JP6077395B2 - Sheath with grout injection - Google Patents

Description

  The present invention relates to a sheath into which grout is injected in a state in which PC steel is inserted when producing prestressed concrete (PC), and more specifically, a grout injection portion is provided at an intermediate position different from the sheath end. It relates to a sheath. In the following description, the term “sheath” refers to a tubular body into which a tension body (PC steel material) is inserted, and not only a sheath composed of a single tubular body but also a joint sheath (tube) that connects the sheaths together. (Also referred to as a joint).

  In order to produce prestressed concrete, it is necessary to inject grout into a sheath tube into which prestressed PC steel is inserted. In the past grout injection methods, a method of injecting grout from an injection port provided at one end (girder end) of the sheath is often used. By the way, in grout injection, it is important to fill the grout so that an air layer does not remain in the sheath. Therefore, injection methods have been studied from various viewpoints, and contrivances have been made such as using a highly viscous material for the grout (Patent Document 1) or providing the position of the grout inlet at a position other than the sheath end.

  Regarding the position of the grout inlet, for example, Japanese Patent Application Laid-Open No. 2011-21463 (patent document 1) related to one of the applicants of the present invention relates to an injection method in which the grout is filled into the sheath from the lower surface side of the downward bent portion at the intermediate position of the sheath. Document 2). That is, with reference to FIG. 1 of the same document, the sheath (2) is lowered from the tension part (4) side, raised through the lower bent part (6), and lowered again through the upper bent part (7). To the fixing unit (5). A grout injection hose (8) is connected to the lower surface of the downward bent portion (6). An injection hose (8) is opened to the lower part of the sheath (2) and fed into the sheath (2) to fill the grout from the lower part. In this grouting method, from the viewpoint of reducing or removing residual bubbles in the sheath, the principle of grouting is that grouting is injected from a low position of the sheath and discharged from a high position of the sheath. From the idea, the grout is purposely injected from the lower surface side of the downward bent portion of the sheath.

  In addition, as another method of preventing residual bubbles when injecting grouting, since air bubbles are likely to accumulate at a higher position than the lower position of the sheath, a re-injection port is provided on the upper surface of the upper bent portion of the sheath where air bubbles are likely to accumulate. It is disclosed that reinjection is provided when bubbles are generated (Patent Document 3).

JP 2002-47802 A JP 2011-21463 A Japanese Unexamined Patent Application Publication No. 2004-121528

As described above, the grouting method is not limited to the conventional method of injecting from the sheath end (girder end), but is applied to the lower surface of the lower bent portion and the upper surface of the upper bent portion at the intermediate position of the sheath. A method of injecting with an inlet (reinjection port) is also employed.
By the way, in the grout injection method in which an injection port is provided at an intermediate position of the sheath, an opening (hole) serving as a grout inlet is formed in a part of the peripheral wall of the sheath, and an external grout injection hose is connected to the opening. However, the following problems have arisen.

  First, when producing prestressed concrete, the reinforcing bars are assembled vertically and horizontally, and a sheath is disposed at a predetermined position between the reinforcing bars (see, for example, FIG. 4 of Patent Document 1). ). Therefore, when the grout inlet is provided at the intermediate position of the sheath, the position of the reinforcing bar and the position of the grout inlet may overlap, and the grout injection hose can be connected to the opening serving as the grout inlet. Therefore, it is necessary to change the position where the opening is provided or to change the position of the sheath.

Second, depending on the positional relationship between the PC steel material inserted into the sheath and the peripheral wall of the sheath, the PC steel material may approach or contact the peripheral wall. That is, the PC steel material in the sheath is biased toward the sheath bottom at the upper bent portion, and biased toward the sheath ceiling surface at the lower bent portion, and is not positioned at the sheath center near the bent portion of the sheath (patent) (See FIG. 2 of Document 2).
Therefore, if an opening serving as a grout inlet is formed at a position where the PC steel material approaches or is in contact with the peripheral wall, smooth injection of the grout into the sheath becomes difficult.

  Thus, the position of the grout inlet formed on the sheath peripheral wall according to the external environment of the prestressed concrete sheath (rebar arrangement, etc.) and the internal environment in the sheath (PC steel material bias, vertical height) There was a need to adjust to an appropriate position.

In view of this, the present invention provides a sheath having a grout injection part for injecting grout from an intermediate position of the sheath, and the opening position provided in the peripheral wall for injecting grout can be freely set according to the external environment and internal environment of the sheath It is an object to provide a sheath with a grout injection part that can be selected.
In addition, the present invention is provided with a grout injection part that can easily connect with a grout injection hose connected from the outside and can inject grout so that residual bubbles in the sheath are not easily generated. An object is to provide a sheath.

(Claim 1) A sheath provided with a grout injection part according to the present invention includes a cylindrical main body and an outer tube. The main body is provided with a grout inlet on the peripheral wall. The outer tube has an inlet opening in the peripheral wall. The outer tube surrounds the main body. By this surrounding, a grout flow path appears between the main body and the outer pipe, the inlet is opened to the flow path, and the inlet to the inlet is rotated by rotating the outer pipe. It is comprised so that the position of the circumferential direction of can be set arbitrarily.

According to the present invention, the peripheral wall of the cylindrical main body is provided with an inflow port for allowing the grout to flow into the main body, and an external grout injection hose is connected to the peripheral wall of the outer tube independently of the inflow port. In order to open the inlet, the flow passage is used for communication. Therefore, the circumferential position of the inlet is set according to the internal environment (internal state) of the main body, and the circumferential position of the inlet according to the external environment (external state) of the sheath is the position of the inlet. The main body and the outer tube can be fixed after being set independently.
By setting the injection port and the inflow port in a desired positional relationship in this way, the grout can be fed into the main body from the inflow port through the flow path by injecting the grout from the injection port.

(Claim 2) The inlet and the inlet may be set so as to maintain a distant positional relationship which is on the transverse section of the main body and is not linearly arranged.
For example, the inlet position is set to a lower position where bubbles are not easily generated in the main body, and the inlet position is set to an upper position or a side position where connection with a grout injection hose (away from the reinforcing bar) is easy. Can be set.

(Claim 3) The main body may include a rib portion in which a rib is formed and a straight tube portion, and the inflow port may be provided in the straight tube portion.
In this way, the main body is not sufficiently deformed even when a large pressure is applied to the surface of the peripheral wall from the inside or outside at the rib portion, and the inflow port is provided in the straight tube portion, so that it is easy to form and deform. There is no fear of being blocked by.

(Claim 4) The flow passage may be exposed by a reduced warp portion formed on the outer peripheral surface of the straight tube portion.
In this way, since the flow passage can be formed only by contracting the straight tube portion, a special forming material is not required for forming the flow passage, and the flow passage is formed by closely surrounding the outer tube with the peripheral wall of the main body. Can be a liquid-tight closed passage.

(Claim 5) A spiral rib is formed in the rib portion of the main body, and a main body extension tube that can be screwed into the spiral rib is screwed and connected to the inside of the rib portion. A sheath may be constituted by the main body extension tube and the outer tube.
If it carries out like this, a main body and an outer tube | pipe can be made into short length of a fixed length, and a main body extension pipe | tube can be made long. And the sheath of arbitrary length can be easily comprised only by changing the length of a main body extension pipe | tube. In other words, the main body and the outer pipe can be a joint sheath (pipe joint), and the main body extension pipe can be a sheath pipe connected to the joint sheath.

(Claim 6) The inlet and the inlet may be directed backward on a straight line passing through the center of the main body.
In this case, since the inlet of the outer tube and the inlet of the main body are back on the same straight line, the flow path becomes a symmetric grout flow, without disturbing the grout flow, and The distance between the inlet and the inlet can be maximized and good filling can be realized. Here, the meaning of “facing back” means that the inlet and the inlet face each other with their backs facing each other.

(Claim 7) A plurality of inflow ports may be formed in the flow passage.
If it carries out like this, depending on the internal environment (internal state) of the main body of a sheath, it will become easy to suppress generation | occurrence | production of a bubble by making it flow simultaneously from several places around the main body.

(Claim 8) The outer tube and the main body may be made of polyethylene.
In this way, polyethylene has high corrosion resistance and strength, and can be used for a long time. The main body extension pipe may be made of polyethylene for the same reason.

  According to the sheath including the grout injection part according to the present invention, the peripheral wall of the cylindrical main body is provided with an inflow port for allowing grout to flow into the main body, and independently of the inflow port, the peripheral wall of the outer tube In addition, an inlet for connecting an external grout injection hose is opened to communicate with the flow passage. Therefore, the circumferential position of the inlet is set according to the internal environment (internal state) of the main body, and the circumferential position of the inlet according to the external environment (external state) of the sheath is the position of the inlet. The main body and the outer tube can be fixed after being set independently.

It is a longitudinal cross-sectional view of the specific example of the sheath provided with the grout injection | pouring part which concerns on this invention. It is the II-II sectional view taken on the line of FIG. 1 is a cutaway view of the sheath of FIG. 1, shown cut along line AA. 3 is a perspective view of the same sheath as in FIG. 3, omitting the left front side of the cross section S in FIG. 3. The modification which rotated the position of the injection port in the sheath of FIG. 1 is shown. The conceptual diagram which shows the aspect which applies the sheath provided with the grout injection part which concerns on this invention to a floor slab, and is filled with grout, E is an exhaust port. It is a longitudinal cross-sectional view of the modified embodiment of FIG. It is explanatory drawing of the effect | action which traps the air which arises by grout filling with the conventional sheath. It is explanatory drawing of the state of the forward flow of the grout along PC steel materials which arises by grout filling with the conventional sheath.

  Hereinafter, a description will be given with reference to FIGS. A sheath including a grout injection part according to the present invention includes a cylindrical main body 1 and an outer tube 2. It is preferable to use a resin material having high corrosion resistance and strength so that these can be used for a long time. Specifically, for example, a polyethylene sheath is preferable.

  The main body 1 is formed of a cylindrical body extending along the direction of the axis X, and includes a rib portion 14 in which a spiral rib 13 is formed on the peripheral wall 11 and a straight cylindrical portion 15 in which the rib 13 is not formed. A part of the outer peripheral surface 16 of the straight tube portion 15 is formed with a reduced diameter portion 17 in which an annular groove is formed by reducing the diameter. An inflow port 12 is provided in the peripheral wall 11 of the reduced diameter portion 17 of the straight tube portion 15.

  The outer tube 2 is formed of a cylindrical body that surrounds the outside of the straight cylindrical portion 15 including the reduced diameter portion 17. The flow passage 3 appears by the reduced diameter portion 17 and the outer tube 2 covering the reduced diameter portion 17. A grout inlet 22 is opened in the peripheral wall 21 of the outer tube 2, and an external grout injection hose (not shown) is connected to the inlet 22 to supply the grout G. It is made to be sent from the inflow port 12 to the inner space of the main body 1 through the above.

The main body 1 and the outer tube 2 are in contact with each other between flat surfaces on both the left and right sides of the reduced diameter portion 17. Therefore, the flow paths 3 in which only the injection port 22 and the inflow port 12 are opened can be formed by sealing the flat surfaces with an adhesive.
The position of the inlet 22 of the outer tube 2 is rotated in advance along the diameter-reduced portion 17 of the main body 1 and is fixed after the inlet 22 and the inlet 12 are freely adjusted so as to have a desired positional relationship. By doing so, the positions of the inlet 22 and the inlet 12 can be set according to the sheath inner environment and the outer environment where the sheath is disposed.

  FIG. 5 is a conceptual diagram showing a variation of the positional relationship between the inlet 22 and the inlet 12 that can be taken by the sheath of FIG. Specifically, FIG. 5A shows an arrangement in which the inlet 22 is vertically upward and the inlet 12 is vertically downward (backward relationship), and FIG. 5B shows the inlet 22 obliquely upward to the right. 5 (c), the inlet 22 is arranged obliquely to the left and the inlet 12 is arranged obliquely to the left, and FIG. 5 (d) is the inlet 22 arranged. Fig. 5 (e) shows a case where the inlet 12 is arranged vertically upward and the inlet 12 is arranged obliquely upward to the right, and Fig. 5 (e) shows the inlet 22 arranged in the right horizontal direction and the inlet 12 arranged in the left horizontal direction (backward relationship). These arrangements are examples of a state in which the inlet 22 and the inlet 12 are set in a separated positional relationship in which the inlets 12 and the inlets 12 are not arranged linearly.

  Here, the use state of the sheath when producing prestressed concrete (PC) will be described. An object to be reinforced by introducing a tension force into the tension member P (FIG. 2) inserted through the sheath body 1 is usually horizontal or nearly horizontal like the concrete floor slab K shown in FIG. It is used in the state. Therefore, the main body 1 through which the tendon P is passed is also used in a state where the axis X is in a horizontal state or a wavy state in which there is some up and down. It is desirable that the grout G filled in the main body 1 for anticorrosion of the tension material P is uniformly filled in the main body 1.

  At this time, when the grout G is filled from the injection port 22 provided above the main body 1 as in the conventional example shown in FIGS. 8 and 9, when a PC steel material is adopted as the tension material P, the upper portion of the steel material flows. Therefore, there is a concern that the air in the main body 1 is not completely removed and the grout G is poorly filled. Moreover, when the corrosive substance of steel materials penetrate | invades from the inlet 22, there exists a possibility that the penetration distance to steel materials is short and steel material corrosion tends to occur.

  Therefore, in the variation shown in FIG. 5, if the arrangement (backward relationship) in which “the inlet 22 is vertically upward and the inlet 12 is vertically downward” shown in FIG. The hose can be simply connected to the inlet 22 so as to descend straight from above. Moreover, since the inlet 22 and the inlet 12 are arranged so as to face away on a straight line L passing through the center C of the main body 1 (FIG. 2), the grout G injected into the inlet 22 of the outer tube 2 is Instead of flowing directly into the main body 1, the flow passage 3 is symmetrically turned and flows upward into the main body 1 from the lower side of the main body 1, so that the grout G is uniformly filled. Due to the inflow of the grout G due to such an upward flow, the grout G flows up from the inlet 12 so that the air of the main body 1 is pushed out and is sequentially filled into the interior from the lower part, and the air remains. As a result, there is no poor filling and the tension material can be reliably rusted. Moreover, since the inlet 22 of the outer tube 2 and the inlet 12 of the main body 1 are separated from each other, corrosion of the steel material can be prevented even if a corrosive substance of the steel material enters.

  In addition, when using the sheath of the present invention, there is a case where it is planned to use it in the back-facing relationship of FIG. In such an application, in order to ensure that the inlet 22 and the inlet 12 are in a back-facing relationship more easily, a convex portion is provided on one of the straight tube portion 15 and the outer tube 2, and a concave portion is provided on the other. Thus, it may be possible to easily maintain the back relationship by aligning them. If a plurality of convex portions and concave portions are formed at a constant angle, it is possible to align each fixed angle.

And when a reinforcing bar exists just above the inlet 22, by arranging the inlet 22 diagonally upward as shown in FIG. 5B, the reinforcing bar can be avoided and connected slightly.
Moreover, what is necessary is just to arrange | position the inflow port 12 diagonally downward like FIG.5 (c), when the tension material P in the main body 1 approaches a main body bottom part.
In addition, the positional relationship between the inlet 22 and the inlet 12 may be set to an arbitrary arrangement depending on the outer environment and the inner environment of the sheath.

  As shown in FIG. 5 (f), it is possible to use the inlet 22 and the inlet 12 as an arrangement in which the inlet 22 and the inlet 12 are linearly arranged. However, the inlet 22 and the inlet 12 are separated from each other. The injection is not related and is not the preferred grout injection method in the present invention.

(Modification)
The sheath body 1 described so far with reference to FIG. 1 has been constituted by a single cylindrical body including a rib portion 14 and a straight cylindrical portion 15. In this case, the length of the entire sheath in the direction of the axis X can be changed by changing the length of the rib portion 14, but it is necessary to form a sheath having a different overall length for each use place.
Therefore, the present invention is applied to the joint sheath so that the length of the sheath can be easily set / changed in the field according to the place of use. It is possible to construct a sheath having an appropriate length on the site.

  That is, as shown in FIG. 7, a sheath composed of the main body 1 and the outer tube 2 is used in the form of a joint sheath. The joint sheath is used by connecting a pair of left and right main body extension tubes 1a (sheath tubes) to extend the tube length. In this document, a cylindrical body into which a PC steel material is inserted is used as a sheath. In this sense, the joint sheath is also an aspect of the sheath.

  In the case of a joint sheath, the lengths of the left and right rib portions 14 of the main body 1 are constant without changing depending on the place of use, and at least two spiral ribs 13 are formed (3.5 circles on one side). It is.

Separately from this, a main body extension tube 1a is prepared which can be screwed into the joint sheath by being inserted inside the main body 1 with respect to the spiral rib 13 of the rib portion 14.
The main body extension tube 1a is cut to a required length and screwed to the joint sheath rib 13 to form a sheath whose main body 1 has an axial length extended by the main body extension tube 1a. Become so.

  In the joint sheath, the main body extension pipe 1a connected to the main body 1 from the left and right is provided with a stopper so that it is not connected too deeply. However, since the reduced diameter portion 17 serves as a stopper, The main body extension pipes 1a cannot be screwed deeper than the reduced diameter portion 17, respectively.

  In the above example, one inlet 12 is formed, but a plurality of inlets 12 may be formed. Depending on the sheath diameter, the number of PC steel materials, etc., it may be preferable to flow in from a plurality of locations.

  Further, in the above example, the position of the inlet 22 with respect to the inlet 12 is rotated in the circumferential direction so that the position is shifted and kept in a separated positional relationship. In addition, the inlet 22 can be slid in the axial direction. By doing so, the distant positional relationship may be maintained. That is, by increasing the width of the reduced diameter portion 17 in FIG. 1 and making the flow passage 3 wide, it is possible to maintain a remote positional relationship in a state where the inlet 22 and the inlet 12 are displaced in the axial direction. You may be able to do it.

DESCRIPTION OF SYMBOLS 1 Main body 2 Outer pipe 3 Flow path 11 Peripheral wall 12 Inlet port 13 Rib 14 Rib part 15 Straight cylinder part 16 Outer peripheral surface 17 Constriction part
21 Peripheral wall 22 Inlet G Grout S Cross section C Center L Straight line K Floor slab P Tensile material X Axis line

Claims (8)

Includes a cylindrical body (1) and an outer tube (2),
The main body (1) is provided with an inlet (12) for grout (G) on the peripheral wall (11),
The outer pipe (2) has a grout (G) inlet (22) on the peripheral wall (21),
The outer pipe (2) surrounds the main body (1), and a flow path (3) of a grout (G) appears between the outer pipe (2) and the flow path (3). (12) is opened, and the circumferential position of the inlet (22) with respect to the inlet (12) is arbitrarily determined by rotating the outer tube (2) in the circumferential direction with respect to the main body (1). A sheath comprising a grout injection part, characterized in that it can be set to   The injection port (22) and the inflow port (12) are set so as to maintain a spaced apart positional relationship on the transverse section (S) of the main body (1) that is not linearly aligned. A sheath comprising the grout injection part according to 1.   The main body (1) includes a rib portion (14) formed with a rib (13) and a straight tube portion (15), and the inflow port (12) is provided in the straight tube portion (15). Item 3. A sheath comprising the grout injection part according to any one of Items 1 and 2.   The sheath having a grout injection portion according to claim 3, wherein the flow passage (3) is exposed by a constricted portion (17) formed on the outer peripheral surface (16) of the straight tube portion (15).   A spiral rib (13) is formed on the rib portion (14) of the main body (1), and a main body extension pipe (1a) that can be screwed to the spiral rib (13) is provided in the rib portion (14). The grout injection portion according to any one of claims 3 to 4, wherein a sheath is constituted by the main body (1), the main body extension pipe (1a), and the outer pipe (2). Sheath provided.   The said inlet (22) and this inflow port (12) are back on the straight line (L) which passes along the center (C) of this main body (1). Sheath with a grout injection part.   The sheath provided with the grout injection part according to any one of claims 1 to 5, wherein a plurality of the inflow ports (12) are formed in the flow passage (3). The sheath provided with a grout injection part according to any one of claims 1 to 7, wherein the outer tube (2) and the main body (1) are made of polyethylene.

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