Half-precast beams and their manufacturing method

Abstract

To provide a half-precast beam and a method for manufacturing it that can reduce the labor involved in setting up and removing formwork, eliminate or reduce the labor required for reinforcing beams, and improve quality. [Solution] The first reinforced precast concrete slab 50A has multiple first reinforcing bars 10A, with first vertical bars 11A embedded in the first precast concrete slab 20A at intervals and upper main bars 30 attached, and the second reinforced precast concrete slab 50B has multiple second reinforcement bars 10B, with second vertical bars 11B embedded in the second precast concrete slab 20B at intervals and lower main bars 40 attached, and the first upper horizontal bar 12A and second upper hook 13B are crossed, and the second lower horizontal bar 14B and first lower hook 15A are crossed, and a post-cast concrete body 60 is provided in the gap G between the first precast concrete slab 20A and the second precast concrete slab 20B to form a half precast beam 100.

Description

Technical Field

[0001] The present invention relates to a half-precast beam and a method for manufacturing the same.

Background Art

[0002] When constructing upper floor beams and foundation beams made of RC (Reinforced Concrete) in a building site (hereinafter referred to as reinforced concrete beams), in order to save labor in installing temporary members and improve workability, a pair of PCa (Precast) concrete slabs manufactured in a factory or the like are installed with a gap at the beam construction position on the site, beam reinforcement is arranged in the gap, and concrete is placed in the gap while using the precast concrete slab as a formwork (side formwork) to construct the reinforced concrete beam. This method may be applied.

[0003] Thus, since a part of the reinforced concrete beam is formed by the precast concrete slab, the reinforced concrete beam constructed by such a construction method can be called a half-precast beam. By applying the half-precast beam, labor can be saved when installing the formwork by using the precast concrete slab as a formwork, and since the precast concrete slab remains as a component of the half-precast beam, labor can also be saved when demolding. Furthermore, the formwork can be included in the cover thickness of the reinforcement, the precast part can be expected to have structural strength, and since the precast concrete slab is factory-made, problems such as concrete janka and cracking, which are problems when the entire reinforced concrete beam is fabricated on-site (constructed on-site), can be suppressed, and by ensuring the reinforcement accuracy, the quality can be improved. Also, in the so-called full-precast beam where the entire reinforced concrete beam is formed by the precast concrete slab, the weight becomes heavy, the transportability decreases, and a heavy crane with a large capacity is required during construction, so the construction cost tends to increase. However, by applying the half-precast beam, these problems can be solved.

[0004] Here, Patent Document 1 proposes a method for constructing beams. This method for constructing a reinforced concrete foundation beam involves embedding the main reinforcement bars at the bottom of the beam in the longitudinal direction and the stirrup bars in the short direction, while precast plates are fabricated in advance with one end of the stirrup bars exposed from the side to form a stirrup anchorage section and the other end exposed from the top surface. A pair of precast plates are then placed vertically on a concrete slab for the floor so that the exposed sides of the stirrup anchorage sections face each other. Intermediate beam reinforcement bars are placed in the space formed by the opposing placement of the pair of precast plates to satisfy the required amount of main reinforcement bars and shear reinforcement bars, and concrete is poured into the space to anchor the intermediate beam reinforcement bars and stirrup anchorage sections in the concrete, thereby constructing the foundation beam. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2016-79695 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] According to the beam construction method described in Patent Document 1, when constructing reinforced concrete beams, the work related to beam formwork at the construction site can be significantly reduced, thereby achieving labor savings in on-site work.

[0007] Incidentally, while the application of half-precast beams significantly improves labor savings during formwork installation and removal as described above, the effort required for reinforcing the beams within the formwork remains. When using half-precast beams, precast concrete panels that function as formwork may be installed in advance at the left and right positions of the beam reinforcement work space, prior to the reinforcement work. This can reduce the work efficiency and safety of the reinforcement work, and although labor savings can be achieved during formwork installation and removal, there is still room for improvement in terms of overall work efficiency, including the reinforcement work.

[0008] This invention has been made in view of the above problems, and aims to provide a half-precast beam and a method for manufacturing the same, which can reduce the labor required for setting up and removing formwork by using precast concrete slabs that constitute the half-precast beam, eliminate or reduce the labor required for reinforcing the beam, and improve quality. [Means for solving the problem]

[0009] To achieve the above objective, one embodiment of the half-precast beam according to the present invention is: A first reinforced concrete slab, comprising a first vertical bar, a first upper transverse bar that bends at the upper end of the first vertical bar and extends laterally, a first upper hook that bends at the end of the first upper transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a first lower hook that bends at the lower end of the first vertical bar and extends upward, each of the first vertical bars of the multiple first reinforcing bars is embedded at intervals along the longitudinal direction of the first precast concrete slab, and upper main bars extending along the longitudinal direction are attached below the multiple first upper transverse bars, The second reinforcement bar is a precast concrete slab with a second reinforcement bar, each of which is embedded at intervals along the longitudinal direction of the second precast concrete slab, and a lower main reinforcement bar extending along the longitudinal direction is attached above the multiple lower reinforcement bars, each of which is embedded at intervals along the longitudinal direction of the second precast concrete slab, and a lower main reinforcement bar extending along the longitudinal direction is attached above the multiple lower reinforcement bars, the second vertical reinforcement bar is bent at the lower end of the second vertical reinforcement bar and extends laterally, the second lower hook is a 90-degree hook, a 135-degree hook, or a 180-degree hook that bends at the end of the second lower horizontal reinforcement bar and extends downward, forming a substantially L-shape. The first precast concrete slab and the second precast concrete slab are arranged with a gap between them, with the first upper horizontal reinforcement and the second upper hook intersecting, and the second lower horizontal reinforcement and the first lower hook intersecting, and a post-cast concrete body provided in the gap.

[0010] According to this embodiment, a first reinforced precast concrete slab, in which each of the first longitudinal bars constituting a plurality of roughly L-shaped first reinforcing bars is embedded, and a second reinforced precast concrete slab, in which each of the second longitudinal bars constituting a plurality of roughly L-shaped second reinforcing bars is embedded, are arranged with gaps between them, with the first upper transverse bars and second upper hooks constituting the first and second reinforcing bars respectively intersecting, and the second lower transverse bars and first lower hooks intersecting, and a post-cast concrete body is provided in the gaps. As a result, when the first reinforced precast concrete slab and the second reinforced precast concrete slab are installed, the beam reinforcement is automatically arranged. Therefore, the first and second precast concrete slabs reduce the labor required for formwork installation and removal, eliminate or reduce the labor required for beam reinforcement, and ensure quality because they are factory-made.

[0011] Here, "approximately L-shaped" refers to a configuration in which 90-degree hooks, 135-degree hooks, and 180-degree hooks are provided at both ends of an L-shaped reinforcing bar consisting of a first vertical bar and a first upper horizontal bar, or at both ends of an L-shaped reinforcing bar consisting of a second vertical bar and a second lower horizontal bar, respectively.

[0012] Furthermore, by intersecting the first and second reinforcing bars of the first reinforced precast concrete slab and the second reinforced precast concrete slab, a half-precast beam can be formed that has high torsional strength and ensures ductility due to the expected sufficient restraint area.

[0013] Herein, the half-precast beam of this embodiment can be applied to the beams of the upper floors and foundation beams that make up a building. When the beam width is small, it is extremely difficult for workers to enter the pair of precast concrete slabs to perform reinforcement work, and even in the case of foundation beams with a beam depth of about 2m to 3m, it is difficult to perform reinforcement work on the beam by entering the pair of precast concrete slabs. Therefore, being able to eliminate or reduce the labor required for reinforcement work by entering the first and second precast concrete slabs is desirable as it significantly improves the constructability of the foundation beam.

[0014] Furthermore, other embodiments of the half-precast beam according to the present invention include: In the first precast concrete slab, some of the upper main reinforcement bars of the multiple upper main reinforcement bars are embedded, The second precast concrete slab is characterized in that some of the lower main reinforcement bars among the multiple lower main reinforcement bars are embedded within it.

[0015] According to this embodiment, a portion of the upper main reinforcement bars (for example, one upper main reinforcement bar) of the multiple upper main reinforcement bars is embedded in the first precast concrete slab, and a portion of the lower main reinforcement bars (for example, one lower main reinforcement bar) of the multiple lower main reinforcement bars is embedded in the second precast concrete slab. As a result, in addition to the first and second longitudinal reinforcement bars that constitute the first and second reinforcing bars, a portion of the upper and lower main reinforcement bars is embedded in the first and second precast concrete slabs, respectively. This makes it possible to suppress cracking during transportation and installation of the first and second precast concrete slabs that constitute the first and second precast concrete slabs with reinforcement bars before the half-precast beam is manufactured.

[0016] Furthermore, other embodiments of the half-precast beam according to the present invention include: The first precast concrete slab comprises a first vertical slab extending in the vertical direction and a first upper horizontal slab extending horizontally from the upper end of the first vertical slab. The second precast concrete slab comprises a second vertical slab extending in the vertical direction and a second lower horizontal slab extending horizontally from the lower end of the second vertical slab. The present invention is characterized in that some of the upper main reinforcement bars of the plurality of upper main reinforcement bars are embedded in the first upper horizontal plate, and some of the lower main reinforcement bars of the plurality of lower main reinforcement bars are embedded in the second lower horizontal plate.

[0017] In this embodiment, the first precast concrete slab comprises a first vertical slab and a first upper horizontal slab extending laterally from the upper end of the first vertical slab, and the second precast concrete slab comprises a second vertical slab and a second lower horizontal slab extending laterally from the lower end of the second vertical slab. In this embodiment, a portion of the upper main reinforcement bars of a plurality of upper main reinforcement bars (for example, one upper main reinforcement bar) is embedded in the first upper horizontal slab, and a portion of the lower main reinforcement bars of a plurality of lower main reinforcement bars (for example, one lower main reinforcement bar) is embedded in the second lower horizontal slab. In addition to the first and second longitudinal bars that constitute the first and second reinforcing bars, the upper and lower main bars are embedded in the first and second precast concrete slabs, which are equipped with the first upper and second lower transverse slabs, respectively. This suppresses cracking during transportation and installation of the first and second precast concrete slabs that constitute the first and second precast concrete slabs with reinforcement bars before the half-precast beams are manufactured.

[0018] Furthermore, other embodiments of the half-precast beam according to the present invention include: The first precast concrete slab comprises a first vertical slab extending in the vertical direction and a first lower horizontal slab extending horizontally from the lower end of the first vertical slab. The second precast concrete slab comprises a second vertical slab extending in the vertical direction and a second lower horizontal slab extending horizontally from the lower end of the second vertical slab. The first lower hook is located above the first lower horizontal plate. A plurality of the lower main reinforcing bars are embedded in the second lower horizontal plate. The end faces of the first lower horizontal plate and the second lower horizontal plate are in contact with each other.

[0019] According to this aspect, the first precast concrete plate includes a first vertical plate and a first lower horizontal plate extending horizontally from the lower end of the first vertical plate, and the second precast concrete plate includes a second vertical plate and a second lower horizontal plate extending horizontally from the lower end of the second vertical plate. In a form in which a gap is formed above in a posture where the end faces of the first lower horizontal plate and the second lower horizontal plate of both are in contact with each other, the first lower hook is located above the first lower horizontal plate, and a plurality of lower main reinforcing bars are embedded in the second lower horizontal plate. As a result, in addition to the second vertical bars constituting the second reinforcing bars, the lower main reinforcing bars are embedded in the second precast concrete plate provided with the second lower horizontal plate. It is possible to suppress cracking during transportation and installation of the second precast concrete plate that constitutes the second precast concrete plate with reinforcing bars before manufacturing the half-precast beam.

[0020] Another aspect of the half-precast beam according to the present invention is The first precast concrete plate includes a first vertical plate extending in the vertical direction. The second precast concrete plate includes a second vertical plate extending in the vertical direction. A first upper recess and a first lower recess are provided inside the upper end and the lower end of the first vertical plate, respectively. A second upper recess and a second lower recess are provided inside the upper end and the lower end of the second vertical plate, respectively. The upper main reinforcing bar adjacent to the first upper recess is separated horizontally, and the lower main reinforcing bar adjacent to the second lower recess is separated horizontally.

[0021] According to this aspect, the first vertical bars provided in the first precast concrete slab and the second vertical bars provided in the second precast concrete slab respectively have first upper recesses and first lower recesses, and second upper recesses and second lower recesses on the inner sides of their upper and lower ends. The upper main bars adjacent to the first upper recess are separated horizontally, and the lower main bars adjacent to the second lower recess are separated horizontally. As a result, when forming a cast-in-place concrete body around the upper main bars adjacent to the first vertical slab and the lower main bars adjacent to the second vertical slab, the concrete can be fully wrapped around, and the upper main bars and lower main bars arranged at the ends can be embedded in the cast-in-place concrete body without gaps.

[0022] Moreover, another aspect of the half-precast beam according to the present invention is a plurality of first reinforcing bars including a first vertical bar, a first upper horizontal bar that bends at the upper end of the first vertical bar and extends horizontally, and a first upper hook that is a 90-degree hook, a 135-degree hook, or a 180-degree hook that bends and extends at the end of the first upper horizontal bar, and a first lower hook that bends at the lower end of the first vertical bar and extends upward, continuously presenting a substantially L-shaped configuration. a plurality of separate first reinforcing bars including a separate first vertical bar, a separate first upper horizontal bar that bends at the upper end of the separate first vertical bar and extends horizontally, and a separate first lower hook that bends at the lower end of the separate first vertical bar and extends upward, continuously presenting a substantially L-shaped configuration. The separate first vertical bars of the plurality of separate first reinforcing bars are embedded at intervals in the longitudinal direction of the first precast concrete slab. The first upper horizontal bar of the corresponding first reinforcing bar is wrapped and arranged to be tied or welded to the separate first upper horizontal bar of each of the separate first reinforcing bars. a precast concrete slab with third reinforcing bars, to which upper main bars extending in the longitudinal direction are attached below the plurality of first upper horizontal bars. The structure comprises multiple second reinforcing bars, each having a second longitudinal bar, a second lower transverse bar that bends at the lower end of the second longitudinal bar and extends laterally, a second lower hook that bends at the end of the second lower transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a second upper hook that bends at the upper end of the second longitudinal bar and extends downward, forming a roughly L-shape. It is equipped with multiple separate second reinforcing bars, each having a separate second vertical bar, a separate second upper hook that bends at the upper end of the separate second vertical bar and extends downward, and a separate second lower transverse bar that bends at the lower end of the separate second vertical bar and extends laterally, forming a roughly L-shape in a continuous manner. Each of the aforementioned separate second reinforcing bars is embedded at intervals along the longitudinal direction of the second precast concrete slab. The second lower transverse bar of the corresponding second reinforcing bar is arranged to overlap with the second lower transverse bar of each of the aforementioned separate second reinforcing bars, and is then tied or welded together. It comprises a precast concrete slab with a fourth reinforced concrete slab, to which the longitudinally extending lower end main reinforcement is attached above a plurality of the aforementioned second lower transverse reinforcements, The first precast concrete slab and the second precast concrete slab are arranged with a gap between them, with the first upper horizontal reinforcement and the second upper hook intersecting, and the second lower horizontal reinforcement and the first lower hook intersecting, and a post-cast concrete body provided in the gap.

[0023] In this embodiment, each of the separate first longitudinal bars forming a plurality of separate first reinforcing bars exhibiting a roughly L-shape is embedded at intervals along the longitudinal direction of the first precast concrete slab, and the corresponding first upper transverse bar of the first reinforcing bar is arranged to overlap with the separate first upper transverse bar of each separate first reinforcing bar and tied together, and the upper main bars are attached below the plurality of first upper transverse bars to form the third reinforced precast concrete slab, and each of the separate second longitudinal bars forming a plurality of separate second reinforcing bars exhibiting a roughly L-shape is embedded at intervals along the longitudinal direction of the second precast concrete slab, and the corresponding second lower transverse bar of the second reinforcing bar is arranged to overlap with the separate second lower transverse bar of each separate second reinforcing bar and tied together, and The lower main reinforcement is attached above the second lower horizontal reinforcement to form the fourth reinforced concrete slab. The third and fourth precast concrete slabs are arranged with gaps between them, with the first upper horizontal reinforcement and the second upper hook crossing, and the second lower horizontal reinforcement and the first lower hook crossing, and a post-cast concrete body is provided in the gap. As a result, when the third and fourth reinforced concrete slabs are installed, the beam reinforcement is automatically arranged. Therefore, the third and fourth precast concrete slabs reduce the labor required for formwork installation and removal, eliminate or reduce the labor required for beam reinforcement, and ensure quality because they are factory-made.

[0024] Furthermore, other embodiments of the half-precast beam according to the present invention include: In the longitudinal direction, a first reinforcing bar is arranged between the first reinforcing bars that are tied or welded to the other first reinforcing bar, and the other first reinforcing bar is not present between them. In the longitudinal direction, the second reinforcing bar is arranged between the second reinforcing bars that are tied or welded to the other second reinforcing bar, in which there is no counterpart to the other second reinforcing bar.

[0025] According to this embodiment, first and second reinforcing bars are arranged between first reinforcing bars that are tied to a separate first reinforcing bar, or between second reinforcing bars that are tied to a separate second reinforcing bar, without the presence of the other separate first or second reinforcing bars. In other words, by arranging first and second reinforcing bars that are not connected to a separate first or second reinforcing bar, in addition to first and second reinforcing bars that are connected to a separate first or second reinforcing bar, it is possible to arrange a number of first and second reinforcing bars that can achieve the desired shear reinforcement effect, without depending on the number of separate first and second reinforcing bars. Here, the first and second reinforcing bars that are not connected to a separate first or second reinforcing bar are all connected together with the first and second reinforcing bars that are connected to a separate first or second reinforcing bar, via upper and lower main bars.

[0026] Furthermore, other embodiments of the half-precast beam according to the present invention include: A first wavy reinforcing bar, which extends in the longitudinal direction and exhibits a wavy shape, is connected to the first longitudinal bar and the separate first longitudinal bar. The invention is characterized in that a second wave-shaped reinforcing bar, which extends in the longitudinal direction and exhibits a wave-like shape, is connected to the second longitudinal bar and the separate second longitudinal bar.

[0027] According to this embodiment, the first wave-shaped reinforcing bars extending in the longitudinal direction and exhibiting a wave-like shape are connected to the first longitudinal bars and a separate first longitudinal bar, and the second wave-shaped reinforcing bars extending in the longitudinal direction and exhibiting a wave-like shape are connected to the second longitudinal bars and a separate second longitudinal bar. This makes it possible to achieve a stronger integration of the separate first reinforcing bars and the first reinforcing bars, which are roughly L-shaped, and the separate second reinforcing bars and the second reinforcing bars. Furthermore, with this configuration, the first longitudinal bars, the separate first longitudinal bars and the first wave-shaped reinforcing bars between them, and the second longitudinal bars, the separate second longitudinal bars and the second wave-shaped reinforcing bars between them can all resist, in the same manner as a truss beam, the pressure acting on the inside of the first precast concrete slab and the second precast concrete slab when concrete is poured during the construction of a post-cast concrete body, and the earth pressure acting on the outside of the first precast concrete slab and the second precast concrete slab when soil is backfilled before concrete is poured.

[0028] Furthermore, other embodiments of the half-precast beam according to the present invention include: Multiple upper main reinforcement bars are provided in multiple stages, and each stage contains multiple upper main reinforcement bars. The lower main reinforcement bars are provided in multiple stages, and each stage contains multiple lower main reinforcement bars.

[0029] According to this embodiment, since multiple upper main reinforcement bars are provided in multiple stages, with multiple upper main reinforcement bars included in each stage, and multiple lower main reinforcement bars are provided in multiple stages, a half-precast beam with even greater strength can be formed.

[0030] Furthermore, other embodiments of the half-precast beam according to the present invention include: The first auxiliary reinforcement, which prevents the sagging or swaying of the first upper horizontal reinforcement to which the upper main reinforcement is attached, is arranged so as to straddle the first upper horizontal reinforcement or the first upper hook and the first vertical reinforcement. The second auxiliary reinforcement, which prevents the sagging or swaying of the second lower horizontal reinforcement to which the lower main reinforcement is attached, is characterized in that it is arranged so as to straddle the second lower horizontal reinforcement or the second lower hook and the second vertical reinforcement.

[0031] According to this embodiment, a first auxiliary reinforcement is provided to prevent the first upper horizontal reinforcement, to which the upper main reinforcement is attached, from sagging or swaying when suspended, and a second auxiliary reinforcement is provided to prevent the second lower horizontal reinforcement, to which the lower main reinforcement is attached, from sagging or swaying when suspended, thereby effectively preventing the first upper horizontal reinforcement and the second lower horizontal reinforcement from sagging or swaying when suspended, caused by the weight of the upper and lower main reinforcement.

[0032] Furthermore, other embodiments of the half-precast beam according to the present invention include: Among the plurality of first and second reinforcing bars arranged in the longitudinal direction, some of the first and second reinforcing bars have relatively large cross-sectional diameters, and these large-diameter reinforcing bars prevent both the first upper transverse bar and the second lower transverse bar from sagging or swaying.

[0033] According to this embodiment, some of the first reinforcing bars among the plurality of first reinforcing bars, and some of the second reinforcing bars among the plurality of second reinforcing bars, are first and second reinforcing bars with relatively large cross-sectional diameters. By preventing both the first upper transverse bar and the second lower transverse bar from sagging or swaying when suspended, the first upper transverse bar and the second lower transverse bar caused by the weight of the upper and lower main bars can be effectively prevented by some of the first and second reinforcing bars without the use of auxiliary bars.

[0034] Furthermore, one embodiment of the method for manufacturing a half-precast beam according to the present invention is: A first reinforced concrete slab, comprising a first vertical bar, a first upper transverse bar that bends at the upper end of the first vertical bar and extends laterally, a first upper hook that bends at the end of the first upper transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a first lower hook that bends at the lower end of the first vertical bar and extends upward, each of the first vertical bars of the multiple first reinforcing bars is embedded at intervals along the longitudinal direction of the first precast concrete slab, and upper main bars extending along the longitudinal direction are attached below the multiple first upper transverse bars, A precast concrete slab with second reinforcing bars is prepared, wherein each of the second vertical bars of the second reinforcing bars, which bends at the lower end of the second vertical bar and extends laterally, and the second lower hooks, which bend at the end of the second lower horizontal bar and are 90-degree hooks, 135-degree hooks, or 180-degree hooks, and the second upper hooks, which bend above the second vertical bar and extend downward, are arranged in a roughly L-shape, and each of the second vertical bars of the second reinforcing bars is embedded at intervals along the longitudinal direction of the second precast concrete slab, and the lower end main bars that extend along the longitudinal direction are attached above the multiple second lower horizontal bars. Position the first reinforced precast concrete slab, move the second reinforced precast concrete slab so that the first upper horizontal bar and the second upper hook intersect, and the second lower horizontal bar and the first lower hook intersect, while positioning the first precast concrete slab and the second precast concrete slab with a gap between them. The method is characterized by producing a half-precast beam by pouring concrete into the aforementioned gap to form a post-cast concrete body.

[0035] According to this embodiment, the first reinforced precast concrete slab, in which each of the first longitudinal bars constituting a plurality of roughly L-shaped first reinforcing bars is embedded, is positioned, and the second reinforced precast concrete slab, in which each of the plurality of roughly L-shaped second reinforcing bars constituting a plurality of second longitudinal bars is embedded, is moved, and the first upper transverse bar and the second upper hook intersect, and the second lower transverse bar and the first lower hook intersect, while positioning with a gap between the first and second precast concrete slabs, and forming a gap, thereby enabling the beam reinforcement to be automatically arranged when the first and second reinforced precast concrete slabs are positioned, eliminating or suppressing the separate beam reinforcement arrangement work. Furthermore, by using the first and second precast concrete slabs as side frames and pouring concrete into the gap between them to form a post-cast concrete body, the labor required for formwork installation and removal can be reduced.

[0036] Furthermore, another aspect of the method for manufacturing a half-precast beam according to the present invention is: The first precast concrete slab comprises a first vertical slab extending in the vertical direction and a first lower horizontal slab extending horizontally from the lower end of the first vertical slab. The second precast concrete slab comprises a second vertical slab extending in the vertical direction and a second lower horizontal slab extending horizontally from the lower end of the second vertical slab. Multiple lower end main reinforcements are embedded in the second lower horizontal plate. By bringing the end faces of the first lower horizontal plate and the second lower horizontal plate into contact with each other, the first vertical plate and the second vertical plate, along with the first lower horizontal plate and the second lower horizontal plate, form a U-shaped formwork with a cross-sectional shape perpendicular to the longitudinal direction that opens upward. The method is characterized by pouring concrete into the formwork to form the post-cast concrete body.

[0037] According to this embodiment, the first precast concrete slab comprises a first vertical slab and a first lower horizontal slab extending laterally from its lower end, and the second precast concrete slab comprises a second vertical slab and a second lower horizontal slab extending laterally from its lower end. By bringing the end faces of the first and second lower horizontal slabs of the first and second reinforced precast concrete slabs together, a U-shaped formwork with a cross-sectional shape perpendicular to the longitudinal direction that opens upward is formed. As a result, the entire formwork, including the side frame and bottom frame, is formed by the first and second reinforced precast concrete slabs. This eliminates the need to separately install formwork (such as its components, the bottom frame) and the need to demold the formwork. Furthermore, because it is a U-shaped formwork with a bottom frame that opens upward, the entire formwork can be made self-supporting.

[0038] Furthermore, another aspect of the method for manufacturing a half-precast beam according to the present invention is: At least one of the first lower hooks of the multiple first reinforcing bars of the first reinforced concrete slab, which is positioned first, is an elongated lower hook, longer than the length of all the second upper hooks of the second reinforcing bars of the second reinforced concrete slab, which is positioned second. When lowering the second reinforced precast concrete slab downwards, the long lower hook is passed in advance between the multiple second lower horizontal reinforcements provided in the second reinforced precast concrete slab, or At least one of the second upper hooks of the multiple second reinforcing bars of the second reinforced concrete slab, which is positioned later, is an elongated upper hook, longer than the length of all the first lower hooks of the first reinforcing bars of the first reinforced concrete slab, which is positioned earlier. When lowering the second reinforced precast concrete slab, the long upper hook is passed through the gaps between the multiple first upper horizontal reinforcements of the first reinforced precast concrete slab in advance.

[0039] According to this embodiment, by making at least one of the first lower hooks of the multiple first reinforcing bars of the first reinforced concrete slab that is positioned first a long lower hook that is longer than the length of all the second upper hooks of the second reinforcing bars of the second reinforced concrete slab that is positioned later, when lowering the second reinforced concrete slab, the long lower hook can be passed first between the multiple second lower horizontal bars of the second reinforced concrete slab that is positioned first, thereby allowing the other second lower hooks of the second reinforced concrete slab that is positioned later to be smoothly passed between the multiple first lower horizontal bars of the first reinforced concrete slab that is positioned first.

[0040] Similarly, by making at least one of the second upper hooks of the multiple second reinforcing bars on the second reinforced concrete slab that is positioned later a long upper hook that is longer than the length of all the first lower hooks of the first reinforcing bars on the first reinforced concrete slab that is positioned earlier, when lowering the second reinforced concrete slab, the long upper hook can be passed first between the multiple first upper horizontal bars on the first reinforced concrete slab, allowing the other second upper hooks of the second reinforced concrete slab that is positioned later to be smoothly passed between the multiple first upper horizontal bars on the first reinforced concrete slab that is positioned earlier.

[0041] Here, "at least one of the first lower hooks" includes forms in which only one first lower hook is positioned behind all of the second upper hooks of the second reinforced concrete slab, or forms in which multiple first lower hooks are positioned behind all of the second upper hooks of the second reinforced concrete slab, but with varying lengths among them, or forms in which all of the first lower hooks are positioned behind all of the second upper hooks of the second reinforced concrete slab. Similarly, variations are also included for "at least one of the second upper hooks".

[0042] Furthermore, for example, if at least one of the first lower hooks of the multiple first reinforcing bars on a first reinforced precast concrete slab that is positioned first is a long lower hook, then the other first lower hooks that are not long lower hooks, and the second upper hooks and second lower hooks of the multiple second reinforcing bars on a second reinforced precast concrete slab that is positioned later, and other hooks other than the long lower hook, will have the minimum necessary length.

[0043] Furthermore, another aspect of the method for manufacturing a half-precast beam according to the present invention is: In the configuration having the long lower hook, of the two first reinforcing bars located at both ends in the longitudinal direction of the first precast concrete slab, the first lower hook of one of the first reinforcing bars is the longest first long lower hook, and the first lower hook of the other first reinforcing bar is the next longest second long lower hook. After passing the first long lower hook through the multiple second lower horizontal reinforcements of the second reinforced concrete slab, the second long lower hook is then passed through the multiple second lower horizontal reinforcements of the second reinforced concrete slab, or In the configuration having the long upper hook, of the two second reinforcing bars located at both ends in the longitudinal direction of the second precast concrete slab, the second upper hook of one of the second reinforcing bars is the longest first long upper hook, and the second upper hook of the other second reinforcing bar is the next longest second long upper hook. The first long upper hook is passed first between the plurality of first upper horizontal reinforcements provided in the first reinforced precast concrete slab, and then the second long upper hook is passed between the plurality of first upper horizontal reinforcements provided in the first reinforced precast concrete slab.

[0044] According to this embodiment, in the configuration having long lower hooks, of the two first reinforcing bars located at both ends in the longitudinal direction of the first precast concrete slab, the first lower hook of one first reinforcing bar is the longest first long lower hook, and the first lower hook of the other first reinforcing bar is the next longest second long lower hook. The first long lower hook is passed first between the multiple second lower cross bars of the second reinforced precast concrete slab which is positioned later, and then the second long lower hook is passed between the multiple second lower cross bars of the second reinforced precast concrete slab. As a result, the first lower hooks located at both ends of the first lower hooks of the multiple first reinforcing bars (the first long lower hook and the second long lower hook) are passed first between the multiple second lower cross bars of the second reinforced precast concrete slab. Therefore, the other first lower hooks located between the first and second long lower hooks can be automatically and smoothly passed between the multiple second lower cross bars of the second reinforced precast concrete slab.

[0045] Similarly, in a configuration having long upper hooks, of the two second reinforcing bars located at both ends in the longitudinal direction of the second precast concrete slab, the second upper hook of one second reinforcing bar is the longest first long upper hook, and the second upper hook of the other second reinforcing bar is the next longest second long upper hook. The first long upper hook is passed first between the multiple first upper horizontal bars of the first reinforced precast concrete slab which has been positioned in advance, and then the second long upper hook is passed between the multiple first upper horizontal bars of the first reinforced precast concrete slab. As a result, the second upper hooks located at both ends of the second upper hooks of the multiple second reinforcing bars (the first long upper hook and the second long upper hook) are passed first between the multiple first upper horizontal bars of the first reinforced precast concrete slab. Therefore, the other second upper hooks located between the first and second long upper hooks can be passed automatically and smoothly between the multiple first upper horizontal bars of the first reinforced precast concrete slab. [Effects of the Invention]

[0046] As can be understood from the above explanation, the half-precast beam and its manufacturing method of the present invention make it possible to reduce the labor required for setting up and removing formwork by using precast concrete slabs that constitute the half-precast beam, while eliminating or reducing the labor required for reinforcing the beam, thereby improving quality. [Brief explanation of the drawing]

[0047] [Figure 1] This is a perspective view of a first reinforced precast concrete slab and a second reinforced precast concrete slab, which constitute an example of a half-precast beam according to the embodiment. [Figure 2] Figures (a) to (e) are process diagrams of the manufacturing method for an example of a half-precast beam according to the embodiment, and each diagram shows a longitudinal cross-sectional view perpendicular to the longitudinal direction of the example of a half-precast beam according to the embodiment. [Figure 3]Figures (a) to (e) are process diagrams of the manufacturing method for another example of a half-precast beam according to the embodiment, and each diagram also shows a longitudinal section of the other example of a half-precast beam according to the embodiment perpendicular to the longitudinal direction. [Figure 4] Figures (a) to (d) are process diagrams of a manufacturing method for yet another example of the half-precast beam according to the embodiment, and each diagram shows a longitudinal section of the yet another example of the half-precast beam according to the embodiment perpendicular to the longitudinal direction. [Figure 5] Figures (a) to (c) are process diagrams of a manufacturing method for yet another example of the half-precast beam according to the embodiment, and both show a longitudinal section view perpendicular to the longitudinal direction of yet another example of the half-precast beam according to the embodiment. [Figure 6] Figures (a) to (e) are process diagrams of a manufacturing method for yet another example of the half-precast beam according to the embodiment, and each diagram shows a longitudinal section of the yet another example of the half-precast beam according to the embodiment perpendicular to the longitudinal direction. [Figure 7] (a) and (b) are perspective views of a first reinforced precast concrete slab, which constitutes yet another example of a half-precast beam according to the embodiment. [Figure 8] This is a perspective view of a pre-positioned precast concrete slab with a first reinforced concrete bar, which constitutes yet another example of a half-precast beam according to the embodiment. [Figure 9] Figures (a) to (e) are process diagrams of the manufacturing method for yet another example of the half-precast beam according to the embodiment, and each shows a longitudinal section perpendicular to the longitudinal direction of the example of the half-precast beam according to the embodiment. [Figure 10] Figures (a) to (e) are process diagrams of the manufacturing method for yet another example of the half-precast beam according to the embodiment, and each shows a longitudinal section perpendicular to the longitudinal direction of the example of the half-precast beam according to the embodiment. [Figure 11]Figures (a) to (e) are process diagrams of the manufacturing method for yet another example of the half-precast beam according to the embodiment, and each shows a longitudinal section perpendicular to the longitudinal direction of the example of the half-precast beam according to the embodiment. [Figure 12] Figures (a) to (e) are process diagrams of the manufacturing method for yet another example of the half-precast beam according to the embodiment, and each shows a longitudinal section perpendicular to the longitudinal direction of the example of the half-precast beam according to the embodiment. [Figure 13] (a) and (b) are both longitudinal cross-sectional views perpendicular to the longitudinal direction, showing a state in which a first reinforced precast concrete slab and a second reinforced precast concrete slab are assembled, constituting yet another example of a half-precast beam according to the embodiment. [Modes for carrying out the invention]

[0048] Hereinafter, an example of a half-precast beam and its manufacturing method according to the embodiment will be described with reference to the attached drawings. In this specification and drawings, substantially identical components may be denoted by the same reference numerals to avoid redundant explanations.

[0049] [Half-precast beam according to an embodiment and its manufacturing method] Referring to Figures 1 to 13, several examples of a half-precast beam according to the embodiment and its manufacturing method will be described. Here, Figure 1 is a perspective view of a first reinforced precast concrete slab and a second reinforced precast concrete slab that constitute an example of a half-precast beam according to the embodiment. Figure 2 is a process diagram of the manufacturing method of an example of a half-precast beam according to the embodiment, in the order of (a) to (e), and shows a longitudinal cross-sectional view perpendicular to the longitudinal direction of the example of a half-precast beam according to the embodiment.

[0050] The half-precast beam 100 shown in Figure 2(e) has a first reinforced precast concrete slab 50A and a second reinforced precast concrete slab 50B arranged with a gap G between them, and a post-cast concrete body 60 provided in the gap G.

[0051] As shown in Figure 1, the first reinforced precast concrete slab 50A is formed by attaching a plurality of first reinforcing bars 10A to the first precast concrete slab 20A at intervals along its longitudinal direction.

[0052] Similarly, the second reinforced precast concrete slab 50B is formed by attaching multiple second reinforcing bars 10B to the second precast concrete slab 20B at intervals along its longitudinal direction.

[0053] The first reinforcing bar 10A consists of a first longitudinal bar 11A, a first upper transverse bar 12A that bends at the upper end of the first longitudinal bar 11A and extends laterally, a first upper hook 13A that bends at the end of the first upper transverse bar 12A and extends diagonally downward, and a first lower hook 15A (180-degree hook) that bends at the lower end of the first longitudinal bar 11A and extends upward, forming a roughly L-shape. Here, the first upper hook 13A in the illustrated example is a 135-degree hook, but it may also be a 90-degree hook or a 180-degree hook.

[0054] On the other hand, the second reinforcing bar 10B consists of a second longitudinal bar 11B, a second lower transverse bar 14B that bends at the lower end of the second longitudinal bar 11B and extends laterally, a second lower hook 15B that bends at the end of the second lower transverse bar 14B and extends diagonally upward, and a second upper hook 13B (180-degree hook) that bends above the second longitudinal bar 11B and extends downward, forming a roughly L-shape. Here, the second lower hook 15B in the illustrated example is a 135-degree hook, but it may also be a 90-degree hook or a 180-degree hook.

[0055] The first precast concrete slab 20A has a first vertical slab 22A that extends in the vertical direction, and the first vertical reinforcement bars 11A that extend in the vertical direction are embedded in the first vertical slab 22A, thereby attaching the first reinforcing bars 10A to the first precast concrete slab 20A.

[0056] Similarly, the second precast concrete slab 20B has a second longitudinal slab 22B that extends in the longitudinal direction, and the second longitudinal reinforcement bars 11B that extend in the longitudinal direction are embedded in the second longitudinal slab 22B, thereby attaching the second reinforcing bars 10B to the second precast concrete slab 20B.

[0057] Here, although not shown in the diagram, the thickness of the precast concrete slabs 20A and 20B may be increased, and a portion of the upper and lower main reinforcement bars (for example, one bar each) may be embedded inside the precast concrete slabs 20A and 20B. In the form where the precast concrete slabs are thicker, it is preferable that cracking of the precast concrete slabs 20A and 20B that make up the reinforced precast concrete slabs 50A and 50B before the half-precast beams are manufactured is suppressed by further embedding a portion of the upper main reinforcement bars 30 and lower main reinforcement bars 40 in addition to the first and second vertical reinforcement bars 11A and 11B.

[0058] Multiple upper main reinforcement bars 30 extending in the longitudinal direction are attached below multiple first upper transverse reinforcement bars 12A, and multiple lower main reinforcement bars 40 extending in the longitudinal direction are attached above multiple second lower transverse reinforcement bars 14B. By attaching multiple upper main reinforcement bars 30 to the first precast concrete slab 20A to which multiple first reinforcing bars 10A are attached, the first reinforced precast concrete slab 50A is formed. Similarly, by attaching multiple lower main reinforcement bars 40 to the second precast concrete slab 20B to which multiple second reinforcing bars 10B are attached, the second reinforced precast concrete slab 50B is formed.

[0059] Here, the entire reinforced precast concrete slabs 50A and 50B shown in the diagram may be manufactured in a factory or the like, transported to the site, and installed in the designated location. Alternatively, the precast concrete slabs 20A and 20B, along with the upper and lower main reinforcements 30 and 40, may be transported to the site without the upper and lower main reinforcements 30 and 40 attached (all parts except the upper and lower main reinforcements 30 and 40 are manufactured in a factory or the like), and after the precast concrete slabs 20A and 20B are installed in the designated location at the site, the upper and lower main reinforcements 30 and 40 are attached to form the reinforced precast concrete slabs 50A and 50B.

[0060] The following explanation assumes that the half-precast beam to be manufactured is a beam on the upper floor. Regarding the manufacturing method of the illustrated example, first, as shown in Figure 2(a), a lower frame 91 is installed at the beam installation position, and the first reinforced precast concrete slab 50A (in the illustrated example, the reinforced precast concrete slab 50A on the left) is positioned on the lower frame 91.

[0061] Here, the left-side precast concrete slab 50A with the first reinforcement bar, which is installed first, has seven upper main reinforcement bars 30 attached to it at equal or approximately equal intervals in the horizontal direction relative to multiple first upper horizontal reinforcement bars 12A.

[0062] On the other hand, the second reinforced precast concrete slab 50B (the example shown is the reinforced precast concrete slab 50B on the right) which is installed later has seven lower main reinforcement bars 40 attached to multiple second lower horizontal bars 14B at equal or approximately equal intervals in the horizontal direction.

[0063] As explained below, the first reinforced concrete slab 50A and the second reinforced concrete slab 50B are designed to integrate the first reinforcing bars 10A and the second reinforcing bars by having one upper main reinforcement bar 30 embedded inside where the first upper hooks 13A and 2 upper hooks 13B of both slabs intersect, and one lower main reinforcement bar 40 embedded inside where the first lower hooks 15A and 2 lower hooks 15B of both slabs intersect.

[0064] Next, as shown in Figure 2(b), the second reinforced precast concrete slab 50B is moved laterally in the X1 direction until the lower main reinforcement 40 at the left end passes the first lower hook 15A and the second upper hook 13B passes the upper main reinforcement 30 at the right end, at which point the lateral movement is stopped.

[0065] Next, as shown in Figure 2(c), the second reinforced precast concrete slab 50B is lowered in the X2 direction so that the lower main reinforcement 40 at the left end is sandwiched between the first lower hook 15A and the second lower hook 15B, and the upper main reinforcement 30 at the right end is sandwiched between the first upper hook 13A and the second upper hook 13B.

[0066] As shown in Figure 2(d), by completely lowering the second reinforced precast concrete slab 50B and installing it on the lower frame 91, the first lower hook 15A and the second lower hook 15B sandwich the lower main reinforcement 40 at the left end, and the first upper hook 13A and the second upper hook 13B sandwich the upper main reinforcement 30 at the right end. Multiple upper main reinforcement bars 30 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the first upper horizontal reinforcement bar 12A, and multiple lower main reinforcement bars 40 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the second lower horizontal reinforcement bar 14B. The reinforcement is then automatically arranged, and a gap G is formed between the first reinforced precast concrete slab 50A and the second reinforced precast concrete slab 50B.

[0067] In this way, when the first reinforced precast concrete slab 50A and the second reinforced precast concrete slab 50B are installed with a gap G between them, the beam reinforcement is placed simultaneously, thus eliminating or reducing the labor required for beam reinforcement placement.

[0068] Next, as shown in Figure 2(e), concrete is poured into the gap G to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100 having a first reinforced precast concrete slab 50A, a second reinforced precast concrete slab 50B, and a post-cast concrete body 60.

[0069] In the manufacturing method shown in the illustration, the first precast concrete slab 20A and the second precast concrete slab 20B function as formwork (side frames) when forming the later-cast concrete body 60, while remaining as components of the half-precast beam 100. This eliminates the need for setting up and removing the side frames, thereby reducing the labor involved in setting up and removing the formwork.

[0070] Thus, the method for manufacturing a half-precast beam using a first reinforced precast concrete slab 50A and a second reinforced precast concrete slab 50B allows for labor savings in formwork installation and removal, while eliminating or reducing the labor required for beam reinforcement work. This method offers superior beam manufacturability (or constructability) and improves overall quality.

[0071] Next, with reference to Figure 3, a method for manufacturing another example of the half-precast beam according to the embodiment will be described. Here, Figures 3(a) to (e) are process diagrams for manufacturing another example of the half-precast beam according to the embodiment, and both show a longitudinal section view perpendicular to the longitudinal direction of the other example of the half-precast beam according to the embodiment.

[0072] The first precast concrete slab 50C, which is made up of the first reinforced precast concrete slab 50C, differs from the first reinforced precast concrete slab 50A and second reinforced precast concrete slab 50B, which are made up of the first reinforced precast concrete slab 20A and second reinforced precast concrete slab 20B, in that the first precast concrete slab 20C, which is made up of the first reinforced precast concrete slab 50C, comprises a first vertical slab 22A extending in the vertical direction and a first upper horizontal slab 24A extending horizontally from the upper end of the first vertical slab 22A, and the second precast concrete slab 20D, which is made up of the second reinforced precast concrete slab 50D, comprises a second vertical slab 22B extending in the vertical direction and a second lower horizontal slab 26B extending horizontally from the lower end of the second vertical slab 22B, in that the first reinforced precast concrete slab 50C, which is made up of the first reinforced precast concrete slab 50C, which is made up of the first reinforced precast concrete slab 20A and second reinforced precast concrete slab 20B, as applied to the manufacturing method shown in Figure 3.

[0073] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 3(a), the first reinforced precast concrete slab 50A is positioned on the lower frame 91.

[0074] Next, as shown in Figure 3(b), the second precast concrete slab 50D is moved laterally in the X3 direction, and the lateral movement is stopped when the lower main reinforcement 40 at the left end passes the first lower hook 15A and the second upper hook 13B passes the upper main reinforcement 30 at the right end.

[0075] Next, as shown in Figure 3(c), the second reinforced precast concrete slab 50D is lowered in the X4 direction so that the lower main reinforcement 40 at the left end is sandwiched between the first lower hook 15A and the second lower hook 15B, and the upper main reinforcement 30 at the right end is sandwiched between the first upper hook 13A and the second upper hook 13B.

[0076] As shown in Figure 3(d), by completely lowering the second reinforced precast concrete slab 50D and installing it on the lower frame 91, the first lower hook 15A and the second lower hook 15B sandwich the lower main reinforcement 40 at the left end, and the first upper hook 13A and the second upper hook 13B sandwich the upper main reinforcement 30 at the right end. Multiple upper main reinforcement bars 30 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the first upper horizontal reinforcement bar 12A, and multiple lower main reinforcement bars 40 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the second lower horizontal reinforcement bar 14B. The reinforcement is then automatically arranged, and a gap G is formed between the first reinforced precast concrete slab 50C and the second reinforced precast concrete slab 50D.

[0077] Next, as shown in Figure 3(e), concrete is poured into the gap G to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100A having a first reinforced precast concrete slab 50C, a second reinforced precast concrete slab 50D, and a post-cast concrete body 60.

[0078] The manufacturing method shown in the illustration reduces the labor involved in setting up and removing formwork, eliminates or reduces the labor required for reinforcing beams, and results in a manufacturing method that offers excellent manufacturability for beams and improves quality.

[0079] Furthermore, the inclusion of the second precast concrete slab 20D with the second lower horizontal slab 26B allows for a stable upright posture when installed on the lower frame 91.

[0080] Furthermore, by providing the first precast concrete slab 20C with a first upper horizontal slab 24A extending laterally, and the second precast concrete slab 20D with a second lower horizontal slab 26B extending laterally, the first upper horizontal slab 24A and the second lower horizontal slab 26B can form an engagement structure with the post-cast concrete body 60 provided in the gap G inside, thereby achieving an even higher degree of integration between the first reinforced precast concrete slab 50C and the second reinforced precast concrete slab 50D and the post-cast concrete body 60.

[0081] Next, with reference to Figure 4, a manufacturing method for yet another example of the half-precast beam according to the embodiment will be described. Here, Figures 4(a) to (e) are process diagrams for the manufacturing method of yet another example of the half-precast beam according to the embodiment, and both show a longitudinal cross-sectional view perpendicular to the longitudinal direction of yet another example of the half-precast beam according to the embodiment.

[0082] The manufacturing method shown in Figure 4 applies to the first precast concrete slab 50E, which comprises a first precast concrete slab 20 having a first vertical slab 22A and a first lower horizontal slab 27A extending laterally from the lower end of the first vertical slab 22A, and the second precast concrete slab 20F having a second vertical slab 22B and a second lower horizontal slab 27B extending laterally from the lower end of the second vertical slab 22B, and the first lower hook 1 It differs from the first reinforced precast concrete slab 50A and second reinforced precast concrete slab 50B, which have a first precast concrete slab 20A and a second precast concrete slab 20B, in that 5A is located above the first lower horizontal slab 27A, 6 of the bottom main reinforcements 40 (7 in the illustrated example) are embedded in relation to the second lower horizontal slab 27B, and the second lower hook 15B and the remaining bottom main reinforcement 40 protrude laterally from the end of the second lower horizontal slab 27B.

[0083] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 4(a), the first reinforced precast concrete slab 50E is positioned on the lower frame 91.

[0084] Next, as shown in Figure 4(b), the second precast concrete slab 50F is moved laterally in the X5 direction, and the lateral movement is stopped when the lower main reinforcement 40 at the left end passes the first lower hook 15A and the second upper hook 13B passes the upper main reinforcement 30 at the right end.

[0085] Next, as shown in Figure 4(c), the second reinforced precast concrete slab 50E is lowered downward in the X6 direction, so that the lower main reinforcement 40 at the left end is sandwiched between the first lower hook 15A and the second lower hook 15B, and the upper main reinforcement 30 at the right end is sandwiched between the first upper hook 13A and the second upper hook 13B.

[0086] As shown in Figure 4(d), by completely lowering the second reinforced precast concrete slab 50F and installing it on the lower frame 91, the first lower hook 15A and the second lower hook 15B sandwich the lower main reinforcement 40 at the left end, and the first upper hook 13A and the second upper hook 13B sandwich the upper main reinforcement 30 at the right end. Multiple upper main reinforcement bars 30 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the first upper horizontal reinforcement bar 12A, and multiple lower main reinforcement bars 40 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the second lower horizontal reinforcement bar 14B. The reinforcement is then automatically arranged, and a gap G is formed between the first reinforced precast concrete slab 50E and the second reinforced precast concrete slab 50F.

[0087] As shown in Figure 4(d), in the installation position of the first reinforced precast concrete slab 50E and the second reinforced precast concrete slab 50F, a U-shaped formwork is formed with a cross-sectional shape perpendicular to the longitudinal direction and opening upwards. As a result, the entire formwork, including the side frame and bottom frame, is formed by the first reinforced precast concrete slab 50E and the second reinforced precast concrete slab 50F, completely eliminating the need to separately install formwork (such as its components, the bottom frame) and the removal of formwork. Here, the bottom frame 91 shown in Figure 4 is not a bottom frame that forms the formwork, but is used as a support platform on which the first reinforced precast concrete slab 50E and the second reinforced precast concrete slab 50F are placed.

[0088] Next, as shown in Figure 4(e), concrete is poured into the gap G to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100B having a first reinforced precast concrete slab 50E, a second reinforced precast concrete slab 50F, and a post-cast concrete body 60.

[0089] The manufacturing method shown in the illustration reduces the labor involved in setting up and removing formwork, eliminates or reduces the labor required for reinforcing beams, and results in a manufacturing method that offers excellent manufacturability for beams and improves quality.

[0090] Next, with reference to Figure 5, a manufacturing method for yet another example of the half-precast beam according to the embodiment will be described. Here, Figures 5(a) to (c) are process diagrams for the manufacturing method of yet another example of the half-precast beam according to the embodiment, and both show a longitudinal cross-sectional view perpendicular to the longitudinal direction of yet another example of the half-precast beam according to the embodiment.

[0091] The reinforced precast concrete slabs 50G and 50H, which are applied to the manufacturing method shown in Figure 5, differ from the reinforced precast concrete slabs 50A and 50B in that the first vertical reinforcement bar 11A of the first reinforcing bar 10A and the second vertical reinforcement bar 11B of the second reinforcing bar 10B protrude from the upper end of the precast concrete slabs 20A and 20B, and the first reinforcing bar 10A and the second reinforcing bar 10B are installed at a relatively higher position relative to the precast concrete slabs 20A and 20B.

[0092] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 5(a), when the first reinforced precast concrete slab 50G and the second reinforced precast concrete slab 50H are installed, the first reinforcing bars 10A and the second reinforcing bars 10B of both, as well as multiple (seven in the illustrated example) upper main reinforcing bars 30, protrude above the first precast concrete slab 20A and the second precast concrete slab 20B.

[0093] Next, as shown in Figure 5(b), floor lower frames 92 are installed on the left and right sides of the first precast concrete slab 20A and the second precast concrete slab 20B. Upper and lower floor reinforcements 93 are placed so as to penetrate laterally above the first reinforcing bars 10A and the second reinforcing bars 10B and above and below the multiple upper main reinforcements 30. Further floor reinforcements 93 are placed in a direction perpendicular to this.

[0094] Next, as shown in Figure 5(c), concrete is poured in a manner that is continuous with the gap G between the first reinforced precast concrete slab 50G and the second reinforced precast concrete slab 50H, and the space above the lower frame 92 for the floor, thereby forming a post-cast concrete body 60 and a concrete floor slab 60A. In this way, a half-precast beam 100C with a floor is manufactured, which has the first reinforced precast concrete slab 50G, the second reinforced precast concrete slab 50H, the post-cast concrete body 60, and a concrete floor slab 60A.

[0095] The manufacturing method shown in the illustration reduces the labor involved in setting up and removing formwork, eliminates or reduces the labor required for reinforcing beams, and results in a manufacturing method that offers excellent manufacturability for beams and improves quality.

[0096] Next, with reference to Figure 6, a manufacturing method for yet another example of the half-precast beam according to the embodiment will be described. Here, Figure 6 is a process diagram of the manufacturing method for yet another example of the half-precast beam according to the embodiment, in the order of (a) to (e), and shows a longitudinal section view perpendicular to the longitudinal direction of yet another example of the half-precast beam according to the embodiment.

[0097] As shown in Figure 6(a), the first reinforcing bar 10C constituting the first reinforced concrete slab 50I has multiple stages (two stages in the illustrated example) of setting up bars 17 that are locked to the first vertical bar 11A and the first upper hook 13A, and multiple upper main bars 30 are attached to each of the first upper horizontal bar 12A and the two stages of setting up bars 17. The second reinforcing bar 10D constituting the second reinforced concrete slab 50J has multiple stages (two stages in the illustrated example) of setting up bars 17 that are locked to the second vertical bar 11B and the second lower hook 15B, and multiple lower main bars 40 are attached to each of the second lower horizontal bar 14B and the two stages of setting up bars 17. These differences are compared to the first reinforced concrete slab 50A and the second reinforced concrete slab 50B which have the first reinforcement bar 10A and the second reinforcement bar 10B.

[0098] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 6(a), the first reinforced precast concrete slab 50I is positioned on the lower frame 91.

[0099] Next, as shown in Figure 6(b), the second reinforced precast concrete slab 50J is moved laterally in the X7 direction until the three lower main reinforcements 40 at the left end pass the first lower hook 15A and the second upper hook 13B passes the three upper main reinforcements 30 at the right end, at which point the lateral movement is stopped.

[0100] Next, as shown in Figure 6(c), the second reinforced precast concrete slab 50J is lowered in the X8 direction, so that the lower main reinforcement 40 at the left end is sandwiched between the first lower hook 15A and the second lower hook 15B, and the upper main reinforcement 30 at the right end is sandwiched between the first upper hook 13A and the second upper hook 13B.

[0101] As shown in Figure 6(d), by completely lowering the second reinforced precast concrete slab 50J and installing it on the lower frame 91, the first lower hook 15A and the second lower hook 15B hold the lower main reinforcement 40 at the left end, and the first upper hook 13A and the second upper hook 13B hold the upper main reinforcement 30 at the right end. Multiple upper main reinforcement bars 30 (7 bars x 3 rows in the illustrated example) are placed at equal or approximately equal intervals horizontally with respect to the first upper horizontal reinforcement bar 12A and the two rows of preparation bars 17 aligned horizontally. Multiple lower main reinforcement bars 40 (7 bars x 3 rows in the illustrated example) are placed at equal or approximately equal intervals horizontally with respect to the second lower horizontal reinforcement bar 14B and the two rows of preparation bars 17 aligned horizontally. The reinforcement is automatically arranged, and a gap G is formed between the first reinforced precast concrete slab 50I and the second reinforced precast concrete slab 50J.

[0102] Next, as shown in Figure 6(e), concrete is poured into the gap G to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100D having a first reinforced precast concrete slab 50I, a second reinforced precast concrete slab 50J, and a post-cast concrete body 60.

[0103] The manufacturing method shown in the illustration reduces the labor involved in setting up and removing formwork, eliminates or reduces the labor required for reinforcing beams, and results in a manufacturing method that offers excellent manufacturability for beams and improves quality.

[0104] Furthermore, the half-precast beam 100D has multiple upper main reinforcement bars 30 in each section, and multiple lower main reinforcement bars 40 in each section, which allows for the formation of a half-precast beam with even greater strength.

[0105] Next, with reference to Figure 7, a reinforced precast concrete slab constituting yet another example of the half-precast beam according to the embodiment will be described. Here, Figures 7(a) and 7(b) are both perspective views of a reinforced precast concrete slab constituting yet another example of the half-precast beam according to the embodiment.

[0106] The first reinforced precast concrete slab 50K shown in Figure 7(a) has a configuration in which a first reinforcing bar 10E with a relatively large cross-sectional diameter is interposed between a plurality of first reinforcing bars 10A that are attached to the first precast concrete slab 20A and arranged in the longitudinal direction.

[0107] The relatively large diameter of the first reinforcing bar 10E prevents the first upper transverse bar 12A from sagging due to the weight of the upper main bar 30, as well as from swaying when lifted by a crane or the like.

[0108] Here, although not shown in the diagram, even in a precast concrete slab with a second reinforcing bar to which the lower main reinforcement 40 is attached, a second reinforcing bar with a relatively large cross-sectional diameter is interposed between the multiple second reinforcing bars 10B that are attached to the second precast concrete slab 20B and arranged in the longitudinal direction. The interposition of the second reinforcing bar with a relatively large cross-sectional diameter prevents the sagging of the second lower horizontal reinforcement 14B caused by the weight of the lower main reinforcement 40 and prevents swaying when lifted by a crane or the like.

[0109] On the other hand, the first reinforced precast concrete slab 50L shown in Figure 7(b) has a configuration in which the first auxiliary reinforcement 18 is arranged so as to span from the first upper transverse reinforcement 12A and the first upper hook 13A to the first vertical reinforcement 11A, and has a first reinforcing bar 10F.

[0110] The first auxiliary reinforcement 18 prevents the first upper transverse reinforcement 12A, to which the upper main reinforcement 30 is attached, from sagging.

[0111] Here, although not shown in the diagram, in the precast concrete slab with the second reinforcement to which the lower main reinforcement 40 is attached, the second auxiliary reinforcement is arranged so as to span from the second lower horizontal reinforcement 14B and the second lower hook 15B to the second vertical reinforcement 11B, and the second auxiliary reinforcement prevents the sagging of the second lower horizontal reinforcement 14B to which the lower main reinforcement 40 is attached. Here, the first reinforcing bars 10F may be arranged in multiples along the longitudinal direction of the precast concrete slab with the first reinforcement 50L, or they may be arranged in combination with other embodiments. For example, in the precast concrete slab with the first reinforcement 50K shown in Figure 7(a), the first reinforcing bar 10F may be provided instead of the first reinforcing bar 10E.

[0112] Next, with reference to Figures 8 and 9, a method for manufacturing yet another example of the half-precast beam according to the embodiment will be described. Here, Figure 8 is a perspective view of a pre-positioned reinforced precast concrete slab that constitutes yet another example of the half-precast beam according to the embodiment. Figures 9(a) to 9(e) are process diagrams of the manufacturing method for yet another example of the half-precast beam according to the embodiment, in that order.

[0113] The first reinforced precast concrete slab 50M shown in Figure 8 differs from the first reinforced precast concrete slab 50 in that, among the multiple (nine in the illustrated example) first reinforcing bars attached to the first precast concrete slab 20A, the lengths t3 and t2 of the first lower hooks 15C and 15D of the first reinforcing bars 10G and 10H at both ends in the longitudinal direction are longer than the length t1 of the first lower hooks 15A of the other seven first reinforcing bars 10A.

[0114] More specifically, of the first reinforcing bars 10G and 10H, the length t3 of the long lower hook 15C of one of the first reinforcing bars 10G is set to be longer than the length t2 of the long lower hook 15D of the other first reinforcing bar 10H, and the relationship between the lengths t3, t2, and t1 of the long lower hooks 15C (first long lower hook), 15D (second long lower hook), and 1st lower hook 15A is set to t3 > t2 > t1.

[0115] Here, the length t1 of the first lower hook 15A of the first reinforcing bar 10A, and the length of the first upper hook 13A, should be the minimum necessary length.

[0116] As shown in Figure 9, in the fabrication of the half-precast beam, the first reinforced precast concrete slab 50M shown in Figure 8 is positioned first, and the second reinforced precast concrete slab 50B, which is positioned later, has all the same length second upper hooks 13B, as explained above.

[0117] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 9(a), the first reinforced precast concrete slab 50M is positioned on the lower frame 91.

[0118] Next, as shown in Figure 9(b), the second reinforced precast concrete slab 50B is moved laterally in the X9 direction until the lower main reinforcement 40 at the left end passes the long lower hook 15C and the second upper hook 13B passes the upper main reinforcement 30 at the right end, at which point the lateral movement is stopped.

[0119] Next, as shown in Figure 9(c), by lowering the second reinforced precast concrete slab 50B downward in the X10 direction, the first long lower hook 15C of the first reinforcing bar 10G, which is the longest of the nine first reinforcing bars 10, 10G, and 10H provided in the first reinforced precast concrete slab 50M, is passed between the multiple second lower horizontal bars 14B of the second reinforced precast concrete slab 50B.

[0120] Furthermore, by lowering the second reinforced precast concrete slab 50B downward in the X10 direction, the second long lower hook 15D of the longer first reinforcing bar 10H will be passed between the multiple second lower horizontal bars 14B of the second reinforced precast concrete slab 50B.

[0121] In this way, by first focusing on passing the first long lower hook 15C between multiple lower horizontal bars 14, and then focusing on passing the second long lower hook 15D between multiple lower horizontal bars 14, once the long lower hooks 15C and 15D of the first reinforcing bars 10H and 10I at both ends of the nine first reinforcing bars 10H and 10I are passed between the corresponding multiple lower horizontal bars 14, the reinforcing precast concrete slabs 50L and 50 on the left and right can be made parallel to each other.

[0122] Therefore, as shown in Figure 9(c), the precast concrete slab 50B with the second reinforcement can be smoothly lowered in the X10 direction, and as shown in Figure 9(d), by completely lowering the precast concrete slab 50B with the second reinforcement and installing it on the lower frame 91, the lower main reinforcement 40 at the left end is held in place by the first lower hook 15C (and other first lower hooks 15A, 15D) and the corresponding second lower hook 15B, and the upper main reinforcement 30 at the right end is held in place by the second With the first upper hook 13A and the second upper hook 13B sandwiching each other, multiple (seven in the illustrated example) upper main reinforcement bars 30 are arranged at equal or approximately equal intervals in the lateral direction with respect to the first upper horizontal reinforcement bar 12A, and multiple (seven in the illustrated example) lower main reinforcement bars 40 are arranged at equal or approximately equal intervals in the lateral direction with respect to the second lower horizontal reinforcement bar 14B, thereby automatically arranging the reinforcement and creating a gap G between the first reinforced precast concrete slab 50M and the second reinforced precast concrete slab 50B.

[0123] Next, as shown in Figure 9(e), concrete is poured into the gap G to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100E having a first reinforced precast concrete slab 50M, a second reinforced precast concrete slab 50B, and a post-cast concrete body 60.

[0124] Here, as shown in the illustrated example, in addition to the configuration in which the first lower hooks of the first reinforcing bars at both ends of the multiple first reinforcing bars provided in the precast concrete slab with the first reinforcing bars that are positioned in advance are long lower hooks, there may also be a configuration in which the first lower hook of any one of the first reinforcing bars is a long lower hook, or for example, there may be a configuration in which the first lower hooks of three or more first reinforcing bars are long lower hooks and all of the long lower hooks are of different lengths (none of which are shown).

[0125] Furthermore, although not shown in the illustration, at least one of the second upper hooks of the multiple second reinforcing bars on the second reinforced precast concrete slab, which is positioned later, is a long upper hook, longer than the length of all the first lower hooks of the first reinforcing bars on the first reinforced precast concrete slab, which is positioned earlier. In this manufacturing method, when lowering the second reinforced precast concrete slab, the long upper hook is passed first between the multiple first upper horizontal bars on the first reinforced precast concrete slab, and then the first reinforced precast concrete slab and the second reinforced precast concrete slab are positioned.

[0126] In this configuration, of the two second reinforcing bars located at both ends in the longitudinal direction of the second reinforced concrete slab, the second upper hook of one of the second reinforcing bars is made the longest first long upper hook, and the second upper hook of the other second reinforcing bar is made the next longest second long upper hook. By passing the first long upper hook first between the multiple first upper horizontal bars of the first reinforced concrete slab, and then passing the second long upper hook between the multiple first upper horizontal bars of the first reinforced concrete slab, the first reinforced concrete slab and the second reinforced concrete slab on the left and right can be made to be parallel to each other, and the second reinforced concrete slab can be smoothly lowered and positioned.

[0127] Next, with reference to Figure 10, a manufacturing method for yet another example of the half-precast beam according to the embodiment will be described. Here, Figures 10(a) to (e) are process diagrams for the manufacturing method of another example of the half-precast beam according to the embodiment, and each shows a longitudinal section view perpendicular to the longitudinal direction of the other example of the half-precast beam according to the embodiment.

[0128] The first precast concrete slab 50A and the second precast concrete slab 50B, which are made up of precast concrete slabs 20A and 20B, differ from the first precast concrete slab 50A and the second precast concrete slab 50B, which are made up of precast concrete slabs 20A and 20B, in that the vertical slab 22A of the first precast concrete slab 20G that constitutes the first precast concrete slab 50N has a first upper recess 28A and a first lower recess 29A on the inside of its upper and lower ends, respectively, and the upper main reinforcement 30 adjacent to the first upper recess 28A is separated laterally, and the vertical slab 22B of the second precast concrete slab 20H that constitutes the second precast concrete slab 50P has a second upper recess 28B and a second lower recess 29B on the inside of its upper and lower ends, respectively, and the lower main reinforcement 40 adjacent to the second lower recess 29B is separated laterally.

[0129] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 10(a), the first reinforced precast concrete slab 50N is positioned on the lower frame 91.

[0130] Next, as shown in Figure 10(b), the second reinforced precast concrete slab 50P is moved laterally in the X11 direction until the lower main reinforcement 40 at the left end passes the first lower hook 15A and the second upper hook 13B passes the upper main reinforcement 30 at the right end, at which point the lateral movement is stopped.

[0131] Next, as shown in Figure 10(c), the second reinforced precast concrete slab 50P is lowered in the X12 direction, so that the lower main reinforcement 40 at the left end is sandwiched between the first lower hook 15A and the second lower hook 15B, and the upper main reinforcement 30 at the right end is sandwiched between the first upper hook 13A and the second upper hook 13B.

[0132] As shown in Figure 10(d), by completely lowering the second reinforced precast concrete slab 50P and installing it on the lower frame 91, the first lower hook 15A and the second lower hook 15B sandwich the lower main reinforcement 40 at the left end, and the first upper hook 13A and the second upper hook 13B sandwich the upper main reinforcement 30 at the right end. Multiple upper main reinforcement bars 30 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the first upper horizontal reinforcement bar 12A, and multiple lower main reinforcement bars 40 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the second lower horizontal reinforcement bar 14B. The reinforcement is then automatically arranged, and a gap G is formed between the first reinforced precast concrete slab 50N and the second reinforced precast concrete slab 50P.

[0133] Next, as shown in Figure 10(e), concrete is poured into the gap G to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100F having a first reinforced precast concrete slab 50N, a second reinforced precast concrete slab 50P, and a post-cast concrete body 60.

[0134] The manufacturing method shown in the illustration reduces the labor involved in setting up and removing formwork, eliminates or reduces the labor required for reinforcing beams, and results in a manufacturing method that offers excellent manufacturability for beams and improves quality.

[0135] Furthermore, the first vertical slab 22A and the second vertical slab 22B of the precast concrete slabs 20G and 20H each have a first upper recess 28A and a first lower recess 29A, and a second upper recess 28B and a second lower recess 29B on the inside of their upper and lower ends, respectively. The upper main reinforcement bars 30 and lower main reinforcement bars 40 adjacent to the first upper recess 28A and the second lower recess 29B are spaced apart laterally, allowing the concrete used to form the post-cast concrete body 60 to sufficiently wrap around the upper main reinforcement bars 30 and lower main reinforcement bars 40 adjacent to the first vertical slab 22A and the second vertical slab 22B, respectively, and enabling the upper main reinforcement bars 30 and lower main reinforcement bars 40 placed at the ends to be embedded without gaps inside the post-cast concrete body 60.

[0136] Next, with reference to Figure 11, a manufacturing method for yet another example of the half-precast beam according to the embodiment will be described. Here, Figures 11(a) to (e) are process diagrams for the manufacturing method of another example of the half-precast beam according to the embodiment, and each shows a longitudinal section view perpendicular to the longitudinal direction of the other example of the half-precast beam according to the embodiment.

[0137] The third reinforced precast concrete slab 50Q, which is applied to the manufacturing method shown in Figure 11, has multiple separate first reinforcing bars 10F that form a roughly L-shape, with each separate first vertical bar 11F embedded at intervals along the longitudinal direction of the first precast concrete slab 20A, and each of the multiple roughly L-shaped first reinforcing bars 10A has a separate first upper horizontal bar 12A that overlaps with each of the separate first upper horizontal bars 12F that form each separate first reinforcing bar 10F, and is tied together, etc., and the fourth reinforced precast concrete slab 50R differs from the first reinforced precast concrete slab 50A and the second reinforced precast concrete slab 50B in that each of the separate second vertical reinforcements 11G forming a plurality of separate second reinforcing bars 10G, which are roughly L-shaped, are embedded at intervals along the longitudinal direction of the second precast concrete slab 20B, and each of the separate second horizontal reinforcements 14G forming each of the separate second reinforcing bars 10G of the plurality of separate second reinforcing bars 10B are arranged to overlap and tie together.

[0138] The separate first reinforcing bar 10F is formed by a series of separate first longitudinal bars 11F, separate first upper transverse bars 12F which bend at the upper end of the separate first longitudinal bar 11F and extend laterally, and separate first lower hook bars 15F which bend at the lower end of the separate first longitudinal bar 11F and extend upward, forming a roughly L-shape.

[0139] On the other hand, the separate second reinforcing bar 10G consists of a separate second longitudinal bar 11G, a separate second lower transverse bar 14G that bends at the lower end of the separate second longitudinal bar 11G and extends laterally, and a separate second upper hook 13G that bends at the upper end of the separate second longitudinal bar 11G and extends downward, forming a roughly L-shape.

[0140] Multiple separate first reinforcing bars 10F each have their own separate first vertical bars 11F embedded in the first vertical slab 22A of the first precast concrete slab 20A at intervals along its longitudinal direction. The first upper horizontal bars 12A of the corresponding first reinforcing bar 10A are then wrapped around the separate first upper horizontal bars 12F of each separate first reinforcing bar 10F and tied or welded together. Multiple upper main bars 30 extending in the longitudinal direction are attached below the multiple first upper horizontal bars 12A to form the third reinforced precast concrete slab 50Q.

[0141] On the other hand, for the second longitudinal slab 22B of the second precast concrete slab 20B, multiple separate second reinforcing bars 10G, each with its own separate second longitudinal bars 11G, are embedded at intervals along its longitudinal direction. The corresponding second lower transverse bars 14B of the second reinforcing bar 10B are then placed overlapping with the separate second lower transverse bars 14G of each separate second reinforcing bar 10G and tied or welded together. Multiple lower main bars 40 extending in the longitudinal direction are attached above the multiple second lower transverse bars 14B to form the fourth reinforced precast concrete slab 50R.

[0142] Here, the entirety of the third reinforced concrete slab 50Q and the fourth reinforced concrete slab 50R shown in the diagram may be manufactured in a factory or the like, transported to the site and installed in the designated location. Alternatively, the first precast concrete slab 20A, the second precast concrete slab 20B, the first reinforced concrete slab 10A, the second reinforced concrete slab 10B, the upper main reinforcement 30, and the lower main reinforcement 40 may be transported to the site without the first reinforced concrete slab 10A, the second reinforced concrete slab 10B, the upper main reinforcement 30, and the lower main reinforcement 40 being attached (all parts except the first reinforced concrete slab 10A, the second reinforced concrete slab 10B, the upper main reinforcement 30, and the lower main reinforcement 40 being manufactured in a factory or the like), and after the first precast concrete slab 20A is installed in the designated location at the site, the first reinforced concrete slab 10A is attached to a separate first reinforced concrete slab 10F, and the upper main reinforcement 30 is attached to the first reinforced concrete slab 10A to form the third reinforced concrete slab 50Q. In this case, the 50R precast concrete slab with the fourth reinforcement bar will also have its transported components attached to each other, similar to the 50Q precast concrete slab with the third reinforcement bar.

[0143] Here, although not shown in the diagram, there may be a configuration in which a first reinforcing bar 10A is provided between a first reinforcing bar 10A connected to a separate first reinforcing bar 10F, without the other separate first reinforcing bar 10F present. For example, in addition to the first reinforcing bars 10A connected to a separate first reinforcing bar 10F, a first reinforcing bar 10A that is not connected to a separate first reinforcing bar 10F may be provided. In other words, any number of first reinforcing bars 10A from the multiple first reinforcing bars 10A constituting the first reinforced concrete slab 50A shown in Figure 1 may be provided in place of the first reinforcing bars 10A connected to the separate first reinforcing bar 10F in this embodiment. In this way, by combining the first reinforcing bars 10A of different embodiments, it is possible to provide a number of first reinforcing bars 10A that can obtain the desired shear reinforcement effect. The same applies to the second reinforcing bar 10B connected to a separate second reinforcing bar 10G.

[0144] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 11(a), the third reinforced concrete slab 50Q is positioned on the lower frame 91.

[0145] Next, as shown in Figure 11(b), the fourth reinforced precast concrete slab 50R is moved laterally in the X13 direction, and the lateral movement is stopped when the lower main reinforcement 40 at the left end passes the first lower hook 15A and the second upper hook 13B passes the upper main reinforcement 30 at the right end.

[0146] Next, as shown in Figure 11(c), the precast concrete slab 50R with the fourth reinforcement bar is lowered in the X14 direction, so that the lower main reinforcement bar 40 at the left end is sandwiched between the first lower hook 15A and the second lower hook 15B, and the upper main reinforcement bar 30 at the right end is sandwiched between the first upper hook 13A and the second upper hook 13B.

[0147] As shown in Figure 11(d), by completely lowering the fourth reinforced precast concrete slab 50R and installing it on the lower frame 91, the first lower hook 15A and the second lower hook 15B sandwich the lower main reinforcement 40 at the left end, and the first upper hook 13A and the second upper hook 13B sandwich the upper main reinforcement 30 at the right end. Multiple upper main reinforcement bars 30 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the first upper horizontal reinforcement bar 12A, and multiple lower main reinforcement bars 40 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the second lower horizontal reinforcement bar 14B. The reinforcement is then automatically arranged, and a gap G is formed between the third reinforced precast concrete slab 50Q and the fourth reinforced precast concrete slab 50R.

[0148] Next, as shown in Figure 11(e), concrete is poured into the gap G to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100G having a third reinforced precast concrete slab 50Q, a fourth reinforced precast concrete slab 50R, and a post-cast concrete body 60.

[0149] The manufacturing method shown in the illustration reduces the labor involved in setting up and removing formwork, eliminates or reduces the labor required for reinforcing beams, and results in a manufacturing method that offers excellent manufacturability for beams and improves quality.

[0150] Furthermore, in addition to the precast concrete slabs 20A and 20B, which have separate first and second vertical reinforcements 11F and 2 vertical reinforcements 11G embedded in them, the shear reinforcement effect of the first and second reinforcements 10A and 2 reinforcing bars 10B, which are bound together and have an approximate L-shape, can be further enhanced by embedding the entirety of the first and second reinforcements 10A and 2 reinforcing bars 10B, which are bound together and have an approximate L-shape, into the later-cast concrete body 60. As a result, even if the degree of integration between the precast concrete slabs 20A and 20B and the later-cast concrete body 60 is not good, a high shear reinforcement effect can be achieved by the first and second reinforcements 10A and 2 reinforcing bars 10B, which have an approximate L-shape.

[0151] Next, with reference to Figure 12, a manufacturing method for yet another example of the half-precast beam according to the embodiment will be described. Here, Figures 12(a) to (e) are process diagrams for the manufacturing method of another example of the half-precast beam according to the embodiment, and each shows a longitudinal section view perpendicular to the longitudinal direction of the other example of the half-precast beam according to the embodiment.

[0152] The third reinforced precast concrete slab 50S, applied to the manufacturing method shown in Figure 12, differs from the third reinforced precast concrete slab 50Q and the fourth reinforced precast concrete slab 50R in that a first corrugated reinforcing bar 19A (truss reinforcement), which extends longitudinally and exhibits a corrugated shape, is connected to the separate first longitudinal reinforcement bar 11F of the separate first reinforcement bar 10F and the first longitudinal reinforcement bar 11A of the first reinforcement bar 10A, while the fourth reinforced precast concrete slab 50T differs from the third reinforced precast concrete slab 50Q and the fourth reinforced precast concrete slab 50R in that a second corrugated reinforcing bar 19B (truss reinforcement), which extends longitudinally and exhibits a corrugated shape, is connected to the separate second longitudinal reinforcement bar 11G of the separate second reinforcement bar 10G and the second longitudinal reinforcement bar 11B of the second reinforcement bar 10B.

[0153] The peaks and valleys of the first corrugated reinforcement bar 19A are welded to the separate first longitudinal reinforcement bar 11F of the separate first reinforcement bar 10F and the first longitudinal reinforcement bar 11A of the first reinforcement bar 10A, thereby joining these three members together. Similarly, the peaks and valleys of the second corrugated reinforcement bar 19B are welded to the separate second longitudinal reinforcement bar 11G of the separate second reinforcement bar 10G and the second longitudinal reinforcement bar 11B of the second reinforcement bar 10B, thereby joining these three members together.

[0154] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 12(a), the third reinforced concrete slab 50S is positioned on the lower frame 91.

[0155] Next, as shown in Figure 12(b), the fourth reinforced precast concrete slab 50T is moved laterally in the X15 direction, and the lateral movement is stopped when the lower main reinforcement 40 at the left end passes the first lower hook 15A and the second upper hook 13B passes the upper main reinforcement 30 at the right end.

[0156] Next, as shown in Figure 12(c), the precast concrete slab 50T with the fourth reinforcement bar is lowered in the X16 direction, so that the lower main reinforcement bar 40 at the left end is sandwiched between the first lower hook 15A and the second lower hook 15B, and the upper main reinforcement bar 30 at the right end is sandwiched between the first upper hook 13A and the second upper hook 13B.

[0157] As shown in Figure 12(d), by completely lowering the fourth reinforced precast concrete slab 50T and installing it on the lower frame 91, the first lower hook 15A and the second lower hook 15B sandwich the lower main reinforcement 40 at the left end, and the first upper hook 13A and the second upper hook 13B sandwich the upper main reinforcement 30 at the right end. Multiple upper main reinforcement bars 30 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the first upper horizontal reinforcement bar 12A, and multiple lower main reinforcement bars 40 (seven in the illustrated example) are arranged at equal or approximately equal intervals horizontally with respect to the second lower horizontal reinforcement bar 14B. The reinforcement is then automatically arranged, and a gap G is formed between the third reinforced precast concrete slab 50S and the fourth reinforced precast concrete slab 50T.

[0158] Next, as shown in Figure 12(e), concrete is poured into the gap G to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100H having a third reinforced precast concrete slab 50S, a fourth reinforced precast concrete slab 50T, and a post-cast concrete body 60.

[0159] The manufacturing method shown in the illustration reduces the labor involved in setting up and removing formwork, eliminates or reduces the labor required for reinforcing beams, and results in a manufacturing method that offers excellent manufacturability for beams and improves quality.

[0160] Furthermore, the first wavy reinforcing bar 19A, which extends vertically and exhibits a wave-like shape, is connected to the first longitudinal bar 11A of the roughly L-shaped first reinforcing bar 10A and to the separate first longitudinal bar 11F of the separately L-shaped first reinforcing bar 10F, and the second wavy reinforcing bar 19B, which extends vertically and exhibits a wave-like shape, is connected to the second longitudinal bar 11B of the roughly L-shaped second reinforcing bar 10B and to the separate second longitudinal bar 11G of the separately L-shaped second reinforcing bar 10G, thereby enabling a stronger integration of the two. Furthermore, this configuration allows the first vertical reinforcement 11A, the separate first vertical reinforcement 11F, and the first corrugated reinforcement 19A between them, as well as the second vertical reinforcement 11B, the separate second vertical reinforcement 11G, and the second corrugated reinforcement 19B between them, to resist, in a mechanism similar to that of a truss beam, the pressure acting on the inside of the precast concrete slabs 20A and 20B when concrete is poured during the construction of the post-cast concrete body 60, and the earth pressure acting on the outside of the precast concrete slabs 20A and 20B when soil is backfilled before concrete is poured.

[0161] The above has described half-precast beams applied to the beams of the upper floors of a building and their manufacturing method with reference to Figures 1 to 12, but as shown in Figure 13, half-precast beams may also be applied to the foundation beams of a building. Here, Figures 13(a) and (b) are both longitudinal cross-sectional views perpendicular to the longitudinal direction, showing a pair of reinforced precast concrete slabs assembled to constitute yet another example of a half-precast beam according to the embodiment, and both show the first reinforced precast concrete slab 50I and the second reinforced precast concrete slab 50J, which were described with reference to Figure 6, as examples of being applied to a foundation beam.

[0162] In the example shown in Figure 13(a), a leveling material (for example, crushed stone 95 or lean concrete 96) is laid on the excavated and prepared ground surface to ensure levelness. A first reinforced precast concrete slab 50I and a second reinforced precast concrete slab 50J are then placed on top of the lean concrete 96, forming a gap G between them. By pouring concrete into the gap G, a foundation beam, which is a half-precast beam (not shown), is fabricated.

[0163] On the other hand, the example shown in Figure 13(b) involves installing a precast concrete slab 20I that also serves as a lower frame on top of crushed stone 95, and then fitting the lower ends of the first reinforced precast concrete slab 50I and the second reinforced precast concrete slab 50J into a pair of recesses 25 provided on the upper surface of the precast concrete slab 20I.

[0164] Since the lower ends of the first reinforced precast concrete slab 50I and the second reinforced precast concrete slab 50J are fitted into the recess 25 of the lower frame-integrated precast concrete slab 20I, the stable upright position of the first reinforced precast concrete slab 50I and the second reinforced precast concrete slab 50J can be maintained while eliminating the need for leveling material.

[0165] Other embodiments may be used in which other components are combined with the configurations listed in the above embodiments, and the present invention is not limited in any way to the configurations shown herein. In this regard, modifications can be made without departing from the spirit of the present invention, and can be appropriately determined according to the application form. [Explanation of Symbols]

[0166] 10A, 10C, 10E, 10F, 10G, 10H: First reinforcing muscle 10B, 10D: Second reinforcing muscle 10F: Separate first reinforcement bar 10G: Additional second reinforcement muscle 11A: First vertical reinforcement (vertical reinforcement) 11B: Second vertical line (vertical line) 11F: Separate first vertical reinforcement 11G: Separate second vertical reinforcement 12A: First transverse muscle (supertransverse muscle) 12F: Separate 1st upper horizontal reinforcement 13A: First upper hook (upper hook, 135-degree hook) 13B: Second upper hook (upper hook, 90-degree hook) 13G: Separate second upper hook 14B: Second lower transverse muscle 14G: Separate second lower horizontal reinforcement 15A: First lower hook (lower hook, 90-degree hook) 15C: Long lower hook (1st long lower hook, 90-degree hook) 15D: Long lower hook (2nd long lower hook, 90-degree hook) 15F: Separate first lower hook (lower hook, 90-degree hook) 15B: Second lower hook (lower hook, 135-degree hook) 17: Planning 18: First accessory muscle 19A: First wave-shaped reinforcing bar 19B: Second wave-shaped reinforcing muscle 20A, 20C, 20E, 20G: First precast concrete slab (precast concrete slab) 20B, 20D, 20F, 20H: Second precast concrete slab (precast concrete slab) 20I: Precast concrete slab (precast concrete slab that also serves as a base frame) 22A: First vertical version 22B: 2nd vertical version 24A: First horizontal edition 26B: 2nd bottom horizontal version 27A: 1st bottom horizontal version 27B: 2nd bottom horizontal version 28A: First upper recess 28B: Second upper recess 29A: First downward recess 29B: Second downward depression 30: Top main reinforcement 40: Bottom main reinforcement 50A, 50C, 50E, 50G, 50I, 50K, 50L, 50M, 50N: First-generation reinforced precast concrete slab (reinforced precast concrete slab) 50B, 50D, 50F, 50H, 50J, 50P: Second-generation reinforced precast concrete slab (reinforced precast concrete slab) 50Q, 50S: Third-generation reinforced precast concrete slab (reinforced precast concrete slab) 50R, 50T: Reinforced concrete slab with 4th-grade steel bars (reinforced concrete slab) 60: Post-cast concrete body 60A: Concrete slab 91: Bottom frame 92: Floor frame 93: Floor line 95: Crushed stone (land leveling material) 96: Lean concrete (ground leveling material) 100, 100A, 100B, 100C, 100D, 100E, 100F, 100G, 100H: Half-precast beams G: Gap

Claims

1. A first reinforced concrete slab, comprising a first vertical bar, a first upper transverse bar that bends at the upper end of the first vertical bar and extends laterally, a first upper hook that bends at the end of the first upper transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a first lower hook that bends at the lower end of the first vertical bar and extends upward, which are continuous and form a roughly L-shape, wherein each of the first vertical bars of the first reinforcement bars is embedded at intervals in the longitudinal direction of the first precast concrete slab, and upper main bars extending in the longitudinal direction are attached below the plurality of first upper transverse bars, The second reinforcement bar is a precast concrete slab with a second reinforcement bar, each of which is embedded at intervals along the longitudinal direction of the second precast concrete slab, and a lower main reinforcement bar extending along the longitudinal direction is attached above the multiple lower reinforcement bars, each of which is embedded at intervals along the longitudinal direction of the second precast concrete slab, and a lower main reinforcement bar extending along the longitudinal direction is attached above the multiple lower reinforcement bars, the second vertical reinforcement bar is bent at the lower end of the second vertical reinforcement bar and extends laterally, the second lower hook is a 90-degree hook, a 135-degree hook, or a 180-degree hook and extends bent at the end of the second lower horizontal reinforcement bar, and a second upper hook is bent above the second vertical reinforcement bar and extends downward, forming a substantially L-shape. A half-precast beam characterized in that the first upper horizontal reinforcement and the second upper hook intersect, and the second lower horizontal reinforcement and the first lower hook intersect, with the first precast concrete slab and the second precast concrete slab being arranged with a gap between them, and a post-cast concrete body being provided in the gap.

2. In the first precast concrete slab, some of the upper main reinforcement bars of the multiple upper main reinforcement bars are embedded, The half-precast beam according to claim 1, characterized in that some of the lower main reinforcement bars of the plurality of lower main reinforcement bars are embedded in the second precast concrete slab.

3. The first precast concrete slab comprises a first vertical slab extending in the vertical direction and a first upper horizontal slab extending horizontally from the upper end of the first vertical slab. The second precast concrete slab comprises a second vertical slab extending in the vertical direction and a second lower horizontal slab extending horizontally from the lower end of the second vertical slab. A half-precast beam according to claim 1 or 2, characterized in that some of the upper main reinforcement bars of the plurality of upper main reinforcement bars are embedded in the first upper horizontal plate, and some of the lower main reinforcement bars of the plurality of lower main reinforcement bars are embedded in the second lower horizontal plate.

4. The first precast concrete slab comprises a first vertical slab extending in the vertical direction and a first lower horizontal slab extending horizontally from the lower end of the first vertical slab. The second precast concrete slab comprises a second vertical slab extending in the vertical direction and a second lower horizontal slab extending horizontally from the lower end of the second vertical slab. The first lower hook is located above the first lower horizontal plate, Multiple lower end main reinforcements are embedded in the second lower horizontal plate. The half-precast beam according to claim 1 or 2, characterized in that the end faces of the first lower cross plate and the second lower cross plate are in contact with each other.

5. The first precast concrete slab comprises a first vertical slab extending in the vertical direction, The second precast concrete slab comprises a second vertical slab extending in the vertical direction, A first upper recess and a first lower recess are provided on the inner side of the upper and lower ends of the first vertical plate, respectively. The upper and lower ends of the second vertical plate are provided with a second upper recess and a second lower recess, respectively. The half-precast beam according to claim 1 or 2, characterized in that the upper main reinforcement adjacent to the first upper recess is separated laterally, and the lower main reinforcement adjacent to the second lower recess is separated laterally.

6. The structure comprises multiple first reinforcing bars, each consisting of a first longitudinal bar, a first upper transverse bar that bends at the upper end of the first longitudinal bar and extends laterally, a first upper hook that bends at the end of the first upper transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a first lower hook that bends at the lower end of the first longitudinal bar and extends upward, forming a substantially L-shape. It comprises a plurality of separate first reinforcing bars, each having a separate first vertical bar, a separate first upper horizontal bar that bends at the upper end of the separate first vertical bar and extends laterally, and a separate first lower hook that bends at the lower end of the separate first vertical bar and extends upward, forming a substantially L-shape in a continuous manner. Each of the aforementioned separate first reinforcing bars is embedded at intervals along the longitudinal direction of the first precast concrete slab. For each of the aforementioned separate first reinforcing bars, the first upper transverse bar of the corresponding first reinforcing bar is arranged to overlap and then tied or welded together. A precast concrete slab with third reinforcement bars, wherein the upper main reinforcement bars extending in the longitudinal direction are attached below a plurality of the first upper transverse reinforcements, The structure comprises multiple second reinforcing bars, each having a second longitudinal bar, a second lower transverse bar that bends at the lower end of the second longitudinal bar and extends laterally, a second lower hook that bends at the end of the second lower transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a second upper hook that bends at the upper end of the second longitudinal bar and extends downward, forming a substantially L-shape. It is equipped with multiple separate second reinforcing bars, each having a separate second vertical bar, a separate second upper hook that bends at the upper end of the separate second vertical bar and extends downward, and a separate second lower transverse bar that bends at the lower end of the separate second vertical bar and extends laterally, forming a roughly L-shape in a continuous manner. Each of the aforementioned separate second reinforcing bars is embedded at intervals along the longitudinal direction of the second precast concrete slab. The second lower transverse bar of the corresponding second reinforcing bar is arranged to overlap with the second lower transverse bar of each of the aforementioned separate second reinforcing bars, and is then tied or welded together. It comprises a precast concrete slab with a fourth reinforced concrete slab, to which the longitudinally extending lower end main reinforcement is attached above a plurality of the second lower transverse reinforcements, A half-precast beam characterized in that the first upper horizontal reinforcement and the second upper hook intersect, and the second lower horizontal reinforcement and the first lower hook intersect, with the first precast concrete slab and the second precast concrete slab being arranged with a gap between them, and a post-cast concrete body being provided in the gap.

7. In the longitudinal direction, a first reinforcing bar is arranged between the first reinforcing bars that are tied or welded to the other first reinforcing bar, and the other first reinforcing bar is not present. The half-precast beam according to claim 6, characterized in that, in the longitudinal direction, the second reinforcing bar is arranged between the second reinforcing bars that are tied or welded to the other second reinforcing bar, and there is no counterpart second reinforcing bar present.

8. A first wavy reinforcing bar, which extends in the longitudinal direction and exhibits a wavy shape, is connected to the first longitudinal bar and the separate first longitudinal bar. The half-precast beam according to claim 6, characterized in that a second corrugated reinforcing bar, which extends in the longitudinal direction and exhibits a corrugated shape, is connected to the second longitudinal bar and the separate second longitudinal bar.

9. Multiple upper main reinforcement bars are provided in multiple stages, and each stage contains multiple upper main reinforcement bars. The half-precast beam according to claim 1 or 6, characterized in that multiple stages of lower main reinforcement are provided, and each stage contains multiple lower main reinforcement bars.

10. The first auxiliary reinforcement, which prevents the sagging or swaying of the first upper horizontal reinforcement to which the upper main reinforcement is attached, is arranged so as to straddle the first upper horizontal reinforcement or the first upper hook and the first vertical reinforcement. The half-precast beam according to claim 9, characterized in that a second auxiliary reinforcement, which prevents the sagging or swaying of the second lower horizontal reinforcement to which the lower end main reinforcement is attached, is arranged so as to straddle the second lower horizontal reinforcement or the second lower hook and the second vertical reinforcement.

11. The half-precast beam according to claim 9, characterized in that, among the plurality of first and second reinforcing bars arranged in the longitudinal direction, some of the first and second reinforcing bars have relatively large cross-sectional diameters, and these large-diameter reinforcing bars prevent both the first upper transverse bar and the second lower transverse bar from sagging or swaying.

12. A first reinforced concrete slab, comprising a first vertical bar, a first upper transverse bar that bends at the upper end of the first vertical bar and extends laterally, a first upper hook that bends at the end of the first upper transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a first lower hook that bends at the lower end of the first vertical bar and extends upward, which are continuous and form a roughly L-shape, wherein each of the first vertical bars of the first reinforcement bars is embedded at intervals in the longitudinal direction of the first precast concrete slab, and upper main bars extending in the longitudinal direction are attached below the plurality of first upper transverse bars, A precast concrete slab with a second reinforcing bar is prepared, wherein each of the second vertical bars of the second reinforcing bar is embedded at intervals along the longitudinal direction of the second precast concrete slab, and a lower main reinforcing bar extending in the longitudinal direction is attached above the multiple second lower horizontal bars, with the second vertical bars of each of the second reinforcing bars being a 90-degree hook, a 135-degree hook, or a 180-degree hook that bends and extends along the end of the second lower horizontal bar and a second upper hook that bends and extends downward above the second vertical bar, forming a roughly L-shape. Position the first reinforced precast concrete slab, move the second reinforced precast concrete slab so that the first upper horizontal bar and the second upper hook intersect, and the second lower horizontal bar and the first lower hook intersect, while positioning the first precast concrete slab and the second precast concrete slab with a gap between them. A method for manufacturing a half-precast beam, characterized by producing a half-precast beam by pouring concrete into the gap to form a post-cast concrete body.

13. The first precast concrete slab comprises a first vertical slab extending in the vertical direction and a first lower horizontal slab extending horizontally from the lower end of the first vertical slab. The second precast concrete slab comprises a second vertical slab extending in the vertical direction and a second lower horizontal slab extending horizontally from the lower end of the second vertical slab. Multiple lower end main reinforcements are embedded in the second lower horizontal plate. By bringing the end faces of the first lower horizontal plate and the second lower horizontal plate into contact with each other, the first vertical plate and the second vertical plate, along with the first lower horizontal plate and the second lower horizontal plate, form a U-shaped formwork with a cross-sectional shape perpendicular to the longitudinal direction that opens upward. A method for manufacturing a half-precast beam according to claim 12, characterized in that concrete is poured into the formwork to form the post-cast concrete body.

14. At least one of the first lower hooks of the multiple first reinforcing bars in the first reinforced precast concrete slab, which is positioned first, is a long lower hook, longer than the length of all the second upper hooks of the second reinforcing bars in the second reinforced precast concrete slab, which is positioned second. When lowering the second reinforced precast concrete slab downwards, the long lower hook is passed in advance between the multiple second lower horizontal reinforcements provided in the second reinforced precast concrete slab, or At least one of the second upper hooks of the multiple second reinforcing bars provided in the second reinforced precast concrete slab, which is positioned later, is an elongated upper hook, longer than the length of all the first lower hooks of the first reinforcing bars provided in the first reinforced precast concrete slab, which is positioned earlier. The method for manufacturing a half-precast beam according to claim 12, characterized in that when lowering the second reinforced precast concrete slab downward, the long upper hook is passed in advance between the plurality of first upper horizontal reinforcements provided in the first reinforced precast concrete slab.

15. In the configuration having the long lower hook, of the two first reinforcing bars located at both ends in the longitudinal direction of the first precast concrete slab, the first lower hook of one of the first reinforcing bars is the longest first long lower hook, and the first lower hook of the other first reinforcing bar is the next longest second long lower hook. After passing the first long lower hook through the multiple second lower horizontal reinforcements of the second reinforced concrete slab, the second long lower hook is then passed through the multiple second lower horizontal reinforcements of the second reinforced concrete slab, or In the configuration having the long upper hook, of the two second reinforcing bars located at both ends in the longitudinal direction of the second precast concrete slab, the second upper hook of one of the second reinforcing bars is the longest first long upper hook, and the second upper hook of the other second reinforcing bar is the next longest second long upper hook. A method for manufacturing a half-precast beam according to claim 14, characterized in that the first long upper hook is passed first between the plurality of first upper horizontal reinforcements provided in the first reinforced precast concrete slab, and then the second long upper hook is passed between the plurality of first upper horizontal reinforcements provided in the first reinforced precast concrete slab.

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