Attachment Structure of the Nose Tip PC to the Steel Frame Structure and Method of Attaching the Nose Tip PC

Abstract

To provide a fitting structure of a nose tip PC to a steel construction reduced in construction labor, and a fitting method of the nose tip PC.SOLUTION: A fitting structure of a nose tip PC to a steel construction comprises: a nose tip PC20 forming a tip end part of a horizontally extending cantilever slab (eaves 2) and formed of precast concrete; a plate 30 provided on a bottom face of the nose tip PC20 and having a first hole (second fixing hole 32); a first steel beam (fixed steel beam 11) having a second hole (fixing hole 13a) corresponding to the first hole (second fixing hole 32) and fixing the plate 30 by a fixing tool (bolt and nut) inserted through the first hole (second fixing hole 32) and the second hole (fixing hole 13a); a second steel beam (supporting steel beam 14) horizontally extending from the first steel beam (fixed steel beam 11); and a loading part (plate member 40) provided on the second steel beam (supporting steel beam 14), formed in the same thickness as the plate 30, and placing the nose tip PC20.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to an attachment structure of a nose tip PC to a steel frame structure and a method for attaching a nose tip PC.

Background Art

[0002] Conventionally, a building having a cantilever slab is known. For example, it is as described in Patent Document 1.

[0003] Patent Document 1 describes a mid-rise building having a balcony formed of concrete. When constructing a cantilever slab such as the above balcony by RC construction, it is necessary to place concrete in a formwork separately for each floor. In addition, the nose tip portion where a handrail, a waist wall, etc. are provided in the above balcony has a relatively complicated shape. Therefore, for the construction of the above nose tip portion, it is necessary to assemble a relatively complicated formwork.

[0004] As described above, the construction of the nose tip portion of a cantilever slab by RC construction is time-consuming in the work of transporting and assembling formworks and formwork support works for each floor, and particularly in a steel frame structure, it is difficult to install formwork support works itself, so improvement is desired from the viewpoint of workability.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The present invention has been made in view of the above circumstances, and the problem to be solved is to provide an attachment structure of a nose tip PC to a steel frame structure and a method for attaching a nose tip PC that can reduce the labor of construction. Although it has already been put into practical use in RC construction, a method for constructing an RC nose tip portion in a steel frame structure has not been established.

Means for Solving the Problem

[0007] The problem to be solved by the present invention is as described above. Next, the means for solving this problem will be described.

[0008] That is, in claim 1, it constitutes the tip of a cantilever slab that projects horizontally, a nose tip PC formed of precast concrete, a plate provided on the bottom surface of the nose tip PC and having a first hole, a first steel beam having a second hole corresponding to the first hole and fixed to the plate by a stopper inserted through the first hole and the second hole, a second steel beam projecting horizontally from the first steel beam, and a placement portion provided on the second steel beam, formed to have the same thickness as the plate, and on which the nose tip PC is placed.

[0009] In claim 2, a deck plate on which the concrete of the cantilever slab is placed is provided on the upper part of the first steel beam. The nose tip PC extends in a predetermined first direction in the horizontal direction and is arranged at intervals in a second direction orthogonal to the first direction in plan view. It has a plurality of reinforcing bars that are fixed to the concrete. The deck plate is formed in a corrugated shape having a plurality of ridge portions and valley portions that are continuous in the second direction. The reinforcing bars and the valley portions are arranged so as to overlap each other in plan view.

[0010] In claim 3, the nose tip PC has a connecting portion capable of connecting the scaffolding wall joints.

[0011] In claim 4, it comprises a plate fixing step of fixing a plate to the bottom surface of the nose tip PC formed of precast concrete, which constitutes the tip of the cantilever slab projecting horizontally; a temporary fixing step of temporarily fixing a plurality of the nose tip PCs via the plate to a first steel girder that supports the cantilever slab from below; a deck plate installation step of installing a deck plate on the first steel girder; a position adjustment step of adjusting the positions of the plurality of temporarily fixed adjacent nose tip PCs by sandwiching them with a common adjustment jig; and a fixing step of fixing the deck plate, the first steel girder, and the nose tip PCs with adjusted positions to each other.

[0012] In claim 5, in the fixing step, after the first steel girder and the nose tip PC are fixed with bolts, the concrete of the cantilever slab is placed, whereby the deck plate and the nose tip PC are integrally fixed by the concrete.

[0013] In claim 6, in the position adjustment step, the vertical positions of the plurality of adjacent nose tip PCs are adjusted by sandwiching them vertically with the adjustment jig.

[0014] In claim 7, in the position adjustment step, the horizontal positions of the plurality of adjacent nose tip PCs are adjusted by sandwiching them horizontally with the adjustment jig.

Advantages of the Invention

[0015] As an effect of the present invention, the following effects are achieved.

[0016] In claim 1, the labor of construction can be reduced.

[0017] In claim 2, it is possible to suppress interference between the ridge portion of the deck plate and the reinforcing bars of the nose tip PC.

[0018] In claim 3, it is possible to easily replace the build-up of the connection between the scaffold walls.

[0019] In claim 4, the labor required for construction can be reduced.

[0020] In claim 5, the deck plate and the nose tip PC can be preferably integrated.

[0021] In claim 6, by adjusting the vertical position of the nose tip PC using an adjustment jig, the construction accuracy can be improved.

[0022] In claim 7, by adjusting the horizontal position of the nose tip PC using an adjustment jig, the construction accuracy can be improved.

Brief Description of the Drawings

[0023]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Modes for Carrying Out the Invention

[0024] Hereinafter, with reference to FIGS. 1 to 10, the attachment structure 1 of the nose tip PC20 (the attachment structure of the nose tip PC20 to the steel frame structure) according to an embodiment of the present invention will be described. Further, hereinafter, based on the arrows in the drawings, the front-rear direction, the left-right direction, and the up-down direction will be defined and the description will be made.

[0025] The attachment structure 1 according to the present embodiment is a structure for attaching a nose tip PC20 that constitutes the tip of an eaves 2 provided on a building A with a steel frame structure to a steel beam 10 of the building A.

[0026] First, the building A will be described with reference to FIGS. 1 and 2.

[0027] In the building A, columns and beams constituting the building body are formed of steel members. The building A has a plurality of floors. In FIG. 1, a predetermined floor of the building A above the second floor is shown. The building A has an eaves 2.

[0028] The eaves 2 is a cantilever slab that projects horizontally (forward in the illustrated example) from the outer wall 3 of the building A. The eaves 2 is formed on each floor above the second floor and the rooftop of the building A, respectively. The eaves 2 can be used as the floor of a balcony (veranda) that can be accessed from the interior of the building A (inside the outer wall 3). The eaves 2 is provided at a predetermined position of the building A. Hereinafter, the eaves 2 provided mainly in the front part of the building A will be mainly focused on for the description of the eaves 2.

[0029] The eaves 2 is formed in a rectangular shape that is long in the left-right direction in plan view. The eaves 2 is supported from below by a steel beam 10. The eaves 2 is formed of cast-in-place concrete 60 except for the tip portion (front end portion). The tip portion (nose tip) of the eaves 2 is formed by a nose tip PC20 formed of precast concrete. The detailed description of the nose tip PC20 will be described later.

[0030] Figure 2 shows the eaves 2 (building A) in the area B surrounded by the dashed line in Figure 1. Also, Figure 2 shows the eaves 2 in the construction stage. In this state, a work scaffold 4 is installed around the frame of building A. The scaffold 4 is connected to the frame of building A via a wall connection 5 provided at a predetermined interval (for example, 1800 mm).

[0031] Next, the details of the attachment structure 1 of the nose tip PC20 will be described with reference to Figures 1 to 6. The attachment structure 1 according to this embodiment mainly includes a steel beam 10, a nose tip PC20, a plate 30, a plate member 40, a deck plate 50, and concrete 60.

[0032] The steel beam 10 shown in Figures 1 to 4 supports the eaves 2 from below. The steel beam 10 is formed by combining H-shaped steel with flanges and webs. The steel beam 10 includes a fixed steel beam 11 and a support steel beam 14.

[0033] The fixed steel beam 11 is for fixing the plate 30 described later. The fixed steel beam 11 is provided so as to project horizontally from a beam (main beam) connecting the columns of building A (see Figure 1). In plan view, the fixed steel beam 11 overlaps with a portion of the eaves 2 behind the nose tip portion (main body portion 21 of the nose tip PC20). The fixed steel beam 11 includes a first fixed steel beam 12 and a second fixed steel beam 13.

[0034] The first fixed steel beam 12 is a cantilever beam projecting horizontally (forward) from the main beam of building A. The first fixed steel beam 12 is arranged with its longitudinal direction in the front-rear direction. The rear end portion (fixed end) of the first fixed steel beam 12 is fixed to the main beam side of building A. A plurality of first fixed steel beams 12 are provided at a predetermined interval in the left-right direction.

[0035] The second fixed steel frame beam 13 connects the tip portions (free ends) of a plurality of first fixed steel frame beams 12. The second fixed steel frame beam 13 is arranged with its longitudinal direction oriented in the left - right direction. As shown in FIG. 3, the upper surface of the second fixed steel frame beam 13 is located at approximately the same height as the upper surface of the first fixed steel frame beam 12. The second fixed steel frame beam 13 has fixing holes 13a.

[0036] The fixing holes 13a shown in FIGS. 2, 3, and 8 are holes used for fixing a plate 30 described later. The fixing holes 13a are formed so as to penetrate the upper flange of the second fixed steel frame beam 13 vertically. As shown in FIG. 8, the fixing holes 13a are formed at the rear portion of the upper flange of the second fixed steel frame beam 13. A plurality of fixing holes 13a are provided at a predetermined interval in the left - right direction.

[0037] The support steel frame beam 14 shown in FIGS. 2 to 4 is a cantilever beam that supports the nose tip PC20. The support steel frame beam 14 is provided so as to project horizontally (forward) from the fixed steel frame beam 11. The rear end portion (fixed end) of the support steel frame beam 14 is fixed to the fixed steel frame beam 11. As shown in FIG. 3, the upper surface of the support steel frame beam 14 is located at approximately the same height as the upper surfaces of the first fixed steel frame beam 12 and the second fixed steel frame beam 13.

[0038] A plurality of support steel frame beams 14 are provided at a predetermined interval in the left - right direction. The support steel frame beam 14 is provided, for example, on the extension line of the longitudinal direction of the first fixed steel frame beam 12 (see FIG. 2). Note that the support steel frame beam 14 is not limited to being on the extension line of the first fixed steel frame beam 12 and can be provided at an appropriate position of the second fixed steel frame beam 13 as needed.

[0039] The nose tip PC20 shown in FIGS. 2 to 6 constitutes the tip portion (nose tip) of the eaves 2. The nose tip PC20 is formed of precast concrete pre - manufactured at a factory or the like. The nose tip PC20 includes a main body portion 21, upper reinforcing bars 22, and lower reinforcing bars 23.

[0040] The main body part 21 is the main structure of the nose tip PC 20. The main body part 21 is formed in a long shape in the longitudinal direction (left - right direction) of the eaves 2. As shown in FIGS. 3 and 5, the front end part of the main body part 21 is formed to rise upward. A predetermined handrail, waist wall, etc. can be installed on the rising part of the main body part 21.

[0041] On the bottom surface of the main body part 21, screw holes 21a used for fixing the plate 30 are formed. The screw holes 21a are formed to be able to attach a predetermined bolt. The screw holes 21a are formed, for example, in inserts embedded in the bottom surface of the main body part 21. As shown in FIGS. 3 and 5, a pair of screw holes 21a are formed at intervals in the front - rear direction. Also, a plurality (for example, three) of the pair of screw holes 21a are formed at a predetermined interval in the left - right direction.

[0042] On the front surface of the main body part 21, screw holes 21b used for fixing the wall connection 5 are formed. The screw holes 21b are formed to be connectable to the end part of the wall connection 5. The screw holes 21b are formed, for example, in inserts embedded in the front surface of the main body part 21. The screw holes 21b are formed in a plurality (for example, two) at a predetermined interval (for example, 1800 mm) in the left - right direction.

[0043] The upper reinforcement bars 22 shown from FIGS. 3 to 6 are reinforcing bars protruding rearward from the rear surface of the main body part 21. A plurality of upper reinforcement bars 22 are provided in the left - right direction at a predetermined pitch (for example, about 150 mm). As the protruding dimension of the upper reinforcement bars 22, a dimension of about 600 mm can be adopted, for example. Note that the upper reinforcement bars 22 are appropriately bent from the viewpoint of ensuring the cover of the concrete 60, etc.

[0044] The lower reinforcement bars 23 are reinforcing bars protruding rearward from the rear surface of the main body part 21 below the upper reinforcement bars 22. A plurality of lower reinforcement bars 23 are provided in the left - right direction at a pitch larger than that of the upper reinforcement bars 22. In this embodiment, the pitch of the lower reinforcement bars 23 is formed to be about twice the pitch of the upper reinforcement bars 22 (for example, about 300 mm). The protruding dimension of the lower reinforcement bars 23 is formed to be smaller (for example, 300 mm) than the protruding dimension of the upper reinforcement bars 22.

[0045] As shown in Fig. 1, a plurality of nose tips PC20 are provided along the circumferential direction (left - right direction or front - back direction) of the eaves 2. A gap of a predetermined dimension (for example, about 20 mm) is formed between adjacent nose tips PC20.

[0046] As shown in Fig. 1 and Fig. 6(a), the main body 21 of the nose tip PC20 located in the middle part in the left - right direction of the eaves 2 is formed in a substantially rectangular shape in plan view. Also, as shown in Fig. 1 and Fig. 6(b), the main body 21 of the nose tip PC20 located at the corner part of the eaves 2 is formed in a shape in which the end portion abutted against other nose tips PC20 at the corner part is obliquely cut out in plan view.

[0047] The plate 30 shown in Figs. 2, 3 and 5 is provided on the bottom surface of the nose tip PC20 (main body 21). The plate 30 is formed in a plate shape with the plate surface facing the up - down direction. Also, the plate 30 is formed in a substantially rectangular shape that is long in the front - back direction in plan view. The plate 30 is formed of metal. A plurality (for example, three) of plates 30 are provided at a predetermined interval in the left - right direction with respect to the nose tip PC20. The plate 30 is provided with a first fixing hole 31 and a second fixing hole 32.

[0048] The first fixing hole 31 is a hole used for fixing to the nose tip PC20. The first fixing hole 31 is formed so as to penetrate the plate 30 vertically. A pair of first fixing holes 31 are formed at intervals in the front - back direction in the front - side portion of the plate 30.

[0049] The second fixing hole 32 is a hole used for fixing to the second fixing steel girder 13 (fixing steel girder 11). The second fixing hole 32 is formed so as to penetrate the plate 30 vertically. The second fixing hole 32 is formed in the rear - side portion of the plate 30.

[0050] The plate member 40 shown in FIGS. 2, 3, and 8 is provided on the supporting steel frame beam 14 and the tip PC 20 is placed thereon. The plate member 40 is formed in a plate shape with the plate surface facing in the vertical direction. Further, the plate member 40 is formed in a substantially rectangular shape in plan view. The plate member 40 is formed of metal. The thickness dimension of the plate member 40 is formed to be the same as the thickness dimension of the plate 30. The plate member 40 is fixed by welding to the tip portion on the upper surface of the supporting steel frame beam 14.

[0051] The deck plate 50 shown in FIGS. 2 to 4 is a portion that serves as a base for the portion of the eaves 2 behind the tip PC 20. The deck plate 50 is disposed on the upper surface of the fixed steel frame beam 11. Concrete 60 described later is placed on the upper surface of the deck plate 50. As shown in FIG. 4, the deck plate 50 is formed in a corrugated plate shape in which a ridge portion 51 protruding upward and a valley portion 52 recessed downward are continuously formed in the left-right direction. The ridge portion 51 and the valley portion 52 are formed so as to extend in the front-rear direction over the entire deck plate 50. The valley portion 52 is formed to have a pitch substantially the same as the pitch of the lower bars 23.

[0052] Here, generally, the deck plate 50 is disposed with the extending directions of the ridge portion 51 and the valley portion 52 facing the longitudinal direction of the eaves 2. On the other hand, in the present embodiment, the deck plate 50 is disposed with the extending directions of the ridge portion 51 and the valley portion 52 facing the short side direction (front-rear direction) of the eaves 2.

[0053] In a state where the deck plate 50 and the tip PC 20 are provided as described above, the lower bars 23 of the tip PC 20 and the valley portion 52 are positioned so as to overlap in the vertical direction. Thereby, interference between the lower bars 23 and the deck plate 50 can be suppressed. Further, when the concrete 60 is placed on the deck plate 50, cover of the lower bars 23 with respect to the concrete 60 can be ensured.

[0054] The concrete 60 shown in FIG. 3 constitutes the floor surface of the portion of the eaves 2 behind the nose tip PC20. The concrete 60 is placed on the deck plate 50 by the in-situ casting method (on-site casting method). Note that predetermined reinforcing bars, wire meshes, etc. are provided on the deck plate 50 as required.

[0055] The concrete 60 placed on the deck plate 50 adheres to the upper reinforcement 22 and the lower reinforcement 23 of the nose tip PC20. Thereby, the concrete 60 and the nose tip PC20 are integrally fixed.

[0056] Next, with reference to FIGS. 7 to 10, the attachment method (construction method) of the nose tip PC20 will be described. As shown in FIG. 7, the attachment method of the nose tip PC20 includes a plate fixing step (step S10), a temporary fixing step (step S11), a deck plate installation step (step S12), a position adjustment step (step S13), a bolt fixing step (step S14), a concrete placing step (step S15), and a wall joint replacement step (step S16).

[0057] The plate fixing step (step S10) is a step of fixing the plate 30 to the bottom surface of the main body portion 21 of the nose tip PC20. As shown in FIGS. 5 and 8, the plate 30 is fixed to the nose tip PC20 by screwing a bolt inserted through the first fixing hole 31 of the plate 30 into the screw hole 21a of the nose tip PC20. The plate fixing step is performed, for example, at the construction site after the nose tip PC20 is transported to the construction site. Instead of the above-described aspect, the plate fixing step may be performed at a predetermined factory before the nose tip PC20 is transported to the construction site.

[0058] The temporary fixing step (step S11) is a step of temporarily fixing the nose tip PC20 to which the plate 30 is fixed to the steel beam 10 (the second fixing steel beam 13). As shown in FIG. 8, in the temporary fixing step, the nose tip PC20 to which the plate 30 fixed by a predetermined crane is lifted is moved to the fixing position of the steel beam 10.

[0059] In the temporary fixing process, as shown in FIGS. 3 and 8, with the nose tip PC20 placed on the upper surface of the support steel girder 14, nuts are attached to the bolts inserted through the second fixing holes 32 of the plate 30 and the fixing holes 13a of the second fixing steel girder 13, and the plate 30 and the second fixing steel girder 13 are fastened using the bolts and nuts. Note that the above fastening is performed to such an extent that the position of the nose tip PC20 can be adjusted in the position adjustment process described later. Thereby, the nose tip PC20 is temporarily fixed to the steel girder 10 (the first fixing steel girder 12). Note that in the state where the nose tip PC20 is placed, the bottom surface of the main body portion 21 of the nose tip PC20 is placed on the upper surface of the plate member 40.

[0060] Also, as shown in FIG. 8, at the time of the temporary fixing process, the wall connection 5 of the scaffold 4 is fixed to the steel girder 10 (the second fixing steel girder 13).

[0061] The deck plate installation process (step S12) is a process of installing (fixing) the deck plate 50 on the upper surface of the fixing steel girder 11 (see FIG. 10). The deck plate installation process is performed after the temporary fixing process. In the deck plate installation process, as shown in FIGS. 2 and 4, the deck plate 50 is arranged such that the extending directions of the ridge portions 51 and the valley portions 52 face the short side direction (front-rear direction) of the eaves 2.

[0062] The position adjustment process (step S13) is a process of adjusting the position of the temporarily fixed nose tip PC20. In the position adjustment process, the positions of two adjacent nose tip PC20s are adjusted using the adjustment jig 70. The position adjustment process is performed after the deck plate installation process.

[0063] The adjustment jig 70 shown in FIGS. 9 and 10 adjusts the positions of adjacent nose tip PC20s by sandwiching them. The adjustment jig 70 includes an angle member 71 and a connecting portion 72.

[0064] The angle member 71 is a member that is long in the left - right direction and has a substantially L - shaped cross - section when viewed in cross - section. The angle member 71 is formed of metal. As shown in FIG. 10, the angle member 71 has a first plate portion 71a arranged along a predetermined surface (a surface facing in the vertical direction or the front - rear direction) of the main body portion 21 of the nose tip PC20, and a second plate portion 71b orthogonal to the first plate portion 71a. A hole penetrating the first plate portion 71a is formed in the angle member 71. A pair of angle members 71 are provided with the main body portion 21 therebetween.

[0065] The connecting portion 72 connects a pair of angle members 71. The connecting portion 72 is formed by a bolt inserted into a hole formed in the first plate portion 71a of the angle member 71 and a nut attached to the bolt.

[0066] By tightening the bolt and nut of the connecting portion 72 with a pair of adjacent nose tips PC20 sandwiched by a pair of angle members 71 as described above, the pair of angle members 71 can be moved in a direction approaching each other. Thereby, the relative positional relationship between adjacent nose tips PC20 can be adjusted.

[0067] Specifically, as shown in FIGS. 9 and 10, with adjacent main body portions 21 sandwiched vertically by a pair of angle members 71, by tightening the bolt and nut of the connecting portion 72, the relative positional relationship in the vertical direction between adjacent nose tips PC20 can be adjusted. Also, as shown in FIGS. 9 and 10, with adjacent main body portions 21 sandwiched front - rear by a pair of angle members 71, by tightening the bolt and nut of the connecting portion 72, the relative positional relationship in the front - rear direction between adjacent nose tips PC20 can be adjusted.

[0068] In the examples shown in FIGS. 9 and 10, an example is shown in which two adjusting jigs 70 are used to adjust the vertical and front-rear positional relationships between adjacent nose tip PCBs 20. Here, for example, as shown in FIGS. 1 and 6(b), when adjusting the positional relationship between the nose tip PCBs 20 that abut at the corner portion of the eaves 2, one adjusting jig 70 may be used to adjust only the relative positional relationship in the vertical direction.

[0069] Here, when performing position adjustment using the adjusting jig 70, if a gap is formed between the bottom surface of the main body portion 21 of the nose tip PCB 20 and the upper surface of the plate member 40, an appropriate metal plate is used to fill the gap. The metal plate is fixed to the plate member 40 by welding or the like.

[0070] The bolt fixing step (step S14) is a step of fixing the plate 30 of the nose tip PCB 20 after position adjustment to the steel beam 10 (second fixing steel beam 13). The above fixing is performed by completely fastening the plate 30 and the second fixing steel beam 13 using bolts and nuts. In the bolt fixing step, welding may be performed to prevent loosening of the above bolts and nuts. After the bolt fixing step is executed, the adjusting jig 70 is removed from the nose tip PCB 20.

[0071] The concrete placing step (step S15) is a step of placing concrete 60 on the upper surface of the deck plate 50 (see FIG. 3). The concrete placing step is performed after the bolt fixing step. By placing the concrete 60, a slab is formed in the portion of the eaves 2 behind the nose tip PCB 20. Further, when the concrete 60 hardens and the upper reinforcement 22 and the lower reinforcement 23 of the nose tip PCB 20 are fixed to the concrete 60, the nose tip PCB 20 and the concrete 60 are integrally fixed. Also, thereby, the deck plate 50, the fixing steel beam 11, and the nose tip PCB 20 are integrally fixed by the concrete 60.

[0072] The wall connection replacement process (step S16) is a process of replacing the wall connection 5 fixed to the steel beam 10 to be fixed to the nose PC20 (see FIGS. 3 and 10). The wall connection replacement process is performed after the concrete 60 has hardened. In the wall connection replacement process, the end of the wall connection 5 is fixed to the screw hole 21b of the nose PC20. Then, the wall connection 5 fixed to the steel beam 10 is removed.

[0073] By performing the above-described process, the attachment of the nose PC20 is completed. According to the method for attaching the nose PC20 according to the present embodiment, the labor for constructing the eaves 2 can be reduced. That is, if a building with a RC structure forms eaves (cantilever slabs), it is considered that the work of transporting and assembling formwork and formwork support work for each floor is laborious in the construction of the nose portion of the eaves. According to the present embodiment, by using the nose PC20 for the nose portion of the eaves 2 of the steel-frame building A, the labor for construction such as transporting and assembling formwork and formwork support work for each floor can be reduced.

[0074] Further, in the present embodiment, in the temporary fixing process, with the nose PC20 placed on the plate member 40 of the support steel beam 14, the plate 30 and the second fixed steel beam 13 are fastened using bolts and nuts, so that the nose PC20 and the second fixed steel beam 13 can be easily temporarily fixed via the plate 30.

[0075] Further, in the present embodiment, in the temporary fixing process, after adjusting the vertical and front-rear positions of the nose PC20 using the adjustment jig 70 in a state where the nose PC20 is temporarily fixed, the nose PC20 is fixed to the second fixed steel beam 13. Thereby, the construction accuracy can be improved.

[0076] Conventionally, when replacing the wall connection 5 fixed to the steel beam 10 of a steel-framed building, it was common to fix the end of the wall connection 5 to the joint part of the finishing material of the building, etc. In this embodiment, in the wall connection replacement process, the wall connection 5 can be easily replaced by fixing the wall connection 5 to the screw hole 21b of the insert embedded in the nose tip PC20 in advance. Further, according to this embodiment, the strength of the wall connection 5 can be improved compared to the conventional method of removing the wall connection 5 from the joint part, and the safety of the scaffold 4 can be improved.

[0077] Also, when fixing the wall connection 5 to a RC building, it was common to insert an insert into the formwork before pouring the concrete on a certain floor and fix the wall connection 5 to the insert after the concrete hardened. In this case, the scaffold 4 could only be extended upward one floor at a time, every time the concrete pouring for each floor was completed. In this embodiment, by fixing the wall connection 5 to the screw hole 21b formed in the nose tip PC20 in advance, the scaffold 4 can be extended upward over multiple layers.

[0078] As described above, the attachment structure 1 of the nose tip PC20 according to an embodiment of the present invention constitutes the tip of a cantilever slab (eaves 2) projecting in the horizontal direction, and a nose tip PC20 formed of precast concrete, a plate 30 provided on the bottom surface of the nose tip PC20 and having a first hole (second fixing hole 32), a first steel beam (fixed steel beam 11) having a second hole (fixing hole 13a) corresponding to the first hole (second fixing hole 32), and the plate 30 being fixed by a stopper (bolt and nut) inserted through the first hole (second fixing hole 32) and the second hole (fixing hole 13a), a second steel beam (support steel beam 14) projecting horizontally from the first steel beam (fixed steel beam 11), and a mounting portion (plate member 40) provided on the second steel beam (support steel beam 14), formed to have the same thickness as the plate 30, and on which the nose tip PC20 is mounted.

[0079] With such a configuration, the labor required for construction can be reduced. That is, by using the nose tip PC20 at the nose tip portion of the cantilever slab (eaves 2) of the steel frame building A, unlike the case of forming the nose tip portion of the cantilever slab (eaves 2) by RC construction, for example, the labor of transporting and assembling formwork and formwork support work for each floor can be reduced. Further, with the nose tip PC20 placed on the placement portion (plate member 40) of the second steel beam (support steel beam 14), the nose tip PC20 can be easily fixed to the first steel beam (fixed steel beam 11) using fasteners (bolts and nuts).

[0080] Also, on the upper part of the first steel beam (fixed steel beam 11), a deck plate 50 on which the concrete 60 of the cantilever slab (eaves 2) is placed is provided. The nose tip PC20 extends in a predetermined first direction in the horizontal direction and is arranged at intervals in a second direction orthogonal to the first direction in plan view, and has a plurality of reinforcing bars (lower reinforcing bars 23) that are fixed to the concrete 60. The deck plate 50 is formed in a corrugated plate shape having a plurality of ridge portions 51 and valley portions 52 that are continuous in the second direction. The reinforcing bars (lower reinforcing bars 23) and the valley portions 52 are arranged so as to overlap each other in plan view.

[0081] With such a configuration, it is possible to suppress interference between the ridge portion 51 of the deck plate 50 and the reinforcing bars (lower reinforcing bars 23) of the nose tip PC20. Also, it is possible to ensure the cover of the reinforcing bars (lower reinforcing bars 23) with the concrete 60.

[0082] Also, the nose tip PC20 has a connecting portion (screw hole 21b) that can connect the wall joint 5 of the scaffold 4.

[0083] With such a configuration, it is possible to easily replace the wall joint 5 of the scaffold 4.

[0084] In addition, the method for attaching the nose tip PC according to an embodiment of the present invention is as follows: A plate fixing step (step S10) of fixing a plate 30 to the bottom surface of the nose tip PC20 formed of precast concrete, which constitutes the tip of a cantilever slab (eaves 2) projecting horizontally; A temporary fixing step (step S11) of temporarily fixing a plurality of the nose tip PCs 20 via the plate 30 to a first steel beam (fixed steel beam 11) that supports the cantilever slab (eaves 2) from below; A deck plate installation step (step S12) of installing a deck plate 50 on the first steel beam (fixed steel beam 11); A position adjustment step (step S13) of adjusting the positions of a plurality of the temporarily fixed nose tip PCs 20 by sandwiching the adjacent temporarily fixed nose tip PCs 20 with a common adjustment jig 70; A fixing step (steps S14 and S15) of fixing the deck plate 50, the first steel beam (fixed steel beam 11), and the nose tip PC 20 with adjusted positions to each other.

[0085] With such a configuration, the labor of construction can be reduced. That is, by using the nose tip PC20 at the nose tip portion of the cantilever slab (eaves 2) of the steel-frame building A, the labor of construction such as transporting and assembling formwork and formwork support work for each floor can be reduced, which is different from the case of forming the nose tip portion of the cantilever slab (eaves 2) by RC construction. Further, with the nose tip PC20 temporarily fixed, after adjusting the position of the nose tip PC20 using the adjustment jig 70, the nose tip PC20 is fixed to the first steel beam (fixed steel beam 11). Thereby, the construction accuracy can be improved.

[0086] In addition, in the fixing step (steps S14 and S15), After the first steel beam (fixed steel beam 11) and the nose tip PC20 are fixed with bolts (step S14), the concrete 60 of the cantilever slab (eaves 2) is placed, so that the deck plate 50 and the nose tip PC20 are integrally fixed by the concrete 60.

[0087] With such a configuration, the deck plate 50 and the nose tip PC 20 can be suitably integrated.

[0088] Also, in the position adjustment step (step S13), the vertical positions of the plurality of adjacent nose tip PCs 20 are adjusted by sandwiching the plurality of adjacent nose tip PCs 20 in the vertical direction with the adjustment jig 70.

[0089] With such a configuration, by adjusting the vertical position of the nose tip PC 20 using the adjustment jig 70, the construction accuracy can be further improved.

[0090] Also, in the position adjustment step (step S13), the horizontal positions of the plurality of adjacent nose tip PCs 20 are adjusted by sandwiching the plurality of adjacent nose tip PCs 20 in the horizontal direction with the adjustment jig 70.

[0091] With such a configuration, by adjusting the horizontal position of the nose tip PC 20 using the adjustment jig 70, the construction accuracy can be further improved.

[0092] Note that the eaves 2 in the present embodiment is a form of the cantilever slab according to the present invention. Also, the fixed steel beam 11 according to the present embodiment is a form of the first steel beam according to the present invention. Also, the support steel beam 14 according to the present embodiment is a form of the second steel beam according to the present invention. Also, the second fixing hole 32 according to the present embodiment is a form of the first hole according to the present invention. Also, the fixing hole 13a according to the present embodiment is a form of the second hole according to the present invention. Also, the plate member 40 according to the present embodiment is a form of the placement part according to the present invention. Also, the bottom reinforcement 23 according to the present embodiment is a form of the reinforcing bar according to the present invention. Also, the screw hole 21b according to the present embodiment is a form of the connection part according to the present invention.

[0093] The above describes one embodiment of the present invention. However, the present invention is not limited to the above configuration, and various modifications are possible within the scope of the invention described in the claims.

[0094] For example, in this embodiment, an example is shown in which a screw hole 21b capable of connecting the wall joint 5 is provided in the main body portion 21 of the nose tip PC20. However, it is not limited to such a mode. For example, the screw hole 21b may not be provided in the main body portion 21.

[0095] Also, in this embodiment, an example is shown in which the extending directions of the ridge portion 51 and the groove portion 52 of the deck plate 50 are arranged in the short side direction (front-rear direction) of the eaves 2. However, it is not limited to such a mode. For example, the extending directions of the ridge portion 51 and the groove portion 52 of the deck plate 50 may be arranged in the longitudinal direction (left-right direction) of the eaves 2. In this case, in order to avoid interference between the lower reinforcing bar 23 and the deck plate 50, the lower reinforcing bar 23 may be bent as appropriate.

[0096] Also, in this embodiment, an example is shown in which three plates 30 are provided for the nose tip PC20. However, it is not limited to such a mode. The number of plates 30 for the nose tip PC20 may be two or less, or four or more.

[0097] Also, in this embodiment, an example is shown in which the plate 30 is fixed to the second fixed steel frame beam 13 of the fixed steel frame beam 11. However, it is not limited to such a mode. For example, the plate 30 may be fixed to the first fixed steel frame beam 12. In this case, a hole corresponding to the second fixing hole 32 of the plate 30 may be formed in the first fixed steel frame beam 12.

[0098] Also, in this embodiment, an example is shown in which the position adjustment step (step S13) is executed after the deck plate installation step (step S12). However, it is not limited to such a mode. For example, the deck plate installation step may be executed after the position adjustment step. Also, the deck plate installation step may be executed after the bolt fixing step (step S14).

[0099] In addition, in this embodiment, an example in which the eaves 2 are a cantilever slab that can be used as the floor of a balcony has been shown, but the present invention is not limited to such an aspect. For example, the eaves 2 may be a cantilever slab that can be used as a corridor or the like, or may be an eaves mainly used for sunshade and rain protection.

Explanation of reference numerals

[0100] 1 Attachment structure of the nose tip PC 2 Eaves 10 Steel frame beam 20 Nose tip PC 30 Plate 40 Plate member 50 Deck plate 60 Concrete 70 Adjusting jig

Claims

1. It constitutes the tip of a cantilever slab that projects horizontally, and includes a nose tip PC formed of precast concrete, a plate provided on the bottom surface of the nose tip PC and having a first hole, a first steel beam having a second hole corresponding to the first hole and with the plate fixed by a stopper inserted through the first hole and the second hole, a second steel beam projecting horizontally from the first steel beam, and a mounting portion provided on the second steel beam, formed to have the same thickness as the plate and on which the nose tip PC is placed. The mounting structure of the nose tip PC to the steel structure.

2. On the upper part of the first steel beam, a deck plate is provided on which the concrete of the cantilever slab is placed, The nose tip PC extends in a predetermined first direction in the horizontal direction and is arranged at intervals in a second direction orthogonal to the first direction in plan view, and has a plurality of reinforcing bars that are fixed to the concrete, The deck plate is formed in a corrugated plate shape having a plurality of ridges and valleys continuous in the second direction, The reinforcing bars and the valleys are arranged so as to overlap each other in plan view. The mounting structure of the nose tip PC to the steel structure according to Claim 1.

3. The nose tip PC has a connecting portion capable of connecting the scaffolding wall joints. The mounting structure of the nose tip PC to the steel structure according to Claim 1 or Claim 2.

4. A plate fixing step of fixing a plate to the bottom surface of a nose tip PC formed of precast concrete, which constitutes the tip of a cantilever slab that projects horizontally, A temporary fixing step of temporarily fixing a plurality of the nose tip PCs via the plate to a first steel beam that supports the cantilever slab from below, A deck plate installation step of installing a deck plate on the first steel beam, A position adjustment step of adjusting the positions of a plurality of the temporarily fixed adjacent nose tip PCs by sandwiching them with a common adjusting jig, And a fixing step of fixing the deck plate, the first steel beam, and the nose tip PC whose position has been adjusted to each other. The method of mounting the nose tip PC.

5. In the fixing step, after the first steel beam and the nose tip PC are fixed with bolts, the concrete of the cantilever slab is placed, whereby the deck plate and the nose tip PC are integrally fixed by the concrete. The method of mounting the nose tip PC according to Claim 4.

6. In the position adjustment step, Adjusting the vertical positions of the plurality of adjacent nose tip PCs by sandwiching them in the vertical direction with the adjustment jig. The method for attaching a nose tip PC according to claim 4 or claim 5.

7. In the position adjustment step, Adjusting the horizontal positions of the plurality of adjacent nose tip PCs by sandwiching them in the horizontal direction with the adjustment jig. The method for attaching a nose tip PC according to any one of claims 4 to 6.

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