Column-beam joint structure and construction method therefor

Abstract

To provide a column-beam joint structure of a composite structural beam which does not require cast-in-place concrete, and in which the usage amount of a filling material is reduced, and a construction method therefor.SOLUTION: A column-beam joint structure 1 comprises a column 7 including a column-beam joint 3 made of precast concrete, and a first composite structural beam 4. The first composite structural beam 4 includes a steel frame part 11, and an RC part 12. The first composite structural beam 4 is configured such that a plastic hinge which may be produced during an earthquake is produced at a position shifted to the central side of a beam span from a beam end part. The first composite structural beam 4 includes a first PCa member 19 made of precast concrete including the RC part 12 and at least a part 18 of the steel frame part 11. The first PCa member 19 includes a joint member 16 for joining a reinforcing-bar 24 projecting from a surface of the column-beam joint 3 to a beam main reinforcement 14 buried inside the RC part 12. The joint member 16 is placed in the vicinity of an end part at the side of the columnar-beam joint 3 in the RC part 12.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a column-beam joint structure including a column having a column-beam joint made of precast concrete and a composite structural beam whose end is made of precast concrete, and a method for constructing the same. [Background technology]

[0002] Conventionally, composite structural beams have been known in which the ends of the beam are made of highly rigid reinforced concrete (RC) and the center of the beam span is made of lightweight steel. Composite structural beams are also called composite beams or hybrid beams. For example, Patent Documents 1 to 3 disclose the use of precast concrete members in beam-column joint structures and construction methods for composite structural beams.

[0003] Patent Document 1 discloses installing a composite structural beam on a reinforced concrete or precast concrete column and pouring concrete at the column-beam joint. Patent Document 2 discloses using a precast reinforced concrete section at the end of the composite structural beam to function as the column-beam joint. Patent Document 3 shows that the concrete sections of the columns and composite structural beams are formed using cast-in-place concrete, and also discloses that reinforced concrete sections, including the joints between beams, may be constructed using precast concrete members. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-280541 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-252304 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-204249 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the invention described in Patent Document 1, the column-beam joint had to be formed with cast-in-place concrete. In the invention described in Patent Document 2, another composite structural beam is joined to a precast reinforced concrete section that functions as a column-beam joint, but the reinforced concrete section of the other composite structural beam had to be formed with cast-in-place concrete. Patent Document 3 did not disclose a specific joining method when using precast concrete members.

[0006] In light of this background, the inventors of the present invention have studied a beam-column joint structure for a composite structural beam that does not require cast-in-place concrete and a method for constructing the same, and have discovered the following further problems.

[0007] The inventors of the present invention have studied a beam-column joint structure 101, as shown in Figure 8, that does not require cast-in-place concrete. The beam-column joint structure 101 includes a column member 102, a beam-column joint 103 connected to the column member 102, and a first composite structural beam 104 and a second composite structural beam 105 joined to the beam-column joint 103. The first composite structural beam 104 includes a reinforced concrete section 106 and a steel frame section 107. The second composite structural beam 105 includes a reinforced concrete section 108 and a steel frame section 109. The first and second composite structural beams 104, 105 are arranged on opposite sides of the beam-column joint 103 and are joined to the beam-column joint 103 at the reinforced concrete sections 106, 108. The beam-column joint 103 and the reinforced concrete sections 106, 108 are precast concrete members.

[0008] The main beam reinforcement 110 protruding from the RC portion 108 of the second composite structural beam 105 is inserted into the through hole 111 provided in the column-beam joint 103 and the receiving hole 112 provided in the RC portion 106 of the first composite structural beam 104, and is connected to the main beam reinforcement 114 embedded in the RC portion 106 of the first composite structural beam 104 via a joint member 113 embedded in the RC portion 106 of the first composite structural beam 104.

[0009] Here, if the design were based on conventional thinking, the location of a plastic hinge (yield hinge) that could occur during an earthquake would be the end of the RC section 106 on the side of the beam-to-column joint 103 (the part indicated by the arrow in the figure). Since the joint member 113 needed to be positioned away from the position where the plastic hinge would occur, it was placed on the central side of the beam span in the RC section 106. This resulted in a problem in that the protrusion length of the beam main reinforcement 110 from the RC section 108 became longer, and the length of the receiving hole 112 into which the filler material 115 should be filled also became longer.

[0010] The present invention aims to provide a beam-column joint structure for a composite structural beam and a method for constructing the same, which does not require cast-in-place concrete and reduces the amount of filler used. [Means for solving the problem]

[0011] In order to solve the above-mentioned problems, a beam-column joint structure (1, 41, 51) according to one aspect of the present invention comprises a column (7) including a beam-column joint (3, 52) made of precast concrete, a steel frame section (11) of steel construction extending in a predetermined direction, and a reinforced concrete section (12, 45) of reinforced concrete construction connected to an end of the steel frame section in the predetermined direction, and a first composite structural beam (4, 42) joined to the beam-column joint at the reinforced concrete section, wherein the first composite structural beam is configured such that plastic hinges that may occur during an earthquake are prevented from forming within the beam span of the first composite structural beam in the reinforced concrete section. The first composite structural beam is configured to occur at the end toward the center, or closer to the center of the beam span than the RC portion of the steel frame portion, and the first composite structural beam includes a first PCa member (4, 42) made of precast concrete including the RC portion and at least a portion (18, 46) of the steel frame portion, and the first PCa member includes a joint member (16) that connects a reinforcing bar (24, 53) protruding from the surface of the beam-column joint to a main beam reinforcement (14) embedded in the RC portion, and the joint member is located near the end of the RC portion on the beam-column joint side.

[0012] According to this aspect, poured-in-place concrete is not required to construct the beam-column joint structure, thereby shortening the construction period. In addition, by shifting the position where plastic hinges may occur from the beam end and positioning the joint member near the beam end, the amount of filler used is reduced, thereby reducing the amount of work at the construction site.

[0013] In the above aspect, the column-beam joint structure (1, 41) is arranged on the opposite side of the column-beam joint (3) from the first composite structural beam (4, 42), and includes a steel frame section (11) of steel construction extending in the predetermined direction, and a reinforced concrete section (23) of reinforced concrete connected to an end of the steel frame section in the predetermined direction, and further includes a second composite structural beam (26) joined to the column-beam joint at its reinforced concrete section, the column-beam joint including a through hole (27) extending in the predetermined direction, and the reinforcing bar (24) protruding from the surface of the column-beam joint may have one end embedded in the reinforced concrete section of the second composite structural beam and the other end protruding from the reinforced concrete section of the second composite structural beam, passing through the through hole to reach the joint member (16).

[0014] According to this aspect, two composite structural beams located on opposite sides of a beam-column joint can be joined to the beam-column joint without using cast-in-place concrete.

[0015] In the above-described aspect, the column-beam joint structure (51) may be such that the reinforcing bars (53) protruding from the surface of the column-beam joint (52) are included in the column-beam joint as a precast concrete member.

[0016] According to this aspect, composite structural beams that do not have a beam on the opposite side of the column-beam joint, such as those found on the exterior of a building, where three beams are joined to a column-beam joint and arranged in a T-shape in plan view, can also be joined to the column-beam joint without using cast-in-place concrete.

[0017] One aspect of the present invention is a method for constructing a column-beam joint structure (1, 41, 51) with a first composite structural beam (4, 42) that includes a precast concrete column-beam joint (3, 52), a steel frame section (11) of steel construction extending in a predetermined direction, and a reinforced concrete section (12, 45) of reinforced concrete connected to an end of the steel frame section in the predetermined direction, and that joins the column-beam joint with the reinforced concrete section, the method comprising the steps of: installing the column-beam joint; and installing a first P made of precast concrete that includes the reinforced concrete section and at least a portion of the steel frame section at the column-beam joint. and a step of joining a PCa member (19, 47) to the first composite structural beam, wherein the first composite structural beam is configured so that a plastic hinge that may occur during an earthquake occurs at the end of the first composite structural beam in the RC section closer to the center of the beam span, or at the steel frame section closer to the center of the beam span than the RC section, and the first PCa member includes a joint member (16) that connects a reinforcing bar (24, 53) protruding from the surface of the beam-column joint to a main beam reinforcement (14) embedded in the RC section, and the joint member is arranged near the end of the RC section on the side of the beam-column joint.

[0018] According to this aspect, poured-in-place concrete is not required to construct the beam-column joint structure, thereby shortening the construction period. In addition, by shifting the position where plastic hinges may occur from the beam end and positioning the joint member near the beam end, the amount of filler used is reduced, thereby reducing the amount of work at the construction site.

[0019] In the above aspect, the first composite structural beam (4, 42) includes two of the first PCa members (19, 47) and an intermediate steel member (20) that is arranged between the two first PCa members and forms part of the steel frame section (11), and may further include a step of connecting the intermediate steel member to the first PCa member, which is performed after the step of joining the first PCa member to the column-beam joint section (3, 52).

[0020] According to this aspect, even if a column-beam joint of the same level has already been installed on a column adjacent to the column to be joined in the extension direction of the beam, the first PCa member, which is shorter than the overall length of the beam, can be moved in the extension direction of the beam toward the column-beam joint, thereby increasing the flexibility of the construction order.

[0021] In the above aspect, the first composite structural beam (4, 42) includes two of the first PCa members (19, 47) connected to each other, and the method may further include a step of connecting the two first PCa members to each other, which is performed after the step of joining the first PCa members to the column-beam joint (3, 52).

[0022] According to this aspect, compared to constructing the first composite structural beam by connecting three components including an intermediate steel frame component, fewer components need to be lifted by a crane, thereby reducing work time at the construction site. [Effects of the Invention]

[0023] According to the above aspects, it is possible to provide a column-beam joint structure for a composite structural beam and a construction method thereof, which does not require cast-in-place concrete and reduces the amount of filler used. [Brief explanation of the drawings]

[0024] [Figure 1] Front view of the column-beam joint structure according to the first embodiment [Figure 2] Reinforcement diagram of the frame structure according to the first embodiment [Figure 3] Reinforcement diagram of the cross section along line III-III in Figure 2 [Figure 4] FIG. 1 is a perspective view showing a method for constructing a beam-column joint structure according to a first embodiment; [Figure 5] FIG. 10 is a front view showing a first composite structural beam according to a modified example of the first embodiment; [Figure 6] Front view of the column-beam joint structure according to the second embodiment [Figure 7] Front view of the column-beam joint structure according to the third embodiment [Figure 8] Front view of the column-beam joint structure in the study example DETAILED DESCRIPTION OF THE INVENTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 shows a column-beam joint structure 1 according to a first embodiment, Fig. 2 is a reinforcement diagram of a frame structure including the column-beam joint structure 1, Fig. 3 is a reinforcement diagram of a cross section taken along line III-III in Fig. 2, and Fig. 4 is an explanatory diagram showing a method of constructing the column-beam joint structure 1. Note that some reinforcing bars are not shown in Figs. 1 and 4, and beams that lie in a direction perpendicular to the plane of the drawing are not shown in Figs. 1 and 2.

[0026] As shown in Figure 1, the column-beam joint structure 1 comprises a column member 2 extending in the vertical direction, a column-beam joint 3 attached to the column member 2, a first composite structural beam 4 extending in a predetermined horizontal direction and joined to the column-beam joint 3, and a second composite structural beam 5 extending on an extension line of the first composite structural beam 4 and joined to the column-beam joint 3 on the opposite side of the column-beam joint 3 from the first composite structural beam 4.

[0027] As shown in FIGS. 1 and 2, the column member 2 is a reinforced concrete (RC) member made of precast concrete (PCa).

[0028] The column-beam joint 3 is a reinforced concrete member made of precast concrete, and is fixed to the upper end of a column member 2 installed on a predetermined floor and the lower end of a column member 2 installed on the floor above. A filler 6 such as grout is filled between the opposing concrete surfaces of the column member 2 and the column-beam joint 3. The concrete part of the column-beam joint 3 has an outer shape of a roughly rectangular parallelepiped, and has an outer contour that roughly matches the outer contour of the column member 2 or is slightly larger than the outer contour of the column member 2 in a plan view.

[0029] As shown in Fig. 2, a column 7 composed of a column member 2 and a beam-column joint 3 includes a plurality of column main reinforcements 8 extending in the vertical direction and a plurality of ties 9 forming a horizontal frame surrounding the plurality of column main reinforcements 8. As shown in Fig. 4, the column main reinforcements 8 of the beam-column joint 3, which is a precast concrete member, protrude vertically from the concrete part and enter receiving holes 10 provided in the column member 2, and are connected to the column main reinforcements 8 embedded in the concrete of the column member 2 via joint members (not shown), such as sleeve joints, embedded in the concrete of the column member 2. The receiving holes 10 are filled with a filler material (not shown), such as grout.

[0030] 1 and 2, the first composite structural beam 4, when classified by constituent materials, includes a steel frame section 11 of steel construction extending in a predetermined direction, and a reinforced concrete section 12 connected to the end of the steel frame section 11 in the predetermined direction. The first composite structural beam 4 is joined to a beam-column joint 3 at the reinforced concrete section 12. A filler 13 such as grout is filled between the opposing concrete surfaces of the beam-column joint 3 and the reinforced concrete section 12.

[0031] As shown in FIGS. 1 to 3 , the RC section 12 includes a plurality of beam main reinforcements 14 extending in the extension direction of the first composite structural beam 4, a plurality of stirrups 15 arranged to surround the beam main reinforcements 14, joint members 16 such as sleeve joints attached to the ends of the beam main reinforcements 14 on the beam-to-column joint 3 side, and a concrete section 17 in which the beam main reinforcements 14, the stirrups 15, and the joint members 16 are embedded. The beam main reinforcements 14 are arranged in two upper and lower rows at the top and bottom of the RC section 12. Note that in FIGS. 1 and 4 , the number of beam main reinforcements 14 shown is reduced to one row at each end, but the beam main reinforcements 14 not shown have the same configuration as the illustrated beam main reinforcements 14 (the same applies to FIG. 6 showing a second embodiment described later). The RC section 12 may also include a connecting rebar 31 that extends in the beam width direction, is partially embedded in the concrete section 17, and has one or both ends protruding from the surface of the concrete section 17. The connecting rebar 31 is used to connect to a floor slab (not shown) supported by the first composite structural beam 4.

[0032] The end of the steel frame part 11 in the extension direction is embedded in the concrete part 17 of the RC part 12, so that the steel frame part 11 and the RC part 12 are integrated with each other. The RC part 12 is provided with a facility opening 30 that penetrates in the beam width direction, and this facility opening 30 also penetrates the part of the steel frame part 11 that protrudes into the RC part 12.

[0033] As shown in Figures 2 and 4, the first composite structural beam 4 can be classified into main components that are manufactured in a factory and assembled together at the construction site. These components include two first PCa members 19, each including an end steel member 18 that forms the end of the reinforced concrete section 12 and the steel section 11, and an intermediate steel member 20 that forms the middle section of the steel section 11. The first PCa member 19 is a precast concrete member. The end of the end steel member 18 on the side of the reinforced concrete section 12 extends over substantially the entire length of the reinforced concrete section 12 in the extension direction and is embedded in the concrete section 17 of the reinforced concrete section 12. The end of the end steel member 18 on the side of the intermediate steel member 20 protrudes from the concrete section 17. The end steel member 18 and the intermediate steel member 20 are made of H-shaped steel and are connected by sandwiching their webs and flanges with connecting plates 21 and fastening them with high-strength bolts 22 or the like.

[0034] As shown in Figure 1, the first composite structural beam 4 is configured so that plastic hinges that may occur during an earthquake occur at the end of the reinforced concrete section 12 closer to the beam span center of the first composite structural beam 4 or at the steel frame section 11 closer to the beam span center than the reinforced concrete section 12. Such hinge relocation can be achieved by placing reinforcing bars between the beam-column joint 3 and the reinforced concrete section 12 and / or by increasing the number or diameter of the main beam reinforcement bars 24 located at the end of the reinforced concrete section 12 closer to the beam span center of the first composite structural beam 4. In addition to the main beam reinforcement bars 24, the number or diameter of stirrups 15 (see Figures 2 and 3) may also be increased. Hinge relocation can also be achieved by providing a portion of the steel frame section 11 closer to the beam span center than the reinforced concrete section 12 that is more likely to yield. The joint member 16 is located near the end of the reinforced concrete section 12 near the beam-column joint 3. Arranging the joint member 16 near the end of the RC section 12 means, for example, that the end face of the joint member 16 on the side of the beam-to-column joint 3 is located in a range of 0 to 500 mm, preferably 0 to 200 mm, from the end face of the RC section 12 on the side of the beam-to-column joint 3. Although the joint member 16 cannot be installed in a location where a plastic hinge may occur during an earthquake, this arrangement of the joint member 16 is possible because the plastic hinge is shifted from the end of the first composite structural beam 4 by hinge relocation.

[0035] In explaining the second composite structural beam 5, components common to the first composite structural beam 4 are given the same reference numerals and explanations thereof will be omitted. As shown in Figures 1 and 2, the second composite structural beam 5, classified by constituent materials, includes a steel frame portion 11 and a reinforced concrete portion 23 connected to the end of the steel frame portion 11 in a predetermined direction. The second composite structural beam 5 is joined to the beam-column joint 3 at the reinforced concrete portion 23. A filler 13 is filled between the opposing concrete surfaces of the beam-column joint 3 and the reinforced concrete portion 23.

[0036] As shown in FIGS. 1 to 3, the RC section 23 of the second composite structural beam 5 includes a plurality of main beam reinforcements 24 extending in the extension direction of the second composite structural beam 5, a plurality of stirrups 15, and a concrete section 25 in which the main beam reinforcements 24 and the stirrups 15 are embedded. The main beam reinforcements 24 are arranged in two upper and lower rows at the top and bottom of the RC section 23 (as with the first composite structural beam 4, some of the main beam reinforcements 24 are not shown in FIGS. 1 and 4). The ends of the steel frame sections 11 in the extension direction are embedded in the concrete sections 25 of the RC section 23, thereby integrating the steel frame sections 11 and the RC section 23. The concrete sections 25 of the RC section 23 have approximately the same outer shape as the concrete sections 17 of the RC section 12 of the first composite structural beam 4.

[0037] As shown in Figures 2 and 4, the second composite structural beam 5, classified by its main components that are manufactured in a factory and assembled together at the construction site, includes two second PCa members 26, each including an RC section 23 and an end steel member 18, and an intermediate steel member 20. The second PCa member 26 is a precast concrete member. The end of the end steel member 18 on the RC section 23 side extends over substantially the entire length of the RC section 23 in the extension direction and is embedded in the concrete section 25 of the RC section 23. The end of the end steel member 18 on the intermediate steel member 20 side protrudes from the concrete section 25.

[0038] As shown in FIGS. 1 and 4 , the beam main reinforcement bars 24 of the second PCa member 26 are embedded in the concrete portion 25 at one end and protrude from the concrete portion 25 toward the first PCa member 19 at the other end. The reinforcement bars pass through through holes 27 provided in the beam-column joint 3, enter receiving holes 28 provided in the reinforced concrete portion 12 of the first PCa member 19, and are connected to the coupling members 16 disposed within the receiving holes 28. The beam main reinforcement bars 24 of the second PCa member 26 are connected to the beam main reinforcement bars 14 of the first PCa member 19 via the coupling members 16. Each beam main reinforcement bar 24 and its corresponding through holes 27 and receiving holes 28 are coaxially arranged, and the receiving holes 28 open toward the beam-column joint 3. The through holes 27 and receiving holes 28 are filled with a filler material 29, such as grout.

[0039] Like the first composite structural beam 4, the second composite structural beam 5 is configured so that plastic hinges that may occur during an earthquake occur at the end of the second composite structural beam 5 in the RC section 23 toward the center of the beam span, or closer to the center of the beam span than the RC section 12 in the steel frame section 11.

[0040] A method for constructing a beam-column joint structure 1 in which beams are joined in a cross shape in plan view will be described with reference to FIG.

[0041] At the factory, workers manufacture the precast concrete members: column member 2, column-beam joint 3, first PCa member 19, and second PCa member 26. Also at the factory, workers manufacture intermediate steel frame member 20. At the factory, workers attach a set of first PCa member 19 and second PCa member 26 to column-beam joint 3 so that they are positioned on opposite sides of column-beam joint 3. The column member 2, column-beam joint 3 to which the set of first PCa member 19 and second PCa member 26 is attached, the first PCa member 19 and second PCa member 26 that are not attached to column-beam joint 3, and intermediate steel frame member 20 are transported to the construction site at the appropriate time.

[0042] At the construction site, workers use a lifting machine such as a crane (not shown) to place the column member 2 in a predetermined position (FIG. 4(A)). Using the lifting machine such as a crane, workers place the column-beam joint 3, to which a set of first PCa member 19 and second PCa member 26 has already been attached, on the column member 2 so that the column main reinforcement bars 8 protruding from the underside of the concrete of the column-beam joint 3 are received in the receiving holes 10 (FIG. 4(B)). A filler material (not shown) is filled into the receiving holes 10, and a filler material 6 (see FIG. 1) is filled between the opposing concrete surfaces of the column member 2 and the column-beam joint 3. The filler material (not shown) filled into the receiving holes 10 and the filler material 6 filled between the surfaces of the column member 2 and the column-beam joint 3 may be the same or different.

[0043] Next, workers use a lifting machine such as a crane to attach another set of first and second PCa members 19 and 26 to the side of the column-beam joint 3 to which the first and second PCa members 19 and 26 are not attached ( FIG. 4(C) ). The second PCa member 26 is lifted to a predetermined height and then moved in the extension direction of the second composite structural beam 5 so that the beam main reinforcement bars 24 are received in the through holes 27 of the column-beam joint 3. After the other of the first and second PCa members 19 and 26 is placed in a predetermined position, one of the first and second PCa members 19 and 26 is lifted to a predetermined height, aligned, and moved in the extension direction of the beam so that the beam main reinforcement bars 24 protruding from the concrete portion 25 of the second PCa member 26 are received in the receiving holes 28 of the first PCa member 19. Filler 29 (see FIG. 1) is filled into through-hole 27 and receiving hole 28, and filler 13 (see FIG. 1) is filled between the opposing concrete surfaces of beam-column joint 3 and first PCa member 19 and second PCa member 26. Fillers 13 and 29 may be the same or different.

[0044] Next, workers use a lifting machine such as a crane to attach a new column member 2 to the column-beam joint 3 (Fig. 4(D)). The new column member 2 is hung down so that the column main reinforcement bars 8 protruding from the upper surface of the concrete at the column-beam joint 3 are received in the receiving holes 10 provided on the underside of the concrete part of the new column member 2. A filler material (not shown) is filled in the receiving holes 10, and a filler material 6 (see Fig. 1) is filled between the opposing concrete surfaces of the column member 2 and the column-beam joint 3. The filler material (not shown) filled in the receiving holes 10 and the filler material 6 filled between the surfaces of the column member 2 and the column-beam joint 3 may be the same as or different from each other.

[0045] In addition, in parallel with or before or after the installation of the new column member 2, workers use a lifting machine such as a crane to attach an intermediate steel frame member 20 to each of the two first PCa members 19 and two second PCa members 26 attached to the column-beam joint 3. It is preferable that the intermediate steel frame member 20 be installed after the two first PCa members 19 and / or second PCa members 26, the ends of which are to be connected, have been installed.

[0046] The effects of the beam-column joint structure 1 according to the first embodiment will be described with reference to FIGS.

[0047] Since the column-beam joint 3, the first PCa member 19 and the second PCa member 26 are precast concrete members, the construction period is shorter than if any of these were constructed using cast-in-place concrete.

[0048] Because the location where plastic hinges may occur during an earthquake is not at the end of the first composite structural beam 4 but closer to the center of the beam span, joint members 16 for the beam main reinforcement bars 14, 24 can be provided at the end of the RC section 12 on the beam-column joint 3 side. This allows the receiving holes 28 in the RC section 12 of the first PCa member 19 to be shortened or eliminated, and the filling range of the filler 29 can be narrowed.

[0049] During work at a construction site, the second PCa member 26 needs to be moved in the extension direction of the second composite structural beam 5 in order to insert the beam main reinforcement 24 protruding from the concrete portion 25 into the through hole 27 of the beam-column joint 3. Furthermore, when the first PCa member 19 is installed before the corresponding second PCa member 26, it only needs to be moved vertically. However, when the first PCa member 19 is installed after the corresponding second PCa member 26, it needs to be moved in the extension direction of the first composite structural beam 4 in order to insert the beam main reinforcement 24 into the joint member 16. Because the first composite structural beam 4 and the second composite structural beam 5 are divided into two first or second PCa members 19, 26 and an intermediate steel member 20, installation work for the first or second PCa member 19, 26 is possible even if the beam-column joint 3 to which the first composite structural beam 4 or the second composite structural beam 5 is to be joined has already been installed on the opposite side of its extension direction, allowing for greater flexibility in the construction order.

[0050] A set of first and second PCa members 19, 26, which are arranged coaxially with each other, are attached at a factory to a beam-column joint 3 where the beams are joined in a cross shape in plan view. This reduces the amount of work at the construction site compared to attaching two sets of first and second PCa members 19, 26 at the construction site. Furthermore, compared to attaching two sets of first and second PCa members 19, 26 at a factory, the width of the members to be transported is narrower, increasing the amount that can be transported by one transport vehicle, and the weight is relatively lighter, allowing for the use of smaller lifting equipment at the construction site.

[0051] Figure 5 shows a modified example of the first embodiment. This modified example differs from the above-described embodiment in that the first composite structural beam 4 does not include an intermediate steel frame member 20 (see Figure 4), and two PCa members 19 are connected to each other at the end portions of the central steel frame members 18. This configuration reduces the number of members that need to be lifted by a crane, thereby shortening the work time at the construction site.

[0052] Next, a beam-column joint structure 41 according to a second embodiment of the present invention will be described with reference to Fig. 6. In the description, components common to the first embodiment will be denoted by the same reference numerals and will not be described again.

[0053] The column-beam joint structure 41 comprises a column member 2, a column-beam joint 3, a first composite structural beam 42 extending in a predetermined horizontal direction and joined to the column-beam joint 3, and a second composite structural beam 43 extending on an extension line of the first composite structural beam 42 and joined to the column-beam joint 3 on the opposite side of the column-beam joint 3 from the first composite structural beam 42.

[0054] The first composite structural beam 42, when classified by constituent materials, includes a steel frame section 44 of steel construction extending in a predetermined direction and an RC section 45 of reinforced concrete construction connected to the end of the steel frame section 44 in the predetermined direction, and when classified by main components manufactured in a factory and assembled together at the construction site, includes two first PCa members 47 including end steel frame members 46 that form the ends of the RC section 45 and the steel frame section 44, and an intermediate steel frame member 20 (see FIG. 2) that forms the middle section of the steel frame section 44. The first composite structural beam 42 differs from the first composite structural beam 4 of the first embodiment in the connection structure between the RC section 45 and the end steel frame member 46, but has a common configuration in other respects.

[0055] The first PCa member 47 further includes a steel boundary plate 48 that abuts the end face of the RC section 45 on the beam span center side, and a shear stopper 49 such as a headed stud welded to the boundary plate 48 and embedded in the concrete section of the RC section 45. An end steel frame member 46 is welded to the face of the boundary plate 48 on the beam span center side. The end of the beam main reinforcement 14 on the beam span center side has a thread on its outer periphery, passes through a through-hole 48a in the boundary plate 48, protrudes further toward the beam span center side than the boundary plate 48, and is fixed to the boundary plate 48 by screwing in a nut 50.

[0056] The differences and similarities between the second composite structural beam 43 and the second composite structural beam 5 of the first embodiment (see Figure 1) are similar to the differences and similarities between the first composite structural beam 42 and the first composite structural beam 4 of the first embodiment (see Figure 1), so explanations will be omitted.

[0057] The construction method at a construction site and the effects of the beam-column joint structure 41 of the second embodiment are similar to those of the beam-column joint structure 1 of the first embodiment (see FIG. 1).

[0058] Next, a beam-column joint structure 51 according to a third embodiment of the present invention will be described with reference to Fig. 7. In the description, components common to the first embodiment will be denoted by the same reference numerals and will not be described again.

[0059] The column-beam joint structure 51 of the third embodiment comprises a column member 2, a column-beam joint 52 attached to the column member 2, and a first composite structural beam 4 extending in a predetermined horizontal direction and joined to the column-beam joint 52.

[0060] The column-beam joint structure 51 has three beams joined to a column-beam joint 52 to form a T-shape in a plan view, and although not shown, beams corresponding to the first composite structural beam 4 and the second composite structural beam 5 (see Figure 4) of the first embodiment are joined to the column-beam joint 52 from opposite sides perpendicular to the plane of the paper in Figure 7 in a configuration similar to that of the first embodiment.

[0061] The beam-column joint 52 as a precast concrete member includes a joint reinforcing bar 53 joined to the beam main reinforcement bars 14, and a concrete portion 54 in which the joint reinforcing bar 53 is partially embedded. The joint reinforcing bar 53 is U-shaped, with its middle portion embedded in the concrete portion 54 and both ends protruding from the surface of the concrete portion 54 toward the first composite structural beam 4 that is not paired with the second composite structural beam 5 (see FIG. 1). The joint reinforcing bar 53 may have one end embedded in the concrete portion 54 and the other end protruding from the surface of the concrete portion 54.

[0062] In the method for constructing the beam-column joint structure 51, it is necessary to move the first PCa member 19 toward the beam-column joint 52 so that the joint rebars 53 are received in the receiving holes 28 of the first PCa member 19, but in other respects it is the same as the method for constructing the beam-column joint structure 1 in the first embodiment (see FIG. 1). The beam-column joint structure 51 has the same effects as the beam-column joint structure 1 in the first embodiment (see FIG. 1).

[0063] Although the description of specific embodiments has been completed above, the present invention is not limited to the above embodiments and modifications, and can be widely modified and implemented. The column members may be cast-in-place reinforced concrete structures instead of precast reinforced concrete structures, or may be constructed of steel members. The column main reinforcements between the column members and the beam-column joints may be connected by connecting the column main reinforcements protruding from the concrete of the beam-column joint to the column main reinforcements provided in the column member via a joint member provided in the column member, or by connecting the column main reinforcements protruding from the concrete of the column member to the column main reinforcements provided in the beam-column joint via a joint member provided in the column member, or by passing through the beam-column joint and connecting to the column main reinforcements provided in the other column member via a joint member provided in the other column member. The beam-column joint may be a footing, and the first and second composite structural beams may be footing beams.

[0064] The composite structural beam may have RC sections with receiving holes and coupling members at both ends, or RC sections with beam main reinforcing bars protruding toward the beam to be connected at both ends, or an RC section with receiving holes and coupling members at one end and an RC section with beam main reinforcing bars protruding toward the beam to be connected at the other end. In these cases, the hinge relocation described in the above embodiment is essential for the RC section with coupling members to be positioned near the ends of the coupling members. [Explanation of symbols]

[0065] 1,41,51: Column beam joint structure 3,52:Column beam joint 4,42: 1st composite structural beam 5,43:Second composite structural beam 7: Pillar 10: Receptor hole 11,44: Steel frame section 12,45: RC section of the first composite structural beam 14: Main beam reinforcement of the first composite structural beam 16: Joint material 17: Concrete part of the RC part of the first composite structural beam 18,46: End steel member 19.47: First PCa member 20: Intermediate steel member 23: RC section of second composite structural beam 24: Main beam reinforcement of the second composite structural beam 25: Concrete part of the RC part of the second composite structural beam 26: Second PCa member 28: Receiving hole (first PCa member) 53: Jointed rebar

Claims

1. a column including a beam-column joint made of precast concrete; a first composite structural beam including a steel frame portion of steel construction extending in a predetermined direction and a reinforced concrete portion of reinforced concrete connected to an end portion of the steel frame portion in the predetermined direction, the first composite structural beam being joined to the beam-column joint portion at the reinforced concrete portion; Equipped with The first composite structural beam is configured so that a plastic hinge that may occur during an earthquake occurs at an end of the RC portion of the first composite structural beam on the beam span center side, or at a position closer to the beam span center than the RC portion of the steel frame portion, The first composite structural beam includes a first PCa member made of precast concrete including the RC portion and at least a portion of the steel frame portion, The first PCa member includes a joint member that connects the reinforcing bars protruding from the surface of the column-beam joint to the main beam reinforcement embedded in the RC section, and the joint member is positioned near the end of the RC section on the column-beam joint side, thereby forming a column-beam joint structure.

2. The second composite structural beam is arranged on the opposite side of the first composite structural beam with respect to the column-beam joint, and includes a steel frame section of steel construction extending in the predetermined direction and a reinforced concrete section of reinforced concrete connected to an end of the steel frame section in the predetermined direction, and is joined to the column-beam joint at the reinforced concrete section; The column-beam joint includes a through hole extending in the predetermined direction, 2. The column-beam joint structure according to claim 1, wherein the reinforcing bar protruding from the surface of the column-beam joint is embedded in the RC portion of the second composite structural beam at one end, and protrudes from the RC portion of the second composite structural beam at the other end, passes through the through hole, and reaches the joint member.

3. The column-beam joint structure according to claim 1 , wherein the reinforcing bars protruding from the surface of the column-beam joint are included in the column-beam joint as a precast concrete member.

4. A method for constructing a column-beam joint structure with a first composite structural beam, the first composite structural beam including a precast concrete column-beam joint, a steel frame portion of steel construction extending in a predetermined direction, and a reinforced concrete portion of reinforced concrete connected to an end of the steel frame portion in the predetermined direction, the first composite structural beam being joined to the column-beam joint at the reinforced concrete portion, installing the beam-to-column joint; Joining a first PCa member made of precast concrete including the RC portion and at least a portion of the steel frame portion to the column-beam joint; Equipped with The first composite structural beam is configured so that a plastic hinge that may occur during an earthquake occurs at an end of the RC portion of the first composite structural beam on the beam span center side, or at a position closer to the beam span center than the RC portion of the steel frame portion, A method for constructing a column-beam joint structure, wherein the first PCa member includes a joint member that connects a reinforcing bar protruding from the surface of the column-beam joint to a main beam reinforcement buried in the RC section, and the joint member is positioned near the end of the RC section on the column-beam joint side.

5. The first composite structural beam includes two of the first PCa members and an intermediate steel member that is arranged between the two first PCa members and constitutes a part of the steel frame portion, 5. A method for constructing a column-beam joint structure as described in claim 4, further comprising a step of connecting the intermediate steel frame member to the first PCa member, which is performed after the step of joining the first PCa member to the column-beam joint.

6. The first composite structural beam includes two of the first PCa members connected to each other, 5. A method for constructing a column-beam joint structure as described in claim 4, further comprising a step of connecting two of the first PCa members to each other, which is performed after the step of joining the first PCa member to the column-beam joint.

Images