Reinforced precast concrete slabs and half-precast beams

Abstract

To provide reinforced precast concrete panels and half-precast beams that reduce the labor involved in setting up and removing formwork, eliminate or reduce the labor required for reinforcing beams, and improve quality. [Solution] In the reinforced precast concrete slab 50, each of the vertical bars 11 of the multiple reinforcing bars 10, each having at least one vertical bar 11, is connected to a plurality of separate reinforcing bars 10D, each having at least one additional vertical bar 11D, and each separate vertical bar 11D is embedded at intervals in the longitudinal direction of the precast concrete slab 20, the reinforcing bars 10 are not embedded in the precast concrete slab 20, and upper main bars 30 and lower main bars 40 are attached to the plurality of reinforcing bars 10. The half-precast beam 100 is formed by arranging a pair of reinforced precast concrete slabs 50 with a gap G between them, and providing a post-cast concrete body 60 in the gap G.

Description

Technical Field

[0001] The present invention relates to a precast concrete slab with reinforcement bars and a half-precast beam.

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), as a measure to save the labor of installing temporary members and improve workability, a pair of PCa (Precast) concrete slabs manufactured in a factory or the like are installed at the beam construction position on the site with a gap, beam bars are 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] In this way, 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 bars, the precast part can be expected to have structural strength, and since the precast concrete slab is manufactured in a factory, it is possible to suppress problems such as concrete janka and cracking that occur when the entire reinforced concrete beam is fabricated on-site (constructed on-site), and by ensuring the reinforcement arrangement accuracy, the quality can be improved.

[0004] Furthermore, in the case of so-called full precast beams, where the entire reinforced concrete beam is formed from precast concrete panels, the weight becomes heavy, reducing transportability, and construction costs tend to increase because large-capacity lifting equipment is required during construction. However, these problems can be resolved by applying half-precast beams.

[0005] Here, Patent Document 1 proposes a method for constructing beams. This construction method is for constructing a reinforced concrete foundation beam, in which the main reinforcement on the lower end of the beam is embedded in the longitudinal direction, the stirrup reinforcement is embedded in the short direction, and one end of the stirrup reinforcement is exposed from the side to form a stirrup anchorage part, and the other end is exposed from the upper surface of a precast plate which is manufactured in advance, and a pair of precast plates are installed vertically on a concrete base plate so that the exposed sides of the stirrup anchorage parts face each other, and intermediate beam reinforcement is placed in the space formed by the opposing installation of the pair of precast plates to satisfy the required amount of main reinforcement and shear reinforcement, and concrete is poured into the space to anchor the intermediate beam reinforcement and the stirrup anchorage part in the concrete and construct the foundation beam. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2016-79695 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] 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.

[0008] 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.

[0009] This invention has been made in view of the above problems, and aims to provide a reinforced precast concrete panel and a half-precast beam that can reduce the labor required for setting up and removing formwork by using a precast concrete panel that constitutes a half-precast beam, while eliminating or reducing the labor required for reinforcing beams, thereby improving quality. [Means for solving the problem]

[0010] To achieve the aforementioned objective, one embodiment of the reinforced precast concrete slab according to the present invention is: A pair of reinforced precast concrete panels are arranged with a gap between them to form a half-precast beam, Each of the longitudinal bars of a plurality of reinforcing bars, each having at least longitudinal bars, is connected to a plurality of separate reinforcing bars, each having at least separate longitudinal bars, each of the separate longitudinal bars is embedded at intervals in the longitudinal direction of the precast concrete slab, the reinforcing bars are not embedded in the precast concrete slab, and at least one of the upper or lower main bars is attached to the plurality of reinforcing bars.

[0011] According to this embodiment, in each of the pair of reinforced precast concrete slabs forming a half-precast beam, separate longitudinal reinforcing bars are embedded within the precast concrete slab at intervals along its longitudinal direction, and reinforcing bars are connected to these separate reinforcing bars. At least one of the upper or lower main reinforcing bars is attached to multiple reinforcing bars not embedded in the precast concrete slab, thereby automatically arranging the beam reinforcement when the pair of reinforced precast concrete slabs are installed. This allows for labor savings in formwork installation and demolding using precast concrete slabs, while eliminating or reducing the labor required for beam reinforcement arrangement. Furthermore, since it is factory-made, quality can be ensured. In addition, because the separate reinforcing bars partially embedded within the precast concrete slab and the reinforcing bars to which the main reinforcing bars (upper or lower main reinforcing bars) are connected are formed separately, the precast concrete slab with integrated separate reinforcing bars and the beam reinforcement with main reinforcing bars can be formed (manufactured) separately. This makes it possible to mass-produce precast concrete slabs regardless of the beam reinforcement configuration.

[0012] Furthermore, one embodiment of the half-precast beam according to the present invention is: A pair of reinforced precast concrete panels are arranged with a gap between them, and a post-cast concrete body is provided in the gap.

[0013] According to this embodiment, a pair of precast concrete slabs with reinforced bars are arranged with a gap between them, and a post-cast concrete body is provided in the gap. As a result, the entire reinforcing bar to which at least one of the upper or lower main reinforcements is attached is embedded in the post-cast concrete body, thereby enhancing the shear reinforcement effect. Consequently, even if the degree of integration between the precast concrete slab and the post-cast concrete body is not good, a high shear reinforcement effect can be achieved by the reinforcing bar.

[0014] Furthermore, other embodiments of the half-precast beam according to the present invention include: The device comprises a plurality of first reinforcing bars, each having 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 extends downward, a first lower transverse bar that bends at the lower end of the first longitudinal bar and extends laterally, and a first lower hook that bends at the end of the first lower transverse bar and extends upward, which are arranged in a continuous C-shape. It comprises a plurality of separate first reinforcing bars, each having a separate first longitudinal bar and connected to the separate first longitudinal bar, to which are wavy reinforcing bars that extend longitudinally and exhibit a wavy shape, or a plurality of separate first reinforcing bars, each having a pair of separate first longitudinal bars and connected to the pair of separate first longitudinal bars, to which are wavy reinforcing bars that extend longitudinally and exhibit a wavy shape. At least one of the separate first reinforcing bars, each of which has a separate first longitudinal bar, is embedded at intervals in the longitudinal direction of the first precast concrete slab. The first longitudinal bar of the corresponding first reinforcing bar is tied or welded to the wavy reinforcing bar or the separate first longitudinal bar of each of the aforementioned separate first reinforcing bars. The present invention comprises a pair of precast concrete slabs with first reinforcement bars, wherein multiple upper main reinforcement bars extending in the longitudinal direction are attached below multiple first upper transverse reinforcement bars, and multiple lower main reinforcement bars extending in the longitudinal direction are attached above multiple first lower transverse reinforcement bars. The pair of reinforced precast concrete slabs are arranged with gaps between them, overlapping the first upper horizontal reinforcements of both slabs and overlapping the first lower horizontal reinforcements of both slabs, and a post-cast concrete body is provided in the gap.

[0015] In this embodiment, at least one of the separate first longitudinal bars of each of the multiple separate first reinforcing bars, to which separate first longitudinal bars and corrugated reinforcing bars (truss bars) are connected, is embedded at intervals along the longitudinal direction of the first precast concrete slab. The first longitudinal bars of the C-shaped first reinforcing bars corresponding to each corrugated reinforcing bar or separate first longitudinal bar are tied or welded together. The upper main bars are attached below the first upper transverse bars of the multiple first reinforcing bars, and the lower main bars are attached above the first lower transverse bars of the multiple first reinforcing bars. A post-cast concrete body is provided in the gap between a pair of precast concrete slabs with first reinforcing bars, so that the beam reinforcement is automatically arranged when the pair of precast concrete slabs with first reinforcing bars are installed. This makes it possible to reduce the labor involved in setting up and removing formwork using precast concrete slabs, eliminate or reduce the labor involved in arranging beam reinforcement, and ensure quality because it is factory-made.

[0016] Furthermore, by embedding the entire C-shaped first reinforcing bar, which is tied or otherwise secured, into the later-cast concrete body, the shear reinforcement effect can be enhanced. This means that even if the degree of integration between the first precast concrete slab and the later-cast concrete body is not good, a high shear reinforcement effect can be achieved by the C-shaped first reinforcing bar.

[0017] Furthermore, when constructing a post-cast concrete body, the first longitudinal reinforcement, separate first longitudinal reinforcement, and the corrugated reinforcement between them can resist the pressure acting on the inside of the precast concrete slab when concrete is poured, as well as the earth pressure acting on the outside of the precast concrete slab when soil is backfilled before concrete is poured, in a mechanism similar to that of a truss beam.

[0018] Furthermore, by wrapping the first reinforcing bars on both sides of a pair of precast concrete slabs with first reinforcing bars, a half-precast beam having high torsional strength and capable of ensuring sufficient confinement area can be formed, thus ensuring toughness performance.

[0019] Here, "at least the separate first longitudinal bars of the separate first reinforcing bars are embedded in the first precast concrete slab" means a form in which only the separate first longitudinal bars are embedded in the first precast concrete slab, and a form in which a part of the corrugated reinforcing bars is embedded in addition to the separate first longitudinal bars.

[0020] The half-precast beam of this aspect can be applied to the upper beams 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 carry out the steel bar arrangement work. Also, in the case of a foundation beam with a beam height of about 2m to 3m, it is difficult to enter the pair of precast concrete slabs to arrange the beam steel bars. Therefore, it is preferable that the steel bar arrangement work in the pair of precast concrete slabs can be eliminated or labor-saving, which can significantly improve the construction performance of the foundation beam.

[0021] Also, another aspect of the half-precast beam according to the present invention is comprising a plurality of first reinforcing bars in which a first longitudinal bar, a first upper horizontal bar that bends at the upper end of the first longitudinal bar and extends horizontally, a first upper hook that bends at the end of the first upper horizontal bar and extends downward, a first lower horizontal bar that bends at the lower end of the first longitudinal bar and extends horizontally, and a first lower hook that bends at the end of the first lower horizontal bar and extends upward are continuously in a C shape. comprising a plurality of separate first reinforcing bars in which a pair of separate first longitudinal bars, a separate first upper horizontal bar, and a separate first lower horizontal bar are continuously in a rectangular frame shape. at least one of the separate first longitudinal bars of the plurality of separate first reinforcing bars is embedded at intervals in the longitudinal direction of the first precast concrete slab. each of the separate first reinforcing bars and the corresponding first reinforcing bar are wrapped around each other. A plurality of upper end main bars extending in the longitudinal direction are attached below the plurality of first upper horizontal bars, and a plurality of lower end main bars extending in the longitudinal direction are attached above the plurality of first lower horizontal bars. At least one of the upper end main bar and the lower end main bar is disposed at a lapping portion of the separate first reinforcing bar and the first reinforcing bar. It has a pair of precast concrete slabs with first reinforcing bars. The pair of precast concrete slabs with reinforcing bars are arranged with a gap while lapping the first upper horizontal bars of both sides and lapping the first lower horizontal bars of both sides, and a post-cast concrete body is provided in the gap.

[0022] According to this aspect, at least the separate first longitudinal bars of the plurality of separate first reinforcing bars in which a pair of separate first longitudinal bars, separate first upper horizontal bars, and separate first lower horizontal bars are continuously in a rectangular frame shape are spaced apart in the longitudinal direction of the first precast concrete slab. After being embedded, after the corresponding first reinforcing bars are lapped with the respective separate first reinforcing bars, upper end main bars are attached below the first upper horizontal bars of the plurality of first reinforcing bars, and lower end main bars are attached above the first lower horizontal bars of the plurality of first reinforcing bars. By providing a post-cast concrete body in the gap between the pair of precast concrete slabs with first reinforcing bars, the reinforcement of the beam bars is automatically performed when the pair of precast concrete slabs with first reinforcing bars are installed. As a result, while labor saving in the installation and removal of the formwork can be achieved by the precast concrete slab, the reinforcement work of the beam bars can be eliminated or labor saving can be achieved, and quality assurance can be achieved because it is factory production.

[0023] Furthermore, since the entire first reinforcing bar having a C shape in which a part of it laps around a separate first reinforcing bar in which at least a separate first longitudinal bar is embedded in the first precast concrete slab is embedded in the post-cast concrete body, the shear reinforcement effect can be enhanced. As a result, even if the degree of integration between the first precast concrete slab and the post-cast concrete body is not good, a high shear reinforcement effect is achieved by the first reinforcing bar having a C shape.

[0024] Furthermore, by overlapping the first reinforcing bars of both precast concrete slabs with first reinforcing bars, a half-precast beam can be formed that has high torsional strength and ensures ductility due to the expected sufficient restraint area.

[0025] Here, "at least the separate first vertical reinforcement bars of the separate first reinforcing bars are embedded in the first precast concrete slab" means that the configuration includes both a configuration in which only the separate first vertical reinforcement bars are embedded in the first precast concrete slab, and a configuration in which, in addition to the separate first vertical reinforcement bars, a portion of the separate first upper horizontal reinforcement bars and a portion of the separate first lower horizontal reinforcement bars are embedded.

[0026] Furthermore, other embodiments of the half-precast beam according to the present invention include: The structure comprises multiple second reinforcing bars, each having a second longitudinal bar, a second upper transverse bar that bends at the upper end of the second longitudinal bar and extends laterally, a second upper hook that bends at the end of the second upper transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a second lower hook that bends at the lower end of the second longitudinal bar and extends upward, forming a roughly L-shape. It comprises a plurality of separate second reinforcing bars, each having a separate second longitudinal bar and connected to the separate second longitudinal bar, to which are wavy reinforcing bars that extend longitudinally and have a wavy shape, or a plurality of separate second reinforcing bars, each having a pair of separate second longitudinal bars and connected to the pair of separate second longitudinal bars, to which are wavy reinforcing bars that extend longitudinally and have a wavy shape, sandwiched between them. At least one of the separate second reinforcing bars, each of which has a separate second longitudinal reinforcement bar, is embedded at intervals in the longitudinal direction of the second precast concrete slab. The corresponding second longitudinal reinforcement is tied or welded to the wavy reinforcement or the separate second longitudinal reinforcement of each of the aforementioned second reinforcement bars. A precast concrete slab with second reinforcement bars, wherein the upper main reinforcement bars extending in the longitudinal direction are attached below a plurality of the aforementioned second upper transverse reinforcements, The third reinforcing bar comprises a third longitudinal bar, a third lower transverse bar that bends at the lower end of the third longitudinal bar and extends laterally, a third lower hook that bends at the end of the third lower transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a third upper hook that bends at the upper end of the third longitudinal bar and extends downward, forming a continuous, approximately L-shape. It comprises a plurality of separate third reinforcing bars, each having a separate third longitudinal bar and connected to the separate third longitudinal bar, to which are wavy reinforcing bars that extend longitudinally and have a wavy shape, or a plurality of separate third reinforcing bars, each having a pair of separate third longitudinal bars and connected to the pair of separate third longitudinal bars, to which are wavy reinforcing bars that extend longitudinally and have a wavy shape, sandwiched between them. At least one of the separate third reinforcing bars, each of which has a separate third longitudinal bar, is embedded at intervals in the longitudinal direction of the third precast concrete slab. The third longitudinal bar of the corresponding third reinforcing bar is tied or welded to the wavy reinforcing bar or the third longitudinal bar of each of the aforementioned separate third reinforcing bars. It comprises a precast concrete slab with a third reinforced concrete slab, to which the longitudinally extending lower end main reinforcement is attached above a plurality of the third lower transverse reinforcements, The second upper horizontal reinforcement and the third upper hook intersect, and the third lower horizontal reinforcement and the second lower hook intersect, while the second precast concrete slab and the third precast concrete slab are arranged with a gap between them, and a post-cast concrete body is provided in the gap.

[0027] According to this embodiment, at least the separate second longitudinal bars of each of the multiple separate second reinforcing bars, to which separate second longitudinal bars and corrugated reinforcing bars are connected, are embedded at intervals in the longitudinal direction of the second precast concrete slab, and the second longitudinal bars of the second reinforcing bars that are substantially L-shaped and corresponding to each corrugated reinforcing bar or separate second longitudinal bar are tied or welded, and the upper main bars are attached below the second upper transverse bars of the multiple second reinforcing bars to form the second reinforced precast concrete slab, and at least the separate third longitudinal bars of each of the multiple separate third reinforcing bars, to which separate third longitudinal bars and corrugated reinforcing bars are connected, are embedded at intervals in the longitudinal direction of the third precast concrete slab. The third longitudinal bars of the third reinforcing bars, which are roughly L-shaped and correspond to each corrugated reinforcing bar or a separate third longitudinal bar, are tied or welded together. The lower main bars are then attached above the third lower transverse bars of multiple third reinforcing bars to form a precast concrete slab with third reinforcing bars. The second and third precast concrete slabs are then placed with gaps between them, with the second upper transverse bars and the third upper hooks intersecting, and the third lower transverse bars and the second lower hooks intersecting. A post-cast concrete body is provided in the gaps, so that the beam reinforcement is automatically arranged when the second and third precast concrete slabs with reinforcing bars are installed. This allows for labor savings in the installation and removal of formwork using the second and third precast concrete slabs, while eliminating or reducing the labor required for beam reinforcement. Furthermore, quality can be ensured because the product is manufactured in a factory.

[0028] Furthermore, by intersecting the second and third reinforcing bars of the second and third reinforced concrete slabs and the third reinforced concrete slabs, a half-precast beam can be formed that has high torsional strength and ensures ductility due to the sufficient restraint area.

[0029] 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 second vertical bar and a second upper horizontal bar, or at both ends of an L-shaped reinforcing bar consisting of a third vertical bar and a third lower horizontal bar, respectively.

[0030] Furthermore, other embodiments of the half-precast beam according to the present invention include: It has at least a fourth longitudinal bar and is equipped with multiple fourth reinforcing bars that are C-shaped, roughly L-shaped, or annular in shape, The structure comprises a plurality of separate fourth reinforcing bars, each having at least one separate fourth longitudinal bar and a wavy reinforcing bar or another separate fourth longitudinal bar connected to the separate fourth longitudinal bar, or a plurality of separate fourth reinforcing bars, each comprising a pair of separate fourth longitudinal bars and a wavy reinforcing bar extending in the longitudinal direction and exhibiting a wavy shape, sandwiched between and connected to the pair of separate fourth longitudinal bars. At least one of the separate fourth reinforcing bars, each of which has a separate fourth longitudinal bar, is embedded at intervals in the longitudinal direction of the fourth precast concrete slab. Each of the aforementioned wavy reinforcing bars or the aforementioned separate fourth longitudinal bars is bound or welded to the corresponding fourth longitudinal bar of the fourth reinforcing bar. The present invention has a pair of precast concrete slabs with fourth reinforcing bars, each having upper and lower main reinforcing bars extending in the longitudinal direction attached above and below a plurality of the aforementioned fourth reinforcing bars, respectively. The pair of precast concrete slabs with fourth reinforcing bars are arranged in a position facing each other, and a post-cast concrete body is provided in the gap between the pair of the fourth precast concrete slabs.

[0031] According to this embodiment, multiple separate fourth reinforcing bars, each having at least one fourth longitudinal bar and corrugated reinforcing bars or other separate fourth longitudinal bars connected to the separate fourth longitudinal bar, are embedded at intervals along the longitudinal direction of the fourth precast concrete slab. The fourth longitudinal bars of the corresponding C-shaped, approximately L-shaped, or annular fourth reinforcing bars are tied or welded to each corrugated reinforcing bar or other separate fourth longitudinal bar, and upper and lower main reinforcing bars are attached above and below the multiple fourth reinforcing bars to form a fourth reinforced precast concrete slab. A pair of fourth reinforced precast concrete slabs are arranged facing each other, and a post-cast concrete body is provided in the gap between the two fourth precast concrete slabs, thereby automatically arranging the beam reinforcement when the pair of fourth reinforced precast concrete slabs are installed. This makes it possible to reduce the labor involved in setting up and removing formwork using a pair of fourth precast concrete slabs, eliminate or reduce the labor involved in arranging the beam reinforcement, and ensure quality because it is factory-made. Here, there may be a gap between the fourth reinforcing bars of each of the pair of precast concrete slabs with fourth reinforcing bars, or there may be no gap, with the fourth longitudinal bars at both ends touching or intersecting.

[0032] Furthermore, other embodiments of the half-precast beam according to the present invention include: The present invention is characterized in that a steel beam is embedded in the aforementioned post-cast concrete body.

[0033] According to this embodiment, by embedding a steel beam in a post-cast concrete body, a high-strength and high-rigidity half-precast beam made of SRC (Steel Reinforced Concrete) can be formed. [Effects of the Invention]

[0034] As can be understood from the above explanation, the reinforced precast concrete slab and half-precast beam of the present invention make it possible to reduce the labor required for formwork installation and removal by using the precast concrete slab that constitutes the half-precast beam, while eliminating or reducing the labor required for reinforcing the beam, thereby improving quality. [Brief explanation of the drawing]

[0035] [Figure 1] This is a perspective view of a pair of reinforced precast concrete panels according to the embodiment, 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, showing both a reinforced precast concrete slab and a longitudinal section 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 for the manufacturing method of another example of a half-precast beam according to the embodiment, showing both a reinforced precast concrete slab according to the embodiment and a longitudinal section view perpendicular to the longitudinal direction of another example of a half-precast beam. [Figure 4] (a) to (e) are process diagrams of the manufacturing method for yet another example of the half-precast beam according to the embodiment, showing both a reinforced precast concrete slab and a longitudinal section perpendicular to the longitudinal direction of yet another example of the half-precast beam according to the embodiment. [Figure 5] Figures (a) to (f) are process diagrams of the manufacturing method for yet another example of the half-precast beam according to the embodiment, showing both a reinforced precast concrete slab and a longitudinal section perpendicular to the longitudinal direction of yet another example of the half-precast beam according to the embodiment. [Figure 6] Figures (a) to (f) are process diagrams of the manufacturing method for yet another example of the half-precast beam according to the embodiment, showing both a reinforced precast concrete slab and a longitudinal section perpendicular to the longitudinal direction of yet another example of the half-precast beam according to the embodiment. [Figure 7] (a) and (b) are diagrams showing the process of manufacturing another example of a half-precast beam according to the embodiment, and both show a reinforced precast concrete slab and a longitudinal section perpendicular to the longitudinal direction of another example of a half-precast beam according to the embodiment. [Modes for carrying out the invention]

[0036] The following describes a half-precast beam according to an embodiment, its manufacturing method, and an example of a reinforced precast concrete slab forming the half-precast beam, with reference to the attached drawings. In this specification and the drawings, substantially identical components are denoted by the same reference numerals to avoid redundant explanations.

[0037] [Precast concrete slab with reinforcement and half-precast beam according to this embodiment] Referring to Figures 1 to 6, several examples of reinforced precast concrete slabs and half-precast beams according to the embodiment will be described along with their manufacturing methods. Here, Figure 1 is a perspective view of a pair of reinforced precast concrete slabs according to the embodiment, which 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 both a reinforced precast concrete slab according to the embodiment and a longitudinal cross-sectional view perpendicular to the longitudinal direction of the example of a half-precast beam.

[0038] The half-precast beam 100 shown in Figure 2(e) has a pair of first reinforced precast concrete slabs 50 (an example of reinforced precast concrete slabs) arranged with a gap G between them, and a post-cast concrete body 60 provided in the gap G.

[0039] As shown in Figure 1, each of the pair of precast concrete slabs 50 with first reinforcement bars is embedded at intervals along the longitudinal direction of the first precast concrete slab 20, with each of the separate first longitudinal bars 11D (an example of separate longitudinal bars) and the separate first longitudinal bars 19 (truss bars) that extend longitudinally and have a wavy shape connected to the separate first longitudinal bars 11D being connected to the separate first longitudinal bars 11D, forming a plurality of separate first longitudinal bars 10D. Each of the first longitudinal bars 11 of the plurality of C-shaped first reinforcement bars 10 is connected to each wavy bar 19 by binding or welding. Here, although not shown in the figure, the separate first reinforcement bar may consist of two separate first longitudinal bars and a wavy bar placed between them and connected to them, with one of the separate first longitudinal bars embedded in the first precast concrete slab and the first longitudinal bar of the first reinforcement bar connected to the other separate first longitudinal bar.

[0040] The first reinforcing bar 10 (an example of a reinforcing bar) is formed by a series of C-shaped elements: a first longitudinal bar 11 (an example of a longitudinal bar), a first upper transverse bar 12 (an example of an upper transverse bar) that bends at the upper end of the first longitudinal bar 11 and extends laterally, a first upper hook 13 (an example of an upper hook) that bends at the end of the first upper transverse bar 12 and extends downward, a first lower transverse bar 14 (an example of a lower transverse bar) that bends at the lower end of the first longitudinal bar 11 and extends laterally, and a first lower hook 15 (an example of a lower hook) that bends at the end of the first lower transverse bar 14 and extends upward. In the illustrated example, both the first upper hook 13 and the first lower hook 15 are 90-degree hooks.

[0041] The first precast concrete slab 20 has a first longitudinal slab 22 that extends in the longitudinal direction, and multiple separate first longitudinal bars 11D and a portion of the corrugated reinforcing bars 19 (the area of ​​the corrugated reinforcing bars 19 on the side of the separate first longitudinal bars 11D) are embedded in the first longitudinal slab 22, thereby attaching multiple separate first reinforcing bars 10D to the first precast concrete slab 20, and a corresponding first reinforcing bar 10 is attached to each separate first reinforcing bar 10D.

[0042] Here, although not shown in the diagram, the thickness of the precast concrete slab may be increased, and a portion of the upper and lower main reinforcement bars (for example, one of each) may be embedded inside the precast concrete slab. In the form with a thicker precast concrete slab, it is preferable that, in addition to the first vertical reinforcement bars 11, a portion of the upper main reinforcement bars 30 and lower main reinforcement bars 40 are further embedded, thereby suppressing cracking of the precast concrete slab that constitutes the reinforced precast concrete slab before the half-precast beam is manufactured.

[0043] Multiple upper main reinforcement bars 30 extending in the longitudinal direction are attached below multiple first upper transverse reinforcement bars 12, and multiple lower main reinforcement bars 40 extending in the longitudinal direction are attached above multiple first lower transverse reinforcement bars 14. By attaching the multiple upper main reinforcement bars 30 and lower main reinforcement bars 40 to the first precast concrete slab 20 to which multiple first reinforcing bars 10 are attached, the first reinforced precast concrete slab 50 is formed.

[0044] Here, the entire first reinforced precast concrete slab 50 shown in the diagram may be manufactured in a factory or the like, transported to the site and installed in the designated location, or the first precast concrete slab 20, the upper main reinforcement 30 and the lower main reinforcement 40 may be transported to the site with the upper main reinforcement 30 and the lower main reinforcement 40 not attached (all parts except the upper main reinforcement 30 and the lower main reinforcement 40 may be manufactured in a factory or the like), and after the first precast concrete slab 20 is installed in the designated location at the site, the upper main reinforcement 30 and the lower main reinforcement 40 may be attached to form the first reinforced precast concrete slab 50.

[0045] Although not shown in the diagram, there may be a configuration in which a first reinforcing bar 10 is arranged between a first reinforcing bar 10 that is connected to a separate first reinforcing bar 10D, without the corresponding separate first reinforcing bar 10D present. For example, in addition to the first reinforcing bars 10 that are connected to a separate first reinforcing bar 10D, there may also be first reinforcing bars 10 that are not connected to a separate first reinforcing bar 10D. In other words, any number of first reinforcing bars 10 from the plurality of first reinforcing bars 10 that constitute the first reinforced concrete slab 50 with first reinforcing bars shown in Figure 1 may be provided in place of the first reinforcing bars 10 that are connected to the separate first reinforcing bars 10D in this embodiment. In this way, by combining first reinforcing bars 10 that do not have a corresponding separate first reinforcing bar 10D, it is possible to arrange a number of first reinforcing bars 10 that can obtain the desired shear reinforcement effect.

[0046] 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 one of the pair of first reinforced precast concrete slabs 50 (in the illustrated example, the left first reinforced precast concrete slab 50) is positioned on the lower frame 91.

[0047] Here, the left-side precast concrete slab 50 with the first reinforcement bar, which is installed first, has four upper main reinforcement bars 30 attached to multiple first upper horizontal reinforcement bars 12 at equal or approximately equal intervals in the horizontal direction, and three lower main reinforcement bars 40 attached to multiple first lower horizontal reinforcement bars 14 at equal or approximately equal intervals in the horizontal direction.

[0048] On the other hand, the right-side precast concrete slab 50 with the first reinforcement bars, which is installed later, has three upper main reinforcement bars 30 attached to multiple first upper horizontal reinforcement bars 12 at equal or approximately equal intervals in the horizontal direction, and four lower main reinforcement bars 40 attached to multiple first lower horizontal reinforcement bars 14 at equal or approximately equal intervals in the horizontal direction.

[0049] As explained below, in a pair of precast concrete slabs 50 with first reinforcement bars, one upper main reinforcement bar 30 is placed between the two first upper hooks 13, and one lower main reinforcement bar 40 is placed between the two first lower hooks 15, so that the two first reinforcing bars 10 overlap. However, in this case, to prevent the upper main reinforcement bars 30 from interfering with each other and the lower main reinforcement bars 40 from interfering with each other at the overlapping position of the two precast concrete slabs 50 with first reinforcement bars, the installation of the upper main reinforcement bars 30 and lower main reinforcement bars 40 at the overlapping position of one of the precast concrete slabs 50 with first reinforcement bars is omitted (in the illustrated example, one upper main reinforcement bar 30 and one lower main reinforcement bar 40 are each omitted).

[0050] In the illustrated example, the installation of the upper main reinforcement 30 at the lap position is omitted from the left precast concrete slab 50 with the first reinforcement, and the installation of the lower main reinforcement 40 at the lap position is omitted from the right precast concrete slab 50 with the first reinforcement. However, it is also possible that the installation of the upper main reinforcement 30 and the lower main reinforcement 40 at the lap position of one of the left and right precast concrete slabs 50 with the first reinforcement is omitted, while both the upper main reinforcement 30 and the lower main reinforcement 40 are installed at the lap position of the other precast concrete slab 50 with the first reinforcement.

[0051] However, in a configuration where one of the first reinforced precast concrete slabs 50 does not have both the upper main reinforcement 30 and the lower main reinforcement 40 at the lap position, the amount of reinforcement in the left and right first reinforced precast concrete slabs 50 will differ, causing one of the first reinforced precast concrete slabs 50 to become excessively heavy. Furthermore, since the first reinforced precast concrete slabs 50 are among the heaviest members lifted by the crane, in order to reduce the weight of the first reinforced precast concrete slabs 50 as much as possible, it is preferable, as shown in the illustrated example, that the amount of reinforcement in the pair of reinforced precast concrete slabs 50 is approximately the same, and that one of the upper main reinforcement and the lower main reinforcement at the lap position is omitted on each side.

[0052] Next, as shown in Figure 2(b), the other first reinforced precast concrete slab 50 (in the illustrated example, the right first reinforced precast concrete slab 50) is moved laterally in the X1 direction, and its first lower horizontal reinforcement 14, first lower hook 15, and one lower main reinforcement 40 are passed between the first upper hook 13 and the first lower hook 15 of the left first reinforced precast concrete slab 50. The lateral movement is stopped when the first upper hook 13 of the right first reinforced precast concrete slab 50 passes the right upper main reinforcement 30 of the left first reinforced precast concrete slab 50.

[0053] Next, as shown in Figure 2(c), the first reinforced precast concrete slab 50 on the right side is lowered downward in the X2 direction, thereby moving the first upper hook 13 downward so as to straddle one of the upper main reinforcement bars 30 at the lap position.

[0054] As shown in Figure 2(d), by completely lowering the right-side first reinforced precast concrete slab 50 and placing it on the lower frame 91, multiple (seven in the illustrated example) upper main reinforcement bars 30 are arranged at equal or approximately equal intervals in the lateral direction for both overlapping first upper horizontal reinforcement bars 12, with the central upper main reinforcement bar 30 surrounded by the left and right first upper hooks 13. Similarly, multiple (seven in the illustrated example) lower main reinforcement bars 40 are arranged at equal or approximately equal intervals in the lateral direction for both overlapping first lower horizontal reinforcement bars 14, with the central lower main reinforcement bar 40 surrounded by the left and right first lower hooks 15. The reinforcement is automatically arranged, and a gap G is formed between the pair of first reinforced precast concrete slabs 50.

[0055] In this way, when a pair of precast concrete slabs 50 with first reinforcement bars are installed while forming a gap G between them, the beam reinforcement is placed at the same time, thus eliminating or reducing the labor required for beam reinforcement placement.

[0056] 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 pair of first reinforced precast concrete slabs 50 and a post-cast concrete body 60.

[0057] In the manufacturing method shown in the illustration, the first precast concrete slab 20 functions as formwork (side frame) when forming the later-cast concrete body 60, while remaining as a component of the half-precast beam 100. This eliminates the need for setting up and removing the side frame, thus saving labor in setting up and removing the formwork.

[0058] Thus, by using a pair of precast concrete slabs 50 with first reinforcement bars to manufacture a half-precast beam, it is possible to reduce the labor involved in setting up and removing formwork, eliminate or reduce the labor involved in arranging the beam reinforcement, and improve the manufacturability (or constructability) of the beam, thereby improving quality.

[0059] Furthermore, since the entire C-shaped first reinforcing bar 10, which is tied or otherwise bound to a separate first vertical reinforcement bar 11D embedded in the first precast concrete slab 20, is embedded in the later-cast concrete body 60, the shear reinforcement effect of the first reinforcing bar 10 can be enhanced. As a result, even if the degree of integration between the first precast concrete slab 20 and the later-cast concrete body 60 is not good, a high shear reinforcement effect can be achieved by the C-shaped first reinforcing bar 10.

[0060] Furthermore, the first longitudinal reinforcement bars 11 of the roughly C-shaped first reinforcing bar 10 and the separate first longitudinal reinforcement bars 11D of the separate first reinforcing bar 10D are connected by corrugated reinforcing bars 19 that extend in the longitudinal direction and exhibit a corrugated shape, thereby enabling a stronger integration of the two. In addition, with this configuration, the first longitudinal reinforcement bars 11, the separate first longitudinal reinforcement bars 11D, and the corrugated reinforcing bars 19 between them can resist, in a mechanism similar to that of a truss beam, the pressure acting on the inside of the first precast concrete slab 20 when concrete is poured during the construction of the later-cast concrete body 60, and the earth pressure acting on the outside of the first precast concrete slab 20 when soil is backfilled before concrete is poured.

[0061] Next, with reference to Figure 3, a method for manufacturing another example of a half-precast beam according to the embodiment will be described. Here, Figures 3(a) to (e) are process diagrams for manufacturing another example of a half-precast beam according to the embodiment, and both show a reinforced precast concrete slab according to the embodiment and a longitudinal section perpendicular to the longitudinal direction of the other example of a half-precast beam.

[0062] A pair of precast concrete slabs 50A with first reinforcement bars applied to the manufacturing method shown in Figure 3 differs from a precast concrete slab 50 with first reinforcement bars that has separate first reinforcement bars 10D, in that it has multiple separate first reinforcing bars 10E, in which a pair of separate first vertical bars 11E, separate first upper horizontal bars 12E, and separate first lower horizontal bars 14E are continuously arranged in a rectangular frame shape (ring).

[0063] The rectangular frame-shaped first reinforcing bar 10E overlaps with the first reinforcing bar 10, with one upper and one lower main reinforcing bar 30 and one lower main reinforcing bar 40 arranged inside, and the overlapping sections are bound together by tying or other means.

[0064] By embedding one of the separate first vertical bars 11E of each of the multiple separate first reinforcing bars 10E into the first vertical slab 22, multiple separate first reinforcing bars 10E are attached to the first precast concrete slab 20, and a corresponding first reinforcing bar 10 is attached to each separate first reinforcing bar 10E.

[0065] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 3(a), one of the first reinforced precast concrete panels 50A is positioned on the lower frame 91.

[0066] Next, as shown in Figure 3(b), the other first reinforced precast concrete slab 50A is moved laterally in the X3 direction, and its first lower horizontal reinforcement 14, first lower hook 15, and one lower main reinforcement 40 are passed between the first upper hook 13 and the first lower hook 15 of the left first reinforced precast concrete slab 50A. The lateral movement is stopped when the first upper hook 13 of the right first reinforced precast concrete slab 50A passes the right upper main reinforcement 30 of the left first reinforced precast concrete slab 50A.

[0067] Next, as shown in Figure 3(c), the first reinforced precast concrete slab 50A on the right side is lowered in the X4 direction, thereby moving the first upper hook 13 downward so that it straddles one of the upper main reinforcement bars 30 at the lap position.

[0068] As shown in Figure 3(d), by completely lowering the right-side first reinforced precast concrete slab 50A and installing it on the lower frame 91, multiple (seven in the illustrated example) upper main reinforcement bars 30 are arranged at equal or approximately equal intervals in the horizontal direction for both overlapping first upper horizontal reinforcement bars 12, with the central upper main reinforcement bar 30 surrounded by the left and right first upper hooks 13. Similarly, multiple (seven in the illustrated example) lower main reinforcement bars 40 are arranged at equal or approximately equal intervals in the horizontal direction for both overlapping first lower horizontal reinforcement bars 14, with the central lower main reinforcement bar 40 surrounded by the left and right first lower hooks 15. The reinforcement is automatically arranged, and a gap G is formed between the pair of first reinforced precast concrete slabs 50A.

[0069] 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 pair of first reinforced precast concrete slabs 50A and a post-cast concrete body 60.

[0070] 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.

[0071] Furthermore, since the entire C-shaped first reinforcing bar 10, which is tied or otherwise bound to a separate first vertical reinforcement bar 11E embedded in the first precast concrete slab 20, is embedded in the later-cast concrete body 60, the shear reinforcement effect of the first reinforcing bar 10 can be enhanced. As a result, even if the degree of integration between the first precast concrete slab 20 and the later-cast concrete body 60 is not good, a high shear reinforcement effect can be achieved by the C-shaped first reinforcing bar 10.

[0072] 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 show both the reinforced precast concrete slab according to the embodiment and the longitudinal section view perpendicular to the longitudinal direction of yet another example of the half-precast beam.

[0073] The second reinforced precast concrete slab 50B (another example of a reinforced precast concrete slab) and the third reinforced precast concrete slab 50C (yet another example of a reinforced precast concrete slab), which are applied to the manufacturing method shown in Figure 4, differ from the first reinforced precast concrete slab 50, which has a C-shaped first reinforcing bar 10, in that they each have a second reinforcing bar 10A and a third reinforcing bar 10B that are roughly L-shaped.

[0074] The second reinforced precast concrete slab 50B is formed by attaching multiple separate second reinforcing bars 10F (another example of separate reinforcing bars) to the second precast concrete slab 20A at intervals along its longitudinal direction, and then attaching a second reinforcing bar 10A (another example of reinforcing bars) to each of the separate second reinforcing bars 10F.

[0075] Similarly, the third reinforced precast concrete slab 50C is formed by attaching multiple additional third reinforcing bars 10G (yet another example of additional reinforcing bars) to the third precast concrete slab 20B at intervals along its longitudinal direction, and then attaching a third reinforcing bar 10B (yet another example of additional reinforcing bars) to each additional third reinforcing bar 10G.

[0076] The second reinforcing bar 10A consists of a second longitudinal bar 11A, a second upper transverse bar 12A that bends at the upper end of the second longitudinal bar 11A and extends laterally, a second upper hook 13A that bends at the end of the second upper transverse bar 12A and extends diagonally downward, and a second lower hook 15A (180-degree hook) that bends at the lower end of the second longitudinal bar 11A and extends upward, forming a roughly L-shape. Here, the second 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.

[0077] On the other hand, the third reinforcing bar 10B consists of a third longitudinal bar 11B, a third lower transverse bar 14B that bends at the lower end of the third longitudinal bar 11B and extends laterally, a third lower hook 15B that bends at the end of the third lower transverse bar 14B and extends diagonally upward, and a third upper hook 13B (180-degree hook) that bends above the third longitudinal bar 11B and extends downward, forming a roughly L-shape. Here, the third 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.

[0078] The second precast concrete slab 20A has a second vertical slab 22A that extends in the vertical direction, and multiple separate second vertical reinforcements 11F and a portion of the corrugated reinforcement bars 19A (the area of ​​the corrugated reinforcement bars 19A on the side of the separate second vertical reinforcements 11F) are embedded in the second vertical slab 22A, thereby attaching multiple separate second reinforcement bars 10F to the second precast concrete slab 20A, and a corresponding second reinforcement bar 10A is attached to each separate second reinforcement bar 10F.

[0079] On the other hand, the third reinforcing bar 10B consists of a third longitudinal bar 11B, a third lower transverse bar 14B that bends at the lower end of the third longitudinal bar 11B and extends laterally, a third lower hook 15B that bends at the end of the third lower transverse bar 14B and extends diagonally upward, and a third upper hook 13B (180-degree hook) that bends above the third longitudinal bar 11B and extends downward, forming a roughly L-shape. Here, the third 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.

[0080] The third precast concrete slab 20B has a third longitudinal slab 22B that extends in the vertical direction, and multiple separate third longitudinal bars 11G and a portion of the corrugated reinforcing bars 19B (the area of ​​the corrugated reinforcing bars 19B on the side of the separate third longitudinal bars 11G) are embedded in the third longitudinal slab 22B, thereby attaching multiple separate third reinforcing bars 10G to the third precast concrete slab 20B, and a corresponding third reinforcing bar 10B is attached to each separate third reinforcing bar 10G.

[0081] Multiple upper main reinforcement bars 30 extending in the longitudinal direction are attached below multiple second upper transverse reinforcement bars 12A, and multiple lower main reinforcement bars 40 extending in the longitudinal direction are attached above multiple third lower transverse reinforcement bars 14B. By attaching multiple upper main reinforcement bars 30 to a second precast concrete slab 20A to which multiple second reinforcing bars 10A are attached, a second reinforced precast concrete slab 50B is formed. Similarly, by attaching multiple lower main reinforcement bars 40 to a third precast concrete slab 20B to which multiple third reinforcing bars 10B are attached, a third reinforced precast concrete slab 50C is formed.

[0082] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 4(a), the second reinforced precast concrete slab 50B is positioned on the lower frame 91.

[0083] Next, as shown in Figure 4(b), the precast concrete slab 50C with the third reinforcement bar is moved laterally in the X5 direction, and the lateral movement is stopped when the lower main reinforcement bar 40 at the left end passes the second lower hook 15A and the third upper hook 13B passes the upper main reinforcement bar 30 at the right end.

[0084] Next, as shown in Figure 4(c), the precast concrete slab 50C with the third reinforcement is lowered in the X6 direction, so that the lower main reinforcement 40 at the left end is sandwiched between the second lower hook 15A and the third lower hook 15B, and the upper main reinforcement 30 at the right end is sandwiched between the second upper hook 13A and the third upper hook 13B.

[0085] As shown in Figure 4(d), by completely lowering the third reinforced precast concrete slab 50C and installing it on the lower frame 91, the second lower hook 15A and the third lower hook 15B sandwich the lower main reinforcement 40 at the left end, and the second upper hook 13A and the third 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 second 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 third lower horizontal reinforcement bar 14B. The reinforcement is then automatically arranged, and a gap G is formed between the second reinforced precast concrete slab 50B and the third reinforced precast concrete slab 50C.

[0086] 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 second reinforced precast concrete slab 50B, a third reinforced precast concrete slab 50C, and a post-cast concrete body 60.

[0087] 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.

[0088] Furthermore, a wavy reinforcing bar 19A, which extends vertically and exhibits a wave-like shape, is connected to the second longitudinal bar 11A of the roughly L-shaped second reinforcing bar 10A and to a separate second longitudinal bar 11F of a separate second reinforcing bar 10F, and a wavy reinforcing bar 19B, which extends vertically and exhibits a wave-like shape, is connected to the third longitudinal bar 11B of the roughly L-shaped third reinforcing bar 10B and to a separate third longitudinal bar 11G of a separate third reinforcing bar 10G, thereby enabling a stronger integration of the two. Furthermore, this configuration allows the second vertical reinforcement 11A, the separate second vertical reinforcement 11F, and the corrugated reinforcement 19A between them, as well as the third vertical reinforcement 11B, the separate third vertical reinforcement 11G, and the 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 second precast concrete slab 20A and the third precast concrete slab 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 second precast concrete slab 20A and the third precast concrete slab 20B when soil is backfilled before concrete is poured.

[0089] 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 (f) are process diagrams for the manufacturing method of yet another example of the half-precast beam according to the embodiment, and show both the reinforced precast concrete slab according to the embodiment and the longitudinal section view perpendicular to the longitudinal direction of yet another example of the half-precast beam.

[0090] The half-precast beam 100C shown in Figure 5 differs from the half-precast beam 100 in that it is made of SRC (steel-reinforced concrete) with a steel beam 70 embedded inside a later-cast concrete body 60.

[0091] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 5(a), one of the first reinforced precast concrete panels 50 is positioned on the lower frame 91, and a steel beam 70 is placed to its side.

[0092] Next, as shown in Figure 5(b), the steel beam 70 is moved in the X7 direction and housed inside one of the first reinforced precast concrete panels 50.

[0093] Next, as shown in Figure 5(c), the other first reinforced precast concrete slab 50 is moved laterally in the X6 direction, and its first lower horizontal reinforcement 14, first lower hook 15, and one lower main reinforcement 40 are passed between the first upper hook 13 and first lower hook 15 of the first reinforced precast concrete slab 50. The lateral movement is then stopped when the first upper hook 13 of the other first reinforced precast concrete slab 50 has passed the upper main reinforcement 30 on the right side of the first reinforced precast concrete slab 50.

[0094] Next, as shown in Figure 5(d), the other first reinforced precast concrete slab 50 is lowered in the X9 direction, thereby moving the first upper hook 13 downward so as to straddle one of the upper main reinforcement bars 30 at the lap position.

[0095] As shown in Figure 5(d), by completely lowering the other first reinforced precast concrete slab 50 and installing it on the lower frame 91, multiple (seven in the illustrated example) upper main reinforcement bars 30 are arranged at equal or approximately equal intervals in the lateral direction for both overlapping first upper horizontal reinforcement bars 12, with the central upper main reinforcement bar 30 surrounded by the left and right first upper hooks 13. Similarly, multiple (seven in the illustrated example) lower main reinforcement bars 40 are arranged at equal or approximately equal intervals in the lateral direction for both overlapping first lower horizontal reinforcement bars 14, with the central lower main reinforcement bar 40 surrounded by the left and right first lower hooks 15. The reinforcement is automatically arranged, and a gap G is formed between the pair of first reinforced precast concrete slabs 50.

[0096] Next, as shown in Figure 5(e), the steel beam 70 is moved in the X10 direction to the center of the gap G, thereby arranging the pair of first reinforced precast concrete slabs 50 and the steel beam 70 in the correct relative positions.

[0097] Next, as shown in Figure 5(f), concrete is poured into the gap G and the steel beam 70 is embedded to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100C having a pair of first reinforced precast concrete slabs 50, a steel beam 70, and a post-cast concrete body 60.

[0098] 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.

[0099] Furthermore, because it is made of SRC (steel-reinforced concrete) with a steel beam 70 embedded inside the later-cast concrete body 60, it is possible to form a half-precast beam that is both high-strength and highly rigid.

[0100] Furthermore, the first longitudinal reinforcement bars 11 of the roughly C-shaped first reinforcing bar 10 and the separate first longitudinal reinforcement bars 11D of the separate first reinforcing bar 10D are connected by corrugated reinforcing bars 19 that extend in the longitudinal direction and exhibit a corrugated shape, thereby enabling a stronger integration of the two. In addition, with this configuration, the first longitudinal reinforcement bars 11, the separate first longitudinal reinforcement bars 11D, and the corrugated reinforcing bars 19 between them can resist, in a mechanism similar to that of a truss beam, the pressure acting on the inside of the first precast concrete slab 20 when concrete is poured during the construction of the later-cast concrete body 60, and the earth pressure acting on the outside of the first precast concrete slab 20 when soil is backfilled before concrete is poured.

[0101] 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, Figures 6(a) to (f) are process diagrams for the manufacturing method of yet another example of the half-precast beam according to the embodiment, and show both the reinforced precast concrete slab according to the embodiment and the longitudinal section view perpendicular to the longitudinal direction of yet another example of the half-precast beam.

[0102] The half-precast beam 100D shown in Figure 6 differs from the half-precast beam 100B in that it is made of SRC (steel-reinforced concrete) with a steel beam 70 embedded inside a later-cast concrete body 60.

[0103] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 6(a), one of the second reinforced precast concrete panels 50B is positioned on the lower frame 91, and the steel beam 70 is placed to its side.

[0104] Next, as shown in Figure 6(b), the steel beam 70 is moved in the X11 direction and housed inside the second reinforced precast concrete slab 50B.

[0105] Next, as shown in Figure 6(c), the precast concrete slab 50C with the third reinforcement bar is moved laterally in the X12 direction, and the lateral movement is stopped when the lower main reinforcement bar 40 at the left end passes the second lower hook 15A and the third upper hook 13B passes the upper main reinforcement bar 30 at the right end.

[0106] Next, as shown in Figure 6(d), the precast concrete slab 50C with the third reinforcement is lowered in the X13 direction, so that the lower main reinforcement 40 at the left end is sandwiched between the second lower hook 15A and the third lower hook 15B, and the upper main reinforcement 30 at the right end is sandwiched between the second upper hook 13A and the third upper hook 13B.

[0107] As shown in Figure 6(d), by completely lowering the third reinforced precast concrete slab 50C and installing it on the lower frame 91, the second lower hook 15A and the third lower hook 15B sandwich the lower main reinforcement 40 at the left end, and the second upper hook 13A and the third 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 second 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 third lower horizontal reinforcement bar 14B. The reinforcement is then automatically arranged, and a gap G is formed between the second reinforced precast concrete slab 50B and the third reinforced precast concrete slab 50C.

[0108] Next, as shown in Figure 6(e), the steel beam 70 is moved in the X14 direction to the center of the gap G, thereby arranging the second reinforced precast concrete slab 50B, the third reinforced precast concrete slab 50C, and the steel beam 70 in the correct relative positions.

[0109] Next, as shown in Figure 6(f), concrete is poured into the gap G and the steel beam 70 is embedded to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100D having a second reinforced precast concrete slab 50B, a third reinforced precast concrete slab 50C, a steel beam 70, and a post-cast concrete body 60.

[0110] 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.

[0111] Furthermore, because it is made of SRC (steel-reinforced concrete) with a steel beam 70 embedded inside the later-cast concrete body 60, it is possible to form a half-precast beam that is both high-strength and highly rigid.

[0112] Furthermore, a wavy reinforcing bar 19A, which extends vertically and exhibits a wave-like shape, is connected to the second longitudinal bar 11A of the roughly L-shaped second reinforcing bar 10A and to a separate second longitudinal bar 11F of a separate second reinforcing bar 10F, and a wavy reinforcing bar 19B, which extends vertically and exhibits a wave-like shape, is connected to the third longitudinal bar 11B of the roughly L-shaped third reinforcing bar 10B and to a separate third longitudinal bar 11G of a separate third reinforcing bar 10G, thereby enabling a stronger integration of the two. Furthermore, this configuration allows the second vertical reinforcement 11A, the separate second vertical reinforcement 11F, and the corrugated reinforcement 19A between them, as well as the third vertical reinforcement 11B, the separate third vertical reinforcement 11G, and the 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 second precast concrete slab 20A and the third precast concrete slab 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 second precast concrete slab 20A and the third precast concrete slab 20B when soil is backfilled before concrete is poured.

[0113] Next, with reference to Figure 7, a method for manufacturing another example of a half-precast beam according to the embodiment will be described. Here, Figures 7(a) and 7(b) are process diagrams for manufacturing yet another example of a half-precast beam according to the embodiment, and both show a reinforced precast concrete slab according to the embodiment and a longitudinal section view perpendicular to the longitudinal direction of yet another example of a half-precast beam.

[0114] The pair of precast concrete slabs 50D with fourth reinforcement bars applied to the manufacturing method shown in Figure 7 differ from the precast concrete slab 50 with first reinforcement bars in that they are equipped with a pair of fourth longitudinal bars 11H and a ring-shaped (rectangular frame shape in the illustrated example) fourth reinforcing bar 10C having a fourth upper transverse bar 12C and a fourth lower transverse bar 14C. Furthermore, the half-precast beam 100E shown in Figure 7 differs from the half-precast beam 100 in that the parts of the fourth reinforcing bars 10C of the pair of precast concrete slabs 50D with fourth reinforcement bars do not overlap.

[0115] Multiple (four in the illustrated example) upper main reinforcement bars 30 are attached below the fourth upper transverse reinforcement bar 12C of the annular fourth reinforcing bar 10C, and multiple (four in the illustrated example) lower main reinforcement bars 40 are attached above the fourth lower transverse reinforcement bar 14C.

[0116] Each of the separate fourth longitudinal bars 11H, which form a plurality of separate fourth longitudinal bars 10H, is embedded at intervals along the longitudinal direction of the fourth precast concrete slab 20C, and each of the separate fourth longitudinal bars 11H, which are connected to the separate fourth longitudinal bars 11H, is connected to the separate fourth longitudinal bars 11H, which are connected to the separate fourth longitudinal bars 11H, which are connected to the separate fourth longitudinal bars 11H, which are connected to the separate fourth longitudinal bars 19, which are connected to the plurality of annular fourth longitudinal bars 10C, by binding or welding.

[0117] Regarding the manufacturing method of the illustrated example, first, as shown in Figure 7(a), a pair of precast concrete slabs 50D with fourth reinforcing bars are positioned on the lower frame 91 in a manner in which the two fourth reinforcing bars 10C do not overlap, thereby forming a gap G between the pair of fourth precast concrete slabs 20D.

[0118] Next, as shown in Figure 7(b), concrete is poured into the gap G to form a post-cast concrete body 60, thereby manufacturing a half-precast beam 100E having a pair of fourth reinforced precast concrete slabs 50D and a post-cast concrete body 60.

[0119] 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.

[0120] In the illustrated example, the fourth reinforcing bar 10C is annular in shape, but a pair of fourth reinforcing bars that are C-shaped or roughly L-shaped may be arranged in a manner that they do not overlap with each other. Also, in the illustrated example, there is a gap between the pair of fourth reinforcing bars, but a form in which there is no gap between the pair of fourth reinforcing bars is also possible (the fourth longitudinal bars 11H at both ends are in contact, or the fourth longitudinal bars 11H at both ends are intersecting).

[0121] The above has described half-precast beams and their manufacturing methods that are applied to the beams of the upper floors of buildings with reference to Figures 1 to 7, but half-precast beams may also be applied to the foundation beams of buildings that are not shown. In this case, a leveling material (for example, crushed stone or lean concrete) is laid on the floor surface created by excavating the ground, a pair of reinforced precast concrete slabs are placed on top of the lean concrete to create a gap between them, and concrete is poured into the gap to manufacture the foundation beam, which is a half-precast beam that is not shown.

[0122] Alternatively, the installation method may involve placing a precast concrete slab (not shown) that also serves as a lower frame on top of crushed stone, and then fitting the lower ends of a pair of reinforced precast concrete slabs into a pair of recesses provided on the upper surface of the precast concrete slab that also serves as a lower frame. In this configuration, since the lower ends of the reinforced precast concrete slabs are fitted into the recesses of the precast concrete slab that also serves as a lower frame, it is possible to maintain a stable upright position of the reinforced precast concrete slabs while eliminating the need for leveling materials.

[0123] 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]

[0124] 10: First reinforcing muscle (reinforcing muscle) 10A: Second reinforcing muscle (reinforcing muscle) 10B: Third reinforcing muscle (reinforcing muscle) 10C: Fourth reinforcing muscle (reinforcing muscle) 10D, 10E: Additional first reinforcing bar (additional reinforcing bar) 10F: Additional second reinforcement (additional reinforcement) 10G: Additional third reinforcement muscle (additional reinforcement muscle) 10H: Additional 4th reinforcement muscle (additional reinforcement muscle) 11: First vertical line (vertical line) 11A: Second vertical reinforcement (vertical reinforcement) 11B: Third vertical line (vertical line) 11C: 4th vertical line (vertical line) 11D, 11E: Separate first vertical reinforcement (separate vertical reinforcement) 11F: Additional second vertical reinforcement (additional vertical reinforcement) 11G: Separate third vertical reinforcement (separate vertical reinforcement) 11H: Separate 4th vertical reinforcement (separate vertical reinforcement) 12: First transverse muscle (supertransverse muscle) 12A: Second superior transverse muscle (superior transverse muscle) 12C: Fourth superior transverse muscle (superior transverse muscle) 12E: Separate first upper transverse reinforcement (separate upper transverse reinforcement) 13: First upper hook (90-degree hook) 13A: Second upper hook (135-degree hook) 13B: Third upper hook (180-degree hook) 14: First lower transverse muscle (lower transverse muscle) 14B: Third inferior transverse muscle (inferior transverse muscle) 14C: Fourth inferior transverse muscle (inferior transverse muscle) 14E: Separate first lower transverse reinforcement (separate lower transverse reinforcement) 15: First lower hook (90-degree hook, lower hook) 15B: Third lower hook (135-degree hook, lower hook) 19, 19A, 19B: Wavy reinforcing bars 20: First precast concrete slab 20A: Second precast concrete panel 20B: Third precast concrete panel 20C: 4th Precast Concrete Slab 22: First vertical version 22A: Second vertical version 30: Top main reinforcement 40: Bottom main reinforcement 50, 50A: First reinforced precast concrete slab (reinforced precast concrete slab) 50B: Second-generation reinforced precast concrete slab (reinforced precast concrete slab) 50C: Third-generation reinforced precast concrete slab (reinforced precast concrete slab) 50D: Reinforced concrete slab with 4th reinforcing bars (reinforced concrete slab) 60: Post-cast concrete body 70: Steel beam 100, 100A, 100B, 100C, 100D, 100E: Half-precast beams G: Gap

Claims

1. A pair of reinforced precast concrete panels are arranged with a gap between them to form a half-precast beam, A reinforced precast concrete slab characterized in that each of the longitudinal bars of a plurality of reinforcing bars having at least longitudinal bars is connected to a plurality of separate reinforcing bars having at least separate longitudinal bars, each of the separate longitudinal bars is embedded at intervals in the longitudinal direction of the precast concrete slab, the reinforcing bars are not embedded in the precast concrete slab, and at least one of the upper or lower main bars is attached to the plurality of reinforcing bars.

2. A half-precast beam characterized in that a pair of reinforced precast concrete slabs according to claim 1 are arranged with a gap between them, and a post-cast concrete body is provided in the gap.

3. The device comprises a plurality of first reinforcing bars, each having 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 extends downward, a first lower transverse bar that bends at the lower end of the first longitudinal bar and extends laterally, and a first lower hook that bends at the end of the first lower transverse bar and extends upward, which are arranged in a continuous C-shape. It comprises a plurality of separate first reinforcing bars, each having a separate first longitudinal bar and connected to the separate first longitudinal bar, to which are wavy reinforcing bars that extend in the longitudinal direction and have a wavy shape, or a plurality of separate first reinforcing bars, each having a pair of separate first longitudinal bars and connected to the pair of separate first longitudinal bars, to which are wavy reinforcing bars that extend in the longitudinal direction and have a wavy shape, sandwiched between them. At least one of the separate first reinforcing bars, each of which has a separate first longitudinal bar, is embedded at intervals in the longitudinal direction of the first precast concrete slab. The first longitudinal bar of the corresponding first reinforcing bar is tied or welded to the wavy reinforcing bar or the separate first longitudinal bar of each of the aforementioned separate first reinforcing bars. The present invention comprises a pair of precast concrete slabs with first reinforcement bars, wherein multiple upper main reinforcement bars extending in the longitudinal direction are attached below multiple first upper transverse reinforcement bars, and multiple lower main reinforcement bars extending in the longitudinal direction are attached above multiple first lower transverse reinforcement bars. A half-precast beam characterized in that the pair of reinforced precast concrete slabs are arranged with gaps between them, overlapping the first upper horizontal reinforcements of both slabs and overlapping the first lower horizontal reinforcements of both slabs, and a post-cast concrete body is provided in the gap.

4. The device comprises a plurality of first reinforcing bars, each having 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 extends downward, a first lower transverse bar that bends at the lower end of the first longitudinal bar and extends laterally, and a first lower hook that bends at the end of the first lower transverse bar and extends upward, which are arranged in a continuous C-shape. It comprises multiple separate first reinforcing bars, each consisting of a pair of separate first vertical bars, a separate first upper horizontal bar, and a separate first lower horizontal bar, which are arranged in a continuous rectangular frame shape. At least one of the separate first longitudinal bars of each of the multiple separate first reinforcing bars is embedded at intervals in the longitudinal direction of the first precast concrete slab. Each of the aforementioned separate first reinforcing bars and the corresponding first reinforcing bar overlap each other. The present invention comprises a pair of precast concrete slabs with first reinforcing bars, wherein a plurality of upper main reinforcing bars extending in the longitudinal direction are attached below a plurality of first upper transverse reinforcing bars, and a plurality of lower main reinforcing bars extending in the longitudinal direction are attached above a plurality of first lower transverse reinforcing bars, and at least one of the upper main reinforcing bars and the lower main reinforcing bar are arranged at the overlapping portion of the separate first reinforcing bars and the first reinforcing bars. A half-precast beam characterized in that the pair of reinforced precast concrete slabs are arranged with gaps between them, overlapping the first upper horizontal reinforcements of both slabs and overlapping the first lower horizontal reinforcements of both slabs, and a post-cast concrete body is provided in the gap.

5. The structure comprises multiple second reinforcing bars, each having a second longitudinal bar, a second upper transverse bar that bends at the upper end of the second longitudinal bar and extends laterally, a second upper hook that bends at the end of the second upper transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a second lower hook that bends at the lower end of the second longitudinal bar and extends upward, forming a substantially L-shape. It comprises a plurality of separate second reinforcing bars, each having a separate second longitudinal bar and connected to the separate second longitudinal bar, to which are wavy reinforcing bars that extend longitudinally and have a wavy shape, or a plurality of separate second reinforcing bars, each having a pair of separate second longitudinal bars and connected to the pair of separate second longitudinal bars, to which are wavy reinforcing bars that extend longitudinally and have a wavy shape. At least one of the separate second reinforcing bars, each of which has a separate second longitudinal reinforcement bar, is embedded at intervals along the longitudinal direction of the second precast concrete slab. The corresponding second longitudinal reinforcement is tied or welded to the wavy reinforcement or the separate second longitudinal reinforcement of each of the aforementioned second reinforcement bars. A precast concrete slab with a second reinforcement bar, wherein the upper main reinforcement bars extending in the longitudinal direction are attached below a plurality of the aforementioned second upper transverse reinforcements, The device comprises multiple third reinforcing bars, each having a third longitudinal bar, a third lower transverse bar that bends at the lower end of the third longitudinal bar and extends laterally, a third lower hook that bends at the end of the third lower transverse bar and is a 90-degree hook, a 135-degree hook, or a 180-degree hook, and a third upper hook that bends at the upper end of the third longitudinal bar and extends downward, forming a roughly L-shape. It comprises a plurality of separate third reinforcing bars, each having a separate third longitudinal bar and connected to the separate third longitudinal bar, to which are wavy reinforcing bars that extend longitudinally and have a wavy shape, or a plurality of separate third reinforcing bars, each having a pair of separate third longitudinal bars and connected to the pair of separate third longitudinal bars, to which are wavy reinforcing bars that extend longitudinally and have a wavy shape. At least one of the separate third reinforcing bars, each of which has a separate third longitudinal bar, is embedded at intervals in the longitudinal direction of the third precast concrete slab. The third longitudinal bar of the corresponding third reinforcing bar is tied or welded to the wavy reinforcing bar or the third longitudinal bar of each of the aforementioned separate third reinforcing bars. It comprises a precast concrete slab with a third reinforced concrete board, to which the longitudinally extending lower end main reinforcement is attached above a plurality of the third lower transverse reinforcements, A half-precast beam characterized in that the second upper horizontal reinforcement and the third upper hook intersect, and the third lower horizontal reinforcement and the second lower hook intersect, with the second precast concrete slab and the third precast concrete slab being arranged with a gap between them, and a post-cast concrete body being provided in the gap.

6. It comprises multiple fourth reinforcing bars, each having at least a fourth longitudinal bar and exhibiting a C-shape, approximate L-shape, or annular shape, The structure comprises a plurality of separate fourth reinforcing bars, each having at least one separate fourth longitudinal bar and a wavy reinforcing bar or another separate fourth longitudinal bar connected to the separate fourth longitudinal bar, or a plurality of separate fourth reinforcing bars, each comprising a pair of separate fourth longitudinal bars and a wavy reinforcing bar extending in the longitudinal direction and exhibiting a wavy shape, sandwiched between and connected to the pair of separate fourth longitudinal bars. At least one of the separate fourth reinforcing bars, each of which has a separate fourth longitudinal bar, is embedded at intervals in the longitudinal direction of the fourth precast concrete slab. Each of the aforementioned wavy reinforcing bars or the aforementioned separate fourth longitudinal bars is bound or welded to the corresponding fourth longitudinal bar of the fourth reinforcing bar. The present invention has a pair of precast concrete slabs with fourth reinforcing bars, each having upper and lower main reinforcing bars extending in the longitudinal direction attached above and below a plurality of the aforementioned fourth reinforcing bars, respectively. A half-precast beam characterized in that the pair of precast concrete slabs with fourth reinforcing bars are arranged in a position facing each other, and a post-cast concrete body is provided in the gap between the pair of the fourth precast concrete slabs.

7. A half-precast beam according to any one of claims 2 to 6, characterized in that a steel beam is embedded in the aforementioned post-cast concrete body.

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