Method for joining components in precast concrete structures

Abstract

To improve the degree of freedom of construction in a precast concrete structure and to reduce the cost.SOLUTION: A first member (12) having a first reinforcement receiving hole (23) on a side surface is erected at a predetermined position, and a temporary support member (28) is attached to the first member (12) (ST1, ST2). A second member (13) having a second reinforcement receiving hole (22) on an end surface is placed on the temporary support member (28), and the first reinforcement receiving hole (23) and the second reinforcement receiving hole (22) are opposed to each other (ST3). A falling-off prevention reinforcement 24 is arranged so as to extend over the first reinforcement receiving hole (23) and the second reinforcement receiving hole (22) (ST4). A filling material 14 is filled (ST5) in a gap G between the second member (13) and the first member (12), a tension material 15 is arranged (ST6), and after the filling material 14 is cured, prestress is introduced (ST7) into the second member (13) and the first member (12) by applying tensile force to the tendon 15. Thereafter, the temporary support member (28) is removed (ST8).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a method for joining members in a precast concrete structure and a structure for joining members in a precast concrete structure. [Background technology]

[0002] Prestressed concrete structures have been known as structures with higher elastic strength than reinforced concrete structures (Patent Document 1). In these prestressed concrete structures, a large number of precast concrete columns with integrally molded girder support jaws are erected on concrete foundations, and precast concrete girders with protrusions at their ends are supported by the girder support jaws and installed between each column. Filler is provided at the joint between the girder support jaws and the protrusions, and the prestressed precast concrete girders are tensioned and fixed to the precast concrete columns by tensioning the PC steel wires.

[0003] Another known building construction method that can shorten the construction period is one that uses multiple unbonded precast prestressed concrete columns (Patent Document 2). In this method, a predetermined number of stories are constructed in the core of the building, which includes multiple unbonded precast prestressed concrete columns, and then a predetermined number of stories are constructed in the outer periphery of the building. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 5-280092 [Patent Document 2] Japanese Patent Publication No. 2020-56165 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the prestressed concrete structure described in Patent Document 1, the girder support jaws are integrally formed with the precast concrete column so that they protrude from the outer surface of the column. The precast concrete beams have protruding ends formed with recesses for receiving the girder support jaws. When the girder support jaws are formed protrudingly on the precast concrete column in this way, the flexibility of construction is limited. Furthermore, because the girder support jaws and protrusions are integrally formed on the column and girder, the manufacturing costs of these precast concrete members are high. Furthermore, because the girder support jaws are integrally formed on the precast concrete column, they are bulky, and transportation costs are also high.

[0006] On the other hand, in the building construction method described in Patent Document 2, the core columns are constructed as unbonded precast prestressed concrete columns, but the core beams are reinforced concrete beams. Therefore, there is room for improvement in terms of increasing construction flexibility and reducing costs. Furthermore, paragraph

[0022] of Patent Document 2 discloses that the core beams may be unbonded precast prestressed concrete beams, precast prestressed concrete beams, etc., but does not disclose the specific configuration of the column-beam joints or the specific construction method for the column-beam joints.

[0007] In view of the above background, an object of the present invention is to improve the flexibility of construction in precast concrete structures and reduce costs. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, one aspect of the present invention is a method for joining members of a precast concrete structure, comprising the steps of: (ST2) erecting a first member (12) having a first reinforcing bar receiving hole (23) on a side surface at a predetermined position; (ST1) attaching a removable temporary support member (28) to the first member; (ST3) placing a second member (13) having a second reinforcing bar receiving hole (22) on an end surface of the second member (13) on the temporary support member, and aligning the first reinforcing bar receiving hole and the second reinforcing bar receiving hole; the step (ST4) of placing anti-fall-off reinforcement bars (24) across the second member and the first member; the step (ST5) of filling a filler (14) into a gap (G) formed between the second member and the first member; the step (ST6) of placing tension members (15) across the second member and the first member; the step (ST7) of applying tension to the tension members after the filler has hardened to introduce prestress into the second member and the first member; and the step (ST8) of removing the temporary support members after the tension members have been applied to the tension members.

[0009] Here, the term "precast concrete structure" refers to a structure made of concrete that has been poured in advance in a factory or the like, and includes reinforced concrete structures and prestressed concrete structures.

[0010] According to this aspect, since there is no need to provide a protrusion on the first member to support the second member, the second member can be positioned from either above or horizontally, and the freedom of construction is not limited. In addition, the manufacturing and transportation costs of the first member can be reduced. Construction is easy because a detachable temporary support member can be attached to the first member and the second member can be placed on the temporary support member. Furthermore, the appearance of the member joint can be improved by removing the temporary support member after tensioning the tendon. When the member joint is covered with a board or the like, dead space can be reduced by removing the temporary support member. In addition, material costs can be reduced because the temporary support member can be reused.

[0011] In the above aspect, the anti-fall-off bar (24) is pre-positioned so that the entire bar is received in one of the first reinforcing bar receiving hole (23) and the second reinforcing bar receiving hole (22), and in the step (ST4) of placing the anti-fall-off bar, the anti-fall-off bar may be moved from one of the first reinforcing bar receiving hole and the second reinforcing bar receiving hole to the other.

[0012] According to this aspect, the entire bar is received in one of the first reinforcing bar receiving holes or the second reinforcing bar receiving holes, so the bar does not get in the way when placing the second component. Also, the bar can be placed in the hole in advance and then moved to a predetermined position, making the work of placing the bar easier.

[0013] In the case where the anti-fall-off bars are pre-positioned, an extrusion hole (25) is connected to the rear end of one of the first reinforcing bar receiving holes (23) and the second reinforcing bar receiving holes (22), and in the step (ST4, Figure 6 (C)) of positioning the anti-fall-off bars (24), an extrusion member (26) may be pushed into the extrusion hole to move the anti-fall-off bars.

[0014] According to this aspect, the anti-fall-off ribs can be reliably moved by pushing the anti-fall-off ribs with the push-out member.

[0015] In the case where the anti-fall-off bars are pre-positioned, an extrusion spring (31) is compressed at the rear of one of the first reinforcing bar receiving holes (23) and the second reinforcing bar receiving holes (22), and in the step of positioning the anti-fall-off bars (24) (ST4, Figure 9 (C)), the anti-fall-off bars may be moved by the spring force of the extrusion spring.

[0016] According to this aspect, the anti-fall-off bars can be moved by the spring force of the push-out spring without the worker having to directly move the anti-fall-off bars, making it easy to place the anti-fall-off bars.

[0017] In the case where the anti-falling bars are pre-positioned, an extrusion grout filling hole (41) is connected to the rear end of one of the first reinforcing bar receiving holes (23) and the second reinforcing bar receiving holes (22), and in the step (ST4, Figure 11 (C)) of placing the anti-falling bars (24), grout (42) may be filled into the extrusion grout filling hole to move the anti-falling bars.

[0018] According to this aspect, the anti-fall-off reinforcement can be moved by utilizing the filling pressure of the grout, making it easy to place the anti-fall-off reinforcement.

[0019] In the above aspect, the first reinforcing bar receiving hole (23) penetrates the first member (12), and in the step (ST4, Figure 13 (C)) of placing the anti-fall-off bar (24), the anti-fall-off bar may be inserted from the side of the first member opposite the second member (13).

[0020] According to this aspect, even if the anti-fall-off bars are not placed in the holes beforehand, they can be placed in predetermined positions by inserting them from the side of the first member.

[0021] In order to solve the above problem, another aspect of the present invention is a precast concrete member joint structure (11), comprising a first member (12) erected at a predetermined position and having a first reinforcing bar receiving hole (23) on its side, a second member (13) having a second reinforcing bar receiving hole (22) on its end face and arranged so that the first reinforcing bar receiving hole faces the second reinforcing bar receiving hole, anti-fall bars (24) arranged to span the first reinforcing bar receiving hole and the second reinforcing bar receiving hole, a filler (14) filled in a gap (G) formed between the second member and the first member, and a tension member (15) arranged to span the second member and the first member and to introduce prestress into the second member and the first member.

[0022] According to this aspect, since the first member does not have a protrusion for supporting the second member, the second member can be placed from either above or horizontally, and the degree of freedom in construction is not limited. Furthermore, since the first member does not have a supporting protrusion, the manufacturing cost and transportation cost of the first member can be reduced compared to when such a protrusion is provided.

[0023] In the above aspect, a holding member (27) may be provided in a portion of the first member (12) below the second member (13) to detachably hold a temporary support member (28) for temporarily supporting the second member.

[0024] According to this aspect, the temporary support member for temporarily supporting the second member can be attached to the first member, and the second member can be placed on the temporary support member, which makes construction easy.

[0025] In the above aspect, the second member (13) may have a second through hole (18) extending longitudinally to allow the tension member to pass therethrough, and the first member (12) may have a first through hole (19) extending horizontally at a position aligned with the second through hole, the second through hole and the first through hole being separated from the gap and communicating with each other, and the tension member may be inserted through the second through hole and the first through hole to be in an unbonded state with respect to the second member and the first member.

[0026] According to this aspect, the member joints are unbonded prestressed concrete structures. Therefore, the elastic deformation performance of the member joint structure can be improved compared to bonded structures. In addition, since the second member and the first member can be separated by removing the tendons, the precast members can be reused, reducing the life cycle cost of the member joint structure. Furthermore, by reusing precast members, environmental impacts such as CO2 emissions can be reduced compared to constructing new members. [Effects of the Invention]

[0027] According to the above-mentioned aspects, it is possible to improve the degree of freedom in construction of precast concrete structures and reduce costs. [Brief explanation of the drawings]

[0028] [Figure 1] Front view of the building according to the first embodiment [Figure 2] Elevation section of the building shown in Figure 1 [Figure 3] Enlarged view of part III in Figure 2 [Figure 4] Plan cross-section of the main part of the building shown in Figure 3 [Figure 5] Flow diagram of the building construction procedure according to the first embodiment [Figure 6] An explanatory diagram of the building construction procedure according to the first embodiment [Figure 7] An explanatory diagram of the building construction procedure according to the first embodiment [Figure 8] Enlarged elevational cross-sectional view of the main part of the column-beam joint structure according to the second embodiment [Figure 9] An explanatory diagram of a building construction procedure according to the second embodiment [Figure 10] Enlarged elevational cross-sectional view of the main part of the column-beam joint structure according to the third embodiment [Figure 11] An explanatory diagram of a building construction procedure according to the third embodiment [Figure 12] Enlarged elevational cross-sectional view of the main part of the column-beam joint structure according to the fourth embodiment [Figure 13] An explanatory diagram of a building construction procedure according to the fourth embodiment. [Figure 14] Front view of the building according to the fifth embodiment DETAILED DESCRIPTION OF THE INVENTION

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention is applied to a rigid-frame building 1 made of reinforced concrete or steel-reinforced concrete.

[0030] First Embodiment First, a first embodiment of the present invention will be described with reference to FIGS. 1 to 7. FIG. 1 is a front view of a building 1 according to the first embodiment. As shown in FIG. 1, the building 1 includes a pair of columns 2 and beams 3, both ends of which in the extension direction are joined to the pair of columns 2. The columns 2 are arranged at predetermined positions at predetermined intervals in the X and Y directions, which are orthogonal to each other in a plan view. The columns 2 may be arranged in three or more rows in at least one of the X and Y directions. The beams 3 are arranged to extend in each of the X and Y directions. The beams 3 are also arranged at predetermined vertical positions on each floor of the building 1, and support floors (not shown). The ends of the beams 3 are joined to the columns 2 by column-beam joint structures 11.

[0031] The column 2 includes at least one precast column member 12. The precast column member 12 is erected at a predetermined position, such as on a lower column or foundation constructed below. The precast column member 12 may have the same length as the height of one story, or may have a length longer than the height of one story. Alternatively, the precast column member 12 may have a length shorter than the height of one story. The precast column member 12 is preferably connected to the lower column or foundation below by unbonded tendons.

[0032] The beam 3 is composed of one precast beam member 13. The precast beam member 13 has a length slightly shorter than the distance between a pair of precast column members 12. The precast beam member 13 is placed between a pair of precast column members 12. Therefore, a gap G (see Figure 6 (B)) is formed between the end of the precast beam member 13 and the opposing precast column member 12. This gap G is filled with filler material 14. After filling with filler material 14, the precast beam member 13 has both ends joined to a pair of precast column members 12 and is spanned across the pair of precast column members 12.

[0033] The precast column members 12 and precast beam members 13 are fabricated in advance in a factory using precast concrete and then transported to the construction site. The filler 14 is a fluid material that hardens over time, and may be, for example, mortar or cement milk. It is preferable to use fiber-reinforced mortar or low-elasticity, high-toughness mortar as the filler 14 so that the filler 14 is less likely to break after hardening.

[0034] In this way, the beam-column joint structure 11 is a precast concrete joint structure between one end of a precast beam member 13 and a precast column member 12, and is configured at both ends of the precast beam member 13. In this embodiment, each end of the precast beam member 13 is pressure-joined to the corresponding precast column member 12 by means of tendons 15 arranged so as to span from one precast column member 12 to the other precast column member 12. In this way, the beam-column joint structure 11 is made of prestressed concrete.

[0035] Specifically, one tendon 15 is arranged at each of the upper and lower parts of the precast beam member 13. In other embodiments, multiple tendons 15 may be arranged at each of the upper and lower parts of the precast beam member 13. The tendons 15 are fixed at both ends to the outer side surfaces of the precast column members 12 by fasteners 16 while under tension. This introduces prestress into the precast column members 12 and the precast beam members 13, and each end of the precast beam members 13 is pressed against the corresponding precast column members 12.

[0036] The tendons 15 are made of PC steel rods, PC steel wires, PC steel strands, or rods or cables made of fiber-reinforced plastic such as aramid fiber, carbon fiber, or glass fiber. The tendons 15 are unbonded tendons that are not bonded to the precast column members 12 and precast beam members 13. By making the tendons 15 unbonded, residual deformation after the end of an earthquake is reduced.

[0037] 2 is an elevational cross-sectional view of the building 1 shown in FIG. 2. As shown in FIG. 2, the precast beam member 13 has a beam-side through hole 18 formed therein as a second through hole for inserting the tendon 15 therethrough. The beam-side through hole 18 extends horizontally along the longitudinal direction of the precast beam member 13. In this embodiment, one beam-side through hole 18 is formed at each of the upper and lower parts of the precast beam member 13. The precast column member 12 has a column-side through hole 19 formed therein for inserting the tendon 15 therethrough. The column-side through hole 19 is formed as a first through hole, extends horizontally at a position aligned with the beam-side through hole 18, and is continuous with the beam-side through hole 18.

[0038] Figure 3 is an enlarged view of the main part of Figure 2. As shown in Figure 3, concave beam-side shear keys 20 are formed on both end surfaces of the precast beam member 13. Concave column-side shear keys 21 are formed on the inner side surface of the precast column member 12 at positions facing the beam-side shear keys 20.

[0039] A beam-side rebar receiving hole 22 is formed as a second rebar receiving hole at approximately the center in the height direction of both end faces of the precast beam member 13. In this embodiment, one beam-side rebar receiving hole 22 is formed at approximately the center in the width direction of each end face of the precast beam member 13. In other embodiments, multiple beam-side rebar receiving holes 22 may be formed at approximately the center in the height direction of each end face of the precast beam member 13, offset in the width direction. The beam-side rebar receiving hole 22 extends horizontally in a straight line along the longitudinal direction of the precast beam member 13 for a predetermined length from the end face of the precast beam member 13.

[0040] A column-side reinforcing bar receiving hole 23 is formed as a first reinforcing bar receiving hole at a position facing the beam-side reinforcing bar receiving hole 22 on the inner side surface of the precast column member 12. The column-side reinforcing bar receiving hole 23 is a linear, bottomed hole that is arranged coaxially with the opposing beam-side reinforcing bar receiving hole 22, and extends horizontally from the side surface of the precast column member 12 over a predetermined length.

[0041] Anti-fall bars 24 are arranged across the beam-side reinforcing bar receiving holes 22 and the column-side reinforcing bar receiving holes 23. In this embodiment, the anti-fall bars 24 are straight reinforcing bars. The anti-fall bars 24 may be deformed reinforcing bars or round steel bars. In other embodiments, the anti-fall bars 24 may be carbon fiber reinforcing bars or aramid fiber reinforcing bars, and may be curved. When the anti-fall bars 24 are curved, it is preferable that the beam-side reinforcing bar receiving holes 22 and the column-side reinforcing bar receiving holes 23 are also curved to match the shape of the anti-fall bars 24.

[0042] One end of the anti-fall-off bar 24 is located at the bottom of the column-side rebar receiving hole 23, and the longitudinal center of the anti-fall-off bar 24 is aligned with the gap G (see FIG. 6(B)) between the precast beam member 13 and the precast column member 12. The anti-fall-off bar 24 has a length that allows it to be received in the beam-side rebar receiving hole 22 and the column-side rebar receiving hole 23 by approximately 8 times (8d) the diameter d. In this embodiment, since the beam-side shear key 20 and the column-side shear key 21 are formed on the end face of the precast beam member 13 and the side face of the precast column member 12, the length of the anti-fall-off bar 24 is approximately 20 times (20d) the diameter d. The beam-side rebar receiving hole 22 has a length that is approximately twice the length of the column-side rebar receiving hole 23, specifically, approximately the same length as the anti-fall-off bar 24. Therefore, the other end of the anti-fall-off bar 24 is located in the longitudinal middle of the beam-side rebar receiving hole 22.

[0043] An extrusion hole 25 is connected to the bottom (rear end) of the beam-side reinforcing bar receiving hole 22. One end of the extrusion hole 25 is connected to the bottom of the beam-side reinforcing bar receiving hole 22, and the other end opens to the outer surface of the precast beam member 13. In this embodiment, the other end of the extrusion hole 25 opens to the top surface of the precast beam member 13. In other embodiments, the other end of the extrusion hole 25 may open to the side surface or bottom surface of the precast beam member 13.

[0044] Figure 4 is a plan cross-sectional view of the main part of the building 1 shown in Figure 3. As shown in Figure 4, the beam-side through hole 18 is arranged in the center in the width direction of the precast beam member 13. The beam-side reinforcing bar receiving hole 22 is arranged between the upper and lower beam-side through holes 18, that is, at a position where the beam-side through holes 18 overlap in the plan view of Figure 4. Therefore, the extrusion hole 25 is formed obliquely with respect to the axial direction of the precast beam member 13 in the plan view, and the other end of the extrusion hole 25 is arranged in a position offset from the center in the width direction on the top surface of the precast beam member 13.

[0045] As shown in Figure 3, the extrusion hole 25 is used to extrude the anti-fall bar 24 that was placed on the bottom side of the beam-side rebar receiving hole 22 and place it in the specified position shown in Figure 3. Specifically, a flexible extrusion member 26 (see Figure 6(C)), such as a piano wire, is inserted into the extrusion hole 25 from the other end, and the extrusion member 26 is pushed in with the tip of the extrusion member 26 engaged with the rear end of the anti-fall bar 24, thereby moving the anti-fall bar 24 forward. The anti-fall bar 24 should be pushed in until it abuts against the bottom of the column-side rebar receiving hole 23. The position of the anti-fall bar 24 can be estimated by measuring the amount of pushing (insertion) of the extrusion member 26.

[0046] A plurality of embedded anchors 27 are provided in the portion of the precast column member 12 below the precast beam member 13. The embedded anchors 27 have threaded holes opened in the side surface of the precast column member 12 below the precast beam member 13. The embedded anchors 27 are holding members that cooperate with bolts B that screw into the threaded holes to detachably hold brackets 28.

[0047] The brackets 28 are temporary support members for temporarily supporting the precast beam members 13 when joining them to the precast column members 12. The brackets 28 may be made of shaped steel such as angle iron, channel steel, or H-shaped steel. The brackets 28 are preferably attached before the precast column members 12 are erected, and removed after the precast beam members 13 are joined.

[0048] With this configuration, brackets 28 for temporarily supporting the precast beam members 13 can be attached to the precast column members 12, and the precast beam members 13 can be placed on the brackets 28, making construction easier.

[0049] As described above, the gap G (see FIG. 6(B)) formed between the precast beam member 13 and the precast column member 12 is filled with filler 14. The column-side reinforcing bar receiving holes 23, the beam-side reinforcing bar receiving holes 22, and the extrusion holes 25 are also filled with filler 14. As a result, the anti-fall-off bars 24 are covered with filler 14. The filler 14 functions as a rust inhibitor that prevents corrosion of the anti-fall-off bars 24.

[0050] An anti-adhesion material 29 is provided between the precast beam member 13 and the precast column member 12 to prevent the filler material 14 from adhering to the tendon 15. The anti-adhesion material 29 has an annular shape and separates the beam-side through-hole 18 and the column-side through-hole 19 from the gap G, thereby preventing the filler material 14 filled in the gap G from flowing into the beam-side through-hole 18 and the column-side through-hole 19. The anti-adhesion material 29 may be an elastic member provided in a compressed state between the precast beam member 13 and the precast column member 12. In another embodiment, the anti-adhesion material 29 may be a cylindrical member arranged across the gap G and inserted into the beam-side through-hole 18 and the column-side through-hole 19.

[0051] By providing anti-adhesion materials 29 and leaving the tendons 15 in an unbonded state, the beam-column joint becomes an unbonded prestressed concrete structure. This improves the elastic deformation performance of the beam-column joint structure 11 compared to a bonded structure. Furthermore, by removing the tendons 15, the precast beam members 13 and precast column members 12 can be separated. This makes it possible to reuse these precast members, reducing the life cycle cost of the beam-column joint structure 11. Furthermore, by reusing precast members, environmental impacts such as CO2 emissions are reduced compared to constructing new members.

[0052] In the vertical cross section of Figure 3, the upper surface 20a of the beam-side shear key 20 becomes lower from the gap G side toward the back. The upper surface 21a of the column-side shear key 21 also becomes lower from the gap G side toward the back. Therefore, air pockets are prevented from forming in the gap G when the filler 14 is filled into the gap G. The bottom surfaces of the beam-side shear key 20 and the column-side shear key 21 become higher from the gap G side toward the back in the vertical cross section of Figure 3.

[0053] The beam-column joint structure 11 of the building 1 is configured as described above. Next, a method for joining beams and columns of such a precast concrete structure will be described. Fig. 5 is a flow diagram showing the construction procedure of the building 1 according to the embodiment. Figs. 6 and 7 are explanatory diagrams of the construction procedure of the building 1 according to the first embodiment. The building 1 is constructed by workers according to the following procedure.

[0054] Prior to the construction of the building 1, the required number of precast column members 12 and precast beam members 13 configured as described above are prepared. As described above, the precast column members 12 are formed with column-side shear keys 21 and column-side rebar receiving holes 23, but no protrusions such as beam-receiving jaws are formed. Therefore, the precast column members 12 are not bulky, which reduces transportation costs. Furthermore, the precast beam members 13 are formed with beam-side shear keys 20 and beam-side rebar receiving holes 22, but no protruding portions that rest on the beam-receiving jaws are formed at their ends. As such, the absence of protruding portions on the precast column members 12 and precast beam members 13 reduces the manufacturing costs of these precast concrete members.

[0055] At the construction site of the building 1, detachable brackets 28 are attached to the precast column members 12 (step ST1). The precast column members 12 are then erected in predetermined positions (step ST2). This brings the building 1 under construction into the state shown in FIG. 6(A). The brackets 28 may be attached to the precast column members 12 before erecting the precast column members 12. Alternatively, the brackets 28 may be attached to the precast column members 12 after the precast column members 12 are erected in predetermined positions.

[0056] Next, the precast beam member 13 is placed on the bracket 28, and the column-side reinforcing bar receiving holes 23 and the beam-side reinforcing bar receiving holes 22 are aligned (step ST3). Specifically, as shown in FIG. 6(B), the precast beam member 13 is lifted by a crane (not shown) and placed between a pair of precast column members 12, and both ends of the precast beam member 13 are placed on the bracket 28. Anti-fall bars 24 are placed in advance in the beam-side reinforcing bar receiving holes 22 of the precast beam member 13 so that the entire reinforcing bar is received in the holes.

[0057] Since the precast column members 12 and the precast beam members 13 have no protrusions, the precast beam members 13 can be placed either from above or horizontally, allowing for unlimited freedom of construction. In addition, since the entire anti-fall reinforcement bars 24 are received in the beam-side reinforcing bar receiving holes 22, the anti-fall reinforcement bars 24 do not get in the way when placing the precast beam members 13.

[0058] By attaching the brackets 28 to the precast column members 12, the precast beam members 13 can be placed on the brackets 28, facilitating construction. In addition, by detachably attaching the brackets 28 for temporarily supporting the precast beam members 13 to the precast column members 12, the degree of freedom in construction is improved.

[0059] When the precast beam member 13 is placed in a predetermined position on the bracket 28, the beam-side shear key 20 and the column-side shear key 21 face each other. Also, the beam-side reinforcing bar receiving hole 22 and the column-side reinforcing bar receiving hole 23 face each other. When the precast beam member 13 is placed in a predetermined position, an anti-adhesion material 29 (see Figure 3) is placed in a predetermined position.

[0060] Thereafter, the fall prevention bars 24 are arranged so as to span the column-side reinforcing bar receiving holes 23 and the beam-side reinforcing bar receiving holes 22 (step ST4). In other words, the fall prevention bars 24 are moved from the beam-side reinforcing bar receiving holes 22 toward the column-side reinforcing bar receiving holes 23. Specifically, as shown in Fig. 6(C), the push-out members 26 are pushed into the push-out holes 25 to move the fall prevention bars 24.

[0061] In this way, the anti-fall-off bars 24 that have been placed in the holes in advance can be placed in the predetermined position by simply moving them, which facilitates the work of placing the anti-fall-off bars 24. In addition, by pushing the anti-fall-off bars 24 with the push-out member 26, the anti-fall-off bars 24 can be reliably moved.

[0062] Thereafter, the gap G formed between the precast beam member 13 and the precast column member 12 is filled with filler 14 (step ST5). The beam-side reinforcing bar receiving holes 22, the column-side reinforcing bar receiving holes 23, and the extrusion holes 25 are also filled with filler 14. This brings the building 1 into the state shown in Figure 6(D).

[0063] Next, the tendons 15 are placed across the precast beam members 13 and the precast column members 12 (step ST6). This brings the building 1 into the state shown in Figure 7(E). Note that either step ST5 or step ST6 may be performed first.

[0064] After the filler 14 has hardened, prestress is introduced into the precast beam members 13 and the precast column members 12 by applying tension to the tendons 15 (step ST7). As a result, a prestressed concrete beam-column joint structure 11 is constructed, as shown in Figure 7(F).

[0065] Thereafter, the brackets 28 are removed (step ST8). This leaves the building 1 in the state shown in FIG. 7(G). By removing the brackets 28 after joining the precast beam members 13, they can be reused for other joints. This reduces material costs. Furthermore, removing the brackets 28 improves the appearance of the column-beam joint. When covering the column-beam joint with a board or the like, removing the brackets 28 can reduce dead space.

[0066] Second Embodiment Next, a second embodiment of the present invention will be described with reference to Figures 8 and 9. Below, differences from the first embodiment will be described, and overlapping explanations will be omitted. The same applies to the following embodiments.

[0067] FIG. 8 is an enlarged cross-sectional elevation view of a main portion of a beam-column joint structure 11 according to a second embodiment, corresponding to FIG. 3 of the first embodiment. As shown in FIG. 8, in this embodiment, the extrusion holes 25 (FIG. 3) are not provided, and extrusion springs 31 are provided on the bottom sides of the beam-side reinforcing bar receiving holes 22. The extrusion springs 31 are members for extruding the fall prevention bars 24 that were placed so that their entirety was received in the beam-side reinforcing bar receiving holes 22 before the precast beam member 13 was placed. In the illustrated example, a piston member 32 is provided at the front end of the extrusion spring 31, and the bottom side of the beam-side reinforcing bar receiving holes 22 is not filled with filler material 14. In other embodiments, the bottom side of the beam-side reinforcing bar receiving holes 22 may also be filled with filler material 14, and the extrusion springs 31 may be embedded in the filler material 14.

[0068] Next, a column-beam joining method for a building 1 having a column-beam joint structure 11 configured as described above will be described with reference to Figure 9. Figure 9 is an explanatory diagram of the construction procedure for a building 1 according to the second embodiment, and corresponds to Figure 6 of the first embodiment. Note that the procedure corresponding to Figure 7 of the first embodiment is the same in this embodiment, and is therefore omitted from the illustration. As shown in Figure 9(A), as in the first embodiment, a detachable bracket 28 is attached to a precast column member 12 (step ST1), and the precast column member 12 is erected in a predetermined position (step ST2).

[0069] Next, as shown in Figure 9(B), the precast beam member 13 is placed on the bracket 28, and the column-side reinforcing bar receiving holes 23 and the beam-side reinforcing bar receiving holes 22 are aligned (step ST3). Anti-fall bars 24 are placed in advance in the beam-side reinforcing bar receiving holes 22 of the precast beam member 13 so that the entire bar is received in the holes. A cap is fitted into the opening of the beam-side reinforcing bar receiving holes 22 to prevent the anti-fall bars 24, which are biased by the push-out springs 31, from popping out.

[0070] 9(C), the fall prevention bars 24 are arranged so as to span the column-side reinforcing bar receiving holes 23 and the beam-side reinforcing bar receiving holes 22 (step ST4). In other words, the fall prevention bars 24 are moved from the beam-side reinforcing bar receiving holes 22 toward the column-side reinforcing bar receiving holes 23. Specifically, the caps are removed, and the fall prevention bars 24 are moved by the spring force of the push-out springs 31.

[0071] 9(D), the gap G formed between the precast beam member 13 and the precast column member 12 is filled with filler 14 (step ST5). The beam-side reinforcing bar receiving holes 22, the column-side reinforcing bar receiving holes 23, and the extrusion holes 25 are also filled with filler 14. The subsequent procedures are the same as those in the first embodiment.

[0072] In this embodiment, the anti-fall-off bars 24 can be moved by the spring force of the push-out spring 31 without the worker having to directly move the anti-fall-off bars 24, making it easy to place the anti-fall-off bars 24.

[0073] Third Embodiment Next, a third embodiment of the present invention will be described with reference to Figures 10 and 11. As shown in Figure 10, in this embodiment, instead of providing the extrusion hole 25 (Figure 3), an extrusion grout filling hole 41 is connected to the bottom (rear end) of the beam-side reinforcing bar receiving hole 22. One end of the extrusion grout filling hole 41 is connected to the bottom of the beam-side reinforcing bar receiving hole 22, and the other end opens to the outer surface of the precast beam member 13. The extrusion grout filling hole 41 is provided to extrude the anti-fallout bars 24 that were placed so that they were entirely received in the beam-side reinforcing bar receiving hole 22 before the precast beam member 13 was placed. In the illustrated example, a piston member 32 is provided to support the rear end of the anti-fallout bars 24, and grout 42 filled from the extrusion grout filling hole 41 is filled into the bottom side of the beam-side reinforcing bar receiving hole 22.

[0074] Next, a column-beam joining method for a building 1 having such a column-beam joint structure 11 will be described with reference to Fig. 11. Fig. 11 is an explanatory diagram of the construction procedure for a building 1 according to the third embodiment, and corresponds to Fig. 6 of the first embodiment. The procedures shown in Figs. 11(A) and 11(B) are the same as those in the first embodiment. Anti-fall reinforcement bars 24 are pre-placed in the beam-side reinforcing bar receiving holes 22 of the precast beam members 13 so that the entire reinforcing bars are received therein.

[0075] 11(C), the anti-fall-out bars 24 are moved from the beam-side reinforcing bar receiving holes 22 toward the column-side reinforcing bar receiving holes 23, and the anti-fall-out bars 24 are arranged so as to span the column-side reinforcing bar receiving holes 23 and the beam-side reinforcing bar receiving holes 22 (step ST4). Specifically, the extrusion grout filling holes 41 are filled with grout 42, and the anti-fall-out bars 24 are moved. The procedure from the step shown in FIG. 11(D) onwards is the same as in the first embodiment.

[0076] In this manner, in this embodiment, the anti-fall-off reinforcement bars 24 can be moved by utilizing the filling pressure of the grout 42, making the work of placing the anti-fall-off reinforcement bars 24 easy.

[0077] Fourth Embodiment Next, a fourth embodiment of the present invention will be described with reference to Figures 12 and 13. As shown in Figure 12, in this embodiment, no extrusion holes 25 are provided in the precast beam member 13. In addition, the beam-side reinforcing bar receiving holes 22 have approximately the same length as the column-side reinforcing bar receiving holes 23 (Figure 3) in the first embodiment. On the other hand, the column-side reinforcing bar receiving holes 23 in this embodiment are formed so as to penetrate the precast column member 12. The column-side reinforcing bar receiving holes 23 are filled with a filler material 14.

[0078] Next, a column-beam joining method for a building 1 having the beam-column joint structure 11 configured as described above will be described with reference to Fig. 13. Fig. 13 is an explanatory diagram of the construction procedure for a building 1 according to the fourth embodiment, and corresponds to Fig. 6 of the first embodiment. The procedures shown in Figs. 13(A) and 13(B) are the same as those in the first embodiment. However, the fall prevention bars 24 are not placed in the beam-side reinforcing bar receiving holes 22 of the precast beam members 13 or in the column-side reinforcing bar receiving holes 23 of the precast column members 12.

[0079] After the precast beam member 13 is placed as shown in Fig. 13(B), as shown in Fig. 13(C), the anti-fall-out bars 24 are inserted into the column-side reinforcing bar receiving holes 23, and the anti-fall-out bars 24 are arranged so as to span the column-side reinforcing bar receiving holes 23 and the beam-side reinforcing bar receiving holes 22 (step ST4). The procedure from the step shown in Fig. 13(D) onwards is the same as in the first embodiment.

[0080] In this manner, in this embodiment, the anti-fall-off bars 24 are inserted from the side of the precast column member 12 opposite the precast beam member 13. Therefore, even if the anti-fall-off bars 24 are not placed in the holes beforehand, they can be placed in the predetermined positions by inserting them from the side of the precast column member 12.

[0081] Fifth Embodiment Next, a fifth embodiment of the present invention will be described with reference to Fig. 14. Fig. 14 is a front view of a building 1 according to the fifth embodiment. As shown in Fig. 14, this embodiment differs from the first embodiment in that both ends of a precast beam member 13 are joined to a pair of precast column members 12 by pressure bonding using discontinuous tendons 15. This will be described in detail below.

[0082] The precast beam member 13 has beam widening portions 51 at both ends that are wider than the middle portion in the longitudinal direction. The beam widening portions 51 form shoulder surfaces 51a on the side opposite the end faces of the precast beam member 13 that engage the fasteners 16. The shoulder surfaces 51a are formed on both sides in the width direction in the cross section of the precast beam member 13.

[0083] Even if the precast beam member 13 is configured in this manner and both ends of the precast beam member 13 are pressure-attached to the precast column member 12 by discontinuous, independent tendons 15, the same effects as in the first embodiment can be achieved.

[0084] Although the specific embodiment has been described above, the present invention is not limited to the above embodiment and can be widely modified and implemented.

[0085] For example, in the first to third embodiments, the beam-side reinforcing bar receiving holes 22 are formed longer than the column-side reinforcing bar receiving holes 23, and the fall-out prevention bars 24 are arranged so that the entire reinforcing bar is received in the beam-side reinforcing bar receiving holes 22. In other embodiments, the column-side reinforcing bar receiving holes 23 may be formed longer than the beam-side reinforcing bar receiving holes 22, and the fall-out prevention bars 24 may be arranged so that the entire reinforcing bar is received in the column-side reinforcing bar receiving holes 23. In this case, the extrusion holes 25 (FIG. 3), the extrusion springs 31 (FIG. 8), and the extrusion grout filling holes 41 (FIG. 10) are provided in the precast column member 12.

[0086] In the above embodiment, the precast column member 12 is used as the first member and the precast beam member 13 is used as the second member, but this is not limited to this embodiment. For example, the precast column member 12 may be used as the first member and the second member. Also, the precast beam member 13 may be used as the first member and the second member. Alternatively, a precast wall member or a precast floor member may be used as at least one of the first member and the second member.

[0087] In the above embodiment, the beam-column joint structure 11 is a precast concrete structure using prestressed concrete, but it may be a precast concrete structure using reinforced concrete (RC). Alternatively, the beam-column joint structure 11 may be a bonded prestressed concrete structure instead of an unbonded prestressed concrete structure.

[0088] In addition, the specific configuration, arrangement, quantity, material, procedure, etc. of each member or part can be changed as appropriate within the scope of the spirit of the present invention. Furthermore, the configurations of the above embodiments can be combined with each other. Meanwhile, not all of the components shown in the above embodiments are necessarily required, and can be selected as appropriate. [Explanation of symbols]

[0089] 11: Column beam joint structure 12: Precast column members 13: Precast beam member 14: Filling material 15: Tensile material 18: Beam side through hole 19: Pillar side through hole 22: Beam side rebar receiving hole 23: Column side rebar receiving hole 24: Fall prevention strip 25: Extrusion hole 26: Extrusion member 27: Embedded anchor (retaining member) 28: Bracket (temporary support member) 31: Extrusion spring 41: Extrusion grout filling hole 42: Grout G: air gap

Claims

1. A method for joining members of a precast concrete structure, comprising: A step of erecting a first member having a first reinforcing bar receiving hole on a side surface at a predetermined position; attaching a removable temporary support member to the first member; a step of placing a second member having a second reinforcing bar receiving hole on an end surface thereof on the temporary support member so that the first reinforcing bar receiving hole faces the second reinforcing bar receiving hole; A step of arranging a fall prevention bar so as to span the first reinforcing bar receiving hole and the second reinforcing bar receiving hole; filling a gap formed between the second member and the first member with a filler; a step of placing an unbonded tendon in a second-member-side through-hole formed in the second member and a first-member-side through-hole formed in the first member so as to span the second member and the first member; After the filler material has hardened, prestressing the second member and the first member by applying tension to the unbonded tendons; and removing the temporary support member after the tension force is applied to the unbonded tendon. The fall prevention bar is pre-arranged so that the entire bar is received in one of the first reinforcing bar receiving hole and the second reinforcing bar receiving hole, and an extrusion hole is connected to the rear end of the one of the first reinforcing bar receiving hole and the second reinforcing bar receiving hole, In the step of arranging the anti-fall-off bar, an extrusion member is pushed into the extrusion hole to move the anti-fall-off bar from one of the first reinforcing bar receiving hole and the second reinforcing bar receiving hole to the other, The second member has a second through hole extending in a longitudinal direction for inserting the unbonded tendon therethrough, and the first member has a first through hole extending in a horizontal direction at a position aligned with the second through hole; The method further includes a step of providing an anti-adhesion material between the second member and the first member placed on the temporary support member before the step of filling the gap with the filler material to prevent the filler material from adhering to the unbonded tendon, and separating the second through hole and the first through hole from the gap by the anti-adhesion material to allow them to communicate with each other, A method for joining components, in which the anti-adhesion material is a cylindrical member that is positioned across the gap and inserted into the beam-side through hole and the column-side through hole.

2. A method for joining members of a precast concrete structure, comprising: A step of erecting a first member having a first reinforcing bar receiving hole on a side surface at a predetermined position; attaching a removable temporary support member to the first member; a step of placing a second member having a second reinforcing bar receiving hole on an end surface thereof on the temporary support member so that the first reinforcing bar receiving hole faces the second reinforcing bar receiving hole; A step of arranging a fall prevention bar so as to span the first reinforcing bar receiving hole and the second reinforcing bar receiving hole; filling a gap formed between the second member and the first member with a filler; a step of placing an unbonded tendon in a second-member-side through-hole formed in the second member and a first-member-side through-hole formed in the first member so as to span the second member and the first member; After the filler material has hardened, prestressing the second member and the first member by applying tension to the unbonded tendons; and removing the temporary support member after the tension force is applied to the unbonded tendon. The fall prevention bar is pre-arranged so that the entire bar is received in one of the first reinforcing bar receiving hole and the second reinforcing bar receiving hole, and an extrusion hole is connected to the rear end of the one of the first reinforcing bar receiving hole and the second reinforcing bar receiving hole, In the step of arranging the anti-fall-off bar, an extrusion member is pushed into the extrusion hole to move the anti-fall-off bar from one of the first reinforcing bar receiving hole and the second reinforcing bar receiving hole to the other, The second member has a second through hole extending in a longitudinal direction for inserting the unbonded tendon therethrough, and the first member has a first through hole extending in a horizontal direction at a position aligned with the second through hole; The method further includes a step of providing an anti-adhesion material between the second member and the first member placed on the temporary support member before the step of filling the gap with the filler material to prevent the filler material from adhering to the unbonded tendon, and separating the second through hole and the first through hole from the gap by the anti-adhesion material to allow them to communicate with each other, a concave-shaped first shear key is formed on the end face of the second member, a concave-shaped second shear key is formed at a position of the first member opposite the first shear key, and the upper surfaces of the first shear key and the second shear key are inclined so as to become lower from the gap side toward the back.

3. A method for joining members of a precast concrete structure, comprising: A step of erecting a first member having a first reinforcing bar receiving hole on a side surface at a predetermined position; attaching a removable temporary support member to the first member; a step of placing a second member having a second reinforcing bar receiving hole on an end surface thereof on the temporary support member so that the first reinforcing bar receiving hole faces the second reinforcing bar receiving hole; A step of arranging a fall prevention bar so as to span the first reinforcing bar receiving hole and the second reinforcing bar receiving hole; filling a gap formed between the second member and the first member with a filler; a step of placing an unbonded tendon in a second-member-side through-hole formed in the second member and a first-member-side through-hole formed in the first member so as to span the second member and the first member; After the filler material has hardened, prestressing the second member and the first member by applying tension to the unbonded tendons; and removing the temporary support member after the tension force is applied to the unbonded tendon. The fall prevention bar is pre-arranged so that the entire bar is received in one of the first reinforcing bar receiving hole and the second reinforcing bar receiving hole, and an extrusion hole is connected to the rear end of the one of the first reinforcing bar receiving hole and the second reinforcing bar receiving hole, In the step of arranging the anti-fall-off bar, an extrusion member is pushed into the extrusion hole to move the anti-fall-off bar from one of the first reinforcing bar receiving hole and the second reinforcing bar receiving hole to the other, The second member has a second through hole extending in a longitudinal direction for inserting the unbonded tendon therethrough, and the first member has a first through hole extending in a horizontal direction at a position aligned with the second through hole; The method further includes a step of providing an anti-adhesion material between the second member and the first member placed on the temporary support member before the step of filling the gap with the filler material to prevent the filler material from adhering to the unbonded tendon, and separating the second through hole and the first through hole from the gap by the anti-adhesion material to allow them to communicate with each other, The fall prevention bar is pre-positioned so that the entire bar is received in the second reinforcing bar receiving hole, In the step of placing the anti-fall-off bar, the anti-fall-off bar is moved from the second reinforcing bar receiving hole toward the first reinforcing bar receiving hole, and after the movement of the anti-fall-off bar, one end of the anti-fall-off bar is located at the bottom of the first reinforcing bar receiving hole, the other end of the anti-fall-off bar is located at the longitudinal middle part of the second reinforcing bar receiving hole, and the longitudinal center of the anti-fall-off bar is aligned with the gap between the second member and the first member, A method for joining components, wherein after the anti-fall-off bar is moved, the anti-fall-off bar is received in each of the second reinforcing bar receiving holes and the first reinforcing bar receiving holes over a length eight times the diameter.

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