Precast structure, rooftop structure, and construction method of rooftop structure

Abstract

To shorten a construction period when a frame-like structure is formed on a rooftop.SOLUTION: A precast structure 20 has a wall body 22 made of precast concrete formed in a frame shape in plan view, a convex part 22A and a concave part 22B which are alternately formed over the lower end face F1 of the wall body 22 and project downward, and a reinforcing bar 30 which projects laterally from the side face of the convex part 22A.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a precast structure, a roof structure and a method for constructing a roof structure. [Background technology]

[0002] Conventionally, in order to shorten the construction period of a building, a structure constructed in advance using precast concrete is sometimes integrated with the building frame at the construction site. For example, in winter construction in cold regions, this technique is sometimes used to avoid working during snowfall.

[0003] As an example of such a technique, Patent Document 1 below discloses a technique in which a precast concrete roof parapet is fabricated on-site, and then lifted by a crane to be integrated with the concrete roof framework of the building. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-156706 Summary of the Invention [Problem to be solved by the invention]

[0005] In the technology disclosed in the above-mentioned Patent Document 1, separate parapets are fabricated in a collapsed position, with rebars embedded in the concrete skeleton protruding from them, and these parapets are then integrated with the skeleton on the top floor of the building.

[0006] However, this technology is difficult to apply to structures with frame-shaped walls. Frame-shaped walls are larger in volume and weight than divided parapets, so if they are constructed in a collapsed or inverted position, it is difficult to return them to the upright position (the position in which they are installed on the building). This makes construction management time-consuming.

[0007] It is also possible to divide the wall into multiple precast members, but in this case, these precast members must be joined on the roof. Therefore, even with this method, construction management is time-consuming. In addition, the fitting of the joints becomes complicated, making the manufacturing of the precast members more difficult.

[0008] In consideration of the above, the present invention aims to shorten the construction period when forming a frame-shaped structure on a roof. [Means for solving the problem]

[0009] The precast structure of claim 1 comprises a precast concrete wall formed in a frame shape when viewed from above, downwardly protruding convex and concave portions alternately formed across the lower end surface of the wall, and reinforcing bars protruding laterally from the side surfaces of the convex portions.

[0010] In the precast structure of claim 1, when the convex part is placed on the rooftop skeleton of a building and slab concrete is poured so that the convex part is buried, the rebar protruding from the convex part is arranged in the slab, thereby integrating the precast structure with the building.

[0011] In addition, by placing the slab reinforcement on the building's roof through the recessed parts, a gap joint is formed between the reinforcing bars protruding from the convex parts, thereby increasing the unity between the precast structure and the building.

[0012] Furthermore, because the convex portion extends across the bottom surface of the wall, the load is distributed when the precast structure is placed on the rooftop skeleton of a building.Similarly, because the concave portion extends across the bottom surface of the wall, it is easy to arrange slab reinforcement.

[0013] In this way, this precast structure can be integrated with the building in the assembled position. Therefore, there is no need to re-erect it from the assembled position as in the conventional technology. Furthermore, since this precast structure is not formed by dividing it into multiple precast members, there is no need to join multiple precast members on the roof. Therefore, the construction period when building a frame-shaped structure on a roof can be shortened.

[0014] A precast structure according to claim 2 is the precast structure according to claim 1, wherein the reinforcing bars protrude toward the inside of the wall body.

[0015] In the precast structure of claim 2, the reinforcing bars protrude toward the inside of the wall, so when lifted using a crane, the reinforcing bars are less likely to interfere with other structures. This makes construction easier than when the reinforcing bars protrude toward the outside of the wall.

[0016] A precast structure according to claim 3 is the precast structure according to claim 1 or 2, wherein the lower end surface is inclined.

[0017] The precast structure of claim 3 has a slope formed on the bottom end surface of the wall. Therefore, when the precast structure is placed along the water gradient of the roof slab, the wall can be installed vertically.

[0018] The rooftop structure of claim 4 comprises a precast structure according to any one of claims 1 to 3, slab reinforcement arranged in the recess to form a gap lap joint with the reinforcing steel, and slab concrete poured into the recess to bury the protrusion.

[0019] The rooftop structure of claim 4 provides the same effects as the precast structure of any one of claims 1 to 3.

[0020] The method for constructing a rooftop structure of claim 5 comprises the steps of pouring concrete into a formwork to construct a frame-shaped wall in a plan view in an upright position in the vertical direction, with convex and concave portions protruding downwardly alternating across the bottom surface and with reinforcing bars protruding laterally from the sides of the convex portions; lifting the wall and installing it on the roof of a building; arranging the slab reinforcement on the roof of the building through the concave portions; and pouring the slab concrete on the roof.

[0021] The rooftop structure construction method of claim 5 provides the same effects as the precast structure of any one of claims 1 to 3. [Effects of the Invention]

[0022] According to the present invention, the construction period when forming a frame-shaped structure on a roof can be shortened. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1A is a side view showing a precast structure according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line BB of FIG. [Figure 2] FIG. 1A is a partially enlarged cross-sectional view showing a method for manufacturing a precast structure according to an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line BB in FIG. [Figure 3] (A) is a side view showing a precast structure according to an embodiment of the present invention placed on the beams of a building and slab reinforcement arranged therein, and (B) is a cross-sectional view along line BB of (A). [Figure 4] FIG. 1A is a side view showing a state in which a precast structure according to an embodiment of the present invention is integrated with a building, and FIG. 1B is a cross-sectional view taken along line BB of FIG. [Figure 5] 1A is an enlarged side view of a convex portion and a concave portion of a wall body, and FIG. 1B is a side view partially showing an example of an embodiment in which the lower end surface of the wall body is not inclined. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, a precast structure, a rooftop structure, and a method for constructing a rooftop structure according to an embodiment of the present invention will be described with reference to the drawings. Components indicated with the same reference numerals in each drawing are the same components. However, unless otherwise specified in the specification, each component is not limited to one, and may be present in multiple numbers.

[0025] Furthermore, descriptions of overlapping configurations and symbols in each drawing may be omitted. Note that the present disclosure is not limited to the following embodiments, and may be implemented by making appropriate modifications, such as omitting configurations, replacing them with different configurations, or combining one embodiment with various modified examples, within the scope of the purpose of the present disclosure.

[0026] In each drawing, the directions indicated by arrows X and Y are directions along the horizontal plane and are perpendicular to each other. The direction indicated by arrow Z is a direction along the vertical direction (up and down). In each drawing, the directions indicated by arrows X, Y, and Z are assumed to be consistent with each other.

[0027] <Precast Structures> 1(A) and 1(B) show a structure 20 according to an embodiment of the present invention. The structure 20 is a box-shaped structure installed on the roof of a building 10, and is also called a pigeon coop or the like. The structure 20 is a precast concrete structure (precast structure) fabricated in a factory or the fabrication yard of the building 10.

[0028] The structure 20 is formed with walls 22 and a roof 24. As shown in Fig. 1(B), the walls 22 are formed in a frame shape in a plan view. The roof 24 is a flat plate erected above the walls 22.

[0029] Convex portions 22A and concave portions 22B that protrude downward are formed on the lower end surface F1 of the wall body 22. The concave portions 22B are spaces sandwiched between adjacent convex portions 22A. The convex portions 22A and the concave portions 22B are alternately formed across the lower end surface F1 of the wall body 22.

[0030] Reinforcing bars 30 are arranged in the vertical direction inside wall body 22. The lower ends of these reinforcing bars 30 are bent laterally at protrusions 22A, and protrude laterally from the side surfaces of protrusions 22A toward the inside of wall body 22.

[0031] It should be noted that reinforcing bars are also arranged inside the wall body 22 along the horizontal direction, but illustration and description of these reinforcing bars are omitted.

[0032] The lower end surface F1 of the wall 22 is inclined. While the wall 22 is aligned in the up-down direction (vertical direction), the lower end surface F1 is inclined at an angle θ with respect to the lateral direction (horizontal direction and direction along the wall 22). The lower end surface F2 of the protrusion 22A also has a similar inclination to the lower end surface F1. These inclinations are at an angle equal to the water gradient of the roof surface of the building 10 on which the structure 20 is installed.

[0033] <Manufacturing method of precast structures> The structure 20 is manufactured in an upright position in a factory or in the manufacturing yard of the building 10. "Upright position" refers to the position in which the structure 20 is installed on the building 10. In other words, the structure 20 is not manufactured upside down so that the bottom end surface F1 of the wall 22 is positioned upward, nor is it manufactured in a lying position so that the wall 22 is aligned horizontally. The structure 20 is manufactured in the position shown in FIG. 1(A) and is lifted onto the roof of the building 10 in this position.

[0034] To manufacture the structure 20, a formwork 40 is constructed as shown in Figures 2(A) and 2(B). The formwork 40 is formed using a bottom plate 42, side plates 44, beam members 46, and bottom support members 48.

[0035] The bottom plate 42 is a formwork material that forms the lower end surface F2 of the protrusion 22A shown in Figure 1. A plurality of beams 46 are placed below the bottom plate 42. The beams 46 each have a different height, and by placing the bottom plate 42 on these beams 46, an inclination of angle θ is formed in the bottom plate 42.

[0036] Furthermore, a plurality of bottom-raising members 48 are arranged on the upper surface of the bottom plate 42. When viewed from the side (as viewed from a direction along the in-plane direction of the bottom plate 42), the bottom-raising members 48 are parallelogram-shaped blocks whose lower and upper end faces are inclined at an angle θ, and are formed using a foam material such as Styrofoam (registered trademark). The bottom-raising members 48 are arranged at intervals on the upper surface of the bottom plate 42.

[0037] When constructing the formwork 40, the reinforcing bars 30 are arranged. The reinforcing bars 30 are placed in a position sandwiched between two side plates 44, and are arranged so that their lower ends penetrate the side plates 44. Through holes for passing the reinforcing bars 30 through are formed in the side plates 44 in advance, and when the reinforcing bars 30 are inserted, the gaps between the reinforcing bars 30 and the through holes are sealed using a stopper material or the like.

[0038] After the formwork 40 is constructed, concrete is poured inside the formwork 40. By pouring concrete into the spaces formed between the bottom-up members 48, the convex portions 22A shown in Fig. 1 are formed. Furthermore, by removing the bottom-up members 48 after pouring the concrete, the concave portions 22B are formed between the convex portions 22A.

[0039] By the above steps, as shown in Figure 1, convex portions 22A and concave portions 22B that protrude downward are formed alternately across the lower end surface F1, and reinforcing bars 30 protrude laterally from the side surfaces of the convex portions 22A, thereby constructing a frame-shaped wall body 22 in a normal vertical position when viewed from above.

[0040] <How to build a rooftop structure> The structure 20 becomes a rooftop structure of the building 10 by being installed on the roof of the building 10. In order to install the structure 20 on the roof of the building 10, the structure 20 is first lifted in an upright position and placed on the roof of the building 10 as shown in Figure 3(A).

[0041] In this case, the structure 20 is supported by beams 12 and the like that constitute the skeleton of the building 10. In Fig. 3, only two beams 12 are shown as the supporting skeleton of the structure 20, but the structure 20 may be supported by three or more beams 12, or by sub-beams (not shown) that are spanned between the beams 12.

[0042] Furthermore, when the structure 20 is supported by the beams 12 or the like, a spacer or the like may be provided between the structure 20 and the beams 12 or the like as appropriate.

[0043] Next, the slab reinforcement 50 on the roof of the building 10 is placed through the recess 22B. A gap lap joint is formed between the slab reinforcement 50 and the reinforcing bars 30 inside the wall 22. The protruding length of the reinforcing bars 30 from the protrusion 22A is set to a length that allows stress to be transmitted between the slab reinforcement 50 passed through the recess 22B and the reinforcing bars 30 via the gap lap joint.

[0044] Next, the rooftop slab concrete 14 is poured, thereby installing the structure 20 integrally with the building 10, as shown in FIG.

[0045] In other words, a rooftop structure is constructed having a structure 20, slab reinforcement 50 that is placed in the recess 22B of the structure 20 to form an open lap joint with the reinforcing bar 30, and slab concrete 14 that is poured into the recess 22B and buries the protrusion 22A.

[0046] <Effects> As shown in Fig. 3(A), the structure 20 according to the embodiment of the present invention can be placed with the protruding portion 22A on the rooftop skeleton (e.g., beam 12) of the building 10. Then, as shown in Fig. 4(A), if the slab concrete 14 is poured so that the protruding portion 22A is buried, the reinforcing bars 30 protruding from the protruding portion 22A are arranged in the slab. This allows the structure 20 to be integrated with the building 10.

[0047] In addition, by arranging the slab reinforcement 50 on the roof of the building 10 through the recess 22B, a gap lap joint is formed with the reinforcing bars 30 protruding from the protrusion 22A, thereby enhancing the unity between the structure 20 and the building 10.

[0048] Furthermore, since the protrusions 22A are formed across the lower end surface F1 of the wall body 22, the load is dispersed when the structure 20 is placed on the beams 12 that serve as the rooftop skeleton of the building 10. For example, since the multiple protrusions 22A aligned in the depth direction of the page in Fig. 3(A) are placed on the beams 12 whose longitudinal direction is the depth direction of the page, the load is dispersed.

[0049] Furthermore, since the recess 22B is also formed across the lower end face F1 of the wall body 22, it is easy to arrange the slab reinforcement 50 across the inside and outside of the wall body 22, as shown in FIG. 3(B).

[0050] In this way, the structure 20 can be integrated with the building 10 in the position in which it was constructed. Therefore, there is no need to re-erect it from the position in which it was constructed to the correct position as in the prior art. Furthermore, since the structure 20 is not formed by dividing it into multiple precast members, there is no need to join multiple precast members on the roof of the building 10. Therefore, the construction period can be shortened compared to when multiple precast members are joined on the roof of the building 10.

[0051] Furthermore, in the structure 20 according to the embodiment of the present invention, the reinforcing bars 30 protrude toward the inside of the wall body 22, so when the structure is lifted using a crane, the reinforcing bars 30 are less likely to interfere with other structures. This makes the structure easier to construct than when the reinforcing bars 30 protrude toward the outside of the wall body 22.

[0052] Furthermore, since the reinforcing bars 30 protrude laterally from the side surfaces of the protrusions 22A, it is easier to form a formwork compared to when the reinforcing bars 30 protrude downward from the lower end surface F1 of the wall body 22 (to the recesses 22B), for example.

[0053] Furthermore, in the structure 20 according to the embodiment of the present invention, a slope is formed on the lower end surface of the wall 22. Therefore, when the structure 20 is placed along the water gradient of the roof slab, the wall 22 can be installed vertically.

[0054] Furthermore, such a slope can be formed, for example, by providing a slope using beams 46 on the bottom plate 42 of the formwork 40 for constructing the structure 20. On the other hand, if the structure 20 is constructed in an inverted position, upside down, it is difficult to form such a slope.

[0055] <Other embodiments> In the above embodiment, the reinforcing bars 30 protrude toward the inside of the wall body 22. However, the present invention is not limited to this embodiment. For example, the reinforcing bars 30 may protrude toward the outside of the wall body 22. Even when the reinforcing bars 30 are formed in this manner, they can form gap lap joints with the slab reinforcement 50.

[0056] In the above embodiment, both the lower end surface F1 of the wall body 22 and the lower end surface F2 of the protrusion 22A are inclined, but the present invention is not limited to this. For example, as shown by the dashed line in Fig. 5(A), both or either one of the lower end surface F1 of the wall body 22 and the lower end surface F2 of the protrusion 22A may be formed along the horizontal direction.

[0057] In both the example shown in FIG. 1 etc. and the example shown in FIG. 5(A), if the straight line CL connecting the centers O of the convex portions 22A is inclined, it can accommodate the water gradient on the roof of the building 10.

[0058] In addition, if no water gradient is formed on the roof of the building 10, or if there is a water gradient but it is small, the straight line CL connecting the centers O of the convex portions 22A does not need to be inclined, as shown in Figure 5(B). In this way, the present invention can be implemented in various modes. [Explanation of symbols]

[0059] 10 Building 14 Slab concrete 20 Structures (precast structures) 22 Wall 22A convex part 22B Recess 30 Reinforced concrete 40 Formwork 50 Slab Reinforcement F1 Lower end surface

Claims

1. A precast concrete wall formed into a frame shape in plan view; downwardly protruding convex portions and concave portions alternately formed on the lower end surface of the wall body; A reinforcing bar protruding laterally from a side surface of the protrusion; A precast structure having:

2. The reinforcing bar protrudes toward the inside of the wall body.

2. The precast structure of claim 1.

3. The lower end surface has an inclination. A precast structure according to claim 1 or 2.

4. A precast structure according to any one of claims 1 to 3; A slab reinforcement arranged in the recess to form an open lap joint with the reinforcing bar; and a slab concrete that is poured into the recessed portion and that embeds the protruding portion. Rooftop structure.

5. A process of pouring concrete into the formwork to construct a wall body that is frame-shaped in plan view in a normal vertical position, the wall body having alternating convex and concave portions that protrude downward across the bottom end surface and reinforcing bars that protrude laterally from the side surfaces of the convex portions; Lifting the wall body and installing it on the roof of a building; A step of placing slab reinforcement on the roof of the building through the recess; Pouring the rooftop slab concrete; A method for constructing a rooftop structure comprising:

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