Footing beam

Abstract

To simplify the arrangement of a lower end beam reinforcement and an upper end beam reinforcement.SOLUTION: A footing beam 30 is a footing beam 30 made of reinforced concrete or steel-reinforced concrete, and of multiple rows of lower end beam main reinforcements 52, a second row of lower end beam main reinforcements 52 is a continuous reinforcement, and a first row of lower end beam main reinforcements 52 is a cut-off reinforcement embedded in at least a beam end 30E.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a foundation beam.

Background Art

[0002] A communication pipe that is provided at the lower end or the middle section of a reinforced concrete foundation beam and allows rainwater and the like to pass through is known (see, for example, Patent Document 1).

[0003] Also, a PC formwork for a reinforced concrete foundation beam, in which a communication hole for passing a communication pipe is formed, is 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, it is conceivable to form, for example, a through hole or a recess, or embed an interfering object (obstacle) or the like on the lower end side or the upper end side in the middle part of a foundation beam such as a reinforced concrete structure.

[0006] However, in this case, the reinforcement arrangement of the lower end beam main reinforcement and the upper end beam main reinforcement of the foundation beam may become complicated.

[0007] In consideration of the above facts, an object of the present invention is to simplify the reinforcement arrangement of the lower end beam main reinforcement and the upper end beam main reinforcement.

Means for Solving the Problems

[0008] The foundation beam according to claim 1 is a foundation beam made of reinforced concrete or steel-reinforced concrete. Among the main bars of the lower end beams in multiple stages, the main bar of the second-stage lower end beam is used as a continuous bar, and the main bar of the first-stage lower end beam is used as a cutoff bar buried at least at the beam end.

[0009] According to the foundation beam according to claim 1, it is made of reinforced concrete or steel-reinforced concrete. In this foundation beam, among the main bars of the lower end beams in multiple stages, the main bar of the second-stage lower end beam is used as a continuous bar. On the other hand, the main bar of the first-stage lower end beam is used as a cutoff bar buried at least at the beam end.

[0010] By using the main bar of the first-stage lower end beam as a cutoff bar in this way, while simplifying the reinforcement arrangement of the main bars of the lower end beam, for example, through holes or recesses can be formed on the lower end side in the middle part of the foundation beam, or interference objects (obstacles) can be buried.

[0011] The foundation beam according to claim 2 is the foundation beam according to claim 1, in which a through hole extending in the beam width direction is formed on the lower end side in the middle part of the beam. The main bar of the second-stage lower end beam is arranged above the through hole, and the main bar of the first-stage lower end beam is arranged on both sides of the through hole.

[0012] According to the foundation beam according to claim 2, a through hole extending in the beam width direction is formed on the lower end side in the middle part of the foundation beam. And the main bar of the second-stage lower end beam is arranged above the through hole. On the other hand, the main bar of the first-stage lower end beam is arranged on both sides of the through hole.

[0013] Even in the case where a through hole extending in the beam width direction is formed on the lower end side in the middle part of the foundation beam in this way, by using the main bar of the first-stage lower end beam as a cutoff bar, while simplifying the reinforcement arrangement of the main bars of the lower end beam, the tensile strength at the lower end of the foundation beam can be ensured.

[0014] The foundation beam according to claim 3 is the foundation beam according to claim 2, in which the through hole is formed by a disposable formwork buried on the lower end side of the middle part of the beam.

[0015] According to the foundation beam according to claim 3, the through hole is formed by a disposable formwork embedded on the lower end side of the middle part of the beam. By forming the through hole with such a disposable formwork, it becomes unnecessary to demold the formwork, so the workability of the through hole is improved.

[0016] The foundation beam according to claim 4 is the foundation beam according to claim 3, wherein the disposable formwork has an open bottom and is composed of a plurality of channel steels arranged in parallel in the span direction.

[0017] According to the foundation beam according to claim 4, the disposable formwork has an open bottom and is composed of a plurality of channel steels arranged in parallel in the span direction. Thereby, with a simple structure, a through hole can be formed on the lower end side in the middle part of the foundation beam.

[0018] The foundation beam according to claim 5 is a foundation beam of reinforced concrete structure or steel frame reinforced concrete structure. Among the upper beam main reinforcements of multiple stages, the second-stage upper beam main reinforcement is used as a continuous bar, and the first-stage upper beam main reinforcement is used as a cutoff bar buried at least at the beam end.

[0019] According to the foundation beam according to claim 5, it is of reinforced concrete structure or steel frame reinforced concrete structure. In this foundation beam, among the upper beam main reinforcements of multiple stages, the second-stage upper beam main reinforcement is used as a continuous bar. On the other hand, the first-stage upper beam main reinforcement is used as a cutoff bar buried at least at the beam end.

[0020] By using the first-stage upper beam main reinforcement as a cutoff bar in this way, while simplifying the reinforcement arrangement of the upper beam main reinforcement, for example, a through hole or a recess can be formed on the upper end side in the middle part of the foundation beam, or an interference object (obstacle) can be buried.

Effects of the Invention

[0021] As described above, according to the present invention, the reinforcement arrangement of the lower beam main reinforcement and the upper beam main reinforcement can be simplified.

Brief Description of the Drawings

[0022]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

MODE FOR CARRYING OUT THE INVENTION

[0023] Hereinafter, an embodiment will be described with reference to the drawings.

[0024] (Structure) FIG. 1 shows the foundation part of the structure 10 according to the present embodiment. The structure 10 is, for example, a pile foundation, and includes a plurality of piles 12, a plurality of footings 14, a plurality of columns 16, and a foundation beam 30.

[0025] The plurality of piles 12 are made of concrete piles, steel piles, etc., and are provided at intervals in the ground G. Further, the pile heads of each pile 12 protrude from the ground G. Footings 14 are respectively provided on the pile heads of these piles 12.

[0026] The plurality of footings 14 are made of, for example, reinforced concrete and are formed in a block shape (rectangular parallelepiped shape). The pile heads of the piles 12 are embedded in each footing 14. Columns 16 are erected on these footings 14.

[0027] The columns 16 are made of reinforced concrete, steel-reinforced concrete, or steel. Further, the columns 16 are joined to the piles 12 via the footings 14. Thereby, the axial force of the columns 16 can be transmitted to the piles via the footings 14.

[0028] Note that the foundation of the structure 10 is not limited to a pile foundation, and for example, a direct foundation or the like may be used.

[0029] (Foundation beam) A foundation beam 30 is installed between adjacent footings 14. The foundation beam 30 is made of reinforced concrete. Further, the foundation beam 30 is formed in a rectangular cross-section. This foundation beam 30 is provided on the discarded concrete 18 provided on the ground G and connects the adjacent footings 14.

[0030] The upper surface (upper end) 30U of the foundation beam 30 is substantially flush with the upper surface (upper end) 14U of the footing 14. For example, a slab (not shown) is provided on these foundation beams 30 and footings 14.

[0031] Note that the upper surface 30U of the foundation beam 30 is not limited to being substantially flush with the upper surface 14U of the footing 14, and for example, a step may be formed between the upper surface 30U of the foundation beam 30 and the upper surface 14U of the footing 14. Further, the foundation beam 30 is not limited to being installed between adjacent footings 14, and for example, it may be installed between adjacent columns or the like.

[0032] As shown in FIG. 2, the plurality of foundation beams 30 are arranged in a rectangular shape in plan view so as to surround the pit 20. Here, two through holes 40 are formed on the lower end side in the middle part 30M of the beam in the span direction (arrow X direction) of the foundation beam 30. More specifically, the two through holes 40 are formed on the lower end side near the central part of the foundation beam 30 in the span direction.

[0033] Note that the middle part 30M of the foundation beam 30 means the central region when the foundation beam 30 is trisected in the span direction, and the end part 30E of the foundation beam 30 means the regions on both sides when the foundation beam 30 is trisected in the span direction. Further, the central part of the foundation beam 30 means the central region when the foundation beam 30 is divided into five equal parts in the span direction.

[0034] The two through holes 40 function as water passage holes (drainage holes) for allowing rainwater, spring water, etc. accumulated in the pit 20 to pass through, for example. Each through hole 40 penetrates the foundation beam 30 in the beam width direction (arrow Y direction). Further, the two through holes 40 are formed adjacent to each other in the span direction (arrow X direction, material axis direction) of the foundation beam 30.

[0035] As shown in FIG. 3, the two through holes 40 are formed in a groove shape extending in the beam width direction on the lower surface (lower end) 30L of the foundation beam 30, and are formed along the upper surface of the waste concrete 18. In other words, each through hole 40 is a rectangular through hole closed by the upper surface of the waste concrete 18.

[0036] As shown in FIG. 4, each through hole 40 is formed by a disposable formwork 42 embedded on the lower end side of the beam middle part 30M. The disposable formwork 42 is a buried formwork that is not removed after the construction of the foundation beam 30 and is buried on the lower end side of the foundation beam 30.

[0037] The disposable formwork 42 is formed by a channel steel with an open bottom. Further, the overall length (material axis length) of the disposable formwork 42 is substantially the same as the beam width of the foundation beam 30, and it is buried on the lower end side of the foundation beam 30 so as not to protrude in the beam width direction from the side surface of the foundation beam 30. Each disposable formwork 42 has a pair of flange portions 42A facing each other in the span direction of the foundation beam 30, and a web portion 42B connecting the upper end portions of the pair of flange portions 42A.

[0038] The two disposable formworks 42 are arranged in parallel in the span direction of the foundation beam 30. More specifically, the two disposable formworks 42 are arranged in a state where the outer surfaces of the respective flange portions 42A are overlapped with each other. Through holes 40 are respectively formed inside these disposable formworks 42. Note that the disposable formwork 42 is not limited to two, and at least one can be provided.

[0039] Here, as described above, the foundation beam 30 is made of reinforced concrete. This foundation beam 30 has a concrete beam 32, a plurality of upper beam main reinforcements 50, a plurality of lower beam main reinforcements 52, and a plurality of shear reinforcement bars 54 embedded inside the concrete beam 32.

[0040] The plurality of shear reinforcement bars 54 are arranged at intervals in the span direction of the foundation beam 30 and surround the plurality of upper beam main reinforcements 50 and the plurality of lower beam main reinforcements 52.

[0041] (Upper beam main reinforcement) The plurality of upper beam main reinforcements 50 are embedded on the upper end side of the foundation beam 30 (concrete beam 32). Further, the plurality of upper beam main reinforcements 50 are arranged along the span direction (material axis direction) of the foundation beam 30 and are arranged at intervals in the beam width direction of the foundation beam 30.

[0042] Each upper beam main reinforcement 50 is a continuous bar arranged above the two through holes 40. That is, each upper beam main reinforcement 50 is embedded over the entire length in the span direction of the foundation beam 30 and extends across adjacent footings 14.

[0043] In this embodiment, the upper beam main reinforcements 50 are arranged in one layer, but the upper beam main reinforcements 50 may be arranged in multiple layers of two or more layers. Further, the upper beam main reinforcements 50 may include cutoff bars.

[0044] (Lower beam main reinforcement) The plurality of lower beam main reinforcements 52 are embedded on the lower end side of the foundation beam 30 (concrete beam 32). Further, they are arranged along the span direction (material axis direction) of the foundation beam 30 and are arranged at intervals in the beam width direction of the foundation beam 30.

[0045] Here, the lower beam main reinforcements 52 are arranged in two layers. Therefore, hereinafter, the first - stage lower beam main reinforcement 52 will be described as the lower first - stage bar 52A, and the second - stage lower beam main reinforcement 52 will be described as the lower second - stage bar 52B.

[0046] The plurality of lower-end two-stage bars 52B are continuous bars arranged above the two through holes 40. That is, each lower-end two-stage bar 52B is embedded over the entire length in the span direction of the foundation beam 30 and extends across adjacent footings 14.

[0047] On the other hand, the plurality of lower-end one-stage bars 52A are arranged below the upper ends of the two through holes 40 (the disposable formwork 42) and are cutoff bars cutoff in front of the through holes 40. That is, the lower-end one-stage bars 52A are embedded across the beam end portion 30E and the beam middle portion 30M of the foundation beam 30.

[0048] One end side (not shown) of the lower-end one-stage bar 52A is embedded in the footing 14. On the other hand, the other end portion 52A1 of the lower-end one-stage bar 52A is embedded in the beam middle portion 30M and faces the disposable formwork 42 in the span direction. Further, the lower-end one-stage bars 52A are arranged (reinforced) on both sides in the span direction of the foundation beam 30 with respect to the two through holes 40. In other words, the lower-end one-stage bars 52A are divided by the two through holes 40 in the beam middle portion 30M of the foundation beam 30.

[0049] Note that the lower-end one-stage bars 52A are embedded at least in the beam end portion 30E so that the fixing length with respect to the foundation beam 30 is equal to or greater than the required fixing length. Therefore, the interval between the other end portion 52A1 of the lower-end one-stage bar 52A and the through hole 40 (the disposable formwork 42) is appropriately changed according to the required fixing length of the lower-end one-stage bar 52A with respect to the foundation beam 30.

[0050] (Function and Effect) Next, the function and effect of the present embodiment will be described.

[0051] According to the present embodiment, the foundation beam 30 is made of reinforced concrete. In this foundation beam 30, the lower-end two-stage bars 52B of the lower-end beam main reinforcement 52 are continuous bars. On the other hand, the lower-end one-stage bars 52A of the lower-end beam main reinforcement 52 are cutoff bars embedded across the beam end portion 30E and the beam middle portion 30M.

[0052] Thus, in this embodiment, by using the lower one - layer bars 52A of the lower - end beam main reinforcement 52 as cutoff bars, while simplifying the reinforcement arrangement of the lower - end beam main reinforcement 52, two through - holes 40 can be formed on the lower - end side in the middle part 30M of the foundation beam 30.

[0053] Also, in this embodiment, by using the lower one - layer bars 52A of the lower - end beam main reinforcement 52 as continuous bars passing through the upper side of the through - holes 40 and the lower two - layer bars 52B of the lower - end beam main reinforcement 52 as cutoff bars arranged on both sides of the through - holes 40, while simplifying the reinforcement arrangement of the lower - end beam main reinforcement 52, the tensile strength on the lower - end side of the foundation beam 30 can be reasonably ensured.

[0054] Furthermore, in this embodiment, two through - holes 40 are formed on the lower - end side in the central part of the foundation beam 30. Thereby, in this embodiment, for example, compared with the case where two through - holes 40 are formed at positions deviated from the central part of the foundation beam 30, the fixing length of the lower one - layer bars 52A with respect to the foundation beam 30 can be easily ensured. Therefore, the tensile strength on the lower - end side of the foundation beam 30 can be increased.

[0055] Here, FIG. 5 shows a foundation beam 100 according to a comparative example. In the foundation beam 100 according to the comparative example, through - holes 110 are respectively formed on the lower - end side at the beam ends 100E. The foundation beam 100 according to this comparative example is constructed as follows, for example.

[0056] That is, first, at the beam ends 100E of the foundation beam 100, a half - split communication pipe 112 serving as a disposable formwork for the through - hole 110 is installed on the disposable concrete 18.

[0057] Next, concrete is over - poured on the disposable concrete 18 to form an over - poured part 104 with the height of the communication pipe 112. At this time, the over - poured part 104 is formed with the same thickness over the entire length of the foundation beam 100 in the span direction. The step difference between the communication pipe 112 and the disposable concrete 18 is absorbed by this over - poured part 104.

[0058] Next, the upper beam main reinforcement 120, the lower beam main reinforcement 122, the shear reinforcement 124, etc. are arranged on the additional casting part 104, and the concrete for the concrete beam 102 is placed. Thereby, the foundation beam 100 having the through hole 110 formed on the lower end side at the beam end 30E is constructed.

[0059] Here, in order to make the level (top end level) of the upper surface 100U of the foundation beam 100 according to the comparative example and the beam height H the same as the level of the upper surface 30U of the foundation beam 30 according to the present embodiment and the beam height H, excavation for the additional casting part 104 occurs, which is laborious and costly.

[0060] On the other hand, in the foundation beam 30 according to the present embodiment, as shown in FIG. 3, two through holes 40 are formed on the lower end side of the beam middle part 30M. And on both sides of the two through holes 40, the lower end one - step bars 52A of the lower beam main reinforcement 52 are arranged.

[0061] Thus, in the present embodiment, by forming the through hole 40 on the lower end side in the beam middle part 30M of the foundation beam 30 and using the lower end one - step bar 52A of the lower beam main reinforcement 52 as a cut - off bar, the additional casting part 104 like the foundation beam 100 according to the comparative example becomes unnecessary, and the excavation for the additional casting part 104 becomes unnecessary.

[0062] Therefore, in the present embodiment, the constructability of the foundation beam 30 is improved and the cost can be reduced.

[0063] Also, in the present embodiment, the through hole 40 is formed by the disposable formwork 42 embedded on the lower end side of the beam middle part 30M of the foundation beam 30. By forming the through hole 40 with the disposable formwork 42 in this way, the removal of the formwork becomes unnecessary, so the constructability of the through hole 40 is further improved.

[0064] Further, the disposable formwork 42 has an opening at the lower part and is composed of a plurality of channel steels arranged in parallel in the span direction. Thereby, with a simple structure, the through hole 40 can be formed on the lower end side in the beam middle part 30M of the foundation beam 30.

[0065] Furthermore, in the present embodiment, two through holes 40 are formed on the lower end side of the middle portion 30M of the foundation beam 30. Thereby, in the present embodiment, clogging of the through hole 40 and the like are suppressed as compared with the case where one through hole 40 is formed on the lower end side of the middle portion 30M of the foundation beam 30.

[0066] (Modification example) Next, a modification example of the above embodiment will be described.

[0067] In the above embodiment, two through holes 40 are formed on the lower end side of the central portion of the foundation beam 30. However, the number of through holes 40 is not limited to two, and may be three or more, or even one. That is, at least one through hole 40 can be formed in the middle portion 30M of the foundation beam 30.

[0068] Also, in the above embodiment, two through holes 40 are formed on the lower end side of the central portion of the foundation beam 30. However, the through holes 40 may be formed in the middle portion 30M of the foundation beam 30, and may be arranged at a position deviated from the central portion of the beam.

[0069] Also, in the above embodiment, the disposable formwork 42 for forming the through hole 40 is made of a channel steel. However, the disposable formwork 42 is not limited to a C-shaped steel, and may be, for example, a C-shaped steel, a half-cut cylindrical pipe, or two L-shaped steels combined in a C-shaped cross-section.

[0070] Also, in the above embodiment, the through hole 40 is formed by the disposable formwork 42. However, the through hole 40 is not limited to the disposable formwork 42, and may be formed by an existing formwork or the like.

[0071] Also, in the above embodiment, the through hole 40 is used as a water passage hole. However, the through hole may be, for example, an equipment hole for passing wiring, piping, etc. Also, when the foundation beam is a drop hunch, the through hole may be a through hole for making the beam formation in the middle portion of the foundation beam lower than the beam end portion.

[0072] In the above-described embodiment, the through hole 40 is formed on the lower end side in the beam intermediate portion 30M of the foundation beam 30. However, on the lower end side in the beam intermediate portion 30M of the foundation beam 30, not limited to the through hole 40, for example, a recess that does not penetrate the foundation beam 30 in the beam forming direction may be formed. Further, on the lower end side in the beam intermediate portion 30M of the foundation beam 30, not limited to the through hole or the recess, for example, an interference object (obstacle) or the like may be embedded. In this case, the lower end first-stage bar 52A of the lower end beam main bars 52 is cut off, for example, in front of the interference object.

[0073] In the above-described embodiment, among the multi-stage lower end beam main bars 52, the lower end second-stage bar 52B is used as a continuous bar, and the lower end first-stage bar 52A is used as a cut-off bar. However, for example, when the upper end beam main bars of the foundation beam 30 are multi-stage, the second-stage upper end beam main bar may be used as a continuous bar, and the first-stage upper end beam main bar may be used as a cut-off bar embedded at least at the beam end portion.

[0074] Thereby, while simplifying the reinforcement arrangement of the upper end beam main bars, for example, a through hole or a recess for passing equipment piping or the like can be formed on the upper end side in the beam intermediate portion 30M of the foundation beam 30, or an interference object (obstacle) or the like can be embedded. Also, it is possible to form a partial underfloor lowering portion on the upper end side in the beam intermediate portion 30M of the foundation beam 30.

[0075] In the above-described embodiment, the foundation beam 30 is made of reinforced concrete. However, the foundation beam according to the above-described embodiment is not limited to the reinforced concrete structure, and may be a steel-reinforced concrete structure.

[0076] As described above, one embodiment of the present invention has been described. However, the present invention is not limited to such an embodiment, and one embodiment and various modifications may be used in appropriate combination, and it goes without saying that the present invention can be implemented in various modes without departing from the gist of the present invention.

Explanation of Reference Numerals

[0077] 30 Foundation beam 30E Beam end portion 30L Lower surface 30M Beam intermediate portion 40 Through-hole 42 Disposable form 52 Main reinforcement bars of the lower end beam 52A Lower end first-stage bars (the first-stage main reinforcement bars of the lower end beam) 52B Lower end second-stage bars (the second-stage main reinforcement bars of the lower end beam) Arrow X Span direction of the foundation beam

Claims

1. A foundation beam made of reinforced concrete or steel-reinforced concrete, among the main bars of the lower-end beams in multiple stages, the main bar of the second-stage lower-end beam is used as a continuous bar, and the main bar of the first-stage lower-end beam is used as a cutoff bar buried at least at the beam end, foundation beam.

2. A through hole extending in the beam width direction is formed on the lower end side in the middle of the beam, the main bar of the second-stage lower-end beam is arranged above the through hole, the main bar of the first-stage lower-end beam is arranged on both sides of the through hole, The foundation beam according to Claim 1.

3. The through hole is formed by a disposable formwork buried on the lower end side of the middle part of the beam, The foundation beam according to Claim 2.

4. The disposable formwork has an opening at the bottom and is made of a plurality of channel steels arranged in parallel in the span direction, The foundation beam according to Claim 3.

5. A foundation beam made of reinforced concrete or steel-reinforced concrete, among the main bars of the upper-end beams in multiple stages, the main bar of the second-stage upper-end beam is used as a continuous bar, and the main bar of the first-stage upper-end beam is used as a cutoff bar buried at least at the beam end, foundation beam.

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