JP2020090781A - Pipe body fixture and method for forming sheath end connection of segment - Google Patents

Abstract

To provide a pipe body fixture capable of improving the adhesive strength between segments.SOLUTION: In a pipe body fixture for fixing an end part of a pipe body 4, provided for inserting a PC steel material into a segment 2, on an inner wall of a formwork 3 for forming the segment 2 comprised of precast concrete to form a sheath end connection 11, there exists an enlarged diameter part 5a whose outer diameter increases toward the inner wall side; and on the outer peripheral surface of the enlarged diameter part 5a, a surface processing part 8 that increases its surface area is there formed. The shape of the surface processing part 8 is transferred to the sheath end connection 11 side in association with the pulling out of from the cured segment 2.SELECTED DRAWING: Figure 2

Description

The present invention relates to a tubular body fixing jig used for manufacturing a segment made of precast concrete used for a bridge or a slab for viaducts on expressways, and a method for forming a sheath connection port of this segment.

For example, as shown in FIG. 2 of Patent Document 1, the segment made of precast concrete has a structure in which a sheath for inserting a PC steel material and an end member connected to this sheath are embedded in the inside thereof. After inserting a connecting member into the sheath connection port of each segment arranged adjacent to each other, in the case of a bridge, pour mortar between both segments in the case of a floor slab with the adhesive applied to the end surface of each segment. The adjacent segments are integrated with each other.

After the plurality of segments are integrated, a PC steel material is inserted into the sheath and tension is applied to both ends of the PC steel material to support the plurality of segments (see FIG. 9 of Patent Document 1). Further, grout is injected into the sheath, and the grout keeps the inside of the sheath alkaline, thereby preventing corrosion of the PC steel material.

The sheath connection port of the segment is provided with a diameter-expanding sheath that expands toward the open end so that the connecting member can be easily inserted. In addition, the connecting member is formed with a flexible bellows so that the adjacent segments can be easily inserted even if the segments are slightly inclined relative to each other. In this case, after the adhesive or the mortar is filled, a cavity not completely filled with the adhesive or the mortar may be formed between the sheath connection port and the bellows-shaped connecting member (for example, Patent Document 1). (See the gap between the bell mouth portion 5 and the bellows-shaped annular protrusion 7 in FIG. 2).

Thus, when the hollow portion is formed, the substantial thickness of the concrete is reduced, which may cause a problem of a decrease in strength of the connecting portion of the segment. In particular, since the thickness of the floor slab segment is originally smaller than that of the bridge segment (for example, about 30 cm), the problem of strength reduction due to the formation of the cavity is likely to be remarkable.

Therefore, in order to prevent the formation of the hollow portion, for example, as shown in FIG. 8, the sheath connection port 101 of the segment 100 is formed in a tapered shape, and the sheath connection port 101 is connected with a flexible hose. The member 102 is inserted to connect the adjacent segments 100 to each other, and in the connected state, the gap between the sheath connection port 101 and the connection member 102 and the mortar 103 between the adjacent segments 100, 100 (in the case of a floor slab) (Refer to FIG. 8)) or a method of pouring an adhesive (in the case of a bridge) to cure it. By doing so, it is possible to prevent a gap from being formed between the sheath connection port 101 and the connection member 102, and it is possible to prevent a decrease in strength due to the formation of the cavity.

The tapered sheath connection port 101 is formed by using a tubular body fixing jig 106 having a cone-shaped expanded portion 105 having a smooth surface, as shown in FIG. 9, for example. The pipe body fixing jig 106 fixes the end of the pipe body 104, which is provided to insert the PC steel material into the segment 100, to the inner wall of the mold when forming the segment 100 using the mold. It is a jig for doing.

Japanese Patent No. 4660803

When the sheath connection port 101 is formed using the tubular body fixing jig 106 shown in FIG. 9, the sheath connection port 101 formed by transferring the enlarged diameter portion 105 has a smooth inner surface as shown in FIG. It becomes the surface condition. The mortar 103 filled in the sheath connection port 101 can secure a predetermined adhesive strength between the segments 100, but it is assumed that higher adhesive strength is required depending on the type of the structure. It

Therefore, an object of the present invention is to improve the adhesive strength between the segments.

In order to solve the above problems, the present invention fixes an end portion of a tubular body provided for inserting a PC steel material into the segment on an inner wall of a formwork for forming a segment made of precast concrete. In a tube fixing jig that forms a sheath connection port, a diameter-increasing portion whose outer diameter increases toward the inner wall side, and a surface-processed portion that increases the surface area is formed on the outer peripheral surface of the diameter-increasing portion. The shape of the surface-processed portion is transferred to the sheath connection port side when the segment is pulled out from the cured segment.

In this way, by forming the surface processed portion on the enlarged diameter portion of the tubular body fixing jig, the surface area of the inner surface of the sheath connection port formed by the transfer is also increased. Therefore, the contact area between the sheath connection port and the mortar or the like can be increased, and the adhesive strength between the segments can be improved.

In the above-mentioned structure, the surface-processed portions are processed in parallel with each other in the axial direction of the diameter-enlarged portion and processed into a step shape extending over the circumferential direction of the diameter-enlarged portion, or the large-diameter portion is enlarged. It can be processed into a groove extending from the radial side to the small diameter side.

With this configuration, the surface area of the expanded diameter portion of the tubular body fixing jig can be easily increased by simple processing.

In each of the above-mentioned configurations, the surface-processed portion may have a draft for facilitating the pulling out from the cured segment.

By doing so, it is possible to prevent troubles such as damage to the concrete on the inner surface of the sheath connection port when the tube fixing jig is forcibly pulled out from the hardened segment.

The tubular body fixing jig according to each of the above configurations has a diameter-expanded portion whose outer diameter increases toward the inner wall side of the mold for forming the segment made of precast concrete, and on the outer peripheral surface of the diameter-enlarged portion, The step of attaching the large-diameter side end of the pipe body fixing jig having the surface processed portion for increasing its surface area to the inner wall, and the small-diameter side end of the pipe body fixing jig were made of PC steel material. Inserting into the end portion of the tubular body for insertion, fixing the tubular body to the inner wall, and filling the uncured concrete inside the formwork, the tubular body in the concrete Step of burying a fixing jig and the tube, and after hardening of the concrete, with removal of the formwork, pulling out the tube fixing jig from the hardened concrete, to the sheath connection port side of the segment, And a step of transferring the shape of the surface-processed portion on the outer peripheral surface of the expanded diameter portion, the method being applicable to a method for forming a sheath connection port of a segment.

By adopting this forming direction, it is possible to easily form the sheath connection port to which the surface processed portion that increases the surface area is transferred.

According to the present invention, a surface-processed portion for increasing the surface area is formed on the outer peripheral surface of the expanded portion of the tubular body fixing jig, and the shape of this surface-processed portion is changed to the sheath connection of the segment when manufacturing the segment. It was transferred to the mouth. In this way, by forming the surface processed portion on the enlarged diameter portion of the tubular body fixing jig, the surface area of the inner surface of the sheath connection port formed by the transfer is also increased. Therefore, the contact area between the sheath connection port and the mortar or the like can be increased, and the adhesive strength between the segments can be improved.

An example (staircase-shaped first example) of a tubular body fixing jig according to the present invention is shown, (a) a perspective view seen from the large diameter side, (b) a sectional view. It is sectional drawing which shows an example of the formation method of the sheath connection port of the segment which concerns on this invention, (a) The state which inserted the pipe fixing jig in the sheath connection pipe, (b) Placing concrete in a formwork. And (c) Form and tube fixing jig removed A partially cutaway perspective view showing a state where a connecting member is being inserted into the sheath connection port. It is sectional drawing which shows the connection process of segments, Comprising: (a) before mortar filling, (b) after mortar filling Sectional drawing which shows the other example of the connection state of a segment It is sectional drawing which shows the other example of the pipe fixing jig which concerns on this invention, Comprising: (a) staircase 2nd example, (b) corrugated 1st example, (c) corrugated 2nd example, (d) staircase Third example, (e) stepwise fourth example, (f) stepwise fifth example, (g) stepwise sixth example, (h) wavy third example It is a perspective view which shows the other example of the pipe fixing jig which concerns on this invention, (a) groove-shaped 1st example, (b) groove-shaped 2nd example, (c) groove-shaped 3rd example. Sectional drawing which shows an example of the connection structure of the segments which concern on a prior art. A perspective view showing an example of a pipe fixing jig according to a conventional technique.

An example of the pipe body fixing jig 1 according to the present invention is shown in FIG. This tubular body fixing jig 1 is provided on the inner wall of a mold 3 (see FIG. 2A, etc.) for forming a segment 2 (see FIG. 2C) made of precast concrete, and a PC inside the segment 2. It is a jig for fixing the end portion of the tubular body 4 (see FIG. 2A, etc.) provided for inserting a steel material (not shown). The pipe body fixing jig 1 is fixed to a predetermined position on the inner wall of the mold 3 when the segment 2 is manufactured. The tubular body fixing jig 1 is composed of a cylindrical jig body 5 and two lids (a large diameter lid 6 and a small diameter lid 7) provided at both ends of the jig body 5, and the inside thereof is hollow. Has become. In this example, polyvinyl chloride resin is used as the material of the tube fixing jig 1, but other materials such as metal can be used.

When the jig body 5 is fixed to the inner wall of the mold 3, the jig body 5 has an enlarged diameter portion 5a whose outer diameter increases toward the inner wall side, and is coaxially connected to the small diameter side of the enlarged diameter portion 5a. It is composed of a constant diameter portion 5b. A surface processed portion 8 is formed on the outer peripheral surface of the expanded diameter portion 5a to increase its surface area. Specifically, the surface-processed portion 8 is a concentric stepped step portion that is arranged in parallel in the axial direction of the expanded diameter portion 5a and extends over the entire circumference in the circumferential direction of the expanded diameter portion 5a. And is formed in a concave shape with respect to the reference surface (the surface indicated by the chain double-dashed line) of the expanded diameter portion 5a. The outer diameter of the constant diameter portion 5b is slightly smaller than the inner diameter of the tubular body 4 (sheath connecting pipe 4b (see FIG. 2A, etc.)) into which the constant diameter portion 5b is inserted.

In some cases, the jig body 5 may be configured so that the small diameter side of the expanded diameter portion 5a is directly inserted into the tube body 4 without the constant diameter portion 5b.

The difference in height between the steps of the stepped portion (the difference in height between the lowest portion and the highest portion of the V-shaped groove formed by the stepped portion when the expanded diameter portion 5a is horizontal) is the mortar. Adhesion (the higher the height difference is, the better (for example, 0.5 mm or more)) and the prevention of concrete damage when pulling out the pipe fixing jig 1 described later (the smaller the height difference, the better). For example, it is preferable that the thickness is in the range of 1 to 3 mm.

The step-like stepped portion in this example has a surface along the pulling direction when pulling out the tube fixing jig 1 from the hardened segment 2 at the time of manufacturing the segment 2 described later, but the pulling out is easy. It is also possible to form a draft for that surface on the surface. Here, the draft angle refers to the inclination angle of the surface forming the expanded diameter portion 5a with respect to the drawing direction, and is defined as 0 degree when the drawing direction is along the surface. The draft is preferably at least 0.1 degree or more, more preferably 0.5 degree or more.

When the tube fixing jig 1 is made of an elastic material such as rubber, it can be pulled out by its elastic deformation, and therefore it is not always necessary to form a draft. In this case, a surface roughening method such as a sandblast method may be adopted for forming the surface processed portion 8. Further, a covering member such as a rubber sheet having an uneven surface may be wound around the outer diameter surface of the expanded diameter portion 5a, and this covering member may function as the surface processed portion 8.

The jig body 5 is formed, for example, by injection molding (injection) using a mold. At this time, by forming a stepped step on the mold side, the shape of the stepped step can be transferred to the surface of the expanded diameter portion 5a of the jig body 5 during this injection molding. it can. When many tube fixing jigs 1 having the same shape are manufactured, it is preferable to use the mold as described above, but in the case of a small lot, a solid tube is fixed by shaving from a massive material. The jig 1 can also be integrally molded. As described above, instead of integrally molding the whole, the expanded diameter portion 5a and the constant diameter portion 5b may be separately formed, and then both may be combined and integrated.

The large diameter lid 6 is attached to the large diameter side end of the expanded diameter portion 5a, and the small diameter lid 7 is attached to the open end of the constant diameter portion 5b. A bolt hole 10 is formed in the center of the large-diameter lid 6 and the small-diameter lid 7 for passing a bolt 9 (see FIG. 2A, etc.) for fixing the tubular body fixing jig 1 to the mold 3. In this example, the large-diameter lid 6 and the small-diameter lid 7 close the both ends of the jig body 5, but the small-diameter lid 7 alone may be attached. In this case, the large-diameter side end of the expanded diameter portion 5a is directly closed by the inner surface of the mold 3 at the time of manufacturing the segment 2 described later.

An example of the steps of the method for forming the sheath connection port 11 of the segment 2 using the above tube fixing jig 1 will be described with reference to FIG. This segment 2 is used, for example, for a slab of a viaduct of a highway.

In this forming method, first, as shown in FIG. 2A, the tubular body fixing jig 1 is attached to the inner wall of the mold 3 for forming the segment 2, and the large-diameter lid 6 is attached to the inner wall of the mold 3. Install with bolts 9 so that it faces. An adhesive or the like may be used to attach the pipe body fixing jig 1 to the mold 3.

A tube body 4 for inserting a PC steel material (not shown) is provided in the mold 3. The tubular body 4 is composed of a tubular sheath 4a and sheath connecting pipes 4b connected to both ends of the sheath 4a. A spiral groove is formed in each of the sheath 4a and the sheath connecting pipe 4b. The sheath 4a and the sheath connecting pipe 4b are connected by screwing the spiral groove formed in the sheath connecting pipe 4b into the spiral groove formed in the sheath 4a. At this time, a waterproof tape may be wrapped around the connecting portion between the sheath 4a and the sheath connecting tube 4b to improve the water tightness.

The end of the tube fixing jig 1 on the small diameter side (constant diameter portion 5b) is inserted into the sheath connecting tube 4b. As a result, the tube body 4 (sheath 4a, sheath connecting tube 4b) is fixed at a predetermined position on the inner wall of the mold 3.

Next, as shown in FIG. 2( b ), the uncured concrete 12 is filled into the inside of the mold 3, and the tubular body fixing jig 1 and the tubular body 4 (sheath 4 a, sheath 4) are filled in the concrete 12. The connecting pipe 4b) is embedded horizontally. When this concrete 12 hardens, as shown in FIG. 2( c ), the form 3 is removed and the tube fixing jig 1 is pulled out from the hardened concrete 12. At this time, the shape of the surface-processed portion 8 (the stepped step portion in the above example) on the outer peripheral surface of the expanded diameter portion 5a of the tubular body fixing jig 1 is transferred to the sheath connection port 11 side of the segment 2. In order to easily pull out the tube fixing jig 1, a release agent may be applied in advance to the surface of the tube fixing jig 1.

According to the method of forming the sheath connection port 11, the shape of the surface-processed portion 8 of the tubular body fixing jig 1 is transferred to the sheath connection port 11 as it is, and the sheath connection port 11 does not need to be processed separately. The manufacturing cost of 2 can be suppressed.

A process of connecting the segments 2 manufactured as described above will be described with reference to FIGS. 3 and 4.

First, as shown in FIG. 3, the connection member 13 for connecting the adjacent segments 2 is inserted into the sheath connection port 11 having the stepped step portion formed on the inner surface. The connecting member 13 has a structure in which tubular end members 13b are fitted to both ends of a flexible tubular member 13a, and the end members 13b are inserted into the sheath connecting pipe 4b. For example, in the case of a slab of a viaduct on an expressway, as shown in FIG. 4A, a predetermined gap d (for example, 30 mm) is secured between the adjacent segments 2 and 2.

Next, as shown in FIG. 4B, the mortar 14 is poured into the gap between the sheath connection port 11 and the connection member 13 and between the adjacent segments 2 and 2 to be cured. Since a step-like step is formed on the inner surface of the sheath connection port 11, the surface area of the sheath connection port 11 is large as compared with the case where there is no step (see FIG. 8). Therefore, the contact area between the sheath connection port 11 and the mortar 14 can be increased, and the adhesive strength between the segments 2 and 2 can be improved.

After the mortar 14 is hardened, a PC steel material (not shown) is inserted into the sheath 4a and the sheath connecting pipe 4b, and tension is applied to the PC steel material to firmly integrate the plurality of segments 2. After that, a low-viscosity grout (not shown) for preventing corrosion of the PC steel material is injected and cured into the sheath 4a and the sheath connecting pipe 4b, and a series of operations is completed.

In the case of the bridge segment 2, as shown in FIG. 5, a tubular body 4 (sheath 4a, sheath connecting pipe 4b) for inserting a PC steel material (not shown) is buried obliquely with respect to the horizontal direction. ing. Then, the segments 2 are arranged with almost no gap, and the segments 2 and 2 are bonded by filling an adhesive 15 between them. Even in this case, since the step-like step is formed on the inner surface of the sheath connection port 11 of the segment 2, the surface area of the sheath connection port 11 is large as compared with the case where there is no step (see FIG. 8). Therefore, the contact area between the sheath connection port 11 and the adhesive 15 can be increased, and the adhesive strength between the segments 2 and 2 can be improved.

Another example of the tubular body fixing jig 1 used for forming the sheath connection port 11 of the segment 2 is shown in FIGS. These tube fixing jigs 1 are provided with stepped surface-processed portions 8 which are arranged in parallel in the axial direction of the expanded diameter portion 5a and extend over the entire circumference of the expanded diameter portion 5a. There is.

The pipe body fixing jig 1 shown in FIG. 6A is similar to that shown in FIG. 1 in that the surface processed portion 8 is a stepped step portion, but the reference surface (two points) of the expanded diameter portion 5a is used. The surface shown by the chain line. The same applies to the following.), the stepped step is formed in a convex shape.

In the tubular body fixing jig 1 shown in FIGS. 6B and 6C, the surface-processed portion 8 is a corrugated step portion with rounded corners. The wavy step portion is formed in a concave shape in FIG. 6B and a convex shape in FIG. 6C with respect to the reference surface of the expanded diameter portion 5a. In this way, since the draft is formed by forming the corrugated step portion, it is possible to prevent the concrete 12 from being damaged when the tube fixing jig 1 is pulled out. Furthermore, since the corrugated step portion has no corners and the tip of the connecting member 13 is less likely to be caught, the connecting member 13 can be easily inserted when connecting the segment 2, and at the time of filling the mortar 14, the step upper part It is possible to prevent the formation of air pockets in the recessed portion.

The pipe body fixing jig 1 shown in FIG. 6(d) is similar to that shown in FIG. 1 in that the surface processed portion 8 is a stepped step portion, but with respect to the reference surface of the expanded diameter portion 5a, The stepped step has both a concave portion and a convex portion.

The pipe body fixing jig 1 shown in FIG. 6(e) is similar to that shown in FIG. 1 in that the surface-processed portion 8 is a stepped step portion, but the stepped stepped portion has an expanded diameter portion. It is formed only on a part of the whole 5a.

The tubular body fixing jig 1 shown in FIGS. 6(f) and 6(g) is similar to that shown in FIG. 1 in that the surface-processed portion 8 is a stepped step, but the stepped step is formed. The enlarged diameter portion 5a has a convex shape in FIG. 6(f) and a concave shape in FIG. 6(g).

The tubular body fixing jig 1 shown in FIG. 6(h) is similar to that shown in FIGS. 6(b) and 6(c) in that the surface processed portion 8 is a corrugated step portion, but the corrugated step portion The tip is extended in the axial direction (drawing direction) of the tube fixing jig 1.

6A to 6H, the contact area between the sheath connection port 11 and the mortar 14 can be increased, and the adhesive strength between the segments 2 and 2 can be improved. be able to.

Another example of the tubular body fixing jig 1 used for forming the sheath connection port 11 of the segment 2 is shown in FIGS. In these tube fixing jigs 1, radial and groove-shaped surface processing portions 8 are formed from the large diameter side of the expanded diameter portion 5a to the small diameter side. In FIG. 7A, a groove whose bottom surface has an arcuate section is formed, in FIG. 7B, a groove having a V-shaped section is formed, and in FIG. 7C, a groove having a rectangular section is formed. 7A to 7C, the contact area between the sheath connection port 11 and the mortar 14 can be increased, and the adhesive strength between the segments 2 and 2 can be improved. be able to.

The configurations shown in FIGS. 1 and 6A to 6H and the configurations shown in FIGS. 7A to 7C can be combined. By doing so, the contact area between the sheath connection port 11 and the mortar 14 can be further increased, and the adhesive strength between the segments 2 and 2 can be further improved.

The tube body fixing jig 1 and the method of forming the sheath connection port 11 of the segment 2 described above are examples in all respects, and the problem of the present invention to improve the adhesive strength between the segments 2 is solved. As far as it can be solved, the shape of the surface processed portion 8 formed on the tube fixing jig 1, the overall shape and material of the tube fixing jig 1, and the procedure of the method for forming the sheath connection port 11 of the segment 2. Etc. can be changed appropriately.

1 tube fixing jig 2 segment 3 form 4 tube 4a sheath 4b sheath connecting tube 5 jig body 5a expanded diameter part 5b constant diameter part 6 large diameter lid 7 small diameter lid 8 surface processing part 9 bolt 10 bolt hole 11 sheath Connection port 12 Concrete 13 Connection member 13a Tubular member 13b End member 14 Mortar 15 Adhesive

Claims (5)

By fixing the end of the tubular body (4) provided for inserting the PC steel material into the segment (2) to the inner wall of the form (3) for forming the precast concrete segment (2) In the tubular body fixing jig that forms the sheath connection port (11),
The inner wall side has an enlarged diameter portion (5a) whose outer diameter increases, and the outer peripheral surface of the enlarged diameter portion (5a) is formed with a surface-treated portion (8) for increasing the surface area thereof. A tubular body fixing jig, wherein the shape of the surface-processed portion (8) is transferred to the sheath connection port (11) side when the segment (2) is pulled out. The surface-processed portion (8) is processed into a step shape extending in the circumferential direction of the expanded diameter portion (5a) while being arranged in parallel in the axial direction of the expanded diameter portion (5a). The pipe body fixing jig according to claim 1. The tubular body according to claim 1 or 2, wherein the surface-processed portion (8) is processed into a groove shape extending from the large diameter side to the small diameter side of the expanded diameter portion (5a). fixing jig. 4. The surface treated portion (8) according to claim 1, wherein the surface treated portion (8) has a draft for facilitating the pulling out of the cured segment (2). Pipe fixing jig. The mold (3) for forming the segment (2) made of precast concrete has an enlarged diameter portion (5a) whose outer diameter increases toward the inner wall side, and on the outer peripheral surface of the enlarged diameter portion (5a), A step of attaching the end portion on the large diameter side of the tubular body fixing jig (1) according to any one of claims 1 to 4 having a surface processed portion (8) formed to increase its surface area to the inner wall. When,
A step of inserting the end portion of the tubular body fixing jig (1) on the small diameter side into the end portion of a tubular body (4) for inserting a PC steel material, and fixing the tubular body (4) to the inner wall. When,
Filling the inside of the mold (3) with uncured concrete (12), and embedding the pipe fixing jig (1) and the pipe (4) in the concrete (12). When,
After the concrete (12) is hardened, the formwork (3) is removed, and at the same time, the tubular body fixing jig (1) is pulled out from the hardened concrete (12), and the sheath connection port (of the segment (2) ( 11) the step of transferring the shape of the surface processed portion (8) on the outer peripheral surface of the expanded diameter portion (5a),
For forming a sheath connection port of a segment having a groove.

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