Construction method of half-precast concrete member and structure of half-precast concrete member

Abstract

To improve productivity such as labor saving, manpower saving, and a shorter construction period by maximizing the advantage of adopting a half-precast method when a half-precast concrete member is manufactured.SOLUTION: A method for constructing a half-precast concrete member composed of a precast concrete member and a cast-in-place concrete member comprises: a step of manufacturing a precast concrete member in a state where a looped reinforcement is projected from the surface off-site; a step of manufacturing a reinforcement unit off-site; a step of installing the precast concrete member at a construction site; a step of mounting the reinforcement unit on the precast concrete member; and a step of installing cast-in-place concrete so as to bury the reinforcement unit in the surface of the precast concrete member. The reinforcement unit is provided with connection means for connection with the looped reinforcement projected from the precast concrete member.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for constructing a half-precast concrete member consisting of a precast concrete member and a cast-in-place concrete member, and to a structure of the half-precast concrete member. [Background technology]

[0002] In concrete composite structures with reinforcing bars, such as reinforced concrete structures, half-precast concrete members (half-precast slabs) that combine precast members and cast-in-place concrete members are used to reduce labor and manpower on site. For example, floor and wall members that make up concrete composite structures are manufactured by joining two concrete members (precast concrete member and cast-in-place concrete member). In such cases, the design requires the placement of shear reinforcement bars at the joint (boundary) between the two concrete members to prevent shear failure.

[0003] For example, Patent Document 1 discloses a half precast deck consisting of two upper and lower blocks of upper and lower reinforcing bars, and a method for joining them. The half precast deck described in Patent Document 1 is manufactured by placing the upper reinforcing bars on spacer bars protruding from the top surface of the lower reinforcing bars and then pouring concrete. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-146715 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventionally, it has been known that upper reinforcing bars embedded inside cast-in-place concrete members, such as the upper reinforcing bars and spacer bars described in Patent Document 1, are placed on-site. However, the placement of reinforcing bars on-site requires skilled craftsmen and is time-consuming, which raises concerns about the prolongation of construction time. In other words, despite the adoption of the half-precast construction method using precast concrete members with the aim of shortening construction time, there has been a problem in that the benefits of this method have not been fully realized.

[0006] Therefore, the object of the present invention is to provide a method for constructing half-precast concrete members and a structure of half-precast concrete members that maximize the benefits of adopting the half-precast construction method when producing half-precast concrete members, and that can improve productivity by reducing labor and manpower and shortening construction time. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, according to the present invention, there is provided a method for constructing a half-precast concrete member consisting of a precast concrete member and a cast-in-place concrete member, comprising the steps of: fabricating the precast concrete member off-site with loop-shaped reinforcing bars protruding from its surface; fabricating reinforcing bar units off-site; installing the precast concrete member at a construction site; mounting the reinforcing bar units on the precast concrete member; and pouring cast-in-place concrete on the surface of the precast concrete member so as to embed the reinforcing bar units, wherein the reinforcing bar units are equipped with connecting means for connecting to the loop-shaped reinforcing bars protruding from the precast concrete member. Here, "off-site" refers to a location different from the installation location, and is a concept that does not include the installation location itself. In other words, the phrase "manufactured off-site" includes, for example, manufacturing in a factory or near the installation location.

[0008] The connecting means may be a hook-shaped reinforcing bar, and the step of mounting the reinforcing bar unit to the precast concrete member may include a step of anchoring the hook-shaped reinforcing bar to the loop-shaped reinforcing bar to connect the precast concrete member and the reinforcing bar unit.

[0009] The connecting means may be a first corrugated reinforcing bar, and in the process of mounting the reinforcing bar unit to the precast concrete member, the reinforcing bar unit may be mounted to the precast concrete member so that the valley side of the first corrugated reinforcing bar is adjacent to the loop-shaped reinforcing bar.

[0010] The reinforcing bar unit may include an upper main reinforcement, an upper distribution reinforcement extending in a direction intersecting the upper main reinforcement, and the hook-shaped reinforcing bar moored to one or both of the upper main reinforcement and the upper distribution reinforcement.

[0011] The loop-shaped reinforcing bar may be a second corrugated reinforcing bar, a portion of which protrudes in a loop shape from the surface of the precast concrete member, and the peak side of the second corrugated reinforcing bar may protrude from the surface of the precast concrete member.

[0012] A plurality of the loop-shaped reinforcing bars may be provided, and a connecting member may be hung between adjacent loop-shaped reinforcing bars, and the hook-shaped reinforcing bar may be moored to the loop-shaped reinforcing bar via the connecting member.

[0013] According to another aspect of the present invention, there is provided a structure for a half-precast concrete member consisting of a precast concrete member and a cast-in-place concrete member, characterized in that it includes a loop-shaped reinforcing bar arranged so that a portion of it protrudes in a loop shape from the surface of the precast concrete member toward the cast-in-place concrete member, and the cast-in-place concrete member has embedded therein a reinforcing bar unit including an upper main reinforcing bar, an upper distribution bar extending in a direction intersecting the upper main reinforcing bar, and a hook-shaped reinforcing bar anchored to one or both of the upper main reinforcing bar and the upper distribution bar, and the hook-shaped reinforcing bar is also anchored to the loop-shaped reinforcing bar.

[0014] Furthermore, according to the present invention, there is provided a structure for a half-precast concrete member consisting of a precast concrete member and a cast-in-place concrete member, characterized in that it includes a loop-shaped reinforcing bar arranged so that a portion of it protrudes in a loop shape from the surface of the precast concrete member toward the cast-in-place concrete member, and the cast-in-place concrete member has embedded therein a reinforcing bar unit including an upper main reinforcing bar, an upper distribution bar extending in a direction intersecting the upper main reinforcing bar, and a first corrugated reinforcing bar whose axis extends in a direction parallel to the upper main reinforcing bar, the peak of the first corrugated reinforcing bar being anchored to the upper distribution bar, and the valley side of the first corrugated reinforcing bar being adjacent to the loop-shaped reinforcing bar. [Effects of the Invention]

[0015] According to the present invention, the benefits of adopting the half-precast construction method when producing half-precast concrete members are maximized, and productivity is improved by reducing labor and manpower and shortening construction time. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic explanatory diagram of a half precast concrete member according to an embodiment of the present invention. [Figure 2] FIG. 1 is a schematic overhead view of a precast concrete member. [Figure 3] FIG. 2 is a schematic overhead view of a reinforcing bar unit. [Figure 4] 1 is a schematic diagram illustrating a loop-shaped reinforcing bar and a hook-shaped reinforcing bar. [Figure 5] FIG. 1 is a schematic explanatory diagram illustrating a method for constructing a half-precast concrete member. [Figure 6] FIG. 2 is a schematic explanatory diagram of a half precast concrete member according to a first modified example of the present invention. [Figure 7] FIG. 10 is a schematic explanatory diagram of a half precast concrete member according to a second modified example of the present invention. [Figure 8] FIG. 10 is a schematic explanatory diagram of a half precast concrete member according to a third modified example of the present invention. [Figure 9] FIG. 10 is a schematic explanatory diagram illustrating a method for constructing a half-precast concrete member according to a third modified example. [Figure 10] FIG. 11 is a schematic explanatory diagram relating to the proximity conditions of the corrugated reinforcing bars in the third modified example. [Figure 11] FIG. 11 is a schematic explanatory diagram relating to the proximity conditions of the corrugated reinforcing bars in the third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this specification and the drawings, components having substantially the same functional configurations may be designated by the same reference numerals to avoid redundant description. In addition, in the embodiments of this specification, for the purpose of explanation, some illustrations of the reinforcing bar structure and reinforcing bar arrangement may be omitted, or reinforcing bars inside the members may be illustrated.

[0018] (Configuration of half precast concrete member according to an embodiment of the present invention) FIG. 1 is a schematic explanatory diagram of a half-precast concrete member 1 according to an embodiment of the present invention, and is a schematic side cross-sectional view thereof. As shown in FIG. 1, the half-precast concrete member 1 is constructed by joining two concrete members, and includes a precast concrete member 10 as the substructure and a cast-in-place concrete member 20 as the superstructure. Here, the precast concrete member 10 is a member that is fabricated in advance in a factory or the like. The cast-in-place concrete member 20 is a member that is fabricated by pouring concrete on-site.

[0019] Inside the precast concrete member 10, there are provided a plurality of lower main reinforcements 12 extending in a predetermined direction (for example, the longitudinal direction of the member) and a plurality of lower distribution reinforcements 14 extending in a direction intersecting (for example, perpendicular to) the lower main reinforcements 12. The lower main reinforcements 12 extend parallel to one another. Similarly, the lower distribution reinforcements 14 also extend parallel to one another.

[0020] 2 is a schematic overhead view of the precast concrete member 10. As shown in Figures 1 and 2, the precast concrete member 10 is provided with looped reinforcing bars 16, portions of which protrude in a loop shape from the surface of the member. The looped reinforcing bars 16 may be, for example, corrugated reinforcing bars, and may be configured so that their valley sides are anchored to one or both of the lower main reinforcements 12 and the lower distribution reinforcements 14, and their peak sides protrude from the surface of the precast concrete member 10.

[0021] Inside the cast-in-place concrete member 20, there are provided a plurality of upper main reinforcements 22 extending in a predetermined direction (for example, the longitudinal direction of the member) and a plurality of upper distribution reinforcements 24 extending in a direction intersecting (for example, perpendicular to) the upper main reinforcements 22. Also, as shown in the figure, there are provided hook-shaped reinforcing bars 26 that are anchored to one or both of the upper main reinforcements 22 and the upper distribution reinforcements 24 and have a so-called hook shape.

[0022] As shown in Figure 1, a hook-shaped reinforcing bar 26 is moored to a loop-shaped reinforcing bar 16 that protrudes from the surface of a precast concrete member 10, and cast-in-place concrete is poured in this state to form a cast-in-place concrete member 20. In the configuration according to this embodiment, a connecting member 30 is provided that spans between adjacent loop-shaped reinforcing bars 16 to connect them, and the hook-shaped reinforcing bar 26 is moored to the loop-shaped reinforcing bar 16 via this connecting member 30. Note that the hook-shaped reinforcing bar 26 may also be moored directly to the loop-shaped reinforcing bar 16. In other words, the hook-shaped reinforcing bar 26 functions as a connecting means when connecting a reinforcing bar unit 40 (described later) and the loop-shaped reinforcing bar 16.

[0023] 3 is a schematic overhead view of a reinforcing bar unit 40. As shown in FIG. 3, the upper main reinforcement 22, the upper distribution reinforcement 24, and the hook-shaped reinforcing bar 26 are integrated in advance to form the reinforcing bar unit 40. The upper main reinforcement 22, the upper distribution reinforcement 24, and the hook-shaped reinforcing bar 26 may be integrated by any means, such as welding or bundling. The reinforcing bar unit 40 may be fabricated in advance in a factory or on-site. The cast-in-place concrete member 20 is fabricated by pouring cast-in-place concrete so that the integrated reinforcing bar unit 40 is embedded inside.

[0024] (Configuration of looped and hooked reinforcing bars) As described above with reference to Figures 1 and 2, in the half precast concrete member 1 according to this embodiment, the precast concrete member 10 is provided with loop-shaped reinforcing bars 16, a portion of which protrudes in a loop shape from its surface. From the viewpoints of ease of transporting the precast concrete member 10 and efficiency in stacking the members, it is desirable to set an upper limit on the exposed height of the loop-shaped reinforcing bars 16 from the surface of the precast concrete member 10. On the other hand, the loop-shaped reinforcing bars 16, when combined with the hook-shaped reinforcing bars 26, constitute shear reinforcement and are required to function to prevent shear failure at the boundary between the two members in the half precast concrete member 1. Therefore, the inventors conducted extensive research into the specific configurations of the loop-shaped reinforcing bars 16 and the hook-shaped reinforcing bars 26 when the loop-shaped reinforcing bars 16 are corrugated reinforcing bars.

[0025] FIG. 4 is a schematic diagram of the loop reinforcing bars 16 and the hook reinforcing bars 26, and is a schematic enlarged view of the loop reinforcing bars 16 and the hook reinforcing bars 26 connected together. As shown in FIG. 4, the exposed height of the loop reinforcing bars 16 from the surface of the precast concrete member 10 is preferably set so that the peak position P1 of the corrugated shape falls within the height range T1 shown in the figure. This height range T1 is defined by position T3, which is at least twice the diameter of the hook reinforcing bars 26 serving as shear reinforcement above the boundary position T2 between the precast concrete member 10 and the cast-in-place concrete member 20, and position T5, which is at least the diameter of the upper main reinforcement 22 below the height position T4 of the upper main reinforcement 22. In other words, it is preferable to design the exposed height of the loop reinforcing bars 16 so that the peak position P1 of the corrugated shape is higher than position T3 and lower than position T5 in the figure.

[0026] If the peak position P1 of the corrugated loop-shaped reinforcing bar 16 is located lower than the position T3, there is a concern that the workability will be reduced when connecting the loop-shaped reinforcing bar 16 and the hook-shaped reinforcing bar 26. On the other hand, if the peak position P1 of the loop-shaped reinforcing bar 16 is located higher than the position T5, there is a risk that the poured-in-place concrete will not fill properly when constructing the poured-in-place concrete member 20.

[0027] Furthermore, when the loop-shaped reinforcing bars 16 are wave-shaped, the inclination angle α of the reinforcing bars that form the wave-shaped shape and extend diagonally is preferably 45° to 90°. It is generally known that in reinforced concrete structures, shear cracks are likely to occur in the range of 0° to 45° with respect to the axial direction, and in order to make the shear reinforcement effective in this range, the inclination angle α is set to 45° to 90°.

[0028] 4, the hook-shaped reinforcing bar 26 may have one end (upper end) that is semicircular hook-shaped and the other end (lower end) that is bent at a predetermined angle β. This angle β is determined based on the ease of connecting the reinforcing bar unit 40 to the loop-shaped reinforcing bar 16 exposed from the surface of the precast concrete member 10, and is specifically, for example, 135°. Note that the shape of the hook-shaped reinforcing bar 26 is not limited to this, and may have, for example, one end that is L-shaped hook-shaped and the other end that is semicircular hook-shaped.

[0029] (Method for constructing half-precast concrete members) Next, a method for constructing the half precast concrete member 1 according to the present embodiment will be described. Figure 5 is a schematic explanatory diagram of the method for constructing the half precast concrete member 1.

[0030] First, as shown in Figure 5(a), a precast concrete member 10 is prepared, which has been fabricated in advance with the loop-shaped reinforcing bars 16 exposed from the surface by the predetermined height described above. The precast concrete member 10 is fabricated at a location different from the installation site (so-called off-site). The precast concrete member 10 is then installed at a predetermined location such as a construction site.

[0031] Next, as shown in Figure 5(b), a prefabricated, integrated reinforcing bar unit 40 is lowered from above the precast concrete member 10 and mounted on the precast concrete member 10. The reinforcing bar unit 40 is also fabricated at a location different from the installation site (so-called off-site). The reinforcing bar unit 40 and the precast concrete member 10 are then connected so that the hook-shaped reinforcing bar 26 is moored to the loop-shaped reinforcing bar 16 (see the arrows in the figure). At this time, the hook-shaped reinforcing bar 26 may be moored to the loop-shaped reinforcing bar 16 via a connecting member 30.

[0032] Then, as shown in Figure 5(c), cast-in-place concrete is poured with the reinforcing bar unit 40 and the precast concrete member 10 connected. That is, cast-in-place concrete is poured so as to bury the part of the loop-shaped reinforcing bar 16 that is exposed from the surface of the precast concrete member 10 and the reinforcing bar unit 40, thereby forming the cast-in-place concrete member 20. In this way, the half precast concrete member 1 according to this embodiment is constructed, with the precast concrete member 10 as the lower structure and the cast-in-place concrete member 20 as the upper structure.

[0033] (Action and effect) According to the half-precast concrete member 1 and its construction method of this embodiment, when joining a precast concrete member 10 and a cast-in-place concrete member 20, the upper main reinforcement 22, upper distribution reinforcement 24, and hook-shaped reinforcing bars 26 are integrated in advance to form a reinforcing bar unit 40. The two members are then joined by pouring cast-in-place concrete while the hook-shaped reinforcing bars 26 and loop-shaped reinforcing bars 16 of the reinforcing bar unit 40 are still connected. This reduces on-site work, maximizes the benefits of adopting the half-precast construction method, and improves productivity by reducing labor, manpower, and shortening construction time.

[0034] Furthermore, in the half precast concrete member 1 according to this embodiment, loop-shaped rebars 16 and hook-shaped rebars 26 are combined inside to form shear reinforcement. This ensures the shear strength at the boundary between the two concrete members while keeping the length of the rebar protruding from the surface of the precast concrete member 10 short. Keeping the length of the rebar protruding from the precast concrete member 10 short improves workability when constructing the half precast concrete member 1. In addition, multiple precast concrete members 10 can be easily stacked when storing or transporting them, thereby reducing costs.

[0035] Furthermore, the half-precast concrete member 1 according to this embodiment employs a so-called half-precast construction method that combines precast concrete members 10 and cast-in-place concrete members 20. This reduces material costs and shortens construction time compared to conventional techniques in which everything is constructed on-site, such as those described in Patent Document 1, and also improves work efficiency during construction and the transportability of the members.

[0036] Although an example of an embodiment of the present invention has been described above, the present invention is not limited to the illustrated embodiment. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the ideas described in the claims, and it is understood that these naturally fall within the technical scope of the present invention. Below, modified examples of the present invention will be described with reference to the drawings, etc. Note that in the following description of the modified examples, components having the same functional configuration as the present embodiment will be illustrated with the same reference numerals, and their description may be omitted.

[0037] (First Modification of the Invention) In the above embodiment, the hook-shaped reinforcing bars 26 are moored to the loop-shaped reinforcing bars 16 protruding from the surface of the precast concrete member 10 via the connecting members 30, but the present invention is not limited to this. Figure 6 is a schematic explanatory diagram of a half precast concrete member 1a according to a first modified example of the present invention.

[0038] In the half precast concrete member 1a of this modified example, the hook-shaped reinforcing bars 26 are directly anchored to the loop-shaped reinforcing bars 16 when connecting the reinforcing bar units 40 to the precast concrete member 10. This not only achieves the effects described in the above embodiment, but also reduces the number of components by eliminating the need for connecting members 30. This further improves workability and reduces costs.

[0039] (Second Modification of the Invention) In the above embodiment, when the hook-shaped reinforcing bars 26 are moored to the loop-shaped reinforcing bars 16 protruding from the surface of the precast concrete member 10, they are moored via connecting members 30 in a positional relationship such that the loop-shaped reinforcing bars 16 and the hook-shaped reinforcing bars 26 overlap in a plan view. However, the present invention is not limited to this. Figure 7 is a schematic explanatory diagram of a half precast concrete member 1b according to a second modified example of the present invention.

[0040] In the half precast concrete member 1b of this modified example, when connecting the reinforcing bar unit 40 and the precast concrete member 10, the hook-shaped reinforcing bars 26 are directly moored to the loop-shaped reinforcing bars 16, and the loop-shaped reinforcing bars 16 and the hook-shaped reinforcing bars 26 are moored at an angle so that they do not overlap in a plan view. This not only achieves the effects described in the above embodiment and the first modified example, but also makes it possible to flexibly change the configuration of the shear reinforcement depending on the design of the structure, etc., and to achieve effective mooring of the reinforcing bars to each other.

[0041] (Third Modification of the Invention) In the above embodiment, the hook-shaped reinforcing bars 26 are used as the connecting means for connecting the reinforcing bar units 40 and the loop-shaped reinforcing bars 16, but the present invention is not limited to this. Fig. 8 is a schematic explanatory diagram of a half precast concrete member 1c according to a third modified example of the present invention, and a schematic side cross-sectional view thereof. Fig. 9 is a schematic explanatory diagram of a method for constructing the half precast concrete member 1c according to this modified example.

[0042] In the half precast concrete member 1c according to this modified example, the reinforcing bar unit 40 is provided with a first corrugated reinforcing bar 50 as a means for connecting to the loop-shaped reinforcing bar 16. The axis of the first corrugated reinforcing bar 50 extends in a direction parallel to the upper main reinforcement 22, and its crest side is anchored to the upper reinforcing bar 24. Here, if the loop-shaped reinforcing bar 16 has a corrugated shape, the loop-shaped reinforcing bar 16 is configured as a second corrugated reinforcing bar different from the first corrugated reinforcing bar 50. As shown in FIG. 8 , the first corrugated reinforcing bar 50 is included in the reinforcing bar unit 40, and is integrated as the reinforcing bar unit 40 with, for example, its crest side anchored to the upper reinforcing bar 24.

[0043] The method for constructing the half precast concrete member 1c is as follows. First, as shown in Figure 9(a), a precast concrete member 10 is prepared, which has been fabricated in advance with the loop-shaped reinforcing bars 16 exposed from the surface by a predetermined height. The precast concrete member 10 is fabricated at a location different from the installation site (so-called off-site). The precast concrete member 10 is then installed at a predetermined location, such as a construction site.

[0044] Next, as shown in Figure 9(b), a prefabricated, integrated reinforcing bar unit 40 is lowered from above the precast concrete member 10 and installed on the precast concrete member 10 (see the arrow in the figure). The reinforcing bar unit 40 is also manufactured at a location other than the installation site (so-called off-site). When the reinforcing bar unit 40 is installed, it is positioned so that the valley side of the first corrugated reinforcing bar 50 is close to the peak of the loop-shaped reinforcing bar (second corrugated reinforcing bar) 16. Then, by pouring cast-in-place concrete in this state, the cast-in-place concrete member 20 is constructed, and the half-precast concrete member 1c is built.

[0045] As described above, in the half precast concrete member 1c according to this modified example, it is required that the valley side of the first corrugated reinforcing bar 50 and the crest of the loop-shaped reinforcing bar (second corrugated reinforcing bar) 16 are close to each other. The inventors have studied the optimum positional relationship (proximity conditions) between the first corrugated reinforcing bar 50 and the loop-shaped reinforcing bar 16. Figures 10 and 11 are schematic explanatory diagrams relating to the proximity conditions between the corrugated reinforcing bars, with Figure 10 being a schematic enlarged view of the close-up portion and Figure 11 being a schematic enlarged view of the close-up portion as viewed from the longitudinal direction of the reinforcing bars.

[0046] As shown in Fig. 10, in the configuration of this modified example, it is desirable that at least a portion including the valley side of the first corrugated reinforcing bar 50 and at least a portion including the crest of the loop-shaped reinforcing bar 16 are positioned so as to overlap in side view. Also, as shown in Figs. 10 and 11, it is desirable that the overlap height l when the first corrugated reinforcing bar 50 and the loop-shaped reinforcing bar 16 overlap in side view and the separation distance a between the two reinforcing bars when viewed from the longitudinal direction of the reinforcing bars satisfy the relationship of the following formula (1). a≦l (1)

[0047] On concrete, force transmission may be limited to within a 45-degree angle. By satisfying the above formula (1), the first corrugated reinforcing bar 50 and the loop-shaped reinforcing bar 16 will be located within a 45-degree angle from the horizontal direction of their tips (see Figure 11). In other words, if the condition of the above formula (1) is not met, the mechanical action between the first corrugated reinforcing bar 50 and the loop-shaped reinforcing bar (second corrugated reinforcing bar) 16 will not be exerted on each other, and there is a risk that the shear strength at the interface between the two concrete members in the half-precast concrete member 1c will not be guaranteed. For this reason, the relationship of the above formula (1) is set.

[0048] As with the above embodiment, the half-precast concrete member 1c of this modification reduces on-site work, maximizes the benefits of adopting the half-precast construction method, and improves productivity by reducing labor and manpower and shortening construction time. In particular, because there is no need to anchor the first corrugated reinforcing bars 50 and the loop-shaped reinforcing bars 16, further labor and manpower savings, shortening construction time, and reducing costs are achieved.

[0049] In this specification, the reinforcing bar structures of the members illustrated and described in the above embodiments and modified examples are merely examples, and the specific numbers and arrangements of the various reinforcing bars (lower main bars, lower distribution bars, upper main bars, upper distribution bars) can be designed as desired. Also, while the half-precast concrete member is illustrated and described as consisting of two members, the scope of application of the technology of the present invention is not limited to this and can also be applied to half-precast concrete members that are composed of, for example, three or more members joined together.

[0050] Furthermore, in the above embodiment, the reinforcing bars protruding from the surface of the precast concrete member 10 serving as the substructure are loop-shaped reinforcing bars 16, and the reinforcing bars included in the reinforcing bar units 40 that are anchored from above are hook-shaped reinforcing bars 26, but the present invention is not limited to this configuration. For example, the reinforcing bars protruding from the surface of the precast concrete member 10 serving as the substructure may be so-called hook-shaped reinforcing bars, and the reinforcing bars included in the reinforcing bar units 40 that are anchored from above may be loop-shaped reinforcing bars. [Industrial Applicability]

[0051] The present invention is applicable to a method for constructing a half-precast concrete member and a structure of a half-precast concrete member. [Explanation of symbols]

[0052] 1, 1a, 1b, 1c...Half precast concrete members 10...Precast concrete members 12...Lower main reinforcement 14...Lower distribution reinforcement 16...Loop-shaped rebar 20...Cast-in-place concrete components 22...Top main reinforcement 24...Upper distribution reinforcement 26...Hooked rebar 30...Connecting member 40...Reinforcing bar unit 50...First corrugated steel bar

Claims

1. A method for constructing a half precast concrete element consisting of a precast concrete element and a cast-in-place concrete element, comprising: fabricating the precast concrete member off-site with the loop reinforcing bars protruding from the surface; The process of fabricating the rebar units off-site; Installing the precast concrete members at a construction site; mounting the reinforcing bar units on the precast concrete members; and pouring cast-in-place concrete into the surface of the precast concrete member to embed the reinforcing bar units therein; A method for constructing a half precast concrete member, characterized in that the reinforcing bar unit is provided with a connecting means for connecting to a loop-shaped reinforcing bar protruding from the precast concrete member.

2. The connecting means is a hook-shaped reinforcing bar, 2. A method for constructing a half precast concrete member as described in claim 1, characterized in that the step of installing the reinforcing bar unit in the precast concrete member includes a step of connecting the precast concrete member and the reinforcing bar unit by anchoring the hook-shaped reinforcing bar to the loop-shaped reinforcing bar.

3. the connecting means is a first corrugated reinforcing bar; 2. A method for constructing a half precast concrete member as described in claim 1, characterized in that in the process of installing the reinforcing bar unit in the precast concrete member, the reinforcing bar unit is installed in the precast concrete member so that the valley side of the first corrugated reinforcing bar is adjacent to the loop-shaped reinforcing bar.

4. 3. The method for constructing a half-precast concrete member according to claim 2, wherein the reinforcing bar unit includes an upper main reinforcement, an upper distribution reinforcement extending in a direction intersecting the upper main reinforcement, and the hook-shaped reinforcing bar anchored to one or both of the upper main reinforcement and the upper distribution reinforcement.

5. A method for constructing a half-precast concrete member described in either claim 2 or 4, characterized in that a plurality of loop-shaped reinforcing bars are provided, connecting members are hung to connect adjacent loop-shaped reinforcing bars, and the hook-shaped reinforcing bar is moored to the loop-shaped reinforcing bar via the connecting member.

6. A method for constructing a half-precast concrete member described in any one of claims 1 to 5, characterized in that the loop-shaped reinforcing bar is a second corrugated reinforcing bar, a portion of which protrudes in a loop shape from the surface of the precast concrete member, and the peak side of the second corrugated reinforcing bar protrudes from the surface of the precast concrete member.

7. A half-precast concrete structure consisting of a precast concrete member and a cast-in-place concrete member, The precast concrete member includes a loop-shaped reinforcing bar that protrudes from the surface of the precast concrete member toward the cast-in-place concrete member in a loop shape. A reinforcing bar unit including an upper main reinforcement, an upper distribution reinforcement extending in a direction intersecting the upper main reinforcement, and a hook-shaped reinforcing bar moored to one or both of the upper main reinforcement and the upper distribution reinforcement is embedded in the cast-in-place concrete member, A structure of a half-precast concrete member, characterized in that the hook-shaped reinforcing bar is also moored to the loop-shaped reinforcing bar.

8. A half-precast concrete structure consisting of a precast concrete member and a cast-in-place concrete member, The precast concrete member includes a loop-shaped reinforcing bar that protrudes from the surface of the precast concrete member toward the cast-in-place concrete member in a loop shape. A reinforcing bar unit including an upper main reinforcement, an upper distribution reinforcement extending in a direction intersecting the upper main reinforcement, and a first corrugated reinforcing bar whose axis extends in a direction parallel to the upper main reinforcement is embedded in the cast-in-place concrete member, A structure of a half-precast concrete member, characterized in that the peak portion of the first corrugated reinforcing bar is anchored to the upper distribution bar, and the valley side of the first corrugated reinforcing bar is adjacent to the loop-shaped reinforcing bar.

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