JP7689892B2 - Structure and method for mounting nose-end PC to steel structure - Google Patents

Description

The present invention relates to a structure for mounting a nose-end PC to a steel structure and a method for mounting a nose-end PC.

Buildings with cantilever slabs are known in the past, such as those described in Patent Document 1.

Patent Document 1 describes a mid-to-high rise building with a balcony made of concrete. When constructing a cantilever slab like the balcony using reinforced concrete, concrete must be poured into the formwork for each floor. In addition, the nose portion of the balcony, where the handrails, waist walls, etc. are provided, has a relatively complex shape. For this reason, the construction of the nose portion requires the assembly of a relatively complex formwork.

As such, construction of the nose of a cantilever slab in reinforced concrete construction requires time-consuming work to transport and assemble formwork and formwork supports for each floor, and since installing formwork supports is particularly difficult in steel-frame construction, improvements are needed from the perspective of workability.

JP 2010-144403 A

The present invention was made in consideration of the above situation, and the problem it aims to solve is to provide a mounting structure and method for a nose PC to a steel frame structure that can reduce the amount of work required for construction. This has already been put to practical use in reinforced concrete structures, but a method for constructing the nose part of reinforced concrete in steel frame structures has not yet been established.

The problem that the present invention aims to solve is as described above, and the means for solving this problem will be explained next.

That is, in claim 1, the slab comprises a nose PC formed of precast concrete that constitutes the tip of a cantilever slab that protrudes horizontally, a plate provided on the bottom surface of the nose PC and having a first hole, a first steel beam that has a second hole corresponding to the first hole and to which the plate is fixed by fasteners inserted through the first hole and the second hole, a second steel beam that protrudes horizontally from the first steel beam, and a support portion provided on the second steel beam, formed to the same thickness as the plate, and on which the nose PC is placed.

In claim 2, a deck plate onto which the concrete of the cantilever slab is poured is provided on top of the first steel beam, the nose PC extends in a predetermined first direction in the horizontal direction and has a plurality of reinforcing bars that are spaced apart in a second direction perpendicular to the first direction in a plan view and are fixed to the concrete, the deck plate is formed in a corrugated shape with a plurality of peaks and valleys that are continuous in the second direction, and the reinforcing bars and the valleys are arranged so as to overlap each other in a plan view.

In claim 3, the nose PC has a connection part that can connect to the wall joint of the scaffolding.

In claim 4, the method includes a plate fixing step of fixing a plate to the bottom surface of the nose PC, which constitutes the tip of the cantilever slab extending horizontally and is made of precast concrete; a temporary fixing step of temporarily fixing the plurality of nose PCs to a first steel beam that supports the cantilever slab from below via the plate; a deck plate installation step of installing a deck plate on the first steel beam; a position adjustment step of adjusting the positions of the plurality of nose PCs by clamping the adjacent temporarily fixed nose PCs with a common adjustment tool; and a fixing step of fixing the deck plate, the first steel beam, and the nose PC whose position has been adjusted to each other.

In claim 5, in the fixing process, the first steel beam and the nose PC are fixed with bolts, and then the concrete of the cantilever slab is poured, so that the deck plate and the nose PC are fixed integrally with the concrete.

In claim 6, in the position adjustment process, the vertical positions of the multiple adjacent nose tips PC are adjusted by clamping the multiple nose tips PC in the vertical direction with the adjustment jig.

In claim 7, in the position adjustment process, the horizontal positions of the multiple adjacent nose tips PC are adjusted by clamping the multiple nose tips PC horizontally with the adjustment jig.

The effects of the present invention are as follows:

In claim 1, the work involved in construction can be reduced.

In claim 2, interference between the peak of the deck plate and the reinforcing bars of the nose PC can be suppressed.

In claim 3, the wall joints of the scaffolding can be easily replaced.

In claim 4, the construction work can be reduced.

In claim 5, the deck plate and nose tip PC can be conveniently integrated.

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

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

1 is a plan view showing a building eave equipped with a nose tip PC mounting structure according to one embodiment of the present invention; FIG. 2 is a plan view showing the mounting structure of the nose tip PC in region B of FIG. 1 . 3 is a cross-sectional view taken along the line X1-X1 in FIG. 2 . 3 is a cross-sectional view taken along the line YY in FIG. 2 . FIG. 1A is a plan view showing a nose tip PC, and FIG. 1B is a plan view showing a nose tip PC used in a corner portion. 4 is a flowchart showing a method for attaching a nose tip PC according to an embodiment of the present invention. A side cross-sectional view showing how the nose PC and panel are temporarily fixed to the steel beam. FIG. 13 is a plan view showing how the position of the nose tip PC is adjusted. 10 is a cross-sectional view taken along the line X2-X2 in FIG.

In the following, a mounting structure 1 for a nose tip PC 20 according to one embodiment of the present invention (mounting structure for mounting a nose tip PC 20 to a steel frame structure) will be described using Figures 1 to 10. In the following, the front-rear direction, left-right direction, and up-down direction will be defined based on the arrows in the figures.

The mounting structure 1 in this embodiment is a structure for mounting a nose tip PC 20, which constitutes the tip of a eaves 2 installed on a steel-framed building A, to a steel beam 10 of the building A.

Below, we will first explain Building A using Figures 1 and 2.

The columns and beams that make up the structure of Building A are made of steel members. Building A has multiple floors. Figure 1 shows a specific floor of Building A, which is the second floor or higher. Building A has eaves 2.

The eaves 2 are cantilever slabs that extend horizontally (forward in the illustrated example) from the exterior wall 3 of building A. The eaves 2 are formed on each floor of building A from the second floor onwards and on the roof. The eaves 2 can be used as a floor for a balcony (veranda) that can be accessed from the interior of building A (inside the exterior wall 3). The eaves 2 are provided at a specified position on building A. Note that the following explanation of the eaves 2 focuses mainly on the eaves 2 provided on the front part of building A.

In plan view, the eaves 2 are formed in a rectangular shape that is long in the left-right direction. The eaves 2 are supported from below by steel beams 10. Except for the tip (front end), the eaves 2 is formed from cast-in-place concrete 60. The tip (nose) of the eaves 2 is formed by a nose tip PC 20 made from precast concrete. A detailed explanation of the nose tip PC 20 will be given later.

Figure 2 shows the eaves 2 (building A) in area B surrounded by a dashed line in Figure 1. Figure 2 also shows the eaves 2 during the construction stage. In this state, work scaffolding 4 is installed around the frame of building A. The scaffolding 4 is connected to the frame of building A via wall connectors 5 that are installed at a specified interval (e.g., 1800 mm).

Next, the details of the mounting structure 1 for the nose PC 20 will be described with reference to Figures 1 to 6. The mounting structure 1 according to this embodiment mainly comprises a steel beam 10, the nose PC 20, a plate 30, a plate member 40, a deck plate 50, and concrete 60.

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 frames having flanges and webs. The steel beam 10 includes a fixed steel beam 11 and a supporting steel beam 14.

The fixed steel beams 11 are fixed to the plate 30 described later. The fixed steel beams 11 are arranged to extend horizontally from the beams (main beams) that connect the columns of building A (see Figure 1). In a plan view, the fixed steel beams 11 overlap with the part of the eaves 2 that is rearward of the nose portion (main body 21 of nose PC 20). The fixed steel beams 11 include a first fixed steel beam 12 and a second fixed steel beam 13.

The first fixed steel beam 12 is a cantilever beam that extends horizontally (forward) from the main girder of building A. The first fixed steel beam 12 is arranged with its longitudinal direction facing the front-to-rear direction. The rear end (fixed end) of the first fixed steel beam 12 is fixed to the main girder side of building A. Multiple first fixed steel beams 12 are provided at predetermined intervals in the left-right direction.

The second fixed steel beam 13 connects the tips (free ends) of the multiple first fixed steel beams 12 together. The second fixed steel beam 13 is arranged with its longitudinal direction facing the left-right direction. As shown in FIG. 3, the top surface of the second fixed steel beam 13 is located at approximately the same height as the top surface of the first fixed steel beam 12. The second fixed steel beam 13 has a fixing hole 13a.

The fixing holes 13a shown in Figures 2, 3 and 8 are holes used to fix the plate 30 described below. The fixing holes 13a are formed so as to penetrate the upper flange of the second fixed steel beam 13 from top to bottom. As shown in Figure 8, the fixing holes 13a are formed in the rear part of the upper flange of the second fixed steel beam 13. A plurality of fixing holes 13a are provided at predetermined intervals in the left-right direction.

The supporting steel beam 14 shown in Figures 2 to 4 is a cantilever beam that supports the nose PC 20. The supporting steel beam 14 is arranged to protrude horizontally (forward) from the fixed steel beam 11. The rear end (fixed end) of the supporting steel beam 14 is fixed to the fixed steel beam 11. As shown in Figure 3, the upper surface of the supporting steel beam 14 is located at approximately the same height as the upper surfaces of the first fixed steel beam 12 and the second fixed steel beam 13.

Multiple supporting steel beams 14 are provided at a predetermined interval in the left-right direction. The supporting steel beams 14 are provided, for example, on the longitudinal extension of the first fixed steel beam 12 (see FIG. 2). Note that the supporting steel beams 14 are not limited to being provided on the longitudinal extension of the first fixed steel beam 12, but are provided at an appropriate position on the second fixed steel beam 13 as necessary.

The nose tip PC20 shown in Figures 2 to 6 constitutes the tip portion (nose tip) of the eaves 2. The nose tip PC20 is formed from precast concrete manufactured in advance in a factory or the like. The nose tip PC20 comprises a main body portion 21, an upper reinforcement 22, and a lower reinforcement 23.

The main body 21 is the main structure of the nose tip PC 20. The main body 21 is formed in an elongated shape in the longitudinal direction (left-right direction) of the eaves 2. As shown in Figures 3 and 5, the front end of the main body 21 is formed to rise upward. A handrail, waist wall, etc. can be installed on the rising portion of the main body 21.

A screw hole 21a used to fix the plate 30 is formed in the bottom surface of the main body 21. The screw hole 21a is formed so that a predetermined bolt can be attached. The screw hole 21a is formed, for example, in an insert embedded in the bottom surface of the main body 21. As shown in Figures 3 and 5, a pair of screw holes 21a are formed with a gap in the front-rear direction. In addition, multiple (e.g., three) of the pair of screw holes 21a are formed with a predetermined gap in the left-right direction.

A screw hole 21b used to fasten the wall connector 5 is formed on the front surface of the main body 21. The screw hole 21b is formed so that it can be connected to the end of the wall connector 5. The screw hole 21b is formed, for example, in an insert that is embedded in the front surface of the main body 21. A plurality of screw holes 21b (for example, two) are formed at a predetermined interval (for example, 1800 mm) in the left-right direction.

The upper reinforcement 22 shown in Figures 3 to 6 is a reinforcing bar that protrudes rearward from the rear surface of the main body 21. Multiple upper reinforcement bars 22 are provided in the left-right direction at a predetermined pitch (e.g., about 150 mm). The protruding dimension of the upper reinforcement bars 22 can be, for example, about 600 mm. The upper reinforcement bars 22 are bent as appropriate to ensure the covering of the concrete 60, etc.

The lower reinforcement bars 23 are reinforcing bars that protrude rearward from the rear surface of the main body 21 below the upper reinforcement bars 22. The lower reinforcement bars 23 are provided in multiples in the left-right direction at a pitch greater than that of the upper reinforcement bars 22. In this embodiment, the pitch of the lower reinforcement bars 23 is approximately twice that of the upper reinforcement bars 22 (e.g., approximately 300 mm). The protruding dimension of the lower reinforcement bars 23 is smaller than the protruding dimension of the upper reinforcement bars 22 (e.g., 300 mm).

As shown in FIG. 1, multiple nose tip PCs 20 are provided along the circumferential direction (left-right direction or front-back direction) of the visor 2. A gap of a predetermined dimension (e.g., about 20 mm) is formed between adjacent nose tip PCs 20.

As shown in Fig. 1 and Fig. 6(a), the main body 21 of the nose tip PC 20 located in the middle of the eaves 2 in the left-right direction is formed in a generally rectangular shape in plan view. Also, as shown in Fig. 1 and Fig. 6(b), the main body 21 of the nose tip PC 20 located in the corner portion of the eaves 2 is formed in a shape in which the end portion that butts against another nose tip PC 20 at the corner portion is cut out at an angle in plan view.

The plate 30 shown in Figures 2, 3 and 5 is provided on the bottom surface of the nose tip PC 20 (main body 21). The plate 30 is formed in a plate shape with the plate surface facing in the up-down direction. The plate 30 is formed in a generally rectangular shape that is elongated in the front-to-back direction in a plan view. The plate 30 is made of metal. A plurality of plates 30 (e.g., three) are provided at a predetermined interval in the left-to-right direction relative to the nose tip PC 20. The plate 30 has a first fixing hole 31 and a second fixing hole 32.

The first fixing holes 31 are holes used for fixing to the nose tip PC 20. The first fixing holes 31 are formed so as to penetrate the plate 30 from top to bottom. A pair of the first fixing holes 31 are formed in the front part of the plate 30 with a gap between them in the front-rear direction.

The second fixing hole 32 is a hole used for fixing to the second fixed steel beam 13 (fixed steel beam 11). The second fixing hole 32 is formed so as to penetrate the plate 30 from top to bottom. The second fixing hole 32 is formed in the rear portion of the plate 30.

The plate member 40 shown in Figures 2, 3 and 8 is provided on the supporting steel beam 14 and has the nose PC 20 placed on it. The plate member 40 is formed in a plate shape with the plate surface facing up and down. The plate member 40 is formed in a substantially rectangular shape in a plan view. The plate member 40 is made of metal. The thickness of the plate member 40 is formed to be the same as the thickness of the plate 30. The plate member 40 is fixed to the tip of the upper surface of the supporting steel beam 14 by welding.

The deck plate 50 shown in Figures 2 to 4 is the base for the portion of the eaves 2 rearward of the nose PC 20. The deck plate 50 is placed on the upper surface of the fixed steel beams 11. Concrete 60, described below, is poured onto the upper surface of the deck plate 50. As shown in Figure 4, the deck plate 50 is formed in a corrugated shape in which upwardly protruding peaks 51 and downwardly recessed valleys 52 are formed continuously in the left-right direction. The peaks 51 and valleys 52 are formed to extend in the front-rear direction over the entire deck plate 50. The valleys 52 are formed to have approximately the same pitch as the pitch of the lower reinforcement bars 23.

Generally, the deck plate 50 is arranged so that the extension direction of the peaks 51 and valleys 52 faces the longitudinal direction of the eaves 2. On the other hand, in this embodiment, the deck plate 50 is arranged so that the extension direction of the peaks 51 and valleys 52 faces the short side direction (front-to-back direction) of the eaves 2.

When the deck plate 50 and nose PC 20 are installed as described above, the lower reinforcement 23 and the valley portion 52 of the nose PC 20 are positioned so as to overlap in the vertical direction. This makes it possible to suppress interference between the lower reinforcement 23 and the deck plate 50. In addition, when concrete 60 is poured on the deck plate 50, it is possible to ensure that the concrete 60 covers the lower reinforcement 23.

The concrete 60 shown in FIG. 3 constitutes the floor surface of the portion of the eaves 2 that is behind the nose PC 20. The concrete 60 is poured onto the deck plate 50 by a cast-in-place method. In addition, predetermined reinforcing bars, wire mesh, etc. are provided on the deck plate 50 as necessary.

The concrete 60 poured onto the deck plate 50 is fixed to the upper reinforcement 22 and lower reinforcement 23 of the nose PC 20. This fixes the concrete 60 and the nose PC 20 together.

Next, the installation method (construction method) of the nose tip PC 20 will be described with reference to Figures 7 to 10. As shown in Figure 7, the installation method of the nose tip PC 20 includes a plate fixing process (step S10), a temporary fixing process (step S11), a deck plate installation process (step S12), a position adjustment process (step S13), a bolt fixing process (step S14), a concrete pouring process (step S15), and a wall connecting and re-laying process (step S16).

The plate fixing process (step S10) is a process of fixing the plate 30 to the bottom surface of the main body 21 of the nose PC 20. As shown in Figs. 5 and 8, a bolt inserted into the first fixing hole 31 of the plate 30 is screwed into the screw hole 21a of the nose PC 20, thereby fixing the plate 30 to the nose PC 20. The plate fixing process is performed at the construction site, for example, after the nose PC 20 is delivered to the construction site. Alternatively, the plate fixing process may be performed at a designated factory before the nose PC 20 is delivered to the construction site.

The temporary fixing process (step S11) is a process of temporarily fixing the nose tip PC 20 to which the plate 30 is fixed to the steel beam 10 (second fixed steel beam 13). As shown in FIG. 8, in the temporary fixing process, the nose tip PC 20 to which the plate 30 is fixed is lifted by a specified crane and moved to the fixing point of the steel beam 10.

In the temporary fixing process, as shown in Figures 3 and 8, with the nose tip PC 20 placed on the upper surface of the supporting steel beam 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 fixed steel beam 13, and the plate 30 and the second fixed steel beam 13 are fastened using the bolts and nuts. Note that the above fastening is performed to an extent that the position of the nose tip PC 20 can be adjusted in the position adjustment process described below. As a result, the nose tip PC 20 is temporarily fixed to the steel beam 10 (first fixed steel beam 12). Note that with the nose tip PC 20 placed, the bottom surface of the main body 21 of the nose tip PC 20 is placed on the upper surface of the plate member 40.

Also, as shown in FIG. 8, at the time of the temporary fixing process, the wall tie 5 of the scaffolding 4 is fixed to the steel beam 10 (second fixed steel beam 13).

The deck plate installation process (step S12) is a process of installing (fixing) the deck plate 50 to the upper surface of the fixed steel beam 11 (see Figure 10). The deck plate installation process is performed after the temporary fixing process. In the deck plate installation process, as shown in Figures 2 and 4, the deck plate 50 is positioned so that the extension direction of the peaks 51 and valleys 52 faces the short side direction (front-to-back direction) of the eaves 2.

The position adjustment process (step S13) is a process for adjusting the position of the temporarily fixed nose tip PC 20. In the position adjustment process, the relative positions of two adjacent nose tip PCs 20 are adjusted using an adjustment jig 70. The position adjustment process is performed after the deck plate installation process is executed.

The adjustment jig 70 shown in Figures 9 and 10 adjusts the positions of adjacent nose tip PCs 20 by clamping them together. The adjustment jig 70 includes an angle bar 71 and a connecting portion 72.

The angle iron 71 is a member that is elongated in the left-right direction and has a generally L-shaped cross section. The angle iron 71 is made of metal. As shown in FIG. 10, the angle iron 71 has a first plate portion 71a that is arranged along a predetermined surface (a surface facing the up-down direction or the front-rear direction) of the main body portion 21 of the nose tip PC 20, and a second plate portion 71b that is perpendicular to the first plate portion 71a. The angle iron 71 has a hole that penetrates the first plate portion 71a. A pair of angle irons 71 are provided, sandwiching the main body portion 21.

The connecting portion 72 connects a pair of angle bars 71 together. The connecting portion 72 is formed by a bolt that is inserted into a hole formed in the first plate portion 71a of the angle bar 71 and a nut that is attached to the bolt.

When adjacent nose tip PCs 20 are sandwiched between a pair of angle bars 71 as described above, the pair of angle bars 71 can be moved closer to each other by tightening the bolts and nuts of the connecting parts 72. This allows the relative positional relationship between the adjacent nose tip PCs 20 to be adjusted.

Specifically, as shown in Figures 9 and 10, the relative positional relationship between adjacent nose tip PCs 20 in the vertical direction can be adjusted by clamping adjacent main body parts 21 vertically with a pair of angle bars 71 and tightening the bolts and nuts of the connecting parts 72. Also, as shown in Figures 9 and 10, the relative positional relationship between adjacent nose tip PCs 20 in the front-to-back direction can be adjusted by clamping adjacent main body parts 21 vertically with a pair of angle bars 71 and tightening the bolts and nuts of the connecting parts 72.

In the example shown in Figures 9 and 10, two adjustment jigs 70 are used to adjust the vertical and front-to-rear positional relationship between adjacent nose tip PCs 20. Here, for example, as shown in Figures 1 and 6(b), when adjusting the positional relationship between nose tip PCs 20 that are butted together at a corner portion of the awning 2, one adjustment jig 70 may be used to adjust only the relative vertical positional relationship.

If a gap is formed between the bottom surface of the main body 21 of the nose tip PC 20 and the top surface of the plate member 40 when the position adjustment is performed using the adjustment jig 70, the gap is filled with an appropriate metal plate. The metal plate is fixed to the plate member 40 by welding or the like.

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

The concrete pouring process (step S15) is a process of pouring concrete 60 onto the upper surface of the deck plate 50 (see FIG. 3). The concrete pouring process is carried out after the bolt fixing process is carried out. Pouring the concrete 60 forms a slab in the portion of the eaves 2 behind the nose PC 20. In addition, the concrete 60 hardens and the upper reinforcement 22 and lower reinforcement 23 of the nose PC 20 are fixed to the concrete 60, so that the nose PC 20 and the concrete 60 are fixed together. In addition, the deck plate 50, the fixed steel beam 11, and the nose PC 20 are fixed together by the concrete 60.

The wall tie replacement process (step S16) is a process of replacing the wall tie 5 that was fixed to the steel beam 10 so that it is fixed to the nose PC 20 (see Figures 3 and 10). The wall tie replacement process is performed after the concrete 60 has hardened. In the wall tie replacement process, the end of the wall tie 5 is fixed to the screw hole 21b of the nose PC 20. Then, the wall tie 5 that was fixed to the steel beam 10 is removed.

By carrying out the above-mentioned steps, the installation of the nose PC 20 is completed. According to the method of installing the nose PC 20 in this embodiment, the labor required for constructing the eaves 2 can be reduced. That is, if eaves (cantilever slabs) are formed in a reinforced concrete building, the construction of the nose part of the eaves can be considered to be labor-intensive, as it requires transporting and assembling formwork and formwork supports for each floor. According to this embodiment, by using the nose PC 20 for the nose part of the eaves 2 of the steel-framed building A, the labor required for construction, such as transporting and assembling formwork and formwork supports for each floor, can be reduced.

In addition, in this embodiment, in the temporary fixing process, the nose PC 20 is placed on the plate member 40 of the supporting steel beam 14, and the plate 30 and the second fixed steel beam 13 are fastened using bolts and nuts, so that the nose PC 20 and the second fixed steel beam 13 can be easily temporarily fixed via the plate 30.

In addition, in this embodiment, in the temporary fixing process, the nose tip PC 20 is temporarily fixed, and the adjustment jig 70 is used to adjust the vertical and front-to-rear position of the nose tip PC 20, and then the nose tip PC 20 is fixed to the second fixed steel beam 13. This improves the accuracy of construction.

In addition, conventionally, when replacing a wall tie 5 fixed to the steel beams 10 of a steel-framed building, the general method was to fix the end of the wall tie 5 to the joints of the building's decorative materials. In this embodiment, in the wall tie replacement process, the wall tie 5 can be easily replaced by fixing the wall tie 5 to the screw hole 21b of the insert that is pre-embedded in the nose PC 20. Furthermore, according to this embodiment, the strength of the wall tie 5 can be improved compared to the conventional method of removing the wall tie 5 from the joints, and the safety of the scaffolding 4 can be improved.

In addition, if the wall ties 5 were to be fixed to a reinforced concrete building, the general method was to place an insert in the formwork before pouring the concrete on a certain floor, and then fix the wall ties 5 to the insert after the concrete had hardened. In this case, the scaffolding 4 could only be extended upwards (one layer at a time) after the concrete had been poured on each floor. In this embodiment, the wall ties 5 are fixed to the screw holes 21b pre-formed in the nose PC 20, allowing the scaffolding 4 to be extended upwards over multiple layers.

As described above, the mounting structure 1 for the nose tip PC 20 according to one embodiment of the present invention is as follows:
A nose tip PC20 made of precast concrete constitutes the tip of the cantilever slab (eaves 2) that protrudes horizontally;
A plate 30 provided on a bottom surface of the nose tip PC 20 and having a first hole (a 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 to which the plate 30 is fixed by fasteners (bolts and nuts) inserted into the first hole (second fixing hole 32) and the second hole (fixing hole 13a);
A second steel beam (supporting steel beam 14) extending horizontally from the first steel beam (fixed steel beam 11);
It is provided on the second steel beam (supporting steel beam 14), is formed to the same thickness as the plate 30, and comprises a mounting portion (plate member 40) on which the nose tip PC 20 is placed.

With this configuration, the construction work can be reduced.
In other words, by using nose tip PC 20 for the nose tip part of the cantilever slab (eaves 2) of steel-framed building A, it is possible to reduce the construction work of transporting and assembling formwork and formwork supports for each floor, which is different from, for example, when forming the nose tip part of a cantilever slab (eaves 2) in reinforced concrete construction.
In addition, with the nose tip PC 20 placed on the mounting portion (plate member 40) of the second steel beam (supporting steel beam 14), the nose tip PC 20 can be easily fixed to the first steel beam (fixed steel beam 11) using fasteners (bolts and nuts).

In addition, a deck plate 50 on which the concrete 60 of the cantilever slab (eaves 2) is poured is provided on the upper part of the first steel beam (fixed steel beam 11),
The nose tip PC 20 is
The concrete structure includes a plurality of reinforcing bars (under bars 23) extending in a predetermined first direction in the horizontal direction and arranged at intervals in a second direction perpendicular to the first direction in a plan view, and fixed to the concrete structure;
The deck plate 50 is
The plate is formed in a corrugated shape having a plurality of peaks 51 and valleys 52 that are continuous in the second direction,
The reinforcing bar (underbar 23) and the valley portion 52 are
They are arranged so as to overlap each other in a plan view.

This configuration can prevent interference between the ridge 51 of the deck plate 50 and the reinforcing bars (underbars 23) of the nose PC 20. It also ensures that the concrete 60 covers the reinforcing bars (underbars 23).

In addition, the nose tip PC 20 is
It has a connection part (screw hole 21b) to which the wall tie 5 of the scaffolding 4 can be connected.

This configuration makes it easy to rearrange the wall ties 5 of the scaffolding 4.

In addition, a method for attaching the nose tip PC according to an embodiment of the present invention includes the steps of:
A plate fixing process (step S10) for fixing a plate 30 to the bottom surface of a nose tip PC 20 made of precast concrete, which constitutes the tip of a cantilever slab (eaves 2) extending horizontally;
A temporary fixing process (step S11) in which a plurality of the nose tip PCs 20 are temporarily fixed 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 process (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 the plurality of adjacent nose tip PCs 20 by clamping the plurality of temporarily fixed nose tip PCs 20 with a common adjustment jig 70;
The method includes a fixing process (steps S14 and S15) of fixing the deck plate 50, the first steel beam (fixed steel beam 11), and the nose tip PC 20 whose position has been adjusted to each other.

This configuration can reduce the amount of work required for construction. In other words, by using the nose PC 20 for the nose portion of the cantilever slab (eaves 2) of steel-framed building A, unlike, for example, forming the nose portion of a cantilever slab (eaves 2) in reinforced concrete construction, it is possible to reduce the amount of work required for construction, such as transporting and assembling formwork and formwork supports for each floor. In addition, with the nose PC 20 temporarily fixed, the position of the nose PC 20 is adjusted using an adjustment jig 70, and then the nose PC 20 is fixed to the first steel beam (fixed steel beam 11). This can improve the accuracy of construction.

In addition, in the fixing step (step S14, step S15),
After the first steel beam (fixed steel beam 11) and the nose end PC 20 are fixed with bolts (step S14), concrete 60 is poured into the cantilever slab (eaves 2), so that the deck plate 50 and the nose end PC 20 are fixed together by the concrete 60.

This configuration allows the deck plate 50 and the nose PC 20 to be integrated in an optimal manner.

In addition, in the position adjustment step (step S13),
The vertical positions of the plurality of adjacent nose tips PC20 are adjusted by vertically clamping the plurality of nose tips PC20 with the adjustment jig 70.

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

In addition, in the position adjustment step (step S13),
The horizontal positions of the plurality of adjacent nose tips PC20 are adjusted by clamping the plurality of nose tips PC20 horizontally with the adjustment jig 70.

With this configuration, the horizontal position of the nose tip PC 20 can be adjusted using the adjustment jig 70, further improving the accuracy of construction.

In addition, the eave 2 in this embodiment is one form of a cantilever slab according to the present invention.
Moreover, the fixed steel beam 11 according to this embodiment is one form of a first steel beam according to the present invention.
Moreover, the supporting steel beam 14 in this embodiment is one form of a second steel beam in accordance with the present invention.
Further, the second fixing hole 32 according to the present embodiment is one form of the first hole according to the present invention.
The fixing hole 13a according to this embodiment is one form of the second hole according to the present invention.
Moreover, the plate member 40 according to this embodiment is one form of a mounting portion according to the present invention.
Moreover, the underbar 23 in this embodiment is one form of reinforcing bar according to the present invention.
Moreover, the screw hole 21b according to this embodiment is one form of a connecting portion according to the present invention.

Although one embodiment of the present invention has been described above, 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.

For example, in the present embodiment, an example is shown in which the main body 21 of the nose PC 20 is provided with a screw hole 21b to which the wall connector 5 can be connected, but this is not limited to such an embodiment. For example, the main body 21 may not be provided with a screw hole 21b.

In addition, in this embodiment, an example is shown in which the extension direction of the peaks 51 and valleys 52 of the deck plate 50 is arranged in the short direction (front-to-back direction) of the eaves 2, but this is not limited to this aspect. For example, the extension direction of the peaks 51 and valleys 52 of the deck plate 50 may be arranged in the longitudinal direction (left-right direction) of the eaves 2. In this case, the lower reinforcement 23 may be appropriately bent to avoid interference between the lower reinforcement 23 and the deck plate 50.

In addition, in this embodiment, an example in which three plates 30 are provided for the nose tip PC 20 is shown, but this is not limited to this embodiment. The number of plates 30 for the nose tip PC 20 may be two or less, or four or more.

In addition, in this embodiment, an example is shown in which the plate 30 is fixed to the second fixed steel beam 13 of the fixed steel beam 11, but this is not limited to this form. For example, the plate 30 may be fixed to the first fixed steel 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 beam 12.

In addition, in this embodiment, an example is shown in which the position adjustment process (step S13) is performed after the deck plate installation process (step S12), but this is not limited to this embodiment. For example, the deck plate installation process may be performed after the position adjustment process. Also, the deck plate installation process may be performed after the bolt fixing process (step S14).

In addition, in this embodiment, an example is shown in which the eaves 2 are a cantilever slab that can be used as a balcony (veranda) floor, but this is not limited to this form. For example, the eaves 2 may be a cantilever slab that can be used as a corridor, etc., or may be an eaves (eaves) that is used mainly as a sunshade or rain shelter.

1 Nose end PC mounting structure 2 Eaves 10 Steel beam 20 Nose end PC
30 Plate 40 Plate member 50 Deck plate 60 Concrete 70 Adjustment jig

Claims (7)

The nose PC, which constitutes the tip of the cantilever slab that protrudes horizontally and is made of precast concrete,
A plate provided on a 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, the first steel beam being fixed to the plate by a fastener inserted through the first hole and the second hole;
A second steel beam extending horizontally from the first steel beam;
A mounting portion is provided on the second steel beam, formed to the same thickness as the plate, and on which the nose tip PC is placed.
Mounting structure for nose PC to steel structure. A deck plate on which the concrete of the cantilever slab is poured is provided on the upper portion of the first steel beam,
The nose tip PC is
The concrete structure includes a plurality of reinforcing bars extending in a first direction in the horizontal direction and spaced apart in a second direction perpendicular to the first direction in a plan view, the reinforcing bars being fixed to the concrete;
The deck plate is
The plate is formed in a corrugated shape having a plurality of peaks and valleys extending continuously in the second direction,
The reinforcing bar and the valley portion are
are arranged so as to overlap each other in a plan view;
A structure for mounting the nose tip PC according to claim 1 to a steel frame structure. The nose tip PC is
Having a connection part that can connect the wall tie of the scaffolding,
3. A structure for mounting the nose tip PC according to claim 1 or 2 to a steel frame structure. A plate fixing process is a process of fixing a plate to the bottom surface of a nose PC made of precast concrete, which constitutes the tip of the cantilever slab that protrudes in the horizontal direction;
A temporary fixing process of temporarily fixing the plurality of nose end PCs via the plate to a first steel beam that supports the cantilever slab from below;
a deck plate installation process for installing a deck plate on the first steel beam;
a position adjustment step of adjusting positions of the plurality of adjacent temporarily fixed nose tips PC by clamping the plurality of nose tips PC with a common adjustment 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.
How to install the nose PC. In the fixing step,
After the first steel beam and the nose end PC are fixed with bolts, the concrete of the cantilever slab is poured, so that the deck plate and the nose end PC are fixed integrally with the concrete.
The method for attaching the nose tip PC according to claim 4. In the position adjustment step,
The vertical positions of the plurality of adjacent nose tips PC are adjusted by vertically clamping the plurality of nose tips PC with the adjustment jig.
6. A method for attaching a nose tip PC according to claim 4 or 5. In the position adjustment step,
The horizontal positions of the plurality of adjacent nose tips PC are adjusted by horizontally clamping the plurality of nose tips PC with the adjustment jig.
A method for mounting a nose tip PC according to any one of claims 4 to 6.

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