JP2023167478A - Construction method for slab-like member - Google Patents

Abstract

To achieve improvement in workability and shortening of a construction period, in construction of a slab-like member made of half-precast concrete.SOLUTION: A construction method for a slab-like member made of half-precast concrete which comprises a precast slab and cast-in-place concrete and which is mounted striding over a pair of support members includes steps of: mounting width direction end parts of the precast slab on the pair of support members; suspending the precast slab by a timbering stretched above the precast slab via a suspension material extending downward from the timbering; constructing a reinforcement structure above the precast slab; placing and curing cast-in-place concrete at an upper part of the precast slab so as to bury at least part of the suspension material and the reinforcement structure; and separating the suspension material from the timbering and removing the timbering.SELECTED DRAWING: Figure 1

Description

The present invention relates to a construction method for constructing a slab-like member made of half precast concrete.

In concrete composite structures having reinforcing bars, such as reinforced concrete structures, half-precast concrete slab-like members are used, which are a combination of precast members and cast-in-place concrete members, for the purpose of saving labor and labor on site. For example, two concrete members (a precast concrete member and a cast-in-place concrete member) are combined to produce members constituting various structures such as a top plate, a beam member, and a column member of a structure.

For example, Patent Document 1 discloses a precast concrete slab and a floor slab structure of a building equipped with the same. According to the invention disclosed in Patent Document 1, by employing a steel frame having vertical ribs as the upper end member constituting the truss structure reinforcement body, it is said that costs can be reduced, construction time can be shortened, and on-site workability can be improved. ing.

Japanese Patent Application Publication No. 2000-1938

However, in the technology described in Patent Document 1, a steel frame having vertical ribs is used as the upper end member, but since this upper end member needs to be strong, there is a concern that the member may become larger and heavier. be done. Therefore, there is room for further improvement in terms of workability, cost, etc. Reinforcing bars for cast-in-place sections are on-site work, and workability is poor, especially in the case of overcrowded reinforcement, so there is a need to improve workability and shorten the construction period of reinforcing bars by unitizing reinforcing bars. The present inventors have conducted intensive studies on techniques that can further improve workability and shorten the construction period regarding methods of constructing slab-like members made of half precast concrete.

In view of the above circumstances, an object of the present invention is to provide a method for constructing a slab-like member made of half precast concrete that can improve workability and shorten the construction period.

In order to achieve the above object, the present invention provides a method for constructing a half precast concrete slab-like member made of a precast slab and cast-in-place concrete and mounted across a pair of supporting members, the method comprising: a step of mounting the widthwise end portion of the precast slab on a supporting member; and suspending the precast slab via a hanging member extending downward from the shoring by a shoring strung above the precast slab. lowering the precast slab, constructing a reinforcing structure above the precast slab, and placing cast-in-place concrete on top of the precast slab so as to bury at least a portion of the hanging material and the reinforcing structure and curing it. and a step of separating the hanging material from the shoring and removing the shoring, wherein the hanging material embedded in the cast-in-place concrete in the slab-like member functions as a shear reinforcement. A method for constructing a slab-like member is provided.

The precast slab may be reinforced by a reinforcing material embedded in the precast slab, and in the step of suspending the precast slab, a lower end of the hanging material may be connected to the reinforcing material or the precast slab.

The upper end of the hanging material is machined with a male thread, and in the process of suspending the precast slab, a nut that is threaded onto the male screw is tightened or loosened at the connecting portion between the shoring and the hanging material. The attitude of the precast slab may be adjusted by raising and lowering the hanging member.

The hanging material has a structure in which an upper hanging material connected to the shoring and a lower hanging material connected to the precast slab are connected by a joint,
In the step of removing the support, the lower hanging member may be separated from the support by removing the joint.

Fixing devices may be provided at the upper and lower ends of the lower hanging member.

The support member includes a shoulder and an apex extending upwardly from the shoulder, the widthwise end of the precast slab is mounted on the shoulder, and the shoring is a top portion of the pair of support members. It may be mounted so as to span over the top.

The support member may be a wall of a culvert, and the slab-like member may be a top plate of the culvert.

The support member may be a column, and the slab-like member may be a beam.

The reinforcing bar structure includes main reinforcing bars installed parallel to the width direction of the precast slab, and distribution bars installed in a direction intersecting the main reinforcing bars, and the hanging members are connected to the main reinforcing bars. It may be moored to one or both of the distribution bars.

A plurality of the precast slabs are mounted adjacent to each other, and a distribution bar extending in the width direction of the precast slab is embedded in the precast slab such that an end of the distribution bar protrudes from the precast slab. In the plurality of precast slabs, the distribution bars of the adjacent precast slabs are connected by joints, and in the step of pouring and curing the cast-in-place concrete, the concrete is removed including between the plurality of adjacent precast slabs. Pouring may also be performed.

The support member may be a wall of the culvert, the slab-like member may be a top plate of the culvert, and a plurality of the precast slabs may be installed in a longitudinal direction of the culvert.

According to the present invention, it is possible to improve workability and shorten the construction period in constructing a slab-like member made of half precast concrete.

Note that the above effects are not necessarily limited, and in addition to or in place of the above effects, any of the effects shown in this specification or other effects that can be understood from this specification may be used. The effect may be achieved.

FIG. 3 is a schematic plan view of the top plate structure. It is a schematic side sectional view of a top plate structure. It is a schematic explanatory view showing an example of the composition of a hanging member. It is a process diagram when constructing a top plate structure. It is a process diagram when constructing a top plate structure. It is a process diagram when constructing a top plate structure. It is a process diagram when constructing a top plate structure. It is a process diagram when constructing a top plate structure. It is a process diagram when constructing a top plate structure. It is a process diagram when constructing a top plate structure. It is a schematic explanatory view showing an example of the composition of a precast slab. It is a schematic explanatory view regarding connection of a precast slab and a suspension member. It is a schematic sectional view when channel steel is used as a support. It is a process diagram when constructing a beam. It is a process diagram when constructing a beam. It is a process diagram when constructing a beam. It is a process diagram when constructing a beam. It is a process diagram when constructing a beam. It is a process diagram when constructing a beam. It is a process diagram when constructing a beam. It is a schematic diagram in the case of installing a shoring via a frame between a shoring and a top part. It is a schematic explanatory drawing which shows the other example of a structure of a hanging material.

Embodiments of the present invention will be described below with reference to the drawings. In this specification and the drawings, components having substantially the same functional configuration may be designated by the same reference numerals to omit redundant explanation. In addition, in this embodiment, the case where the top slab of a culvert is constructed by the method for constructing a slab-like member according to the present invention will be explained as an example. Further, in the embodiments of this specification, some illustrations of the reinforcing bar structure and reinforcement arrangement may be omitted for the sake of explanation, or reinforcing bars inside members may be illustrated.

In the following explanation, the direction in which the internal space of a culvert extends is referred to as the ``length direction'' of the culvert, and the direction that crosses the internal space and is orthogonal to the length direction is referred to as the ``width direction'' of the culvert. The direction perpendicular to the width direction is defined as the "height direction." In the drawings, the length direction is sometimes shown as the "Y axis," the width direction is shown as the "X axis," and the height direction is sometimes shown as the "Z axis." Further, the width direction of the precast slab 20 described later refers to the same direction as the width direction of the culvert described above.

<Composition of top plate structure>
1 and 2 are schematic explanatory views of a top plate structure 1 constructed by the method for constructing a slab-like member according to an embodiment of the present invention, with FIG. 1 being a schematic plan view and FIG. 2 being a schematic side sectional view. It shows. Note that this top slab structure 1 is an example of a slab-like member that uses, for example, a side wall of a culvert as a support member and is mounted across a plurality of support members. Here, for the sake of explanation, in addition to the top slab structure 1, FIG. Also shown are supporting structures 30) and the like.

As shown in FIGS. 1 and 2, the top slab structure 1 is mounted across a pair of support members 10 (10a, 10b), which are, for example, side walls, middle walls, etc. of a culvert. The support member 10 includes a shoulder 12 on the upper surface for mounting a precast slab 20, which will be described later, and a top 14 extending further upward from the shoulder 12. The top plate structure 1 includes a plurality of precast slabs 20 whose ends in the width direction (X direction in the figure) are mounted on shoulders 12, 12 facing each other so as to straddle the pair of support members 10. In the configuration according to this embodiment, a plurality of precast slabs 20 are mounted adjacent to each other in the length direction of the culvert (Y direction in the figure).

Precast slab 20 may be a member (so-called precast member) manufactured in advance in a factory or the like, and may be reinforced by being configured to include reinforcing material 27 . The reinforcing material 27 is not particularly limited, but may be, for example, a steel material such as an H-beam steel or a PC steel material, or a reinforcing bar.

A shoring 30 is installed above the precast slab 20 so as to span over the opposing tops 14, 14 of the support member 10. The shoring 30 may be made of, for example, H-beam steel. A plurality of hanging members 33 extending downward are connected to the shoring 30. As the hanging member 33, various steel materials such as deformed reinforcing bars, separators, PC steel materials, and fully threaded bolts may be used.

The means for connecting the shoring 30 and the hanging material 33 is arbitrary. For example, the shoring 30 may be made with holes, the upper end of the hanging material 33 may be threaded, and the supporting material 30 and the hanging material 33 may be connected. The connection may be made by machining a male thread and fastening a nut at the connection part.

FIG. 3 is a schematic explanatory diagram showing an example of the configuration of the hanging member 33, and is an enlarged illustration of the broken line portion in FIG. As an example, as shown in FIG. 3, the hanging material 33 may be comprised of an upper hanging material 33a connected to the shoring 30 and a lower hanging material 33b connected to the precast slab 20. A fixing device 34 may be provided at the upper end of the lower hanging member 33b. A similar fixing device (not shown in FIG. 3) may also be provided at the lower end of the lower hanging member 33b. As shown in FIG. 3, the upper hanging member 33a and the lower hanging member 33b may be connected by a joint 35 including a nut 35a and a P connector 35b.

Further, when the precast slab 20 is suspended by the shoring 30, the lower end of the hanging member 33 and the precast slab 20 or the reinforcing member 27 are connected. The connection means is arbitrary, and for example, the reinforcing member 27 may be formed with a hole, and a nut (not shown) and a male thread may be screwed together through the hole.

A reinforcing steel structure 40 is constructed above the precast slab 20. This reinforcing bar structure 40 includes a plurality of main reinforcing bars 44 installed in parallel to the width direction of the precast slab 20, a plurality of distribution bars 42 installed in a direction intersecting (for example, perpendicular to) the main reinforcing bars 44, including. Here, at least a portion of the hanging member 33 may be moored to one or both of the main reinforcing bars 44 and the distribution bars 42. Note that this reinforcing bar structure 40 may be manufactured in advance off-site. "Off-site" indicates a location different from the installation location, and is a concept that excludes the installation location itself. That is, the statement "manufactured off-site" includes, for example, manufacturing in a factory or near the installation location.

Above the precast slab 20, a cast-in-place concrete section 50 is constructed by pouring concrete so as to bury at least a portion of the hanging member 33 and the reinforcing steel structure 40. As shown in FIG. 2, when constructing the cast-in-place concrete section 50, at least a portion of the hanging member 33 and the reinforcing steel structure 40 are buried inside, and concrete is also placed on the upper part of the shoulder section 12. For example, concrete may be placed so that its upper surface position coincides with the upper end of the top portion 14 in the height direction.

The top plate structure 1 is configured as described above with reference to FIGS. 1 to 3. In addition, in the top slab structure 1, the shoring 30 shown in FIG. 2 is used in the construction process, and the precast slab 20 is suspended. However, after the final top slab structure 1 is constructed, this shoring 30 is removed. The shoring 30 may be removed, for example, by disconnecting the upper hanging member 33a and the lower hanging member 33b via the joint 35.

<How to construct the top plate structure>
Next, a method of constructing the top plate structure 1 explained above will be explained. 4 to 10 are process diagrams for constructing the top plate structure 1 by applying the method for constructing a slab-like member according to the embodiment of the present invention, and the steps are performed in the order from FIG. 4 to FIG. 10. Ru. 4 to 10, for the purpose of explanation, (a) shows a schematic plan view, (b) shows a schematic side sectional view, and (c) shows an AA sectional view. In FIG. 10, (d) shows a BB sectional view.

First, as shown in FIG. 4, a pair of support members 10 (10a, 10b), which are, for example, side walls of a culvert, are constructed. The support member 10 is constructed to include a shoulder portion 12 and a top portion 14, and reinforcing bars 15 may be embedded therein. Note that the support member 10 may be a member (so-called precast member) manufactured in advance at a factory or the like, or may be constructed by casting on site.

As shown in FIG. 5, by mounting the widthwise ends of the precast slabs 20 on the shoulders 12 of each of the pair of support members 10 (10a, 10b), the precast slabs 20 are mounted on the supporting members 10 facing each other. It is passed over. For example, as shown in FIG. 5(a), a plurality of precast slabs 20 may be installed in the length direction of the culvert, and in this case, the reinforcing material 27 is placed in the gap formed between the adjacent tops 14. The precast slab 20 may be installed as shown in FIG.

Further, as shown in FIGS. 5(c) and 5(d), distribution bars 28 extending in the width direction of the precast slab 20 are embedded in the precast slab 20 so that their ends protrude from the precast slab 20. It's okay if it's done. When a plurality of precast slabs 20 are installed, adjacent precast slabs 20 may be integrally configured by connecting distribution reinforcements 28 to each other, for example, by a joint structure. The specific structure of the joint structure is arbitrary, and may be, for example, a loop joint, a mechanical joint, a half-flap joint, or the like.

As shown in FIG. 6, the shoring 30 is installed above the precast slab 20 so as to span over the tops 14 of the pair of support members 10 (10a, 10b). At this time, a spacer 31 may be installed between the support 30 and the top 14 to adjust the height of the support 30.

Then, as shown in FIG. 7, a plurality of hanging members 33 are installed extending downward from the shoring 30. For example, the hanging member 33 has its upper end connected to the shoring 30, and its lower end connected to the main body of the precast slab 20 or the reinforcing member 27, thereby firmly suspending the precast slab 20. Note that FIG. 7 shows a configuration in which the hanging member 33 and the reinforcing member 27 are connected.

The means for connecting the shoring 30 and the hanging member 33 is arbitrary. For example, the upper end of the hanging material 33 is machined with a male thread, a hole is drilled in the shoring 30, and a nut (not shown) and the male thread are screwed together through the machined hole to connect the material. Also good. Further, for example, in the configuration described with reference to FIG. 3, the upper hanging member 33a may be connected to the shoring 30 in a similar manner.

Moreover, the means for connecting the hanging material 33 and the precast slab 20 is arbitrary. For example, the lower hanging member 33b described with reference to FIG. 3 may be buried in the precast slab 20 in advance. The precast slab 20 may be suspended by connecting the upper hanging member 33a and the lower hanging member 33b configured in this manner with the joint 35.

When the precast slab 20 is suspended by the shoring 30 via the hanging material 33, the suspended precast slab 20 is moved up and down at the connection point between the shoring 30 and the hanging material 33. You can also adjust your posture. The vertical movement of the hanging member 33 may be performed, for example, by tightening or loosening a nut used as a means for connecting the shoring 30 and the hanging member 33.

Then, as shown in FIG. 8, a reinforcing steel structure 40 is constructed above the precast slab 20. At this time, at least a portion of the hanging material 33 may be moored to one or both of the distribution bars 42 and the main reinforcing bars 44 that constitute the reinforcing bar structure 40. The reinforcing structure 40 may be constructed on-site or may be pre-fabricated and installed off-site.

Then, as shown in FIG. 9, concrete is placed and cured so as to bury at least a portion of the hanging members 33 and the reinforcing steel structure 40, thereby forming a cast-in-place concrete section 50 (dashed line in the figure). (see section). As illustrated, concrete may be placed and cured so that the height of the top of the cast-in-place concrete portion 50 matches the height of the top of the top 14 of the support member 10.

Then, as shown in FIG. 10, at least a portion of the shoring 30 and the hanging member 33 are separated, and the shoring 30 is removed (see the broken line in the figure). To remove the shoring 30, for example, in a configuration in which the upper hanging member 33a and lower hanging member 33b shown in FIG. It may be done.

By the construction method described above with reference to FIGS. 4 to 10, the top slab structure 1 as a slab-like member consisting of the precast slab 20 and the cast-in-place concrete portion 50 is constructed.

<Precast slab composition>
The precast slab 20 may be a member manufactured in advance at a factory or the like, and its configuration is arbitrary. That is, the configuration is not limited as long as the lower ends of the hanging members 33 (the lower ends of the lower hanging members 33b) can be connected and hung. An example of the configuration of the precast slab 20 will be described below with reference to FIG. 11. FIG. 11 is a schematic explanatory diagram showing an example of the configuration of the precast slab 20, and both (a) and (b) are cross-sectional views in the width direction.

As shown in FIG. 11(a), as an example of the structure of the precast slab 20, the lower end of the hanging material 33 may be buried inside, and a protrusion 22 that protrudes upward from the precast slab 20 is provided at the buried location. You may have one. By providing the projections 22, it is possible to improve fixing efficiency and pull-out strength when embedding the hanging material 33 in the precast slab 20. Further, as shown in the figure, one or more main reinforcing bars 24 extending in a direction (longitudinal direction) perpendicular to the distribution bars 28 may be buried inside the precast slab 20. Thereby, the strength of the precast slab 20 itself can be improved.

Further, as shown in FIG. 11(b), as an example of the configuration of the precast slab 20, a steel plate 25 may be installed on the lower surface thereof. In addition, the hanging material 33 embedded in the precast slab 20 may be joined to the steel plate 25. Thereby, in addition to improving the fixing efficiency of the hanging material 33, it is possible to suppress or allow the occurrence of cracks in the precast slab 20.

In addition, in manufacturing the precast slab 20, for example, FRC (Fiber Reinforced Concrete) may be used. Thereby, the strength and toughness of the precast slab 20 itself can be increased. For example, if the precast slab 20 is reinforced with the reinforcing material 27 and the above-mentioned FRC and has sufficient bending rigidity against the construction load before concrete placement, the following construction procedure may be adopted. You can also do it. That is, after installing the precast slab 20, the reinforcing structure 40 is constructed, and then the shoring 30 is installed to connect the hanging material 33 with the main body of the precast slab 20 or the reinforcing material 27, and the concrete is placed on the site. A poured concrete portion 50 may also be configured.

When constructing the reinforcing bar structure 40 with the shoring 30 installed as described above with reference to FIGS. 4 to 10, the work is performed with the upper portion partially closed. Therefore, depending on the structural conditions, there is a concern that work efficiency may decrease. On the other hand, according to the procedure of installing the shoring 30 after constructing the reinforcing bar structure 40, the reinforcing bar structure 40 can be constructed with the upper part open, which improves work efficiency such as carrying in materials and assembling reinforcing bars. .

<Connection of precast slab and hanging material>
In the method for constructing the top slab structure 1 described above, an important step is the suspension of the precast slab 20 by the shoring 30 via the hanging members 33 described with reference to FIG. The connecting means and its configuration during hanging are not particularly limited as long as they can reliably connect the hanging material 33 and the precast slab 20. Here, an example of a means for connecting the precast slab 20 and the hanging member 33 and its configuration will be described.

FIG. 12 is a schematic explanatory diagram regarding the connection between the precast slab 20 and the hanging member 33, and schematically illustrates the configuration of the connection. As shown in FIG. 12, various configurations can be considered when connecting the lower end of the hanging member 33 (the lower end of the lower hanging member 33b) to the precast slab 20.

For example, the structure has a fixing device 32 at the lower end of the hanging member 33 (lower end of the lower hanging member 33b), and the lower end of the hanging member 33 including the fixing device 32 is directly attached to a precast slab as shown in FIG. 12(a). 20 may be buried. Thereby, the fixing efficiency and pull-out strength of the hanging material 33 to the precast slab 20 can be improved.

Alternatively, for example, as shown in FIG. 12(b), an insert 36 may be embedded in the precast slab 20, and the lower end of the threaded hanging member 33 may be connected to the insert 36 for connection.

Alternatively, for example, as shown in FIG. 12(c), a notch 37 is formed in the precast slab 20, a hanging member 33 having a fixing member 32 at the lower end is inserted into the notch 37, and the grout 38 is filled. You may do so.

Alternatively, for example, as shown in FIG. 12(d), a steel pipe 39 is installed on the precast slab 20, and a hanging member 33 having a fixing member 32 at the lower end is inserted into the steel pipe 39 and then connected by filling it with grout 38. Also good.

<Shoring structure>
As mentioned above, the support 30 is exemplified by H-beam steel, and the support 30 is connected to the suspension member 33 by drilling a hole in the support 30 and providing a male screw at the upper end of the suspension member 33. This is done by machining a male screw and tightening a nut at the connecting part between the workpiece 30 and the hanging member 33. However, the present invention is not limited to this, and various configurations can be considered for the configuration of the shoring 30 and the connection configuration with the upper end of the hanging member 33.

FIG. 13 is a schematic cross-sectional view when channel steel is used as the shoring 30. As shown in FIG. 13, the shoring 30 is made up of two channel steels 30a and 30b, a hanging member 33 is installed between the two channel steels 30a and 30b, and a fixing plate 60 and a nut 61 are installed. The hanging material 33 may be joined by. This reduces the amount of drilling required.

Further, in installing the shoring 30, a frame 70 made of, for example, H-shaped steel may be interposed between the shoring 30 and the top portion 14. FIG. 21 is a schematic diagram when the shoring 30 is installed between the shoring 30 and the top part 14 via the frame 70. For example, by installing the pedestal 70 so as to straddle the adjacent crests 14 and installing the shoring 30 on the pedestal 70 at the center position between the spans of the adjacent crests 14, the installation interval between the adjacent crests 14 can be designed to be large. I can do it.

<Effect>
According to the construction method of the top slab structure 1 as a slab-like member explained above, in the step of suspending the precast slab 20 using the shoring 30, the hanging material 33 is used, and at least a portion of the hanging material 33 is is buried in the cast-in-place concrete part 50. Thereby, in the top slab structure 1, at least a portion of the hanging member 33 functions as a shear reinforcing bar. That is, sufficient shear strength is ensured in the top slab structure 1 as a slab-like member consisting of the precast slab 20 and the cast-in-place concrete portion 50.

Furthermore, in the top slab structure 1, by allowing the hanging members 33 to function as shear reinforcing bars, there is no need to separately arrange shear reinforcing bars, thereby improving workability and shortening the construction period in reinforcing bar work. In addition, the reinforcing bar construction workability is improved by unitizing the reinforcing bar structure 40 by prefabricating it off-site.

Moreover, when suspending the precast slab 20 via the hanging material 33 using the shoring 30, in the connection between the precast slab 20 and the hanging material 33, and the connection between the shoring 30 and the hanging material 33, By using various connection configurations as described with reference to FIGS. 11 to 13, fixing efficiency and pull-out strength can be improved.

Although an example of the embodiment of the present invention has been described above, the present invention is not limited to the illustrated embodiment. It is clear that those skilled in the art can come up with various changes or modifications within the scope of the idea described in the claims, and these naturally fall within the technical scope of the present invention. It is understood that

For example, in the above embodiment, a configuration using the joint 35 as an example of a connecting means between the upper hanging member 33a and the lower hanging member 33b has been described, but the connecting means is not limited to this. That is, as the connection means, the connection may be made by a penetrating fixing body and a mechanical joint, and a box cutout using a nut and foamed polystyrene may be used. Further, a turnbuckle may be used to eliminate rattling during connection.

In the above embodiment, the configuration of the hanging member 33 is shown in FIG. 3 in which the upper hanging member 33a and the lower hanging member 33b are connected by the joint 35, but the configuration of the hanging member 33 is limited to this. It's not something you can do. FIG. 22 is a schematic explanatory diagram showing another example of the structure of the hanging member 33, in which (a) is an overhead view and (b) is a side view. Note that in FIG. 22, components having the same functional configuration as those in the above embodiment are illustrated with the same reference numerals, and explanations thereof may be omitted.

As shown in FIG. 22, the hanging member 33 includes, for example, a hook-shaped upper hanging member 33c made of non-metal and a hook-shaped lower hanging member 33d made of bamboo-knotted reinforcing bars or screw-knotted reinforcing bars. It's okay. The hook-shaped upper hanging member 33c and the hook-shaped lower hanging member 33d are configured so that they can be locked and connected while facing each other in the height direction. As illustrated, the hook-shaped upper hanging member 33c and the hook-shaped lower hanging member 33d may be connected via the distribution bars 42 of the reinforcing bar structure 40.

When constructing the top slab structure 1, the hook-shaped upper hanging member 33c may be left in place, or may be cut at the upper surface position of the cast-in-place concrete portion 50. Since the hook-shaped upper hanging member 33c is made of non-metal, anti-rust treatment or the like is not necessary. By configuring the hanging member 33 in this manner, there is no need to remove the hook-shaped lower hanging member 33d or to bury the box when using a box cutter, thereby saving labor.

<Other embodiments of the present invention>
In the embodiment described above, the top plate structure 1 constructed by the method for constructing a slab-like member according to the present invention has been illustrated and described as an example, but the scope of application of the present invention is not limited to this. Specifically, it can also be applied when constructing a beam as a slab-like member. Hereinafter, as another embodiment of the present invention, a method of constructing a beam using the method of constructing a slab-like member according to the present invention will be described with reference to the drawings. In addition, in the following description of other embodiments, components having the same functional configuration as those of the above embodiment are illustrated with the same reference numerals, and the description thereof may be omitted.

14 to 20 are process diagrams for constructing the beam 100 by applying the method for constructing a slab-like member according to the present invention, and the steps are performed in the order from FIG. 14 to FIG. 20. 14 to 20, for the sake of explanation, (a) shows a schematic plan view, (b) shows a schematic side sectional view, and (c) shows an AA sectional view, and furthermore, FIGS. In FIG. 10, (d) shows a BB sectional view.

First, as shown in FIG. 14, support members 110 (110a, 110b, 110c, 110d) as pillar members are constructed. The arrangement of the support members 110 is arbitrarily designed depending on the structure of the beam 100. In this embodiment, a case is illustrated in which a beam 100 having a substantially rectangular shape in plan view is constructed, and in that case, support members 110 are arranged at four locations on all sides. Support member 110 is constructed to include a shoulder 112 and a top 114 disposed thereon. A reinforcing bar 115 that projects upward may be embedded in the peripheral edge of the shoulder portion 112. Note that the support member 110 may be a member manufactured in advance at a factory or the like (so-called precast member), or may be constructed by casting on site.

Then, as shown in FIG. 15, by mounting the width direction ends of the precast slabs 20 on the opposing shoulders 112 of the supporting members 110 (110a, 110b, 110c, 110d), the precast slabs 20 are supported by opposing supports. It is spanned over member 110. For example, as shown in FIG. 15(a), four precast slabs 20 may be spanned in a substantially rectangular shape. Here, the reinforcing materials 27 included in adjacent precast slabs 20 may be connected to each other at the intersection 128 by means such as welding.

As shown in FIG. 16, the shoring 30 is installed above the precast slab 20 so as to span over the tops 14 of the support members 110 (110a, 110b, 110c, 110d). At this time, a spacer 31 may be installed between the support 30 and the top portion 114 to adjust the height of the support 30.

Then, as shown in FIG. 17, a plurality of hanging members 33 are installed extending downward from the shoring 30. For example, the hanging member 33 has its upper end connected to the shoring 30, and its lower end connected to the main body of the precast slab 20 or the reinforcing member 27, thereby firmly suspending the precast slab 20. Note that FIG. 17 illustrates a configuration in which the hanging member 33 and the reinforcing member 27 are connected. The means for connecting the shoring 30 and the hanging material 33 and the means for connecting the hanging material 33 and the precast slab 20 are arbitrary, and the connection may be performed in the configuration described in the above embodiment.

Then, as shown in FIG. 18, a reinforcing steel structure 40 is constructed above the precast slab 20. At this time, as in the above embodiment, at least a portion of the hanging member 33 may be moored to the reinforcing steel structure 40. The reinforcing structure 40 may be constructed on-site or may be pre-fabricated and installed off-site.

Then, as shown in FIG. 19, concrete is placed and cured so as to bury at least a portion of the hanging members 33 and the reinforcing steel structure 40, thereby forming a cast-in-place concrete section 50 (dashed line in the figure). (see section). As illustrated, concrete may be placed and cured so that the height of the top of the cast-in-place concrete portion 50 matches the height of the top of the top portion 114.

Then, as shown in FIG. 20, at least a portion of the shoring 30 and the hanging member 33 are separated, and the shoring 30 is removed (see the broken line in the figure). As described in the above embodiment, the shoring 30 may be removed by, for example, disconnecting the joint 35 and removing the nuts 35a and the P connectors 35b.

By the construction method described above with reference to FIGS. 14 to 20, the beam 100 as a slab-like member consisting of the precast slab 20 and the cast-in-place concrete portion 50 is constructed. As described above, by applying the method for constructing a slab-like member according to the present invention to a beam/column structure, when constructing the beam 100, it is possible to improve workability and shorten the construction period in the same manner as in the above embodiment. can be achieved.

Further, the effects described in this specification are merely explanatory or illustrative, and are not limiting. In other words, the technology according to the present disclosure can have other effects that are obvious to those skilled in the art from the description of this specification, in addition to or in place of the above effects.

Note that the following configurations also belong to the technical scope of the present invention.
(1) A method for constructing a half precast concrete slab-like member consisting of a precast slab and cast-in-place concrete and mounted across a pair of supporting members, the widthwise end of the precast slab being mounted on the pair of supporting members. a step of suspending the precast slab via a hanging member extending downward from the shoring by a shoring strung above the precast slab; a step of constructing a structure; a step of pouring and curing cast-in-place concrete on top of the precast slab so as to bury at least a portion of the hanging material and the reinforcing steel structure; and removing the shoring, wherein the hanging material embedded in the cast-in-place concrete in the slab-like member functions as a shear reinforcement. Construction method.
(2) The precast slab is reinforced by a reinforcing material embedded in the precast slab, and in the step of suspending the precast slab, the lower end of the hanging material is connected to the reinforcing material or the precast slab. The method for constructing a slab-like member according to (1).
(3) The upper end of the hanging material is machined with a male thread, and in the process of suspending the precast slab, a nut is screwed into the male screw at the connecting part between the shoring and the hanging material. The method for constructing a slab-like member according to (1) or (2), characterized in that the posture of the precast slab is adjusted by moving the hanging member up and down by tightening and loosening it.
(4) The hanging material has a structure in which an upper hanging material connected to the shoring and a lower hanging material connected to the precast slab are connected by a joint, and the hanging material is connected to the shoring by a joint. Construction of the slab-like member according to any one of (1) to (3), characterized in that in the step of removing, the lower hanging member is separated from the support by removing the joint. Method.
(5) The method for constructing a slab-like member according to (4), characterized in that fixing devices are provided at the upper and lower ends of the lower hanging member.
(6) The support member includes a shoulder portion and a top portion extending upward from the shoulder portion, the widthwise end portion of the precast slab is mounted on the shoulder portion, and the shoring member is provided with a The method for constructing a slab-like member according to any one of (1) to (5), characterized in that the method is mounted so as to span over the top of the support member.
(7) The slab-like member according to any one of (1) to (6), wherein the supporting member is a wall of a culvert, and the slab-like member is a top plate of the culvert. Construction method.
(8) The method for constructing a slab-like member according to any one of (1) to (6), wherein the supporting member is a column and the slab-like member is a beam.
(9) The reinforcing bar structure includes main reinforcing bars installed parallel to the width direction of the precast slab, and distribution bars installed in a direction intersecting the main reinforcing bars, and the hanging material includes the The method for constructing a slab-like member according to any one of (1) to (8), characterized in that the slab-like member is moored to one or both of the main reinforcement and the distribution reinforcement.
(10) A plurality of the precast slabs are mounted adjacent to each other, and the precast slab has distribution bars extending in the width direction of the precast slab such that the ends of the distribution bars protrude from the precast slab. In the plurality of precast slabs, the distribution bars of the adjacent precast slabs are connected by joints, and in the process of pouring and curing the cast-in-place concrete, the adjacent precast slabs are also The method for constructing a slab-like member according to any one of (1) to (7), characterized in that concrete placement is performed including concrete placement.
(11) The supporting member is a wall of the culvert, the slab-like member is a top plate of the culvert, and the plurality of precast slabs are installed in the longitudinal direction of the culvert. The method for constructing a slab-like member according to (10).

The present invention can be applied to a construction method for constructing a slab-like member made of half precast concrete.

1...Top plate structure 10...Supporting member 12...Shoulder part 14...Top part 15...Reinforcement bar 20...Precast slab 27...Reinforcement material 28...Distribution bar (of precast slab) 30...Shoring 33...Hanging material 34...Fixing tool 35...Joint 40...Reinforcement structure 42...Distribution bar 44...Main reinforcing bar 50...Cast-in-place concrete part 100...Beam

Claims (11)

A method for constructing a half-precast concrete slab-like member that is composed of a precast slab and cast-in-place concrete and is mounted across a pair of supporting members, the method comprising:
a step of mounting the width direction end portions of the precast slab on the pair of support members;
a step of suspending the precast slab via a hanging member extending downward from the shoring by a shoring strung above the precast slab;
constructing a reinforcing structure above the precast slab;
pouring and curing cast-in-place concrete on top of the precast slab so as to bury at least a portion of the hanging material and the reinforcing structure;
Separating the hanging material from the shoring and removing the shoring,
A method of constructing a slab-like member, wherein the hanging material embedded in the cast-in-place concrete in the slab-like member functions as a shear reinforcing bar. The precast slab is reinforced by a reinforcing material embedded in the precast slab,
2. The method of constructing a slab-like member according to claim 1, wherein in the step of suspending the precast slab, a lower end of the hanging member is connected to the reinforcing member or the precast slab. The upper end of the hanging material is machined with a male thread, and in the process of suspending the precast slab, a nut that is threaded onto the male screw is tightened or loosened at the connecting portion between the shoring and the hanging material. 3. The method of constructing a slab-like member according to claim 1, wherein the hanging member is raised and lowered to adjust the attitude of the precast slab. The hanging material has a structure in which an upper hanging material connected to the shoring and a lower hanging material connected to the precast slab are connected by a joint,
3. The method for constructing a slab-like member according to claim 1, wherein in the step of removing the support, the lower hanging member is separated from the support by removing the joint. 5. The method of constructing a slab-like member according to claim 4, further comprising fixing devices at the upper and lower ends of the lower hanging member. The support member includes a shoulder and a top extending upward from the shoulder,
a widthwise end of the precast slab is mounted on the shoulder;
3. The method for constructing a slab-like member according to claim 1, wherein the shoring is mounted so as to span over the tops of the pair of support members. 3. The method of constructing a slab-like member according to claim 1, wherein the support member is a wall of a culvert, and the slab-like member is a top plate of the culvert. 3. The method of constructing a slab-like member according to claim 1, wherein the supporting member is a column, and the slab-like member is a beam. The reinforcing bar structure includes main reinforcing bars installed in parallel to the width direction of the precast slab, and distribution bars installed in a direction intersecting the main reinforcing bars,
3. The method of constructing a slab-like member according to claim 1, wherein the hanging member is moored to one or both of the main reinforcing bars and the distribution bars. A plurality of the precast slabs are mounted adjacent to each other,
A distribution bar extending in the width direction of the precast slab is embedded in the precast slab such that an end of the distribution bar protrudes from the precast slab,
In the plurality of precast slabs, the distribution bars of the adjacent precast slabs are connected by joints, and in the process of pouring and curing the cast-in-place concrete, concrete is poured between the plurality of adjacent precast slabs as well. The method for constructing a slab-like member according to claim 1 or 2, characterized in that: 10. The supporting member is a wall of the culvert, the slab-like member is a top plate of the culvert, and the plurality of precast slabs are installed in the longitudinal direction of the culvert. A method for constructing a slab-like member as described in .

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