JP4072895B2 - Grout filling confirmation method and sheath with observation hole - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for confirming the state of grout filling in a sheath through which a tension material, particularly a PC steel material, is inserted in a post-tensioning prestressed concrete member, and a sheath with an observation hole that is preferably used in this method.
[0002]
[Prior art]
One of the methods conventionally used for producing a prestressed concrete (PC) member is a post-tensioning method. In this method, a PC steel material is covered with a cylindrical sheath, and is placed at a predetermined position in a mold to place concrete. And after hardening of concrete, it tensions PC steel materials with a jack. At this time, since the PC steel material is covered with the sheath, it is not restrained by the concrete, and a tensile force is introduced over the entire length. The PC steel material to which the tensile force is introduced is fixed to the concrete through the fixing tool, and a compressive force (prestress) is introduced to the concrete.
[0003]
After prestress is applied in this way, a grout containing cement as a main material is press-fitted into the sheath, and the concrete of the member and the PC steel material are integrated by hardening, and moisture that has entered the sheath, etc. Protects PC steel from corrosion caused by rust. In addition to cement, aluminum powder or the like is mixed with the grout to expand the grout by an appropriate amount at the time of curing, thereby improving the adhesion strength and preventing the generation of gaps due to the shrinkage of the grout. Thereby, improvement of durability against freezing and thawing is achieved.
[0004]
However, if the grout to be injected into the sheath is not completely filled and an unfilled portion exists in the sheath, the durability of the PC steel material subjected to high tension is significantly reduced. That is, the PC steel material is rust-prevented by the alkaline cement grout, but corrosion occurs early in the unfilled portion of the grout. For this reason, during or after construction of grout filling work, the grout filling status around the PC steel material may be inspected to check for the presence or size of unfilled parts of the grout, and to refill or repair. desired.
[0005]
From such a request, several methods for non-destructively inspecting the state of filling grout around the PC steel material have been proposed, and (1) a method using X-rays, 2) Evaluation method based on the decrease in AE energy propagating through PC steel as disclosed in JSCE Proceedings No. 402 (1989.2), (3) Japanese Patent Laid-Open Nos. 4-182568 and 3-255953 (4) Two electrodes are provided in the sheath as disclosed in Japanese Patent Application Laid-Open No. 2000-230915, and there is provided between the electrodes. There is a method of measuring a resistance value, and the like.
[0006]
[Problems to be solved by the invention]
However, the conventional confirmation methods as described above have the following problems.
The above-mentioned method using X-rays has a wide range because a relatively large and expensive apparatus is required, the places where investigation can be performed are limited, and the cost of investigation is high. It is not practical when conducting a survey. In addition, the method of inspecting by measuring AE energy and the method of using the characteristics of elastic waves propagating in PC steel are relatively simple inspection methods, and are effective for simply estimating the grout filling state. However, there is a drawback that the position and size (length) of the unfilled portion of the grout cannot be accurately specified.
[0007]
Furthermore, in the method of providing an electrode in the sheath, it is necessary to arrange a conductor for measuring the electric resistance value from the inside of the sheath to the outside of the concrete member. If this conductor is broken or short-circuited, the presence or absence of grout can be detected. It will disappear. In addition, malfunction may occur when foreign matter adheres to the electrode.
[0008]
The present invention has been made in view of the above problems, and its purpose is to confirm non-destructively, easily and surely the filling state of the grout in the sheath in the prestressed concrete structure. And a sheath with an observation hole that can be used in this method.
[0009]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is a method for confirming a grout filling state in a concrete member in which a tension material covered with a sheath is placed in concrete and grout is injected into the sheath. A cylindrical protrusion is provided on the outer peripheral surface of the sheath, the inside of the cylindrical protrusion is an opening of the sheath, and a closing member having a transparent portion is fitted to the cylindrical protrusion. An observation device that closes the opening by fixing and provides an observation hole from the transparent portion to the outer surface of the concrete member, and guides an image of the state in the sheath having the opening to the outside of the concrete member, or in the sheath An observation device for optically detecting and recording an image in the state is inserted into the observation hole and the inside of the sheath is observed, and a grout filling confirmation method is provided. To.
[0010]
The observation device can use a small camera, a fiberscope, or the like that images the inside of the sheath from a transparent portion of the closing member, and may record an image once or display it on a display or the like in real time It may be. Further, it is desirable to have a light source that irradiates the observation portion with light within the observation hole.
[0011]
When the grout is injected into the sheath and sufficiently filled, the grout comes into close contact with the transparent portion of the closing member that closes the opening formed on the outer peripheral surface of the sheath. The transparent portion can be visually observed from the outside of the concrete member by an observation device inserted into the observation hole, and the grout filling state can be easily and reliably confirmed. In addition, since observation within the sheath is performed by an observation device, the observation hole may be of a diameter into which a small camera or the like can enter, and the cross-sectional area can be reduced. Therefore, the cross-sectional defect | deletion of a concrete member decreases, and it becomes easy to provide an observation hole about each of many tension materials. And by providing such observation holes at predetermined intervals in the axial direction of the tendon, it is possible to confirm the grout filling state over the entire length of the tendon.
[0012]
Further, in this method, by processing a sheath made of a general synthetic resin or the like, the cylindrical protruding portion of the sheath can be formed easily and at low cost. Then, by fitting the closing member to the cylindrical protrusion, the closing member can be easily fixed to the sheath, and the opening of the sheath can be reliably closed by the transparent portion of the closing member.
[0013]
The invention according to claim 2 is the grout filling confirmation method according to claim 1, wherein the observation hole is formed between the closing member and a mold for forming the outer surface of the concrete member. It is assumed that an observation hole forming member that eliminates the above is disposed, and uncured concrete is cast and formed so as to embed the observation hole forming member.
[0014]
The observation hole forming member is a cylindrical member, and the inside becomes an observation hole as it is. By using such an observation hole forming member, an observation hole can be easily formed between the opening formed on the outer peripheral surface of the sheath and the outer peripheral surface of the concrete member, and the sheath is formed via the observation hole. The grout filling state can be confirmed.
[0015]
The invention according to claim 3 includes a sheath body portion in which a tension material is inserted, and other sheaths can be connected to both ends, an opening is formed in the outer peripheral portion, and a transparent portion. A closing member attached to the sheath main body so that a small portion closes the opening, and a cylindrical member attached to the closing member so that an inner space leads to a transparent portion of the closing member closing the opening And providing a sheath with an observation hole.
[0016]
In this sheath with an observation hole, a general sheath can be connected to both ends of the sheath main body to form a series of sheaths through which the tension material is inserted. Then, the opening is closed with a closing member, the cylindrical member is arranged at a predetermined position, and concrete is placed so as to embed these, so that the concrete is not filled in the sheath and the cylindrical member, and the sheath An internal observation hole is formed. Accordingly, when the concrete is hardened and the grout is filled after the tension is introduced into the tendon, a small camera or the like can be inserted from the outside of the concrete member into the observation hole formed inside the cylindrical member. And the grout filling state in a sheath can be image | photographed through the transparent part of a closure member, and it can display on the display etc. outside a concrete member, or the condition in a sheath can be recorded.
[0017]
According to a fourth aspect of the present invention, in the sheath with an observation hole according to the third aspect, the closing member is fitted into the opening and closes the opening so that the inside of the sheath body can be observed from a transparent portion. And a tubular joint that protrudes outside the sheath main body and fits the tubular member, and projects outside the opening in the direction along the outer peripheral surface of the sheath outside the sheath main body. And a bowl-shaped portion.
[0018]
By fitting the closing member into the opening of the sheath body, the opening can be easily closed, and the inside of the sheath body can be observed from here. In addition, the tubular member can be easily attached to the sheath body by fitting the tubular joining portion into the tubular member serving as the observation hole. Further, when concrete is placed and the concrete is hardened, the hook-shaped portion is in close contact with the concrete, and the closing member is firmly fixed. Therefore, when the grout is injected into the sheath, the closing member fitted in the opening can be prevented from being pushed out from the opening even if the grout is pressurized. Further, when the inside of the unfilled portion of the sheath is depressurized in order to promote the filling of the grout, the closing member can be prevented from being sucked and drawn into the sheath.
[0019]
According to a fifth aspect of the present invention, in the sheath with an observation hole according to the fourth aspect, the sheath main body portion has a cylindrical protruding portion protruding outward from the outer peripheral surface, and the portion of the cylindrical portion is formed. The inside is an opening, and the closing part of the closing member is assumed to be fitted inside the protruding part.
[0020]
The cylindrical projecting portion can be formed easily and at low cost by integrally processing when forming a sheath body portion made of a general synthetic resin or the like. Then, the closure member can be placed at a predetermined position of the sheath body by fitting the closure member to the tubular projecting portion.
[0021]
The invention according to claim 6 is the sheath with an observation hole according to claim 3 , wherein the cylindrical member is formed of a material that can be flexibly bent.
[0022]
By bending the tubular member, the observation hole that leads from the sheath main body to the outside of the concrete member can be formed in an arbitrary shape. Therefore, even if a plurality of sheaths are concentrated in the concrete member, observation holes can be provided in the respective sheaths. By inserting a small observation device into the observation hole, the grout filling state in the sheath can be reliably confirmed even when the sheath is disposed at a deep position from the surface of the concrete member.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view for explaining a grout filling confirmation method which is an embodiment of the invention according to claim 1 or claim 2 . The sheath with an observation hole used in the grout filling confirmation method is an embodiment of the invention according to claim 3, claim 4, claim 5 or claim 6 .
In this method, a part of the sheath through which the PC steel strand 2 (tension material) is inserted is set as a sheath 3 with an observation hole having a transparent portion. Then, concrete is poured so as to embed the sheath, and when this concrete is hardened, an observation hole 4 for observing the inside of the sheath is formed in a portion where the sheath 3 with the observation hole is disposed. When the small camera 6 is inserted into the observation hole and the grout 5 is injected into the sheath, or after the injection, the grout filling state in the sheath is observed using a small camera from outside the concrete member.
[0024]
In the present embodiment, the small camera 6 uses an optical image in the sheath as a signal by a large number of photosensitive elements and displays the image on the display 8 via the image processing device 7. However, as long as the grout filling state in the sheath can be optically taken, any type may be used, and a fiberscope or the like may be used. In addition, it is desirable that the video can be displayed or visually confirmed in real time at the site, but it may be temporarily converted into magnetic recording or the like.
In order to optically capture the state in the sheath, it is desirable that the small camera has a light source 6a for illumination.
[0025]
As shown in FIG. 2, the sheath 3 with an observation hole is made of a cylindrical synthetic resin having a predetermined length, and the sheath body 11 having an opening on the outer peripheral surface and the opening of the sheath body 11 is closed with a transparent member. And a closure member 13 to which the tubular member 12 is connected, and a tubular member 12 connected to the closure member 13 and disposed between the outer surface 1a of the concrete member 1 and a sheath body portion. 1 can connect a general sheath 14 to both sides. As the general sheath 14, for example, a thin steel plate joined in a spiral shape and provided with a spiral or nodal projection portion 14 a can be flexibly deformed. Also, a synthetic resin sheath having the same shape can be used.
[0026]
As shown in FIG. 3, a cylindrical projecting portion 11a is formed on the outer peripheral surface of the sheath body 11, and the inside of the projecting portion is an opening 11b. The opening 11b may have a diameter that allows the inside of the sheath body 11 to be observed from the opening 11b by the small camera 6. As shown in FIG. 4, a closing member 13 is attached so as to close the opening 11 b, and the tubular member 12 is connected to the closing member 13.
[0027]
As shown in FIG. 5, the closing member 13 is fitted into the opening 11b, closes the opening 11b, a cylindrical joining portion 22 protruding to the outside of the sheath body 11, and a joining portion. 22 and a bowl-shaped portion 23 having a diameter larger than that of the flange 22. The closing member 13 has at least a closing portion 21 made of a transparent material such as vinyl chloride or acrylic resin, and the inside of the sheath main body 11 can be observed from the closing portion 21.
[0028]
The joint portion 22 has a double cylindrical shape that is bent outward so that a gap 22a is formed in a portion protruding from the sheath main body portion 11 continuously to the closing portion 21. The closing member 13 can be easily attached to the sheath body 11 by fitting the protruding portion 11a of the sheath body 11 into the gap 22a. Moreover, as for this junction part 22, the outer side of the double part is fitted by the cylindrical member 12, and this cylindrical member 12 and the sheath main-body part 11 are connected.
[0029]
The hook-like portion 23 is continuous with the joint portion 22, is folded back along the outer peripheral surface of the sheath body 11, and has a larger diameter than the opening 11 b of the sheath body 11. The hook-like portion 23 is placed so that the concrete is placed and hardened, and then comes into contact with the concrete to restrain the closing member 13 from coming off the opening 11b. Therefore, even if the grout is pressurized and injected into the sheath, or the grout is sucked with the downstream side set to a negative pressure, the closing member 13 is firmly fitted and held in the opening 11b.
[0030]
It is desirable to apply an adhesive to the fitting portion between the protruding portion 11a of the sheath main body 11 and the closing member 13 and the fitting portion between the joining portion 22 of the closing member 13 and the tubular member 12. Thereby, it is possible to prevent the closing member 13 or the cylindrical member 12 from falling off after placing the sheath at a predetermined position until the concrete is placed and during the concrete placement. Moreover, high airtightness and watertightness can be maintained.
[0031]
In the present embodiment, the cylindrical member 12 is made of a flexible synthetic resin, has an inner diameter that is substantially the same as the outer diameter of the joint portion 22 of the closing member 13, and can be inserted into the small camera 6. Then, when the joint portion 22 of the closing member 13 is fitted inside the tubular member 12 and concrete is placed so as to embed the sheath main body portion 11, the end surface of the tubular member 12 is exposed to the outside of the concrete. Placed in. Therefore, when the concrete is hardened, the inside of the cylindrical member 12 becomes an observation hole 4 that communicates from the outside of the concrete member to the opening 11b of the sheath body 11. In this embodiment, since the observation in the sheath body is performed by the observation device, the diameter of the observation hole 4 can be reduced. Therefore, the cross-sectional defect | deletion of the concrete member 1 decreases and it can prevent that the intensity | strength of the concrete member 1 falls.
[0032]
Thus, by using the cylindrical member 12 made of a flexible synthetic resin, the observation hole 4 can be formed in a curved shape. In addition, by inserting a small observation device into the observation hole, it is possible to collect a plurality of PC steel materials and to arrange the grout in the sheath even when the sheath is arranged deep from the surface of the concrete member. The filling state can be confirmed reliably.
[0033]
FIG. 6 is a cross-sectional view showing a closing member that can be used in place of the closing member 13.
The closing member includes a closing portion 31 made of a transparent material, a joint portion 32 that is continuous with the closing portion 31 and is raised to the outside of the sheath main body 11 and to which the cylindrical member 12 serving as an observation hole is connected. The diameter is larger than the protrusion 11 a of the sheath main body 11, and the flange body 33 is provided so as to be integrated with the joint portion 32.
[0034]
In this closing member, the closing member 31 is placed in a predetermined position by fitting the closing portion 31 into the opening 11b inside the protruding portion 11a until the hook-shaped portion 33 contacts the protruding portion 11a. At this time, the opening 11b can be sealed by applying an adhesive to a portion where the closing portion 31 and the joining portion 32 are in contact with the inner surface of the protruding portion 11a. And it can restrain that a closure member remove | deviates from the opening 11b, or falls to the opening 11b by embedding the hook-shaped part 33 in concrete. Moreover, the cylindrical member 12 is fitted so that the outer peripheral surface of the junction part 32 may be followed, and it arrange | positions so that one end surface may contact | abut to the hook-shaped part 33 and the other end surface may be exposed outside the concrete.
[0035]
FIG. 7 is a perspective view showing a sheath main body forming a sheath with an observation hole, which is another embodiment of the invention according to claim 3, claim 4, claim 5 or claim 6 , and the sheath main body. It is an expanded sectional view of the part to which the closure member and the cylindrical member were joined.
The sheath body 41 is a cylindrical body having a predetermined length made of a cylindrical synthetic resin, and can be connected to a general sheath on both sides. An opening 41 a is formed on the outer peripheral surface. The closing member 43 can be fitted into the opening 41 a and the tubular member 42 can be connected to the closing member 43.
[0036]
The closing member 43 includes a closing portion 43a made of a transparent material, a joint portion 43b fitted with the cylindrical member 42, and a flange-like portion 43c whose diameter is larger than that of the opening 41a. When the closing portion 43a is fitted into the opening 41a, the flange portion 43c is brought into contact with the outer peripheral surface of the sheath body 41, and the closing member 43 is disposed at a predetermined position. The hook-shaped portion 43c is provided at an appropriate position so that the closing portion 43a does not enter the sheath body 41 by a predetermined amount or more. In such a sheath with an observation hole, similarly to the sheath with an observation hole shown in FIG. 2, an observation device such as a small camera is inserted into the cylindrical member 42, and the inside of the sheath main body is transparent from the transparent closing portion 43a by this small camera. Can be observed.
[0037]
【The invention's effect】
As described above, in the grout filling confirmation method according to the present invention, it is confirmed by using an observation device such as a small camera whether or not the grout is surely filled in the sheath arranged in the concrete member. This makes it possible to perform a simple and reliable confirmation operation.
In addition, by using the sheath with an observation hole according to the present invention, an observation hole for visually confirming the filling state of the grout in the sheath can be formed easily and at low cost.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view for explaining a grout filling confirmation method according to an embodiment of the invention according to claim 1 or claim 2 ;
2 is a perspective view showing a sheath with an observation hole for forming the observation hole shown in FIG. 1. FIG.
3 is a plan view, a side view, and a cross-sectional view showing a sheath main body for forming the sheath with an observation hole shown in FIG. 2. FIG.
FIG. 4 is an exploded perspective view of the sheath with an observation hole shown in FIG.
FIG. 5 is a partial cross-sectional view of the sheath with an observation hole shown in FIG.
6 is a cross-sectional view showing a closing member that can be used in place of the closing member shown in FIG. 5. FIG.
FIG. 7 is a perspective view showing a sheath main body forming a sheath with an observation hole, which is another embodiment of the invention according to claim 3, claim 4, claim 5, or claim 6 , and It is an expanded sectional view of the part to which the closure member and the cylindrical member were joined.
[Explanation of symbols]
1 Concrete member 2 PC steel strand (tension material)
DESCRIPTION OF SYMBOLS 3 Sheath with observation hole 4 Observation hole 5 Grout 6 Small camera 7 Image processing apparatus 8 Display 11, 41 Sheath main body 12, 42 Cylindrical member 13, 43 Closure member 14 Sheath 21, 31, 43a Closure part 22, 32, 43b Joining Part 23, 33, 43c bowl-shaped part

Claims (6)

A method of confirming the filling state of grout in a concrete member in which a tension material covered with a sheath is placed in concrete and injecting grout into the sheath,
A cylindrical protrusion is provided on the outer peripheral surface of the sheath, and the inside of the cylindrical protrusion is set as an opening of the sheath.
Closing the opening by fitting and fixing a closure member having a transparent portion to the cylindrical protrusion,
Providing an observation hole from the transparent part to the outer surface of the concrete member;
An observation device for guiding an image of the state in the sheath having the opening to the outside of the concrete member, or an observation device for optically detecting and recording the image of the state in the sheath is inserted into the observation hole and inserted in the sheath. Grout filling confirmation method characterized by observing.     The observation hole is formed by disposing an observation hole forming member for removing uncured concrete between the closing member and a mold for forming the outer surface of the concrete member, and embedding the observation hole forming member. 2. The grout filling confirmation method according to claim 1, wherein the uncured concrete is cast and formed as described above. A tension body is inserted, and other sheaths can be connected to both ends, and a sheath body part in which an opening is formed in the outer peripheral part,
A closure member attached to the sheath body so as to have a transparent portion, and the transparent portion closes the opening;
And a tubular member attached to the closing member so that an inner space leads to a transparent portion of the closing member that closes the opening. The closure member is
A closing portion fitted into the opening and closing the opening so that the inside of the sheath body can be observed from a transparent portion;
A cylindrical joint that protrudes outside the sheath body and is fitted with the tubular member;
4. The sheath with an observation hole according to claim 3, further comprising a hook-shaped portion that protrudes from the range of the opening in a direction along the outer peripheral surface of the sheath outside the sheath main body portion. The sheath main body portion has a cylindrical protrusion protruding outward from the outer peripheral surface, and the inside of the cylindrical portion is an opening,
The sheath with an observation hole according to claim 4, wherein the closing portion of the closing member is fitted inside the protruding portion. The sheath with an observation hole according to claim 3, wherein the cylindrical member is formed of a material that can be flexibly bent.

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