JP7478018B2 - How to install a cantilever slab - Google Patents

Description

The present invention relates to a method for constructing a protruding slab, in which a slab member is fixed to a structure in a protruding state in which it protrudes outward from the structure.

The construction method for the above-mentioned cantilever slab involves a temporary fixing process in which the slab member is temporarily fixed to a structure such as a building, and a final fixing process in which the temporarily fixed slab member is integrated with the structure by pouring concrete to permanently fix the slab member (see, for example, Patent Document 1).

In the construction method described in Patent Document 1, a protrusion is provided that protrudes from the base end of the slab member toward the structure, so in the temporary fixing process, the protrusion arranged at the base end of the slab member is connected to a beam or the like on the structure side, and the tip end of the slab member is supported by a temporary support such as a support arranged below it.

Japanese Patent Publication No. 3-48970

However, the construction method described in Patent Document 1 requires the installation of temporary shoring below the leading edge of the slab member, and in the actual fixing process that is carried out after the temporary fixing process, it is necessary to support the leading edge of the slab member until the poured concrete hardens. Therefore, not only does it have to install temporary shoring, it also has to be left in place for a long period of time, making it difficult to ensure work routes, leading to increased costs and reduced workability.

In light of this situation, the main objective of the present invention is to provide a method for constructing a cantilever slab that can ensure proper work flow, reduce costs, and improve workability.

The first characteristic configuration of the present invention is a method for constructing a cantilever slab in which a slab member is fixed to a structure in a cantilevered state in which the slab member is cantilevered outward from the structure,
The base end portion of the slab member is provided with a rising portion extending upward,
a temporary fixing process in which, with a base end portion of the slab member placed on a support member on the structure side, the rising portion of the slab member and an extension member extending from the support member to the inward side of the structure are connected with a connecting material to temporarily fix the slab member to the structure;
The difference is that a final fixing process is carried out in which the slab member , which has been temporarily fixed by pouring concrete, is joined to the structure to final fix the slab member.

According to this configuration, in the temporary fixing process, the base end portion of the slab member is placed on the support member, and the rising portion on the slab member side and the extension member on the structure side are connected with a connecting member. Therefore, even if no temporary shoring is installed to support the tip end portion of the slab member, the slab member can be appropriately temporarily fixed to the structure by utilizing the tensile force of the connecting member. This makes it possible to omit temporary shoring, ensure proper work flow, reduce costs, and improve workability.

The second characteristic feature of the present invention is that the length of the connecting material is freely adjustable.

According to this configuration, the position (height) of the tip end portion of the slab member can be adjusted by adjusting the length of the connecting material, and the position (height) of the tip end portion of the slab member can be adjusted to the desired position (desired height).

A third characteristic configuration of the present invention is a structure in which a beam is arranged in line with the support member on the inner side of the structure, and a reinforcing member is rigidly connected across the support member and the beam,
The reinforcing member is provided as the extension member and is at the point where the connecting member is connected.

Because the slab member is placed on the support member, it is conceivable that the load of the slab member may cause the support member to twist (bend downward). Therefore, according to this configuration, a reinforcing member is provided that is rigidly connected across the support member and the beam. The reinforcing member extends from near the load application point of the slab member placed on the support member in a direction perpendicular to the support member, so that the support member can be prevented from twisting. Moreover, because the connecting material is connected to the reinforcing member, the reinforcing member can be used as a member for temporarily fixing the slab member, which reduces costs and simplifies the configuration.

A fourth characteristic configuration of the present invention is that the slab members are provided in a plurality of states adjacent to each other in the longitudinal direction of the support member,
The extension member is disposed at a position corresponding to the boundary portion of the adjacent slab members, and is a point where two of the connecting members connected to the rising portions of each of the adjacent slab members are connected.

According to this configuration, the connection target of the two connecting members connected to the rising portions of each of the adjacent slab members is an extension member arranged at a position corresponding to the boundary between the adjacent slab members. This allows the two adjacent slab members to be temporarily fixed using a single extension member, reducing costs and simplifying the configuration, and by arranging the extension member in an appropriate position, the two adjacent slab members can be temporarily fixed in a stable position.

In a fifth characteristic configuration of the present invention, the support member is provided with an engaged member at a planned position of the slab member, and an engaging member that can be engaged with the engaged member is provided at a base end portion of the slab member,
In the temporary fixing step, the engaging member of the slab member is engaged with the engaged member of the support member, and a base end portion of the slab member is placed on the support member.

According to this configuration, when the base end portion of the slab member is placed on the support member in the temporary fixing process, the engaging portion of the slab member is engaged with the engaged member of the support member, making it easier to position and place the slab member on the support member, improving workability.

Side view of the protruding slab after installation Plan view with the protruding slab installed FIG. 13 is a diagram showing a process of placing the slab member on the support member. An enlarged side view of the main part of the slab member placed on the support member. An enlarged plan view of the main part of the slab member placed on the support member. Side view showing the temporary fixing process FIG. 13 is a perspective view showing a connection state by a connecting material in a temporary fixing process. FIG. 13 is a perspective view showing a connection state by a connecting material in a temporary fixing process. FIG. 13 is a perspective view showing the connection points between the connecting material and the building during the main fixing process.

An embodiment of a method for constructing a cantilever slab according to the present invention will be described with reference to the drawings.
The method for constructing this cantilever slab is a construction method in which a slab member 1 is fixed to a building 2 (corresponding to a structure) in a cantilevered state in which it cantilevers outward from the building 2, as shown in Figs.

The slab member 1 is made of, for example, precast concrete, and is formed in an L-shape in side view as shown in FIG. 1, and in a horizontally long rectangular shape in plan view as shown in FIG. 2. As shown in FIG. 1, the slab member 1 is provided with a protruding portion 11 extending from the base end side (right side in FIG. 1) to the tip end side (left side in FIG. 1), and a rising portion 12 extending upward from the base end portion of the protruding portion 11. The protruding portion 11 of the slab member 1 is provided on the outer side of the building 2 relative to the exterior wall line A of the building 2, and is provided to function as an eave, and the rising portion 12 of the slab member 1 is provided to function as a parapet extending upward from the protruding portion 11 as the eave. The protruding portion 11 is formed in an inclined shape with its upper surface portion positioned downward as it approaches the tip end. The rising portion 12 is formed in the shape of a standing wall extending upward at the base end side end of the protruding portion 11.

The slab member 1 is provided with an anchoring portion 13 (e.g., an anchor bar), which is fixed to the cast-in-place concrete slab 3, thereby fixing the slab member 1 to the building 2. The anchoring portion 13 extends from the upper side to the lower side at the rising portion 12 of the slab member 1, and is formed in an L-shape by bending it toward the inside of the building 2. A part of the anchoring portion 13 is embedded in the slab member 1, and the part other than the embedded part protrudes from the slab member 1 and extends toward the inside of the building 2, and the part protruding from the slab member 1 is fixed to the concrete slab 3.

As shown in Figures 1 and 2, the outer end of the building 2 is provided with a support member 21 (e.g., a support beam) that supports the slab member 1, and the slab member 1 is provided in a state in which it is placed on the support member 21. As shown in Figure 2, multiple slab members 1 are provided adjacent to each other in the longitudinal direction of the support member 21, and the support member 21 supports multiple slab members 1.

In this embodiment, as shown in FIG. 1, the slab member 1 is not placed directly on the support member 21, but rather the load-receiving portion 14 (e.g., a bolt) of the slab member 1 is placed on a mounting portion-forming member connected to the support member 21, and the load of the slab member 1 is applied to the support member 21.

A rib plate 22 and a plate 23 are connected to the support member 21 as the mounting portion forming members, and the mounting portion that directly receives the load of the slab member 1 is disposed one step above the upper end portion (upper flange 21a) of the support member 21.

The rib plate 22 comprises a first rib plate 22a that spans the upper and lower flanges 21a, 21b of the H-shaped steel that is the support member 21, and a second rib plate 22b that extends upward from the upper flange 21a. The plate 23 comprises a first plate 23a that extends horizontally from the upper flange 21a to the outside of the building 2, and a second plate 23b that extends horizontally while connecting the upper ends of the second rib plate 22b.

In this way, the support portion that directly bears the load of the slab member 1 is the second plate 23b, which is disposed one step above the upper flange 21a of the support member 21. In addition, by disposing the rib plate 22 and the plate 23, the support member 21 is disposed inward from the outer end of the building 2 in the inside-outside direction of the building 2 (left-right direction in FIG. 1).

In this embodiment, a rib plate 22 and a plate 23 are provided as the mounting portion forming members, but it is also possible to place the load receiving portion 14 of the slab member 1 on the upper flange 21a of the support member 21 without providing the rib plate 22 and the plate 23, and to allow the load of the slab member 1 to act directly on the support member 21.

The load-receiving portion 14 (bolt) of the slab member 1 is supported by a support bracket 15, as shown in Figures 4(A) and 5. A portion of the support bracket 15 is embedded in the slab member 1 and supported by the slab member 1, and the load-receiving portion 14 is provided at a portion that protrudes from the base end surface of the slab member 1 (the inner end surface of the building 2). The load-receiving portion 14 is configured so that its height (position) in the vertical direction relative to the support bracket 15 can be freely adjusted by screwing in the screw. By adjusting the vertical height of the load-receiving portion 14, the lower end of the load-receiving portion 14 is brought into contact with the second plate 23b, causing the load-receiving portion 14 to rest on the second plate 23b.

As shown in FIG. 2, the building 2 has a column-beam structure with columns 4 and a first beam (main beam) 5. On the inside of the building 2, the columns 4 are arranged at intervals of a predetermined span in the longitudinal direction of the support member 21, and the first beam 5 is provided so as to span between the columns 4.

As for the beams, as shown in FIG. 2, not only the first beam 5 that spans between the columns 4, but also multiple beams such as the second to fifth beams 6 to 9 are provided. The second beam 6 (small beam) is provided between the first beam 5 and the support member 21, on the side closer to the support member 21, in a state where it is lined up parallel to the first beam 5. The third beam 7 (large beam) extends in a direction perpendicular to the first beam 5 and is provided in a state where it spans the column 4 and the second beam 6. The fourth beam 8 (small beam) extends in a direction perpendicular to the first beam 5 and is provided in a state where it spans the second beam 6 and the support member 21. The fifth beam 9 (small beam) extends in a direction perpendicular to the first beam 5 and is provided in a state where it spans the first beam 5 and the support member 21.

As shown in FIG. 2, an extension member 31 (small beam) extending in a direction perpendicular to the support member 21 is provided at a position corresponding to the boundary portion between adjacent slab members 1. As shown in FIG. 1 and FIG. 2, the extension member 31 is rigidly connected (e.g., welded or bolted) to the first beam 5 and the support member 21 across the first beam 5 and the support member 21, and is configured as a reinforcing member that reinforces the support member 21.

The construction method for the cantilever slab involves sequentially carrying out a temporary fixing process in which the slab member 1 is temporarily fixed to the building 2, and a permanent fixing process in which the slab member 1 is permanently fixed to the building 2 by pouring concrete, thereby fixing the slab member 1 to the building 2. The temporary fixing process and the permanent fixing process are explained below.

(Temporary fixing process)
In the temporary fixing process, as shown in Figure 6, the base end portion of the protruding portion 11 of the slab member 1 is placed on the support member 21, and the rising portion 12 of the slab member 1 and the extension member 31 are connected with a connecting material 41 to temporarily fix the slab member 1 to the building 2.

As shown in FIG. 3, the slab member 1 is lifted by a heavy machine such as a crane and moved to the intended position of the support member 21, and as shown in FIG. 6, the base end portion of the protruding portion 11 of the slab member 1 is placed on the support member 21 via the rib plate 22 and the plate 23. As described above, in this embodiment, the rib plate 22 and the plate 23 constitute the mounting portion forming member, so the load receiving portion 14 of the slab member 1 is placed on the second plate 23b, thereby placing the slab member 1 on the support member 21. Incidentally, as shown in FIG. 3, a deck plate 32 is placed at the location where concrete is poured in this fixing process, but the deck plate 32 is omitted in FIG. 6.

In this embodiment, the rib plate 22 and plate 23 are connected to the support member 21, and the placement portion of the slab member 1 is disposed one step above the support member 21, and as shown in FIG. 1, the lower end of the concrete slab 3 (the position where the deck plate 32 is disposed) is also disposed one step above the support member 21. Therefore, the rib plate 22 and plate 23 are also connected to the second beam 6 disposed one step inward of the building 2 from the support member 21, and the lower end of the concrete slab 3 (the position where the deck plate 32 is disposed) is also disposed one step above the second beam 6.

As shown in FIG. 3, the support member 21 is provided with a pair of left and right engaged members 33 at the planned installation position of the slab member 1, while the base end portion of the protruding portion 11 of the slab member 1 is provided with a pair of left and right engaging members 34 that can be engaged with the pair of left and right engaged members 33, respectively. In the temporary fixing process, as shown in FIG. 4(B) and FIG. 5, the engaging member 34 of the slab member 1 is engaged with the engaged member 33 of the support member 21, and the base end portion of the protruding portion 11 of the slab member 1 is placed on the support member 21. As a result, the engagement between the engaged member 33 and the engaging member 34 adjusts the position of the slab member 1 in the length direction of the support member 21 and in the inside and outside directions of the building 2 with respect to the planned installation position of the support member 21. The engagement between the engaged member 33 and the engaging member 34 is performed by moving the slab member 1 downward from the upper side relative to the support member 21.

As shown in Figures 4(B) and 5, the engaged member 33 has two L-shaped upright wall portions in plan view (see Figure 5), and the two upright wall portions are arranged at a distance from each other. As shown in Figures 4 and 5, a gap is provided between the second plate 23b and the slab member 1 in the inside-outside direction of the building 2 (left-right direction in Figure 4, up-down direction in Figure 5), and a plate 35 is provided to close the gap.

4B and 5, the engaging member 34 includes a first engaging member 34a, a support member 34b, and a second engaging member 34c. The first engaging member 34a is an L-shaped plate-like body in a side view, and is provided so as to be able to abut against the inner side part of the building 2 in the engaged member 33. The second engaging member 34c is a plate-like body, and is provided so as to be able to abut against the outer side part of the building 2 in the engaged member 33. The engaging member 34 engages with the engaged member 33 in a state in which the support member 34b is located between the two upright walls of the engaged member 33 and the engaged member 33 is sandwiched between the first engaging member 34a and the second engaging member 34c in the inside-outside direction of the building 2 (left-right direction in FIG. 4, up-down direction in FIG. 5). The support member 34b is composed of a rod-shaped body that extends inward and outward from the building 2, and supports the first engagement member 34a and the second engagement member 34c while penetrating them. The outer side portion of the building 2 in the support member 34b is embedded in the slab member 1 and supported by the slab member 1, and the first engagement member 34a and the second engagement member 34c are provided at the portion that protrudes from the slab member 1 toward the inside of the building 2.

When placing the slab member 1 on the support member 21, not only is the position of the support member 21 adjusted in the length direction and in the inside and outside directions of the building 2 relative to the intended installation position of the support member 21, but the posture of the slab member 1 and the position of the slab member 1 in the up and down direction (height) are also adjusted.

As shown in Figures 1 and 4 (A), the support member 21 is provided with an abutment member 36 (bolt) that can abut against the base end surface of the slab member 1 (the inner end surface of the building 2). The abutment member 36 is abutted against the base end surface of the slab member 1 to adjust the posture (tilt adjustment) of the slab member 1. By abutting the abutment member 36 against the base end surface of the slab member 1, the posture of the slab member 1 can be adjusted to an appropriate installation posture in which the protruding portion 11 extends horizontally and the rising portion 12 extends vertically.

The abutment member 36 is connected to the second rib plate 22b and is provided in a position extending horizontally (inside and outside the building 2). A receiving plate 37 that is L-shaped in side view is embedded in the slab member 1 at the portion where the abutment member 36 is to be abutted.

As shown in Figure 4 (A), the load receiving portion 14 of the slab member 1 is configured so that its height (position) in the vertical direction can be freely adjusted relative to the support bracket 15 by screwing it in, as shown in Figure 4 (A). Therefore, when placing the load receiving portion 14 of the slab member 1 on the second plate 23b, the position of the slab member 1 in the vertical direction (height) is adjusted by adjusting the height of the load receiving portion 14 in the vertical direction.

In this way, as shown in FIG. 6, the position of the support member 21 is adjusted in the length direction, in the interior/exterior direction of the building 2, and in the vertical direction (height) relative to the planned installation position of the support member 21, and the posture is also adjusted. When the slab member 1 is placed on the support member 21, the rising portion 12 of the slab member 1 is connected to the extension member 31 by the connecting member 41.

The upper part of the extension member 31 is provided with a building side connection part 42 (metal fittings), and the rising part 12 of the slab member 1 is provided with a slab member side connection part 43 (metal fittings). The connecting member 41 is composed of, for example, a chain block, and is connected in a tensioned state (tensile state) across the building side connection part 42 and the slab member side connection part 43. The connecting member 41 is configured so that its length can be freely adjusted. As a result, by adjusting the length of the connecting member 41, the position (height) of the tip side part of the slab member 1 can be adjusted, and the position (height) of the tip side part of the slab member can be adjusted to the desired position (desired height). Incidentally, in FIG. 7, the intermediate part of the connecting member 41 is illustrated in a simplified form.

As described above, the extension member 31 provided with the building side connection part 42 is disposed at a position corresponding to the boundary part of the adjacent slab members 1, as shown in FIG. 2 and FIG. 7. Therefore, as shown in FIG. 7, two connecting members 41 connected to the rising parts 12 of the adjacent slab members 1 are connected to one extension member 31. The rising parts 12 of the adjacent slab members 1 are provided with slab member side connection parts 43, and each of the two slab member side connection parts 43 is connected to a connecting member 41. Each of the two connecting members 41 is connected to one building side connection part 42 provided on the extension member 31. An adjacent connecting part 44 is provided across the rising parts 12 of the adjacent slab members 1, and the adjacent slab members 1 are connected by this adjacent connecting part 44. Incidentally, as shown in FIG. 7, a deck plate 32 is disposed at the location where concrete is poured in this fixing process.

(Main fixing process)
In this fixing process, as shown in FIG. 1, a concrete slab 3 is constructed in such a state that a slab member 1 temporarily fixed by pouring concrete is joined to a building 2.

As shown in FIG. 8, the temporary fixing process connects the rising portion 12 of the slab member 1 and the extension member 31 with the connecting member 41, so in the main fixing process, concrete is poured while maintaining this connection state. Therefore, after the reinforcing bars 51 are arranged, the filler 52 is filled in the area corresponding to the upper part of the building side connection part 42 of the extension member 31, and concrete is poured. As a result, concrete can be poured while maintaining the connection state in which the rising portion 12 of the slab member 1 and the extension member 31 are connected with the connecting member 41, and the concrete slab 3 can be constructed. As shown in FIG. 9, an open space 53 where no concrete exists is formed in the area corresponding to the upper part of the building side connection part 42 of the extension member 31. Therefore, after the concrete hardens, the connecting member 41 is removed from the building side connection part 42 through the open space 53, and concrete or the like is filled into the open space 53 by post-construction. Incidentally, in FIG. 8 and FIG. 9, the intermediate part of the connecting member 41 is illustrated in a simplified manner.

[Another embodiment]
Another embodiment of the present invention will now be described.
The configurations of the embodiments described below are not limited to being applied alone, but may also be applied in combination with the configurations of other embodiments.

(1) In the above embodiment, the extension member 31 is rigidly connected to the first beam 5 and the support member 21 and also serves as a reinforcing member that reinforces the support member 21. However, a reinforcing member that is rigidly connected to the first beam 5 and the support member 21 can also be provided in addition to the extension member 31.

(2) In the above embodiment, two connecting members 41 connected to the rising portion 12 of each of adjacent slab members 1 are connected to one extension member 31, but the number of connecting members 41 connected to one extension member 31 can be changed as appropriate, such as connecting one connecting member 41 connected to the rising portion 12 of a slab member 1 to one extension member 31.

1 Slab member 2 Building (structure)
5. First beam (main beam)
12 Rising portion 21 Support member 31 Extension member (reinforcement member)
33 engaged member 34 engaging member 41 connecting member

Claims (5)

In a method for constructing a cantilever slab, a slab member is fixed to a structure in a cantilevered state so that the slab member is cantilevered outward from the structure,
The base end portion of the slab member is provided with a rising portion extending upward,
a temporary fixing process in which, with a base end portion of the slab member placed on a support member on the structure side, the rising portion of the slab member and an extension member extending from the support member to the inward side of the structure are connected with a connecting material to temporarily fix the slab member to the structure;
This is a construction method for a cantilever slab, which includes a final fixing process in which the slab member , which has been temporarily fixed by pouring concrete, is joined to the structure to final fix the slab member. The method for constructing a spring-loaded slab according to claim 1, wherein the length of the connecting material is freely adjustable. A beam is provided on the inner side of the structure, the beam being arranged in line with the support member, and a reinforcing member is rigidly connected across the support member and the beam,
3. The method for constructing a cantilever slab according to claim 1 or 2, wherein the reinforcing member is provided as the extension member, and the connecting material is connected to the reinforcing member. The slab members are provided in a plurality of positions adjacent to each other in the longitudinal direction of the support member,
A construction method for a protruding slab described in any one of claims 1 to 3, wherein the extension member is arranged at a position corresponding to the boundary portion of adjacent slab members, and two connecting members connected to the rising portions of each of the adjacent slab members are connected. The support member is provided with an engaged member at a planned position of the slab member, and an engaging member that is engageable with the engaged member is provided at a base end portion of the slab member,
A construction method for a protruding slab described in any one of claims 1 to 4, wherein in the temporary fixing process, the engaging member of the slab member is engaged with the engaged member of the support member, and the base end portion of the slab member is placed on the support member.

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