JP2024004957A - Structure construction method and structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of building structures that is easy to construct, etc.

SOLUTION: A bundle of PC steel stranded wires 31 is passed through a wall body 2 of a tank, and its lower end is inserted into the inside of a fixing member 11, which is provided in a foundation plate 1 of the tank and has a hollow expanding portion 111 that expands downward. The fixing member 11 is then filled with hardening material 4a, the lower end of PC steel 3 consisting of a plurality of PC steel stranded wires 31 is fixed to the fixing member 11, and the PC steel 3 is tensed to fix its upper end to the wall body 2. At the lower end of the PC steel 3, a fixing body 32 is provided on the PC steel stranded wires 31 and the height of the fixing body 32 varies depending on the PC steel strands 31.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a method for constructing a structure, a structure, and the like.

As a method of introducing longitudinal prestress into the tank wall, the lower end of the multi-strand passed through the sheath inside the wall is fixed to a fixing member provided on the base plate of the tank, and then the multi-strand is tensioned. It is known to fix the upper end to a wall.

Multi-strand is a bundle of multiple PC steel strands. Patent Document 1 discloses an example of the above-described fixing member, in which stranded PC steel wires each having a fixing body at the lower end are inserted one by one into a flask-shaped fixing member having an enlarged diameter portion, and then fixed. A hardening material is filled into the member to fix the lower end of the multi-strand.

Patent No. 3215381

The diameter of the fixing body is increased relative to the PC steel strands, and the diameter of the lower end of the multi-strand, which is a bundle of PC steel strands, is increased by the fixing body of each PC steel strand. Therefore, if you try to insert multiple PC steel strands that make up a multi-strand into a fixing member all at once, you will need a fixing member with a large opening diameter, a large diameter sheath, etc. The quantity also increases.

The reason why the PC steel strands are inserted one by one into the fixing member in Patent Document 1 is mainly for the above reasons. However, inserting the PC steel strands one by one into the fixing member is time-consuming and reduces construction efficiency.

The present invention has been made in view of the above-mentioned problems, and its purpose is to provide a method for constructing a structure that is easy to construct.

A first invention for achieving the above-mentioned object is to pass a bundle of tendons through an upper member of a structure, and connect the lower end of the bundle to a hollow which is provided in the lower member of the structure and expands in diameter downward. (a) inserting the fixing member into the fixing member having an enlarged diameter portion, filling the fixing member with a hardening material, fixing the lower end portion of the prestressed steel material made of the plurality of tendons to the fixing member; (b) tensioning a prestressing steel material and fixing its upper end to the upper member, wherein a fixing body is provided on the tensioning material at a lower end of the prestressing steel material, and the height of the fixing body is set to the height of the fixing body. This is a method of constructing a structure that differs depending on the tension material.

In the first invention, by inserting a bundle of a plurality of tendons into the fixing member, construction efficiency is improved compared to the case where the tendons are inserted one by one. In addition, at the lower end of the PC steel material, anchors are provided at different heights for each tendon, compared to conventional multi-strands in which anchors are provided at the same height at the lower end of each tendon. The diameter of the tendon bundle becomes smaller, and even if the opening diameter of the fixing member and the diameter of the sheath are made smaller, there will be no obstruction during insertion, and the amount of hardening material can also be reduced, making construction easier. Furthermore, since the fixing bodies can be arranged within the fixing member with their relative positions fixed, quality control is also easy.

For example, the upper member is the wall of the tank and the lower member is the base plate of the tank.
Using the method of the present invention, it is possible to easily construct a tank in which prestress is introduced into the wall.

In step (a), it is preferable that all the bundles of tendons constituting the prestressing steel material be passed through the structure, and their lower ends inserted into the fixing member.
In this way, by inserting all the tendons at once, construction can be completed in a short time. Moreover, when the tendons are inserted one by one, there is a risk that the tendon material inserted later will become entangled with the tendon material inserted earlier, making it impossible to insert the tendon material, but such a risk can be avoided.

A second invention is such that a prestressed steel material made of a plurality of tendons is passed through an upper member of a structure, and a lower end of the prestressed steel material is attached to a hollow hole provided in the lower member of the structure whose diameter increases downward. the fixing member is filled with a hardening material, the upper end of the prestressed steel material is fixed to the upper member under tension, and the lower end of the prestressed steel material is This is a structure characterized in that the tension member is provided with a fixing body, and the height of the fixing body differs depending on the tension member.

According to the present invention, it is possible to provide a method for constructing a structure that is easy to construct.

A diagram showing a tank 10. FIG. 3 is a diagram illustrating a method of constructing a tank 10. FIG. 3 is a diagram showing a cross section of PC steel material 3. The figure which shows the cross section when the fixing body 32 is provided in each PC steel strand 31 at the same height. FIG. 3 is a diagram showing a fixing member 11a. FIG. 7 is a diagram showing a projection 116. A diagram showing a leaf spring 34. FIG. 3 is a diagram showing a PC steel strand 31 and its fixing body 32 constituting a PC steel material 3;

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

(1. Tank 10)
FIG. 1(a) is a diagram showing a tank 10, which is a structure constructed by a construction method according to an embodiment of the present invention.

In the tank 10, a cylindrical wall body 2, which is an upper member, is provided on a disk-shaped foundation plate 1, which is a lower member, and a steel roof 5 is provided at the upper end of the wall body 2. The foundation plate 1 and the wall 2 are constructed of concrete.

A longitudinal prestressing steel material 3 is passed through the wall 2, thereby introducing longitudinal prestress into the wall 2. The PC steel material 3 is a multi-strand made by bundling a plurality of PC steel strands as tendons, and a plurality of PC steel materials 3 are provided at intervals in the circumferential direction of the wall body 2. Although not particularly shown in the drawings, a circumferential prestressing steel material is also arranged within the wall 2, and thereby a prestress in the circumferential direction is also introduced into the wall 2.

FIG. 1(b) is a diagram schematically showing a vertical cross section of the wall 2 in the thickness direction. The PC steel material 3 is passed through a sheath 21 provided inside the wall 2, and its lower end is inserted into the fixing member 11 provided inside the base plate 1. The fixing member 11 and the sheath 21 are filled with hardening materials 4a, 4b (4) such as mortar. The upper end of the PC steel material 3 is fixed onto the wall 2 by the fixing part 33 in a tensioned state.

(2. How to construct tank 10)
When constructing the tank 10, first, a foundation 1 is constructed as shown in FIG. 2(a), and then a wall 2 is constructed on the foundation 1.

The base plate 1 is constructed with the fixing member 11 buried therein, and the wall body 2 is constructed with the sheath 21 buried therein. The upper end of the fixing member 11 communicates with the lower end of the sheath 21.

In this embodiment, a known rib cast anchor is used as the fixing member 11. The rib cast anchor includes a hollow enlarged diameter portion 111 whose diameter expands downward into a flask shape, and a cap 114 provided so as to be continuous from the lower end of the enlarged diameter portion 111. The cap 114 is a cylindrical hollow member with a closed bottom. A ring-shaped rib 115 is formed on the outer periphery of the enlarged diameter portion 111 and projects outward from the outer periphery.

The fixing member 11 is embedded from the upper surface of the base plate 1 with a predetermined cover thickness D. This makes it possible to firmly fix the fixing member 11 within the base plate 1 and prevent the fixing member 11 from being pulled out when bending or tension occurs in the wall 2 of FIG. 1(b).

Note that an injection hole 12 for injecting the hardening material 4a into the fixing member 11 and an overflow pipe 13 for discharging the hardening material 4a from the inside of the fixing member 11 are also provided in advance in the base plate 1. The injection hole 12 communicates the outer surface of the base plate 1 with the lower end of the cap 114, and the overflow pipe 13 communicates the outer surface of the base plate 1 with the vicinity of the upper end of the enlarged diameter portion 111. The injection hole 12 and the overflow pipe 13 are formed by a hose or the like.

After constructing the foundation plate 1 and wall 2 as shown in FIG. 2(a), the PC steel material 3 is passed through the sheath 21 and its lower end is inserted into the fixing member 11, as shown in FIG. 2(b). .

At the lower end of the PC steel material 3, each PC steel strand 31 is provided with an anchor 32. The fixing body 32 is a portion whose diameter is enlarged with respect to the PC steel strands 31, and a crimp grip or the like is used, for example.

In this embodiment, the heights of the fixing bodies 32 of these PC steel strands 31 vary depending on the PC steel strands 31, and the fixing bodies 32 are distributed and arranged at different heights at the lower end of the PC steel material 3.

In this embodiment, all the PC steel strands 31 constituting the PC steel material 3 are tied together with a cable tie (not shown) or the like, and passed through the sheath 21 from above the wall 2 in a bundle. The lower end portion is inserted into the fixing member 11 .

Thereafter, as shown in FIG. 2C, the fixing member 11 is filled with a hardening material 4a such as mortar, and the lower end portion of the PC steel material 3 is fixed to the fixing member 11 by hardening of the hardening material 4a. It is confirmed that the hardening material 4a is injected into the fixing member 11 through the injection hole 12, and that the hardening material 4a is discharged from the overflow pipe 13. This ensures that the curing material 4a is filled up to the vicinity of the upper end of the fixing member 11.

After fixing the lower end of the prestressed steel material 3 in this way, the prestressed steel material 3 is tensioned and its upper end is fixed onto the wall 2 by the fixing part 33 (see FIG. 1(b)). Then, as shown in FIG. 2(d), the hardening material 4b is filled into the sheath 21. Reference numeral 22 in FIGS. 2(a) to 2(d) is an injection hole for injecting the hardening material 4b into the sheath 21, and is formed by a hose or the like. In the examples shown in FIGS. 2(a) to 2(d), the injection hole 22 is provided in the base plate 1, but it may also be provided in the wall 2.

Thereafter, by installing necessary members such as the steel roof 5, the tank 10 shown in FIG. 1(a) is constructed.

(3. Diameter of PC steel material 3)
3(a) to 3(d) are diagrams showing cross sections of the PC steel material 3 at heights H1 to H4 in FIG. 2(b), respectively. In this embodiment, the PC steel material 3 is a bundle of 19 PC steel strands 31 (see FIG. 3(a)), and the fixing body 32 for six of these PC steel strands 31 is arranged in the upper stage ( (See Fig. 3(b)), the fixing bodies 32 for the seven PC steel strands 31 are arranged in the middle stage (see Fig. 3(c)), and the fixing bodies 32 for the remaining six PC steel strands 31 are arranged in the lower stage. (See Figure 3(d)).

By arranging the fixing bodies 32 in a distributed manner in the height direction in this manner, it is possible to prevent the diameter of the PC steel material 3 from increasing. That is, the radius R1 to R4 of the circumscribed circle at each height H1 to H4 of the PC steel material 3 of this embodiment, as shown in FIG. It is smaller than the radius R of the circumscribed circle if they are the same.

As a result, the PC steel material 3 of this embodiment can be easily inserted into the fixing member 11, and even if the diameter of the opening at the upper end of the fixing member 11 is made small, it will not become an obstacle during insertion. For example, the opening at the upper end of the fixing member 11 has a size that includes the circumscribed circle at each height H1 to H4 of the PC steel material 3 shown in FIGS. 3(a) to 3(d); It can be made smaller than the circumscribed circle of the PC steel stranded wire 31. Furthermore, the sheath 21 can also be made smaller in diameter, and the amount of the required hardening materials 4a, 4b (4) can also be reduced. Although not shown in FIGS. 1 to 3, at the lower end of the PC steel material 3, each PC steel strand 31 may be passed through each hole of a plate having a plurality of holes. As a result, the interval between the PC steel strands 31 is fixed, and the shape of the PC steel material 3 is maintained.

As explained above, in this embodiment, by inserting a bundle of a plurality of PC steel strands 31 into the fixing member 11, construction efficiency is improved compared to the case where PC steel strands 31 are inserted one by one. improves. Furthermore, at the lower end of the PC steel material 3, since the fixing bodies 32 are provided at different heights for each PC steel stranded wire 31, the fixing bodies 32 are provided at the same height at the lower end of each PC steel stranded wire 31. Compared to the conventional multi-strand, the diameter of the PC steel strands 31 as a bundle is smaller, and even if the opening diameter of the fixing member 11 and the diameter of the sheath 21 are made smaller, there is no obstacle during insertion, and the hardened material 4a , 4b(4) can also be reduced, making construction easier. Furthermore, since the fixing bodies 32 can be arranged within the fixing member 11 while the relative positions of the fixing bodies 32 are fixed, quality control is also easy.

However, the present invention is not limited to the above embodiments. For example, the fixing member 11 embedded in the base plate 1 may have a hollow diameter-expanding portion 111 that expands downward in diameter, and is not limited to the shape described above. For example, as shown in the fixing member 11a of FIG. 5, the cap 114 may be omitted and the bottom of the enlarged diameter portion 111 may be closed. The injection hole 12 is provided so that the lower end of the enlarged diameter portion 111 and the outer surface of the base plate 1 communicate with each other.

Further, as shown in FIG. 6(a), a conical projection 116 is provided on the bottom surface of the fixing member 11, and as shown in FIG. 6(b), when a bundle of PC steel strands 31 is inserted into the fixing member 11, , the lower end of the bundle may be widened by the protrusion 116 to release the binding band and allow the individual PC steel strands 31 to come apart. This increases the fixing effect of the PC steel strands 31. The shape of the protrusion 116 is not particularly limited as long as it can spread the bundle of the PC steel strands 31. For example, as shown in FIG. 6C, a conical projection 116 with a circular bottom surface or a cone-shaped projection 116 with a star-shaped bottom surface projecting in all directions may be used.

Alternatively, the bundle of PC steel strands 31 may be inserted into the fixing member 11 with a leaf spring 34 exemplified in FIG. 7(a) inserted inside the bundle. The leaf spring 34 is made by rolling a band-shaped steel plate 341, which is an elastic body, into a circle and binding it in that state using a water-soluble binding material 342 such as water-soluble vinylon. As shown in the cross section of FIG. 7(b) corresponding to FIG. 3(d), after inserting the bundle of PC steel strands 31 containing the plate spring 34 into the fixing member 11, water is injected into the fixing member 11. Alternatively, by injecting grout as the hardening material 4a into the fixing member 11, the binding material 342 melts and the steel plate 341 spreads, and as described above, the individual PC steel strands 31 come apart, improving the fixing effect. . The height at which the leaf spring 34 is installed is, for example, the height shown by H4 in FIG. 2(b), but is not particularly limited as long as it is at the lower end of the PC steel material 3.

Furthermore, in the present embodiment, the fixing bodies 32 are arranged in three upper and lower stages in the PC steel material 3, but the number of stages in which the fixing bodies 32 are arranged and the position and number of the fixing bodies 32 in each stage are not limited to this. It can be determined as appropriate depending on the number of lines 31, etc.

In addition, in this embodiment, as shown in FIG. 8(a), the PC steel material 3 is composed of PC steel strands 31 of the same length, and the heights of the upper and lower ends of each PC steel strand 31 are made the same. In this case, the height at which the fixing body 32 is attached to each stranded PC steel wire 31 is changed, but as shown in FIG. In addition, a fixing body 32 may be provided at the lower end of each PC steel strand 31.

Further, in this embodiment, the wall 2 is constructed using cast-in-place concrete, but the wall 2 may be constructed by laminating concrete precast blocks made in advance at a factory or the like on site.

Furthermore, in the present embodiment, in the process shown in FIG. 2(b), all the PC steel strands 31 constituting the PC steel material 3 are bundled and inserted into the fixing member 11 at once, which shortens the construction process. It takes less time, and when inserting the PC steel strands 31 one by one, it is possible to avoid the risk that the later inserted PC steel strands 31 will become entangled with the previously inserted PC steel strands 31 and become impossible to insert. However, the process of bundling a plurality of PC steel strands 31 constituting a part of the PC steel material 3 and inserting them into the fixing member 11 may be repeated.

Furthermore, in the present embodiment, prestress is introduced into the wall 2 of the tank 10 by the PC steel material 3, and thus the tank 10 in which prestress is introduced into the wall 2 can be easily constructed. The structure is not limited to the tank 10, but may include any member that introduces prestress. This member is not limited to walls, and the present invention can be applied to various structures. For example, when temporarily fixing a bridge girder placed on a bridge pier via a rubber bearing, the PC steel material 3 is passed through the bridge girder (upper member) and its lower end is fixed to the fixing member 11 provided on the bridge pier (lower member). It is also possible to tension the steel material 3 and fix its upper end to the bridge girder.

Although preferred embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to such examples. It is clear that those skilled in the art can come up with various changes or modifications within the scope of the technical idea disclosed in this application, and these naturally fall within the technical scope of the present invention. Understood.

1: Basic version 2: Wall body 3: PC steel materials 4, 4a, 4b: Hardened material 5: Steel roof 10: Tanks 11, 11a: Anchoring member 21: Sheath 31: PC steel stranded wire 32: Anchoring body 33: Fixed Part 111: Expanded diameter part 114: Cap

Claims (4)

A process of passing a bundle of tendons through an upper member of a structure and inserting the lower end thereof into an anchoring member having a hollow expanding diameter portion that increases in diameter downward, which is provided in a lower member of the structure. (a) and
Step (b) of filling the fixing member with a hardening material, fixing the lower end of a PC steel material made of a plurality of tension members to the fixing member, and tensioning the PC steel material to fix its upper end to the upper member. )and,
including;
A method for constructing a structure, characterized in that a fixing body is provided on the tendon at a lower end of the prestressing steel material, and the height of the fixing body differs depending on the tendon. 2. The method of constructing a structure according to claim 1, wherein the upper member is a wall of a tank, and the lower member is a foundation plate of the tank. 2. In the step (a), all the bundles of tendons constituting the prestressing steel material are passed through the structure, and their lower ends are inserted into the fixing member. 2. A method for constructing the structure described in 2. A PC steel material consisting of multiple tendons is passed through the upper part of the structure,
The lower end of the prestressing steel material is inserted into a fixing member provided in a lower member of the structure and having a hollow diameter-expanding portion whose diameter increases downward;
The fixing member is filled with a hardening material, and the upper end of the PC steel material is fixed to the upper member in a tensioned state,
A structure characterized in that a fixing body is provided on the tendon at a lower end of the prestressing steel material, and the height of the fixing body differs depending on the tendon.

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