JP6058422B2 - Shear reinforcement method - Google Patents

Description

  The present invention relates to a shear reinforcement method, and more particularly to a shear reinforcement method for reinforcing an existing reinforced concrete wall on which a shear load acts.

  For example, box-shaped reinforced concrete structures such as box culverts that form spaces such as underground spaces support earth pressure and water pressure from the ground, for example, by building a reinforced concrete wall surrounding the space. It has a structure. In addition, the reinforced concrete wall around the space such as the underground space has a predetermined cover thickness between these wall surfaces on one wall side and the other wall side across the central portion in the thickness direction, Main reinforcing bars and distributing reinforcing bars are generally arranged in a grid and are embedded in concrete.

  On the other hand, in response to the recent Great Hanshin-Awaji Earthquake and the Great East Japan Earthquake, for example, box-shaped concrete structures such as box culverts that form spaces such as underground spaces have undergone seismic reinforcement work to improve earthquake resistance. To be done. For example, in the case of seismic reinforcement of underground structures, it is necessary to perform reinforcement work from the inside of the underground space without digging up the underground structure.For example, after reinforcing reinforcement bars are installed along the wall facing the underground space, When concrete is placed and reinforced by increasing the thickness of the reinforced concrete wall, the underground space becomes narrower. For this reason, a plurality of reinforcing material insertion holes are formed in the reinforced concrete wall, a shear reinforcing material is inserted and installed in the formed reinforcing material insertion hole, and the filler is further solidified by filling. Various shear reinforcement methods have been developed to seismically reinforce reinforced concrete walls by integrating the reinforced concrete walls with reinforced concrete walls and improving the shear strength of underground structures without narrowing the underground space (for example, Patent Document 1). , Patent Document 2 and Patent Document 3).

Japanese Patent No. 3932094 Japanese Patent No. 3676799 Japanese Patent No. 3851643

  However, in the conventional shear reinforcement method for reinforced concrete walls, the space between the inner peripheral surface of the drilled reinforcing material insertion hole and the shear reinforcing material is narrow. When filling with filler after inserting and installing the material, it is difficult for the filler to wrap around the shear reinforcement, and it is stronger than the concrete of the existing reinforced concrete wall to be reinforced The filler was not efficiently used as a reinforcing material. Further, in the shear reinforcement method of Patent Document 1, it is desirable to improve the fixing strength of the shear reinforcement material to the reinforced concrete wall. In the shear reinforcement methods of Patent Document 2 and Patent Document 3, the shear reinforcement material is joined to the proximal end portion of the shear reinforcement material. This makes it necessary to form a widened stepped portion for locking the peripheral edge of the fixing member at the proximal end portion of the reinforcing material insertion hole, which complicates the drilling process.

  In the present invention, the filler is sufficiently wound around the shear reinforcing material installed in the reinforcing material insertion hole so that the filler can be efficiently used as the reinforcing material, sufficient fixing strength can be obtained, and complicated. It aims at providing the shear reinforcement construction method which can be simply constructed without requiring a drilling process.

The present invention relates to a shear reinforcement method for reinforcing an existing reinforced concrete wall to which a shear load is applied, in which a bottomed reinforcing material insertion hole is drilled from one wall surface to the other wall surface. Including a hole step, a reinforcing material installation step of inserting and installing a shear reinforcing material in the formed reinforcing material insertion hole, and a filling step of filling the reinforcing material insertion hole in which the shear reinforcing material is installed, The shear reinforcing material is integrally provided with a diameter-enlarged fixing portion having a large cross-sectional shape at a tip portion, and has a sharpened portion with a pointed tip on the tip side with respect to the diameter-enlarged fixing portion, In the drilling step, the reinforcing material insertion hole is formed from the outer diameter of the expansion fixing portion of the shear reinforcing material from the proximal end opening to the depth at which the bottom end hole portion is disposed close to the main reinforcing bar on the other wall surface side. Is also formed with the same large inner diameter In the reinforcing material installation step, the shear reinforcing material causes the tip of the sharpened portion to abut on the bottom of the tip of the reinforcing material insertion hole, and the base end side portion is placed on the reinforcing material insertion hole. Is inserted in a spacer member disposed inside the reinforcing member insertion hole so as to be separated from the inner peripheral surface of the reinforcing material insertion hole. In the filling step, the filling material is the reinforcing material. Supplied from the proximal end opening of the insertion hole, and held between the circulation port and the enlarged diameter fixing portion and the inner peripheral surface of the reinforcing material insertion hole held around the shear reinforcement by the spacer member by wrap around the entire of the reinforcing member insertion hole through the gap, it has become so that filled to fill the inner space of the reinforcing member insertion hole, said spacer member includes a circular ring portion, the circular ring portion Projecting radially inward from With circumferentially has a circular spacer and a plurality of spacers projections arranged at intervals, the shear reinforcement, provides shear reinforcement method to be inserted into a central region surrounded by the tip of the spacer protrusions This achieves the above object.

  In the shear reinforcement method of the present invention, it is preferable that the filler is a filler having thixotropy.

  Further, in the shear reinforcement method of the present invention, the shear reinforcement material is a threaded reinforcing bar having a male screw portion at a tip portion, and the enlarged diameter fixing portion has a nut member screwed onto the male screw portion. By doing so, it is preferable to be provided integrally at the tip of the shear reinforcement.

  Furthermore, in the shear reinforcement method of the present invention, it is preferable that the spacer member is formed by bending a wire member.

  According to the shear reinforcing method of the present invention, the filler can be sufficiently wound around the shear reinforcing material installed in the reinforcing material insertion hole so that the filler can be efficiently used as the reinforcing material, and sufficient fixing strength can be obtained. It can be easily obtained without requiring a complicated drilling step.

1 is a schematic cross-sectional view of a box culvert that is a box-shaped underground structure that is shear-reinforced by a shear reinforcement method according to a preferred embodiment of the present invention. FIG. 2 is an enlarged schematic cross-sectional view of a part A in FIG. 1 for explaining a shear reinforcement structure formed by a shear reinforcement method according to a preferred embodiment of the present invention. (A)-(d) is a schematic sectional drawing explaining the shear reinforcement construction method which concerns on preferable one Embodiment of this invention. It is a schematic side view which illustrates a shear reinforcement. It is a front view which illustrates a spacer member. It is sectional drawing which illustrates the other form of a spacer member. (A)-(e) is a front view which illustrates further another form of a spacer member.

  As shown in FIG. 1, a shear reinforcement method according to a preferred embodiment of the present invention is preferably a box-shaped culvert 10 made of reinforced concrete for an underground tunnel, for example, as a box-shaped existing underground structure that forms an underground space. Used to improve the shear strength and toughness of the reinforced concrete wall 11 of the side wall, bottom wall, top wall, and partition wall that surrounds the underground space 10a. It is. According to the shear reinforcement method of the present embodiment, it can be easily constructed by work from the underground space 10a inside the box culvert 10, and without increasing the wall thickness and narrowing the inner space of the underground space 10a. The reinforced concrete wall 11 can be effectively shear-reinforced. In this embodiment, the case where the reinforced concrete wall 11 of the side wall portion of the box culvert 10 is seismically strengthened will be described. The wall 11 can be similarly seismically reinforced.

And the shear reinforcement method of this embodiment is a reinforcement method which reinforces the existing reinforced concrete wall 11 which a shear load acts, Comprising: As shown to FIG.2 and FIG.3 (a)-(d), the reinforced concrete wall 11 is shown. one wall surface 11a from the other boring step of boring forming the bottom reinforcement insertion hole 12 towards the wall surface 11b (FIG. 3 (a), (b) ) and the formed reinforcing member insertion hole 12 A reinforcing material installation step for inserting and installing the shear reinforcing material 13 (FIG. 3C), and a filling step for filling the reinforcing material insertion hole 12 in which the shear reinforcing material 13 is installed with the filler 14 (FIG. 3D). Including. The shear reinforcement member 13 is integrally provided with a diameter-enlarged fixing portion 16 having a larger cross-sectional shape at the tip portion, and has a sharpened portion 17 having a pointed tip toward the tip side of the diameter-enlarged fixing portion 16. . In the drilling step, the reinforcing material insertion hole 12 has a diameter expansion fixing portion of the shear reinforcing material 13 from the proximal end opening 12a to a depth at which the distal end hole bottom portion 12b is disposed close to the main reinforcing bar 20a on the other wall surface 11b side. The same inner diameter larger than the outer diameter of 16 is formed. In the reinforcing material installation step, the shear reinforcing material 13 causes the distal end of the sharpened portion 17 to abut on the distal end hole bottom portion 12 b of the reinforcing material insertion hole 12, and the base end side portion is disposed inside the reinforcing material insertion hole 12. By being inserted through the spacer member 18, the spacer member 18 is installed in a state of being separated from the inner peripheral surface of the reinforcing material insertion hole 12. In the filling process, the filler 14 is supplied from the proximal end opening 12 a of the reinforcing material insertion hole 12 and is held by the spacer member 18 around the shear reinforcing material 13 (see FIG. 5) and the diameter expansion fixing. The inner space of the reinforcing material insertion hole 12 is filled by filling the entire reinforcing material insertion hole 12 through a gap held between the portion 16 and the inner peripheral surface of the reinforcing material insertion hole 12. It has become. The spacer member 18 is an annular spacer 18 that includes a circular ring portion 18a and a plurality of spacer protrusions 18b that protrude radially inward from the circular ring portion 18a and that are spaced apart in the circumferential direction. The reinforcing member 13 is inserted into a central region 18c surrounded by the tip of the spacer protrusion 18b (see FIG. 5).

  In the present embodiment, the existing reinforced concrete wall 11 to be shear-reinforced is, for example, a reinforced concrete wall of the side wall portion of the box culvert 10, and one wall surface 11a of the reinforced concrete wall 11 faces the underground space 10a. The other wall surface 11b is in close contact with the natural ground 21 and firmly supports earth pressure and water pressure from the natural ground 21. The reinforced concrete wall 11 has a thickness of about 200 to 5000 mm, for example, and is disposed between the wall surfaces 11a and 11b on one wall surface 11a side and the other wall surface 11b side across the central portion in the thickness direction. For example, in a state where a predetermined cover thickness of about 30 to 200 mm is maintained, the main reinforcing bars 20a and the reinforcing reinforcing bars 20b are arranged in, for example, a lattice and embedded in the concrete of the reinforced concrete wall 11.

  Moreover, in this embodiment, as shown in FIG. 4, the shear reinforcement member 13 is a reinforcing reinforcing bar having a thickness of, for example, a reinforcing bar diameter of about 13 to 51 mm, and is preferably provided with a male screw part 13a at the tip part. Reinforcing bar with screws. Further, the diameter-enlarged fixing portion 16 is preferably formed by screwing a hexagon nut 16a having a maximum outer diameter of, for example, about 23 to 75 mm as a nut member to the male screw portion 13a. It is provided as one. The shear reinforcement member 13 has a length of, for example, about 140 to 4600 mm, which is obtained by subtracting the cover thickness on both the one wall surface 11a side and the other wall surface 11b side from the thickness of the reinforced concrete wall 11. As a result, the shear reinforcement member 13 can be arranged so as to straddle or substantially straddle between the main reinforcing bars 20a on both sides arranged on the one wall surface 11a side and the other wall surface 11b side. (See FIG. 2). The shear reinforcing material 13 has a sharpened tip with a sharp tip at the tip of the diameter-enlarged fixing portion 16, for example, by being obliquely cut at a portion protruding toward the tip of the diameter-fixed portion 16. 17.

  In the present embodiment, as shown in FIG. 3A, for example, a drilling step of drilling the bottomed reinforcing material insertion hole 12 from one wall surface 11a to the other wall surface 11b of the reinforced concrete wall 11 is performed. Using a known drilling machine 22 such as a rock drill or a core drill, core drilling is performed in a direction perpendicular to one wall surface 11a by work from the underground space 10a. Accordingly, the reinforcing material insertion hole 12 having a circular cross section having an inner diameter of, for example, about 30 to 80 mm, which is larger than the maximum outer diameter of the diameter-enlarged fixing portion 16 by the hexagon nut 16a, extends from the proximal end opening 12a to the distal end hole bottom portion 12b. They are formed with the same inner diameter up to the depth arranged close to the main reinforcing bar 20a on the natural ground 21 side.

  Here, the reinforcing material insertion holes 12 are preferably arranged in a lattice pattern on one wall surface 11a side of the reinforced concrete wall 11 facing the underground space 10a, and are arranged in a lattice pattern by the main reinforcing bars 20a and the distributed reinforcing bars 20b. With the central portion as a drilling position, a plurality of locations are formed on one wall surface 11a at predetermined intervals in the vertical and horizontal directions. The predetermined interval and the number of the reinforcing material insertion holes 12 formed can be appropriately set in view of the seismic strength after reinforcement of the reinforced concrete wall 11, the size of the box culvert 10, the installation depth, and the like.

  Further, the reinforcing material insertion hole 12 is drilled from the proximal end opening 12a to a depth at which the tip hole bottom 12b is disposed close to the main reinforcing bar 20a on the other wall surface 11b side. If the depth of the reinforcing material insertion hole 12 is too deep, the concrete at the cover portion on the other wall surface 11b facing the natural ground 21 is likely to be damaged. Thus, it is impossible to sufficiently obtain the 11 shear reinforcement effect. The reinforcing material insertion hole 12 is preferably formed to a depth close to the main reinforcing bar 20a on the other wall surface 11b side in a range where the tip hole bottom 12a does not reach the main reinforcing bar 20a on the other wall surface 11b side. Thereby, even when the main reinforcing bar 20a on the other wall surface 11b side facing the natural ground 21 is arranged in a state shifted from the main reinforcing bar 20a on the one wall surface 11a side facing the underground space 10a. When the reinforcing material insertion hole 12 is drilled, it is possible to effectively avoid accidentally damaging the main reinforcing bar 20a on the other wall surface 11b side by the drilling machine.

  Further, the reinforcing material insertion hole 12 is formed with the same inner diameter from the proximal end opening 12a of one wall surface 11a facing the underground space 10a to the depth of the distal end hole bottom 12b. As a result, a drilling machine having the same drilling diameter can be obtained without the need for a setup change for increasing the drilling diameter of the drilling machine, as in the case of forming a widening stepped part on the base end side of the reinforcing material insertion hole. It becomes possible to form the plurality of reinforcing material insertion holes 12 more easily.

  In this embodiment, prior to installing the shear reinforcement material 13 in the formed reinforcement material insertion hole 12, the inside of the reinforcement material insertion hole 12 is cleaned. As shown in FIG. 3B, the inside of each strong material insertion hole 12 is cleaned using, for example, a high-pressure air cleaning tool 23 to which a cleaning nozzle 23b with a brush having a spout 23a at the tip is attached. It is possible to carry out easily while jetting.

  Further, in the present embodiment, the reinforcing material installing step of installing the shear reinforcing material 13 in the reinforcing material insertion hole 12 is performed by replacing the shear reinforcing material 13 having the enlarged diameter fixing portion 16 and the sharpened portion 17 at the tip portion with the underground. The work is performed by inserting and installing the spacer member 18 by being pushed into the reinforcing material insertion hole 12 from the proximal end opening 12a with the spacer member 18 attached thereto by the work from the space 10a.

  In this embodiment, the spacer member 18 is preferably a metal annular spacer formed by cutting out a thin plate made of stainless steel by pressing. For example, as shown in FIG. 5, the annular spacer 18 includes a circular ring portion 18 a and a plurality of spacer protrusions 18 b that protrude radially inward from the circular ring portion 18 a and are spaced apart in the circumferential direction. The shear reinforcing material 13 is inserted into the central region 18c of the annular spacer 18 surrounded by the tip of the spacer protrusion 18b inside the circular ring portion 18a. Thereby, when the shear reinforcement member 13 is installed inside the reinforcement member insertion hole 12 together with the annular spacer 18, a plurality of spacer protrusions are arranged around the shear reinforcement member 13 at intervals in the circumferential direction. The flow port 19 for the air and the filler 14 due to the interval portion 18b is held by the spacer protrusion 18b.

  In the reinforcing material installation step, as shown in FIG. 3C, the base end side portion of the shear reinforcing material 13 is inserted into the central region 18 c of the annular spacer 18, and the annular spacer 18 is attached to the shear reinforcing material 13. Then, the sharpened portion 17 is applied to the shear reinforcing material 13 from the distal end side where the enlarged diameter fixing portion 16 is provided, for example, manually by an operator, into the reinforcing material insertion hole 12 through the proximal end opening 12a. Until the leading end of each of the two contacts the bottom end 12b of the reinforcing material insertion hole 12. In addition, the annular spacer 18 attached to the proximal end portion of the shear reinforcement 13 is positioned and positioned slightly inside the main reinforcing bar 20a on the one wall surface 11a side facing the underground space 10a. As a result, both ends of the shear reinforcement member 13 are supported by the enlarged diameter fixing portion 16 and the annular spacer 18, and are separated from the inner peripheral surface of the reinforcement member insertion hole 12 at a substantially central position of the reinforcement member insertion hole 12. It will be easily installed in the inside of the reinforcing material insertion hole 12 while being arranged in a state and substantially straddling between the main reinforcing bars 20a on both sides.

  In the present embodiment, the filling process of filling the filler material 14 into the reinforcing material insertion hole 12 in which the shear reinforcement material 13 is installed has, for example, high fluidity through the proximal end opening 12 a of the reinforcing material insertion hole 12. This is performed by filling the reinforcing material insertion hole 12 with the filling material 14 having a pressure by filling the reinforcing material insertion hole 12 while replacing the air with the internal air by work from the underground space 10a.

  Here, in the present embodiment, it is preferable to use a filler having thixotropy, which is a property that the viscosity is lowered by stirring and then the viscosity is returned to the original by leaving it agitated. . Further, it is more preferable to use a high fluidity mortar having thixotropic properties and excellent filling properties. As the high fluidity mortar having excellent thixotropic filling property, for example, it is a premix type gap filling grout material having a high thixotropic property that can be used by adding a predetermined amount of water at the time of use and kneading. The trade name “Naoshital” (manufactured by Newtec Co., Ltd.) can be used.

  By using a filler having thixotropy as the filler 14, a mold for preventing the filler 14 supplied to the reinforcing material insertion hole 12 from leaking from the base end opening 12a becomes unnecessary. Reinforcement work can be easily performed. Further, by using a high fluidity mortar excellent in filling property as the filling material 14, the filling material 14 solidified after filling the reinforcing material insertion hole 12 has a higher strength than the concrete of the existing reinforced concrete wall 11. Therefore, it can be effectively used as a stable reinforcing material.

  In the filling step, as shown in FIG. 3 (d), for example, from a mortar discharge nozzle 24a at the distal end of the pressure hose 24 connected to a known mortar pump having a hopper having a considerable capacity, through a proximal end opening 12a. The filler 14 is fed under pressure into the hollow inside of the reinforcing material insertion hole 12 in which the shear reinforcing material 13 is installed.

  In the present embodiment, since the inner diameter of the reinforcing material insertion hole 12 is larger than the outer diameter of the enlarged fixing portion 16 of the shear reinforcing material 13, the shear reinforcing material 13 and the inner peripheral surface of the reinforcing material insertion hole 12 A space having a considerable width is held between the entire circumference of the reinforcing material insertion hole 12. Further, a circulation port 19 having a considerable opening area is held around the proximal end portion side of the shear reinforcement member 13 by the annular spacer 18, and the outer periphery of the enlarged diameter fixing portion 16 including the hexagon nut 16 a on the distal end portion side. A gap having a considerable width is also maintained between the surface and the inner peripheral surface of the reinforcing material insertion hole 12. Further, the shear reinforcement member 13 is positioned inside the reinforcing material insertion hole 12 with the sharpened tip 17 having a sharp tip abutted against the tip hole bottom portion 12 a of the reinforcing material insertion hole 12, so that the sharpened portion 17. A clearance is also maintained between the tip end bottom surface 12a and the tip end surface around the contact point by the pointed tip.

  As a result, the filler 14 pressure-fed and supplied into the hollow interior of the reinforcing material insertion hole 12 is smoothly replaced with the air inside through the space around the shear reinforcing material 13, the circulation port 19, and the gap. Then, it goes around the entire reinforcing material insertion hole 12 in which the shear reinforcing material 13 is installed. As a result, except for a very small part of the shear reinforcement member 13, substantially the entire thickness thereof is interposed between the outer peripheral surface of the shear reinforcement member 13 and the inner peripheral surface of the reinforcing member insertion hole 12. The filler 14 fills the inner space of the reinforcing material insertion hole 12 and is filled without a gap so as to be covered with the filler 14. In addition, the filler 14 is filled in the reinforcing material insertion hole 12 in the portion where the shear reinforcing material 13 is not disposed on the proximal end opening 12a side of the proximal end portion of the installed shear reinforcing material 13 without gaps. It will be.

  In the present embodiment, the filler 14 filled in the reinforcing material insertion hole 12 in the above-described filling step is solidified, so that the solidified filler 14 that exhibits a considerable strength, the shear reinforcement 13, and the existing filler As shown in FIG. 2, a shear reinforcement structure 15 capable of effectively improving the shear strength and toughness of the reinforced concrete wall 11 is formed, in which the concrete of the reinforced concrete wall 11 is integrated.

  And according to the shear reinforcement method of this embodiment provided with the above-mentioned structure, the filler 14 is sufficiently wound around the shear reinforcement material 13 installed in the reinforcement material insertion hole 12, and the filler material 14 is used as a reinforcement material. As well as sufficient fixing strength and simple construction without requiring a complicated drilling step.

  In other words, according to the present embodiment, the shear reinforcement member 13 is integrally provided with the diameter-enlarged fixing portion 16 having a larger cross-sectional shape at the tip portion, and the tip is sharper on the tip side than the diameter-enlarged fixing portion 16. In the drilling process, the reinforcing material insertion hole 12 is expanded to a depth at which the bottom hole bottom portion 12b is disposed close to the main reinforcing bar 20a on the other wall surface 11b side. In the reinforcing material installing step, the shear reinforcing material 13 is formed at the tip end bottom portion 12 b of the reinforcing material insertion hole 12 at the tip of the sharpened portion 17. , And the base end side portion is inserted through the annular spacer 18 so as to be installed in a state of being separated from the inner peripheral surface of the reinforcing material insertion hole 12. Is the annular spacer 18 Therefore, the entire reinforcing material insertion hole 12 is circulated through a clearance held between the flow port 19 and the diameter expansion fixing portion 16 held around the shear reinforcing material 13 and the inner peripheral surface of the reinforcing material insertion hole 12. Thus, the internal space of the reinforcing material insertion hole 12 is filled and filled.

  Therefore, according to the shear reinforcement method of the present embodiment, the space around the shear reinforcement member 13 inside the reinforcement member insertion hole 12 formed with an inner diameter larger than the outer diameter of the enlarged diameter fixing portion 16 of the shear reinforcement member 13. In addition, the filler 14 can be smoothly and sufficiently wrapped around the shear reinforcement member 13 through the circulation port 19 or the like formed by the annular spacer 18, and a considerable thickness is formed around the shear reinforcement member 13. The solidified layer of the filler 14 is formed, and the filler 14 can be efficiently used as a reinforcing material. Further, the shear reinforcement member 13 is provided with a diameter-enlarged fixing portion 16 having a large cross-sectional shape at the tip portion, and this diameter-enlarged fixing portion 16 is located on the other wall surface 11 b side facing the natural ground 21 of the reinforced concrete wall 11. Since the fixing strength can be increased by being arranged close to the arranged main reinforcing bar 20a, it is loaded on the existing concrete cover part on the ground 21 side of the main reinforcing bar 20a during an earthquake. By dispersing the load over a wide range, the shear strength and toughness of the reinforced concrete wall 11 can be effectively improved. Further, the reinforcing material insertion hole 12 in the portion where the shear reinforcing material 13 is not disposed on the base end opening 12a side of the base end portion of the installed shear reinforcing material 13 is filled with strength higher than that of the existing concrete. Since the material 14 is filled without any gaps, the load applied to the existing concrete cover portion on the underground space 10a side of the main rebar 20a is dispersed over a wide range at the time of an earthquake by the filler 14 having a large strength. Thus, the shear strength and toughness of the reinforced concrete wall 11 can be effectively improved. Furthermore, since the reinforcing material insertion hole 12 is formed with the same inner diameter from the proximal end opening 12a to the distal end hole bottom 12b, as in the case of forming a widened stepped portion on the proximal end side of the reinforcing material insertion hole, A plurality of reinforcing material insertion holes 12 can be more easily formed by using a drilling machine having the same drilling diameter without requiring setup change for increasing the drilling diameter of the drilling machine.

  The present invention is not limited to the above-described embodiment, and various modifications can be made. For example, the filler filled in the reinforcing material insertion hole does not necessarily need to be a thixotropic filling material, and does not have thixotropic properties by installing a mold at the proximal end opening of the reinforcing material insertion hole. It can also be constructed using a filler. The enlarged diameter fixing portion does not necessarily need to be a nut member, and can be integrally joined to the shear reinforcement material. The shear reinforcement material may be a reinforcing bar or a steel bar.

  The spacer member is not necessarily an annular spacer composed of a circular ring portion and a plurality of spacer protrusions protruding radially inward from the circular ring portion. Various other shapes of spacer members can be used, in which the shear reinforcing material can be installed in a state of being separated from the inner peripheral surface of the reinforcing material insertion hole and the circulation port can be held around the shear reinforcing material. For example, as shown in FIG. 6, the shear reinforcement member 13 formed by bending a metal wire member made of stainless steel with a thickness of about φ0.5 mm is preferably inserted into the reinforcement member insertion hole 12. A linear spacer member 18 ′ that can be installed in a state of being separated from the peripheral surface and that can hold the flow port 19 around the shear reinforcement 13 may be used. The linear spacer member 18 ′ can also be used after being bent into a shape as shown in FIGS. The linear spacer member 18 ′ can be formed at a lower cost, and spacer members having different dimensions can be easily formed.

  The existing underground structure that is seismically reinforced by the shear reinforcement method of the present invention may be other box-like underground structures such as underground parking lots other than box culverts, and reinforced concrete other than underground structures. For example, it may be a reinforced concrete structure provided with walls. For example, if there is existing equipment on the back side of a reinforced concrete wall, the back side is a waterway, the back side faces a railway or road, or it is difficult to install a scaffold on the back side It is possible to perform shear reinforcement of a reinforced concrete structure by performing the shear reinforcement method of the present invention from the front side opposite to the side.

10 Box culvert (box-like underground structure)
DESCRIPTION OF SYMBOLS 10a Underground space 11 Reinforced concrete wall 11a One wall surface 11b The other wall surface 12 Reinforcement material insertion hole 12a Base end opening 12b Bottom hole bottom portion 13 Shear reinforcement material 13a Male thread portion 14 Filler material 15 Shear reinforcement structure 16 Expansion fixing portion 16a Hexagon nut 17 Pointed portion 18 Spacer member (annular spacer)
18a Circular ring portion 18b Spacer protrusion 18c Central region 18 'Spacer member (linear spacer)
19 Distribution port 20a Main reinforcing bar 20b Power distribution reinforcing bar 21 Ground mountain 22 Drilling machine 23 High-pressure cleaning tool 24 Pressure hose 24a Mortar discharge nozzle

Claims (3)

A shear reinforcement method for reinforcing an existing reinforced concrete wall on which a shear load acts, a drilling step of drilling a bottomed reinforcing material insertion hole from one wall surface to the other wall surface of the reinforced concrete wall; Including a reinforcing material installation step of inserting and installing a shear reinforcing material in the formed reinforcing material insertion hole, and a filling step of filling the reinforcing material insertion hole in which the shear reinforcing material is installed,
The shear reinforcement material is integrally provided with a diameter-enlarged fixing portion having a large cross-sectional shape at the tip portion, and has a sharpened portion with a pointed tip on the tip side from the diameter-enlarged fixing portion,
In the drilling step, the reinforcing material insertion hole has an outer diameter of the expanded diameter fixing portion of the shear reinforcing material from a proximal end opening to a depth at which a bottom end portion of the distal end hole is disposed close to the main reinforcing bar on the other wall surface side. Is formed with the same inner diameter that is larger than
In the reinforcing material installation step, the shear reinforcing material is arranged such that the tip of the sharpened portion abuts on the bottom of the tip of the reinforcing material insertion hole, and the proximal end portion is disposed inside the reinforcing material insertion hole. By being inserted into the spacer member, it is installed in a state separated from the inner peripheral surface of the reinforcing material insertion hole,
In the filling step, the filler is supplied from the proximal end opening of the reinforcing material insertion hole and is held around the shear reinforcing material by the spacer member, the diameter-enlarged fixing portion, and the reinforcing material. by via a gap held between the inner peripheral surface of the insertion hole around to the whole of the reinforcing member insertion holes, it has become so that filled to fill the inner space of the reinforcing member insertion hole,
The spacer member is an annular spacer composed of a circular ring portion and a plurality of spacer protrusions protruding radially inward from the circular ring portion and spaced apart in the circumferential direction, and the shear reinforcement member Is a shear reinforcement method inserted through a central region surrounded by the tips of the spacer protrusions .   The shear reinforcement method according to claim 1, wherein the filler is a filler having thixotropy.   The shear reinforcing material is a threaded reinforcing bar having a male screw portion at a tip portion, and the enlarged diameter fixing portion is screwed onto the male screw portion by screwing a nut member to the tip portion of the shear reinforcing material. The shear reinforcement construction method according to claim 1 or 2, wherein the shear reinforcement construction method is provided as a single unit.

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