pipe 40 after the cast-in-place concrete 20 has hardened, a concrete hole 52 is formed and a manhole 50 is formed so as to penetrate the foundation beam 5 in the beam width direction.

[0029] As described above, the foundation beam 5 and the pile head foundation 8 are integrated together to form the foundation beam structure 1.

[0030] According to the foundation beam structure 1 of the first embodiment, preliminary openings are formed at the locations where the manholes 50 are planned to be formed, void pipes 40 that connect the manholes 50 are provided in the connection space S2, void pipes 40 for forming the through holes 60, 70 are provided in the connection space S1, and cast-in-place concrete 20 is poured into the connection spaces S1, S2. This allows the manufacture of the precast beam members 10 to begin without waiting for the positions of the through holes 60, 70 to be determined, thereby preventing the construction period from being extended. Furthermore, as with the construction of a foundation beam structure using conventional construction methods, the manholes 50 and the through holes 60, 70 can be formed at preferred locations on the foundation beam 5, and opening reinforcement units 53, 63 are arranged to circumferentially surround the manholes 50 and the through holes 60, 70. Therefore, the foundation beam structure 1 can be constructed efficiently while being adapted to the manholes 50 and the through holes 60, 70. Furthermore, 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. Therefore, even when using precast foundation beams in the foundation beam structure, construction can be performed using a lifting machine determined based on the weight of the precast members of the superstructure. Furthermore, reinforcing bars are not required between the precast beam members 10 (joint space S2). Furthermore, because the precast beam members 10 can resist out-of-plane bending moments due to lateral pressure during the pouring of cast-in-place concrete 20, the amount of formwork and support required behind the precast beam members 10 can be significantly reduced compared to conventional construction methods. This reduces construction time, construction labor, and construction costs. The manholes 50 and through-holes 60 and 70 are formed in optimal locations, and the foundation beam structure 1 with appropriately reinforced manholes 50 and through-holes 60 and 70 can be easily constructed.

[0031] [Second embodiment] In the first embodiment, the foundation beam structure 1 had half-precast concrete foundation beam members 10, 10 installed with their main surfaces facing each other at a predetermined distance, but in the second embodiment, as shown in Figures 6(a) and (b), half-precast concrete foundation beam members 30, 30 (hereinafter referred to as precast beam members 30) are installed with their main surfaces (inner surfaces 36, 36) abutting each other.

[0032] 6(a)-(c) and 7(a)-(d) show a foundation beam structure of a foundation beam and a pile head foundation according to a second embodiment of the present invention. In the foundation beam structure 2, the foundation beam 5 and the pile head foundation 8 are integrated by pouring cast-in-place concrete 20 into the joint space S1 between the foundation beam 5 and the pile head foundation 8, and a manhole 50 and through holes 60, 70 are formed in the width direction of the foundation beam 5.

[0033] The foundation beam 5 is a beam with a beam width of 800 mm, and is comprised of precast beam members 30, 30 with a beam height of 1800 mm, a length of 6000 mm, a beam width of 400 mm, and a weight of approximately 10.8 t. The precast beam members 30 are reinforced so that the main beam reinforcement 34 protrudes from the longitudinal end faces 32, 33 of the beam concrete 31. Opening holes 51 in the precast members penetrate the beam width direction as preliminary openings at the planned positions for the formation of manholes 50. Stirrups 35 are arranged within the beam concrete 31. In the joint space S1, the stirrups 21, 22 are arranged to surround the partially different main beam reinforcement 34 (or the beam main reinforcement joint bars 9, described later). A void pipe (pipe member) 40 is installed at the planned positions for the formation of through holes 60, 70 for facility piping, electrical wiring, etc.

[0034] According to the foundation beam structure 2 of the second embodiment, since there is no joint space S2, it is possible to reduce the time and effort required to pour concrete into the joint space S2, the effort required to line up the precast beam members 30, 30 while leaving the joint space S2, etc. Therefore, the construction period, construction effort, and construction costs can be reduced, and the manhole 50 and through holes 60, 70 can be formed in suitable positions, making it easy to construct the foundation beam structure 2 with the manhole 50 and through holes 60, 70 appropriately reinforced.

[0035] [Variations] In the above-described embodiments, the manhole 50 and the through-hole 60 are provided with opening reinforcement units 53, 63 in the circumferential direction. However, for example, reinforcing bars 53A, 63A used for general opening reinforcement using diagonal reinforcement as shown in Fig. 8 may be provided, or pre-made products such as Dialen (registered trademark), Super Harry, Weblen (registered trademark), and Linblen (registered trademark) may be provided. Furthermore, the through-hole 70 is not provided with opening reinforcement units or other reinforcing bars. However, for example, in cases where the through-hole 70 must be positioned so as to overlap the stirrups 21 or 22, reinforcing bars 71 may be provided on the left and right sides of the through-hole 70 with two adjacent stirrups 21, 22 spaced equally apart, as shown in Fig. 8.

[0036] In each of the above embodiments, the opening hole 61 was a circular opening as shown in Figure 1(c), but in order to be able to accommodate changes in the installation height of the equipment piping, it may also be an oval opening in the beam direction that falls within the movable range M1 as shown by the two-dot chain line in Figure 9, for example.

[0037] In the second embodiment described above, the precast beam members 30, 30 were installed so that their main surfaces abutted against each other, but a gap of, for example, about 10 mm is formed between the precast beam members 30, 30, and the gap may be filled with grout material or left as an open space.

[0038] In each of the above embodiments, only manholes 50 were formed in the precast beam members 10, but for example, through holes whose placement has been determined early on may also be formed as long as they meet the criteria for through hole placement.

[0039] In each of the above embodiments, the inner surface 16 of the precast beam member 10 has surface irregularities, but instead of the irregularities, for example, grooves or cotters may be formed, or nothing may be formed.

[0040] Furthermore, in each of the above embodiments, the void pipe 40 that is removed after the foundation beam 5 is constructed is used, but for example, a winding pipe or the like may be left in place.

[0041] In each of the above embodiments, the piles are shell steel pipe concrete piles, but they may also be steel pipe piles, concrete piles, precast concrete piles, etc.

[0042] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. In other words, embodiments obtained by combining technical means modified appropriately within the scope of the claims are also included in the technical scope of the present invention. [Explanation of symbols]

[0043] 1,2 Foundation beam structure 5 Foundation beam 6 pillars 7 Precast concrete column members (precast column members) 8 Pile head foundation 9 Beam main reinforcement connection reinforcement 10,30 Half precast concrete foundation beam member (precast beam member) 11,31 Concrete beams 14,34 Beam main reinforcement 15, 21, 22 Stirrups 20 Cast-in-place concrete 40 Void pipe 50 person through hole 53,63 Opening reinforcement unit 60,70 through holes 80 Mechanical Couplings P Precast pile S1,S2 joint space

Claims

1. A foundation beam structure of a foundation beam having a manhole and a through hole formed in the beam width direction and a pile head foundation, A pair of precast concrete beam members facing each other in the beam width direction of the foundation beam, in which preliminary openings are formed at positions where the manhole is planned to be formed, are placed on the base plate so as to have a first joint space between them and the pile head foundation, a first pipe member for forming the through hole is provided in the first joining space; Cast-in-place concrete is poured into the first joint space excluding the first pipe member, and the through hole is formed in the beam width direction of the foundation beam. Precast concrete foundation beam structure.

2. A second joint space is provided between the pair of precast concrete beam members in the beam width direction of the foundation beam, a second pipe member communicating between the preliminary holes is provided in the second joining space; Cast-in-place concrete is poured into the second joint space excluding the second pipe member, and the through hole is formed in the beam width direction of the foundation beam.

2. The precast concrete foundation beam structure of claim 1.

3. The weight of each of the pair of precast concrete beam members is equal to or less than the weight of the precast concrete column member placed on the top surface of the pile head foundation.

2. The precast concrete foundation beam structure of claim 1.

4. An opening reinforcement bar is arranged around the manhole and the through hole in the circumferential direction, 2. The precast concrete foundation beam structure of claim 1.

5. Above and below the manhole and the through hole, an upper reinforcing bar and a lower reinforcing bar are arranged surrounding the main beam reinforcement arranged at the upper or lower part of the beam and the horizontal reinforcement arranged at the upper or lower part of the opening.

2. The precast concrete foundation beam structure of claim 1.

6. In the first joint space, stirrups are arranged to avoid the top and bottom of the through hole.

2. The precast concrete foundation beam structure of claim 1.

7. The opening reinforcement is arranged so that the position of the through hole can be changed in the beam depth direction.

5. The precast concrete foundation beam structure of claim 4.

8. The first pipe member is a void pipe that is removed after the foundation beam is constructed.

2. The precast concrete foundation beam structure of claim 1.

9. In the first joint space, the stirrups surround the main beam reinforcement protruding from one of the pair of precast concrete beam members and the main beam reinforcement at the outer periphery of the main beam reinforcement protruding from the other precast concrete beam member.

2. The precast concrete foundation beam structure of claim 1.

10. The pair of precast concrete beam members are placed on the base plate so as to be adjacent to each other with a gap in the beam width direction of the foundation beam, The gap is filled with grout material.

2. The precast concrete foundation beam structure of claim 1.

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