JP2006057289A - Shear reinforcement structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shear reinforcement structure of an existing RC structure, which can simply and surely ensure predetermined pull-out rigidity. <P>SOLUTION: This shear reinforcement structure comprises a side wall W of an existing reinforced concrete structure, a shear reinforcement member 20 which is arranged inside a bottomed reinforcing member inserting hole 10 formed in a direction crossing a main reinforcement of the side wall W, and a high-strength fiber filler 30 for being infilled into the hole 10. The hole 10 comprises a general part 11 with an inside diameter larger than a diameter of a leading protrusion 22 of the member 20, a base-end widened part 12 which is formed at the base end of the hole 10 and which has an inside diameter larger than that of the general part 11, and a leading-end widened part 13 which is formed at the leading end of the hole 10 and which has an inside diameter larger than that of the general part 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shear reinforcement structure of a structure of an existing reinforced concrete structure (hereinafter, reinforced concrete may be referred to as “RC”) on which a shearing force acts.

  In various facilities such as subways and water and sewage purification facilities designed and constructed before the Great Hanshin Earthquake, RC box culverts and RC underground walls, slabs, and bridge walls that make up the structure Reinforced concrete structures such as type piers (hereinafter sometimes referred to as “RC structures”) are often not provided with shearing reinforcing bars, and there is a lack of shear strength against Level 2 seismic motion. It is clear from the results of the diagnosis, and it is pointed out that it is necessary to conduct seismic reinforcement promptly.

  These RC structures are mostly embedded in the ground due to their functional characteristics. When reinforcing after construction, the side walls and bottom slabs of the structural frame cannot be reinforced from the outside surface side. It must be reinforced only from the inner side. Here, in this specification, the “outer surface” refers to the surface of the RC structure that faces the ground of the plate material or plate material, and the “inner surface” refers to the outer surface of the same material or plate material. This is the surface that faces the surface and does not face the natural ground.

  Conventionally, as a reinforcing method of these RC structures, a thickening method in which main reinforcing bars and distribution reinforcing bars are arranged along the surface of the RC structure and concrete is placed, or a steel plate is provided around the RC structure. A steel plate winding method or the like in which a gap between the RC structure and the steel plate is filled with a filler such as mortar or resin has been adopted.

  However, these methods cause various inconveniences such as an increase in the thickness of the face material and the plate material after reinforcement and a decrease in the internal cross section of the frame (for example, in the case of a water and sewage purification facility). In some cases, water storage capacity and processing capacity decrease, and in the case of a subway, the construction limit will not be satisfied, and it may become unusable. Furthermore, the thickening method increases the main reinforcement, so that the shear strength is improved while the bending strength is also increased. Therefore, after the reinforcement, the request to shift the shear pre-breaking type to the bending pre-breaking type is realized. It was difficult.

  In addition, large-scale lifting machines are required to carry in and assemble reinforcing members such as reinforcing steel bars and steel plates, and in the limited space such as underground structures and bridges, there are restrictions on these lifting machines. It was sometimes difficult. In addition, in the case of shear reinforcement in road tunnels and railway tunnels that are in service, the conventional reinforcement method described above is required for rapid construction within a limited time zone at night due to restrictions on traffic volume and train operation. Then, there was a case where construction was not possible.

Therefore, in order to solve the above problems, as a method for reinforcing the culvert, from the inner surface side of the outer wall of the culvert, a slit is formed in a vertical direction at a predetermined interval, and after inserting a predetermined steel plate into the slit, A method has been proposed in which a grout material is filled in the slit to integrate the steel plate and the outer wall. (For example, Patent Document 1)
Japanese Patent Laying-Open No. 2003-3556 (page 2 to page 4, FIG. 2)

  However, in the reinforcing method, a predetermined steel plate is simply inserted into the slit, so that when the pulling force is generated in the steel plate, sufficient rigidity (the magnitude of the pulling resistance against the pulling force, hereinafter referred to as “pulling rigidity”). ") Could not be obtained.

  The present invention has been made in order to solve the above-mentioned problems, and it is possible to easily and surely secure a predetermined pulling rigidity, which is a shear reinforcement structure for an existing RC structure (hereinafter simply referred to as “ It is an object to provide a “shear reinforcement structure”.

  In order to solve the above problems, the invention according to claim 1 is a shear reinforcement mainly composed of an existing reinforced concrete structure and a wire disposed inside a reinforcing member insertion hole formed in the reinforced concrete structure. A shear reinforcement structure comprising a member and a filler filled in the reinforcing member insertion hole, wherein the reinforcing member insertion hole has a general portion having an inner diameter larger than the diameter of the wire, and the reinforcing member insertion hole And a base end widened part having an inner diameter larger than that of the general part.

  The invention according to claim 2 is the shear reinforcement structure according to claim 1, wherein a tip widening portion having an inner diameter larger than the general portion is formed at the tip of the reinforcing member insertion hole. It is characterized by having.

Further, the invention according to claim 3 is the shear reinforcement structure according to claim 1 or 2, wherein when the wire material of the filler is a deformed reinforcing bar, the adhesion strength is 60 N / mm ^2. It is the above.

  The invention according to claim 4 is the shear reinforcement structure according to any one of claims 1 to 3, wherein the shear reinforcement member is a shear reinforcement bar that is the wire, and a proximal end of the shear reinforcement bar A proximal fixing member having a cross-sectional shape larger than the diameter of the reinforcing bar of the shear reinforcing bar, and a fixing anchor having a larger cross sectional shape than the diameter of the reinforcing bar of the shear reinforcing bar formed at the distal end of the shear reinforcing bar. And a member.

  The invention according to claim 5 is the shear reinforcement structure according to any one of claims 1 to 4, wherein the filler is a fiber reinforcement in which fibers are mixed in a cementitious matrix. It is a cement-based mixed material.

  The invention according to claim 6 is the shear reinforcement structure according to claim 5, wherein the fiber-reinforced cement-based mixed material is cement, an aggregate having a maximum particle size of 2.5 mm or less, and a particle size. Fibers having a diameter of 0.05 to 0.3 mm and a length of 8 to 16 mm are added to a cement-based matrix obtained by mixing 0.01 to 15 μm pozzolanic reactive particles, at least one kind of dispersion material, and water. 1 to 4% of the volume of the cementitious mixture is mixed.

Here, the target member for reinforcement according to the present invention is a member that requires shear reinforcement, and various existing reinforced concrete structures, such as face materials (walls, etc.) or plate materials (bottom plates, top plates, etc.), (Hereinafter referred to as “RC surface plate material”), and the type of on-site casting, precast concrete product, etc. is not limited regarding the construction object.
Further, the shear reinforcement member secures a predetermined covering concrete thickness from the inner surface side end surface and the outer surface side end surface in the thickness direction of the RC surface plate material so as to avoid the main reinforcing bars and the distributed reinforcing bars that are pre-arranged. Need to be placed in.

  According to the present invention, since the shear reinforcement member and the RC surface plate material concrete are integrated via the filler, this occurs when an out-of-plane shear force is generated in the RC surface plate material. The shear reinforcing member and the RC surface plate material integrally resist the oblique tensile stress. Accordingly, it is possible to improve the shear strength of the existing RC surface plate material and shift the fracture mode due to an earthquake or the like from brittle fracture to tough fracture.

  In addition, according to the present invention, an increase in shear strength and toughness performance can be efficiently realized by directly embedding a shear reinforcement member in the wall without increasing the concrete thickness of the RC surface plate material. Since it can do, it can prevent that the inconvenience that the internal cross section of a housing reduces after reinforcement | strengthening arises. In addition, since the main reinforcing bars are not increased, the out-of-plane shear strength can be improved without increasing the bending strength. The structure can be transferred to a bending predestructive type.

  Further, in the shear reinforcing member, a fixing member (base fixing member and distal fixing member) having a larger cross-sectional shape than the shear reinforcing reinforcing bar is provided at the proximal end portion or the proximal end portion and the distal end portion of the shear reinforcing reinforcing rod which is a wire. If so, the fixing effect of the shear reinforcing member can be enhanced, and the tensile resistance of the shear reinforcing bar and the compressive stress generated in the concrete inside the fixing member can more effectively improve the shear strength and toughness performance. Can be improved. Here, the wire is not limited to a reinforcing bar, and any wire such as a carbon wire, a steel rod, and a PC steel strand can be applied.

In addition, if a material with an adhesive strength of 60 N / mm ² or more is used as the filler, the out-of-plane shear strength can be improved even when the shear reinforcement member is made of only the wire. It becomes possible to make it. In addition, when the shear reinforcement member is made only of a wire, it is possible to reduce the diameter of the reinforcement member insertion hole and to eliminate the labor of processing the shear reinforcement member.

Further, as a filler, cement, an aggregate having a maximum particle size of 2.5 mm or less, preferably 2 mm or less, and a pozzolanic system having a high activity with a particle size of 0.01 to 15 μm, preferably 0.01 to 0.5 μm. A cement-type matrix obtained by mixing reactive particles, low-activity pozzolanic reactive particles of 0.1 to 15 μm, at least one dispersion material and water, and a diameter of 0.05 mm to 0.3 mm. There the fibers of 8Mm～16mm, using fiber reinforced cementitious composite material made by mixing about 1% to 4% relative to the volume of the cement matrix, compressive strength 200 N / mm ^2, bending tensile strength 40N / mm ^2, adhesion strength against deformed bar is realized 60~80N / mm ^2, and the high fixing effect rigidity.

  According to the shear reinforcement structure of the present invention, a predetermined pulling rigidity can be ensured easily and reliably.

  A preferred embodiment of the shear force reinforcing structure of the present invention will be described in detail with reference to the drawings. In the following, a description will be given of a case where the side walls of an RC structure, which is an existing box culvert embedded in the underground ground G, are shear-reinforced. In the following description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.

  Fig.1 (a) is sectional drawing which shows the shear reinforcement structure which concerns on this Embodiment, (b) and (c) are the modifications. FIG. 2A is a schematic cross-sectional view showing the arrangement relationship of the shear reinforcement structure, and FIG. 2B is an enlarged cross-sectional view of the reinforcing member insertion hole. FIG. 3 is an overall perspective view of the shear reinforcement member according to the present embodiment, and FIGS. 4A to 4G are perspective views showing modifications of the tip protrusions of the shear reinforcement member according to the embodiment. It is. FIG. 5 is a side sectional view showing a stress state when a shear force is applied to the shear reinforcement structure according to the present embodiment. Furthermore, FIG. 6 is the result of conducting a drawing experiment to investigate the fixing effect of the shear reinforcement structure of the present invention. When (a) has a widened portion, (b) has a widened portion. It shows a case that is not.

  As shown in FIG. 1A, the shear reinforcement structure 1 according to the present embodiment has an existing reinforced concrete side wall W and a bottomed bottom formed in a direction crossing the main reinforcing bar from the inner surface side of the side wall W. The reinforcing member insertion hole 10 includes a shear reinforcing member 20 and a filler 30 filled in the reinforcing member insertion hole 10.

  The shear reinforcement member 20 includes a shear reinforcement bar 21 that is a wire, a tip protrusion (tip fixing member) 22 formed at the tip of the shear reinforcement bar 21, and a plate fixed to the base end of the shear reinforcement bar 21. A head (base end fixing member) 23 is included.

In addition, the reinforcing member insertion hole 10 includes a general portion 11 having an inner diameter larger than the reinforcing bar diameter of the shear reinforcing reinforcing bar 21 and the outer diameter of the tip protrusion 22 and smaller than the width of the plate head 23, and the base of the reinforcing member insertion hole 10. A base end widening portion 12 having an inner diameter larger than the width of the plate head 23 and an end widening portion 13 having an inner diameter larger than the inner diameter of the general portion 11 are formed at the end portion. It consists of and. Here, in the present specification, the “width” of the fixing member is unified as a diagonal length when the shape of the fixing member is rectangular or polygonal, a diameter when it is circular, and a long side length when it is elliptical. To do.
A space on the inner surface side of the plate head 23 of the base end widened portion 12 is filled with a filler 30.

  Hereinafter, the detail of the shear reinforcement structure 1 which concerns on this embodiment is demonstrated.

  The reinforcing member insertion hole 10 is drilled in order to install the shear reinforcing member 20 from the inner surface side to the outer surface side of the side wall W, and as shown in FIG. Based on the arrangement diagram and the information of the non-destructive test, the horizontal interval is the main reinforcement R1 and the vertical interval is the distribution reinforcement R2 so that the main reinforcement R1 and the distribution reinforcement R2 are not damaged during drilling. It is arranged at the center of both reinforcing bars at the same interval. As shown in FIG. 2 (b), the perforation of the reinforcing member insertion hole 10 is performed in the direction from the inner surface side of the side wall W to the outer surface side in contact with the ground G and in a direction substantially perpendicular to the side wall W surface. And drilling means such as a rotary hammer drill, a core drill, etc., are performed up to the depth of the position of the main muscle R1 on the outer surface side. In addition, the reinforcing member insertion hole 10 is perforated with a slight downward slope, and is provided with a length dimension obtained by subtracting the thickness of the covering concrete of a predetermined dimension on the outer surface side. 3, the outer diameter of the tip protrusion 22 formed at the tip of the shear reinforcement member 20 shown in FIG.

  The reason why the reinforcing member insertion hole 10 is formed to have a slightly downward slope is to facilitate the discharge of internal air when the filler 30 is filled when the shear reinforcing member 20 is inserted. By doing so, the filling material 30 can be filled more completely.

  Further, the perforating means is used so that the peripheral portion of the plate head 23 attached to the base end portion (terminal portion) of the shear reinforcing member 20 is hooked at the base end portion of the reinforcing member insertion hole 10. The base end widened portion 12 is formed by widening the hole diameter. The drilling depth of the base end widened portion 12 is a value obtained by adding the covering concrete thickness to the thickness of the plate head 23, and in this embodiment, the drilling is performed up to the position of the main reinforcement R1 on the inner surface side.

  Further, a tip widening portion 13 is formed at the tip of the reinforcing member insertion hole 10 by attaching a bottom expansion bit (not shown) to the tip of the punching means to widen the tip. In the present embodiment, the bottom portion of the tip widening portion 13 is performed up to the depth of the position of the main reinforcing bar R1 on the outer surface side, and a covering concrete thickness of a predetermined dimension is secured.

  As shown in FIGS. 1 (a) and 3, the shear reinforcement member 20 is formed at a shear reinforcement bar 21 made of a deformed reinforcing bar, and at the distal end and the base end of the shear reinforcement bar 21. A tip projection 22 and a plate head 23 having a cross-sectional shape larger than that of the reinforcing bar 21 are included. Here, the deformed reinforcing bars are used as the shear reinforcing reinforcing bars (wires) 21. However, the wires 21 are not limited to the deformed reinforcing bars, and may be any one that exhibits a function as a linear reinforcing material. For example, a screw rebar, a steel bar, a PC steel strand, a carbon wire, etc. may be used.

  The tip protrusion 22 according to the present embodiment is pressed or hit in the axial direction in a state where the tip of the shear reinforcing bar 21 is heated, and thereby has a diameter larger than the reinforcing bar diameter of the shear reinforcing bar 21 as shown in FIG. It is formed.

  Note that the tip protrusion 22 is not limited to the above-described one, and for example, a metal material such as mild steel or aluminum alloy that is relatively easy to process, such as the tip protrusion 22a shown in FIG. A cylindrical body having a thickness of 15% to 50% of the diameter of the shear reinforcing bar 21 and a length of 100% to 250% of the diameter of the shear reinforcing bar 21 is prepared. Cover the tip and squeeze it from the surroundings using a gripper with two half rings around it, or narrow down (squeeze) the cylindrical body used for squeeze joints of reinforcing bars, The cylindrical body may be manufactured by plastic deformation and integrated with the shear reinforcing bar 21.

  Further, as in the tip protrusion 22b shown in FIG. 4B, a screw reinforcing bar is used as the shear reinforcing bar 21, and a lock nut is screwed into the tip part to remove rattling between the shear reinforcing bar 21 and the lock nut. Therefore, the width of the tip protrusion 22b is 130% to 200% of the diameter of the shear reinforcing bar by using either a double nut or a method of injecting a filler such as epoxy resin into the gap inside the nut. Can also be manufactured so that it becomes 100% to 250% of the diameter of the shear reinforcing bar.

  4C, the thickness is 30% to 80% of the diameter of the shear reinforcing bar 21 and the width is 130% to 200% of the diameter of the shear reinforcing bar 21. The plate may be manufactured by friction welding A to the tip of the shear reinforcing bar 21. As shown in FIG. 4D and FIG. 4E, the thickness is 30% to 80% of the diameter of the shear reinforcing bar 21 and the width is 130% to 200% of the diameter of the shear reinforcing bar 21. Square steel plate, oval shape whose thickness is 30% to 80% of the diameter of the shear reinforcing bar 21 and whose major axis is 130% to 200% of the diameter of the shear reinforcing bar 21 (cut off the side of the oval or circle) May also be manufactured from steel plates. In this case, since a gap is formed between the reinforcing member insertion hole 10 and the reinforcing member insertion hole 10 is filled with the filler 30, the shear reinforcement member 20 is inserted into the reinforcement member insertion hole 10. In addition, the insertion resistance due to the filler 30 can be reduced and the air can be inserted without leaving air behind the tip protrusions 22d and 22e.

Further, by providing a hole h in the circular steel plate, polygonal steel plate, or elliptical steel plate, insertion resistance due to the filler 30 is reduced, and air is not left behind the tip protrusion 22f. It is good also as a structure which can insert the shear reinforcement member 20 (refer FIG.4 (f)). Further, as shown in FIG. 4G, the insertion resistance may be reduced by forming a convex spherical surface on the surface opposite to the surface joined to the shear reinforcement bar of the tip protrusion 22g.
Here, the formation method of the front-end | tip protrusion 22 is not limited, What is necessary is just to be able to integrate it, such as friction welding, gas pressure welding, arc welding joining.

As shown in FIG. 3, the plate head 23 is a square steel plate having a thickness of 40% to 80% of the diameter of the shear reinforcing bar 21 and a width of 130% to 300% of the diameter of the shear reinforcing bar 21. It is integrally fixed to the base end part of the shear reinforcing bar 21. The plate head 23 is fixed to the shear reinforcing bar 21 by using a friction welding machine to press the rotated steel plate against the fixed shear reinforcing bar 21 so that the frictional heat is applied to the rotating steel plate with a predetermined pressure. Can be easily performed by welding the steel plate to the shear reinforcing steel bar 21 (friction welding A).
In addition, the joining method of the plate head 23 and the shear reinforcing steel bar 21 is not limited to the friction welding A, and it is only necessary to be able to integrate them such as gas pressure welding and arc welding welding. The shape of the plate head 23 is not limited to a quadrangle, and may be a circle, an ellipse, a polygon, or the like.

Here, the configuration of the shear reinforcement member 20 is not limited to the above-described configuration. For example, as in the shear reinforcement structure 1 ′ shown in FIG. It is good also as a structure which forms proximal end protrusion 23 'similarly to the front-end | tip protrusion 22 formed in the front-end | tip part.
Further, if it is possible to develop a sufficient pulling force with respect to the shearing force applied to the side wall W, any one of the distal end portion and the proximal end portion as in the shear reinforcement structure 1 ″ shown in FIG. Alternatively, a configuration may be employed in which a shear reinforcing bar 21 that does not form a fixing member is disposed.

The filler 30 includes cement, an aggregate having a maximum particle size of 2.5 mm or less, silica fume which is a highly active pozzolanic reaction particle having a particle size of 0.01 to 0.5 μm, and a particle size of 0.1 to 15 μm. A cementitious matrix obtained by mixing blast furnace slag or fly ash, which is a low-activity pozzolanic reaction particle, and at least one type of dispersion material and water, has a diameter of 0.05 mm to 0.3 mm and a length. A fiber-reinforced cement-based mixed material (hereinafter referred to as “high-strength fiber filler 30”) in which fibers of 8 mm to 16 mm are mixed with about 1% to 4% with respect to the volume of the cement-based matrix is used. The compressive strength is 200 N / mm ² , the bending tensile strength is 40 N / mm ² , and the adhesion strength to the deformed reinforcing bar is 60 to 80 N / mm ² , and a highly rigid fixing effect is realized.

As shown in FIG. 5, the shear reinforcement structure 1 of the present invention directly reinforces the oblique crack c generated when an out-of-plane shear force S is applied with the shear reinforcement member 20 to improve the shear strength. Is.
That is, when an out-of-plane shearing force S acts on the side wall W, an oblique crack c tends to occur. However, since a tensile force acts on the shear reinforcement member 20, the pulling force ft on the tip protrusions 22 and the plate heads 23 at both ends. Works. The tip protrusion 22 and the plate head 23 are integrated with the tip widening portion 13 and the base widening portion 12 by an ultra-high strength high-strength fiber filler 30 filled in the tip widening portion 13 and the base widening portion 12, and are pulled out. A sufficient restraining effect is achieved for the force ft. For this reason, in the concrete inside the tip protrusion 22 and the plate head 23 (hereinafter referred to as “inner concrete”), a supporting pressure acts on the inner concrete as a reaction force, and a field of compressive stress fc is formed. . That is, the inner concrete is subjected to lateral restraint, resulting in an increase in resistance to oblique tension. For this reason, the shear reinforcement member 20 with the tip protrusion 22 and the plate head 23 at the end portion, the tip widening portion 13 and the base end widening portion 12 increase the out-of-plane shear strength of the side wall W and compress the inner concrete. The toughness performance is also increased by the generation of the stress fc (the formation of a compressive stress field).

  When the reinforcement by the shear reinforcement structure 1 according to this embodiment is performed, the fixing effect of the shear reinforcement member 20 is increased because the distal end widening portion 13 and the proximal widening portion 12 are present in the reinforcement member insertion hole 10. become. In order to investigate this fixing effect, the result of an experiment of pulling out the shear reinforcement member 20 by the reinforcing member insertion hole 10 having the widened portion at the end portion and the reinforcing member insertion hole 10 having no widened portion at the end portion. 6A and 6B show the results of conducting an extraction experiment (hereinafter referred to as “comparative example”) of the shear reinforcement member 20, respectively.

  In FIG. 6A, the reinforcing member insertion hole 10 having the widened portion is inserted with the high-strength fiber filler 30 at a depth of 50 mm (C-50), 80 mm (C-80), and 110 mm (C-110), respectively. FIG. 5 is a graph in which a pullout experiment was performed on a test specimen that was filled and the shear reinforcement member 20 was inserted, in which the vertical axis indicates a tensile load and the horizontal axis indicates a pull-out displacement. Moreover, in FIG.6 (b), the high strength fiber filler 30 is 50 mm (B-50), 100 mm (B-100), and 150 mm (B-) to the reinforcing member insertion hole 10 which does not have a wide part, respectively. 150 is a graph in which a pullout experiment was performed on a test body filled with a depth of 150) and the shear reinforcement member 20 was inserted, and the vertical axis indicates the tensile load, and the horizontal axis indicates the pull-out displacement.

  Comparing the results of the two shows that even when the depth of the filler 30 is 50 mm, the fixing effect can be obtained more excellently by providing the widened portion. Further, if the depth of the filler 30 is 80 mm, it is possible to obtain substantially the same fixing effect as in the case where the depth of the filler 30 of the comparative example is 150 mm if the configuration has a widened portion. It is shown that the fixing effect is great. Therefore, by providing the widened portion at the end of the reinforcing member insertion hole, it has been demonstrated that the shear reinforcing member and the widened portion are integrated to resist tensile force, and excellent fixing even when the wall thickness is thin Since an effect can be obtained, the out-of-plane shear strength of the face material or the plate material is increased, and the toughness performance is increased due to the occurrence of compressive stress in the internal concrete, which is preferable.

  Here, in the construction of the shear reinforcement structure 1 according to the present embodiment, after the reinforcing member insertion hole 10 is drilled in the side wall W, the filling material 30 is filled into the general portion 11 and the tip widened portion 13 to insert the reinforcing member. This is done by inserting the shear reinforcement member 20 into the hole 10 and filling the base end widened portion 12 with the filler 30. The order of filling the general portion 11 and the tip widening portion 13 with the filler 30 and inserting the shear reinforcement member 20 into the reinforcement member insertion hole 10 is not limited, and the shear reinforcement member 20 is inserted into the reinforcement member. It is good also as a structure filled with the filler 30 after inserting in the hole 10. FIG. In this case, the filling material 30 may be filled into the general portion 11 and the tip widening portion 13 by forming an injection hole in the plate head 23 and injecting from the injection hole.

  As described above, in the shear reinforcement structure 1 of the present invention, the shear reinforcement member 20 is directly embedded in the RC surface plate material without increasing the concrete thickness of the existing RC surface plate material. Therefore, since the increase in the shear strength and the toughness performance can be realized efficiently, it is possible to prevent the occurrence of the inconvenience that the internal cross section decreases after the reinforcement, as in the conventional reinforced concrete thickening method. In addition, since the main reinforcement is not increased, the out-of-plane shear strength can be improved without increasing the bending strength. Can be moved to a mold. For this reason, it is also effective from the viewpoint of seismic reinforcement.

  Further, the hole diameter for inserting the shear reinforcement member may be slightly larger than the outer diameter of the tip protrusion, and since the hole diameter is small, rapid construction is possible and work efficiency is good.

  Further, the high-strength fiber filler is integrated with the shear reinforcement member, and realizes a highly rigid fixing effect at the widened portions at both ends of the reinforcement member insertion hole. Therefore, the degree of fixation between the widened portions at both ends of the reinforcing member insertion hole and the shear reinforcing member is high, and the effect of fixing the shear reinforcing member can be sufficiently exhibited.

  In addition, the plate head provided at the base end of the shear reinforcing bar and the tip protrusion provided at the tip provide a sufficient fixing effect, and when an out-of-plane shear force is generated, the tensile force is applied to the shear reinforcing bar. As a result, the support pressure acts on the plate head or the tip protrusion and the plate head, and a compressive stress field is formed in the internal concrete. Shear reinforcement.

  Furthermore, since the reinforcing member insertion hole is blocked from the outside by the filler, it can be expected to suppress deterioration from the viewpoint of durability after reinforcement.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiment, and it is needless to say that the above-described constituent elements can be appropriately changed in design without departing from the spirit of the present invention.
In particular, the RC structure as a target of the shear reinforcement structure of the present invention is not limited to the above-described embodiment, and may be a structure such as another underground structure, a wall-type pier, a foot of a pier foundation, or the like.

Further, the existing RC structure to be reinforced may be an RC structure, and there is no limitation on the type such as a cast-in-place reinforced concrete structure or a precast concrete structure, and the part to be reinforced is not limited. It is also applicable to.
Further, the insertion interval and the number of insertions of the shear reinforcement member are not limited to the above embodiment, and can be determined as appropriate.
In the embodiment, the widened portion of the reinforcing member insertion hole is provided at both ends of the distal end portion and the proximal end portion, but may be provided only at the proximal end portion.

In the embodiment, the tip protrusion provided at the tip of the shear reinforcement member is formed at an acute angle so that air is not caught at the tip of the shear reinforcement member when inserted into the reinforcement member insertion hole. Also good.
Moreover, in the said embodiment, although it was set as the structure which fills the whole reinforcing member insertion hole with a high strength fiber filler, it is not limited to this, For example, only a front end wide part and a base end wide part have high strength fiber. It is good also as a structure filled with a filler and filling a general part with a normal-strength filler.
Further, although the bottom is provided as the reinforcing member insertion hole, if the inner wall is reinforced, such as a box culvert, the inner wall may be penetrated.

Further, the composition of the aggregate constituting the filler and the pozzolanic reaction particles is not limited to that described in the above embodiment, and the aggregate has a maximum particle size of 2.5 mm or less, and the pozzolanic reaction. The particles may have a particle diameter in the range of 0.01 to 15 μm.
In addition, although the silica fume is mixed with the filler, the pozzolanic reaction particles are not limited to silica fume.
Further, filler, a predetermined compressive strength (200N / mm ^2), a predetermined flexural tensile strength (40N / mm ^2), it is capable of expressing the adhesion strength between the predetermined deformed bars (60~80N / mm ²⁾ For example, an epoxy resin or the like may be used, and is not limited to that of the above embodiment.

It is sectional drawing which shows the shear reinforcement structure which concerns on this Embodiment, (b) And (c) is the modification. (A) is a schematic sectional drawing which shows the arrangement | positioning relationship of a shear reinforcement structure, (b) is an expanded sectional view of a reinforcement member insertion hole. It is a whole perspective view of the shear reinforcement member which concerns on this Embodiment. (A)-(g) is a perspective view which shows the modification of the front-end | tip protrusion of the shear reinforcement member which concerns on this Embodiment. It is a sectional side view which shows the stress state at the time of a shear force acting on the shear reinforcement structure which concerns on this Embodiment. It is the result of having conducted the drawing experiment in order to investigate the fixing effect of the shear reinforcement structure of the present invention, (a) shows the case where it has a widened part, (b) shows the case where it does not have a widened part. Yes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shear reinforcement structure 10 Reinforcement member insertion hole 11 General part 12 Base end wide part 13 End wide part 20 Shear reinforcement member 21 Shear reinforcement reinforcement (wire)
22 Tip protrusion (tip fixing member)
23 Plate head (base fixing member)
30 High-strength fiber filler (filler)
G Ground S Shear force W Side wall (Reinforced concrete structure)

Claims (6)

An existing reinforced concrete structure, a shear reinforcing member mainly composed of a wire disposed inside a reinforcing member insertion hole formed in the reinforced concrete structure, and a filler filled in the reinforcing member insertion hole A shear reinforcement structure,
The reinforcing member insertion hole includes a general part having an inner diameter larger than the diameter of the wire, and a base end widening part formed at a base end part of the reinforcing member insertion hole and having an inner diameter larger than the general part. A shear reinforcement structure characterized by being configured.   The shear reinforcement structure according to claim 1, wherein a tip widening portion having an inner diameter larger than that of the general portion is formed at a tip portion of the reinforcing member insertion hole. The shear reinforcement structure according to claim 1 or 2, wherein when the wire of the filler is a deformed reinforcing bar, the adhesion strength is 60 N / mm ² or more.   The shear reinforcement member includes a shear reinforcement bar that is the wire, a proximal fixing member that is formed at a proximal end portion of the shear reinforcement bar, and has a cross-sectional shape larger than the reinforcing bar diameter of the shear reinforcement bar, and the shear reinforcement bar The tip fixing member formed in the front-end | tip part of this and having a cross-sectional shape larger than the reinforcing bar diameter of the said shear reinforcement reinforcing bar, It is comprised from any one of Claim 1 thru | or 3 characterized by the above-mentioned. Shear reinforcement structure.   The shear reinforcement structure according to any one of claims 1 to 4, wherein the filler is a fiber-reinforced cement-based mixed material in which fibers are mixed in a cement-based matrix. The fiber reinforced cementitious mixed material comprises a cement, an aggregate having a maximum particle size of 2.5 mm or less, a pozzolanic reactive particle having a particle size of 0.01 to 15 μm, at least one kind of dispersion material, and water. In the resulting cementitious matrix,
6. The fiber according to claim 5, wherein fibers having a diameter of 0.05 to 0.3 mm and a length of 8 to 16 mm are mixed in an amount of about 1 to 4% based on the volume of the cementitious mixture. Shear reinforcement structure.

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