JP4999617B2 - Reinforcement method for concrete structures - Google Patents

Description

  The present invention relates to a method for reinforcing a concrete structure in which a reinforcing bar is newly embedded and fixed in a concrete structure such as an existing concrete pier.

  It is important for the concrete piers of the bridge to satisfy the horizontal strength in the event of an earthquake, and it is necessary to ensure earthquake resistance. Conventionally, RC (Reinforced Concrete) winding method, iron plate winding method, carbon fiber / aramid sheet reinforcing method, PC (Prestressed Concrete) winding method, etc. are known as seismic reinforcement methods for concrete piers. Yes.

  The RC hoisting method is to fix the vertical reinforcement on the surface of the pier in parallel with the main reinforcement arranged inside the pier, and fix the reinforcement by overlapping the reinforcement in the direction perpendicular to the main reinforcement. A reinforcement structure is constructed by forming a frame and placing concrete. In addition to the reinforcing method by RC winding, a reinforcing structure for covering the polymer mortar after the main reinforcing bar and the band reinforcing bar are fixed on the concrete pier surface is also constructed.

  In this way, if it is a reinforcement structure by RC winding or a reinforcement structure covered with polymer mortar, the integration of the existing pier and the reinforcing bar fixed in the direction of the bridge axis is strengthened by winding concrete or polymer mortar. The reinforcing effect is maintained for a long time.

  However, in these reinforcement methods, concrete reinforcement or polymer mortar coating is performed after reinforcing reinforcing bars are fixed to the concrete pier surface, so the diameter of the concrete pier is significantly increased by the concrete winding layer or polymer mortar coating layer. Will do. In addition, the weight of the pier is greatly increased by increasing the winding thickness.

  Therefore, in order to solve such a problem, for example, in Patent Document 1, a groove portion is formed on the surface to be reinforced, and a hole portion is formed in the base portion so as to be continuous with the groove portion. There has been proposed a reinforcing method for a concrete structure in which reinforcing rods are arranged over the hole portions and the groove portions and the hole portions are filled with an adhesive to fix the reinforcing rods. In Patent Document 1, the hole is usually drilled with a concrete core drill, but if the hole is drilled along the surface to be reinforced, the drill interferes with the portion to be reinforced. In addition, it is described that a hole is formed by giving a slight angle to the drilling direction.

  FIG. 7 shows an example in which a fixing hole is drilled in an oblique direction using a rock drill in the footing portion of an existing pier. As shown in FIG. 7, in the construction method described in Patent Literature 1, the drilling drill 50 is drilled in the footing portion 52 in an oblique direction so as not to interfere with the reinforced portion 51. However, when drilling with the drilling drill 50 in this way, since the drilling drill 50 is held manually, it is difficult to drill all the fixing holes at the same angle. Further, in order to insert a reinforcing bar into a fixing hole drilled in an oblique direction, it is necessary to process the reinforcing rod into a square shape as described in Patent Document 1, but fixing is performed at different angles. It is difficult to process the reinforcing rod in accordance with the hole.

  In addition, the inventor has proposed a method for reinforcing a concrete structure as described in Patent Document 2. In this concrete structure reinforcement method, since a vertical fixing hole is drilled in the footing part using a core drill (drilling machine), it is possible to perform drilling work by accommodating the core drill in the lower part of the column part. A core drilling space of a size is provided. According to this construction method, the fixing hole can be formed along the surface to be reinforced, and reinforcement can be performed using a straight reinforcing rod.

JP 2005-54532 A Japanese Patent No. 3778638

  However, when using a commercially available core drill to drill a fixing hole in the vertical direction in the footing part, a core drilling space is provided that can completely accommodate up to the motor part coaxial with the spindle part of the core drill. Therefore, the depth of this core drilling space is required to be 100 mm or more. However, when the concrete cover thickness of the existing pier is only about 100 mm, the core drilling space will interfere with the existing reinforcing bars, so that the necessary core drilling space cannot be cut. appear.

  Therefore, in the present invention, the reinforcement of a concrete structure in which a vertical reinforcing bar can be embedded from the side surface part of the concrete structure to the inside of the footing part without interfering with the existing reinforcing bar of the existing concrete structure. The purpose is to provide a method of construction.

  The concrete structure reinforcement method of the present invention is a method for reinforcing a concrete structure in which a groove is cut in a vertical direction on a side surface of the concrete structure, a vertical reinforcing bar is embedded in the groove, and a resin is injected and fixed. In the construction method, a concave portion having a size that is connected to the groove portion and can accommodate the spindle portion of the core drill and the core bit attached to the spindle portion but not the motor portion can be accommodated in the side surface portion on the footing portion of the concrete structure. A step of cutting, a step of accommodating a spindle portion and a core bit of a core drill in which the spindle portion is offset from the motor portion in the recess, and a fixing hole being drilled in the vertical direction inside the footing portion; Embedding a vertical reinforcing bar over the fixing hole, and injecting and fixing a resin.

  According to the concrete structure reinforcing method of the present invention, when the fixing hole is drilled using a core drill inside the footing portion of the concrete structure, the spindle portion of the core drill and the A recess having a size that can accommodate the core bit attached to the spindle portion and not the motor portion is cut, and the spindle portion and the core bit of the core drill in which the spindle portion is offset from the motor portion are accommodated in the cut recess. Since the fixing hole is drilled in the vertical direction inside the footing part, the depth of the concave part cut into the side part of the concrete structure may be such that the spindle part of the core drill and the core bit attached to the spindle part can be accommodated. Without interfering with the existing reinforcing bars of the existing concrete structure, It can be drilling the fixing holes in the vertical direction inside Chingu unit.

  Here, the depth of the recess is desirably 50 mm or less. If it is 50 mm or less, it will not interfere with the existing reinforcing bars of the existing concrete structure. On the other hand, when it exceeds 50 mm, when the concrete covering thickness of a concrete structure is thinner than a general thing, possibility of interfering with an existing reinforcing bar comes out.

  In the concrete structure reinforcing method according to the present invention, after embedding the vertical reinforcing bar, the upper end of the vertical reinforcing bar is constrained in the groove part by a strip material extending over the groove part, and the resin is cured. Is desirable. Thereby, it is possible to prevent the upper end portion of the vertical reinforcing bar embedded in the recess from drooping when the resin is cured.

(1) When drilling a fixing hole inside a footing part of a concrete structure using a core drill, a spindle part of the core drill and a core bit attached to the spindle part can be stored on the side surface on the footing part of the concrete structure; A recess of a size that cannot be accommodated by the motor unit is cut, and the spindle unit accommodates the spindle unit and core bit of the core drill that is offset from the motor unit, and the fixing hole is vertically formed inside the footing unit. Since the hole is drilled in the direction, the depth of the recess to be cut in the side part of the concrete structure may be such that the spindle part of the core drill and the core bit attached to this spindle part can be accommodated, and the existing reinforcing bar of the existing concrete structure Without fixing, the fixing hole is drilled vertically in the footing part. Rukoto can, it is possible to bury the vertical reinforcement across from the side surface of the concrete structure within footing portion.

(2) Since the depth of the concave portion is 50 mm or less, the possibility of interfering with the existing reinforcing bar of the existing concrete structure can be eliminated, so it is necessary to pay attention to the interference with the existing reinforcing bar when cutting the concave portion. The workability at the time of cutting the recess is improved.

(3) After embedding the vertical reinforcing bars, the upper ends of the vertical reinforcing bars are constrained in the groove portions by a strip plate material having a length straddling the groove portions, and the resin is hardened so that the vertical reinforcing bars are embedded in the concave portions. Can be prevented from dripping when the resin is cured, and the workability at the time of resin curing is improved.

  FIG. 1A is a partial plan sectional view of a reinforced concrete pier constructed by a concrete structure reinforcement method according to an embodiment of the present invention, and FIG. 1B is a partial side sectional view. In FIG. 1, this pier has a reinforced concrete pillar portion 2 formed on a reinforced concrete footing portion 1. A reinforcing covering layer 3 is formed on the entire side surface of the column portion 2.

  Inside the column part 2, main bars 4 a are arranged in the axial direction of the column part 2, that is, in the vertical direction. Grooves 5 are formed on the side surface of the column part 2 outside the main bars 4a and in the same direction as the main bars 4a. In FIG. 1, 4b is a streak. Further, a concave portion 6 to be described later is formed on the side surface portion of the column portion 2 on the footing portion 1. The groove 5 is connected to the recess 6. Further, a fixing hole 7 is formed in the footing portion 1 below the concave portion 6.

  A reinforcing vertical reinforcing bar 8 is inserted and embedded from the inside of the groove 5 to the recess 6 and the fixing hole 7. The vertical reinforcing bars 8 are fixed inside the groove 5, the recess 6 and the fixing hole 7 by filling the inside of the groove 5, the recess 6 and the fixing hole 7 with a resin 9 made of an epoxy resin and curing it. Yes. Further, on the outer side of the vertical reinforcing bar 8, the band 10 is constructed by the flare welding 11, and the reinforcing covering layer 3 is formed on the outer side thereof.

  In the above configuration, the vertical reinforcing bar 8 is fixed in a state of being fitted in the groove portion 5 formed in the side surface portion of the column portion 2. Moreover, since the resin 9 made of epoxy resin is interposed between the vertical reinforcing bar 8 and the groove portion 5, even when the column portion 2 is bent and deformed by a horizontal load at the time of an earthquake, the deformation of the column portion 2 is performed. Is transmitted to the vertical reinforcing bar 8 through the resin 9 in the groove 5.

  That is, since the vertical reinforcing bar 8 is sealed in the groove 5 of the column part 2, even if the column part 2 is displaced due to bending due to a horizontal load at the time of an earthquake, the elasticity of the vertical reinforcing bar 8 is obtained. Within the range, the entire surface of the column part 2 has a high tensile stress by absorbing the displacement. Further, since the vertical reinforcing bars 8 are constrained and sealed inside the groove 5 by the resin 9, they do not float from the groove 5.

  Next, the construction procedure of the reinforcing covering layer 3 will be described with reference to the flowchart of FIG. FIG. 2 is a flowchart of a concrete structure reinforcing method according to an embodiment of the present invention, and FIG. 3 is an explanatory diagram showing a schematic construction procedure.

(S101) Surface Treatment First, the front surface of the pier column 2 (see FIG. 3) to be reinforced is made rough by chipping or sandblasting. A water jet may be used.
(S102) Inking Next, inking is performed at a position where the groove portion 5 and the recess portion 6 on the side surface of the column portion 2 are formed.

(S103) Core Space Cutting Work Then, as shown in FIG. 3A, a recess 6 is formed in the footing portion 1 on the side surface portion on the footing portion 1 below the pillar portion 2. 4 is an enlarged perspective view of the recessed portion 6 formed in the column portion, FIG. 5 is a view showing a state in which the fixing hole 7 is drilled by the special core drill 20, (a) is a sectional plan view, (b) It is side surface sectional drawing. The recess 6 is a core drilling space for accommodating a special core drill (drilling machine) 20 shown in FIG. 5 as a drilling tool for core drilling and performing a drilling operation.

  Unlike the conventional core drill in which the spindle portion to which the core bit is attached and the motor portion are coaxially arranged, the special core drill 20 used in the present embodiment has a spindle portion 22 to which the core bit 21 is attached as shown in FIG. , Offset from the motor unit 23 in the horizontal direction. The spindle unit 22 and the motor unit 23 are connected by a rotation transmission mechanism 24 such as a gear or a belt, and the rotational driving force of the motor unit 23 is transmitted to the core bit 21 via the rotation transmission mechanism 24 and the spindle unit 22. The The motor unit 23, the rotation transmission mechanism 24, and the spindle unit 22 are supported by a support unit 25 so as to be movable up and down with respect to the vertical shaft 26.

  The recess 6 is formed in such a size that the spindle portion 22 and the core bit 21 of the special core drill 20 can be accommodated and the motor portion 23 cannot be accommodated. That is, if the motor part 23 is to be completely accommodated, the depth D of the recess 6 (see FIGS. 4 and 5) must be 100 mm or more, but the depth D of the recess 6 formed in this embodiment is 40 mm. Yes, at most 50 mm or less. The width W of the recess 6 is 130 mm. However, there is no particular limitation on this, and it is sufficient if the spindle 22 and the core bit 21 can be accommodated in the recess 6. Moreover, the height of the recessed part 6 is 1,000 mm.

(S104) Core drilling As shown in FIG. 5, a special core drill 20 is installed in the recess 6 so as to accommodate the spindle portion 22 and the core bit 21, and the support portion 25 is lowered vertically downward. By doing so, the fixing hole 7 having a diameter of 60 mm and a depth of 600 mm is drilled in the vertical direction. In this step, it is desirable to know the position of a steel material (not shown) arranged in advance in the footing unit 1 in advance.

(S105) Embedded Groove Cutting Work Next, as shown in FIG. 3 (a), main bars 4a (FIG. 1) arranged in the column part 2 by a concrete cutter (not shown) on the side surface part of the column part 2. (See Fig.). A slit having a width of about 50 mm and a depth of about 50 mm is made in the direction parallel to the vertical direction (vertical direction), and the concrete inside the cut is suspended by an electric pick to form the groove 5. Thereafter, the concrete dust adhering to the surface of the column part 2, the groove part 5, the recessed part 6 and the fixing hole 7 is removed and cleaned by a method such as high-pressure washing.

(S106) Reinforcing bar setting start Next, as shown in FIG. 3A, the vertical reinforcing bar 8 is inserted into the fixing hole 7, and the vertical reinforcing bar 8 is inserted into the recess 6 and the fixing hole 7 from the groove portion 5. Embed across. 6A is an enlarged view of the upper end portion of the groove portion 5 of the column portion 2, FIG. 6B is a cross-sectional view taken along the line AA in FIG. 6A, and FIG. Here, as shown in FIG. 6B, a wedge 12 made of iron or wood is driven into the gap between the vertical reinforcing bar 8 and the groove portion 5 to restrain the vertical reinforcing bar 8. As shown in FIG. 6A, the wedges 12 are installed in a staggered manner on both sides of the gap between the vertical reinforcing bars 8 and the grooves 5. Here, as shown in FIGS. 6A and 6B, the upper end portion of the vertical reinforcing bar 8 is constrained in the groove portion 5 by a temporary fixing bracket 13 made of a strip plate material having a length straddling the groove portion 5. To do. The temporary fixing metal 13 is fixed by a concrete anchor 14. Then, resin 9 is injected into the gap between the groove 5 and the vertical reinforcing bar 8 and the fixing hole 7 to fix the vertical reinforcing bar 8. The wedge 12 is extracted after the resin 9 is hardened or buried with the resin 9. Further, the temporary fixing metal 13 is removed after the resin 9 is cured.

(S107) As shown in FIG. 3 (b), the reinforcing bars 8 are attached in the direction perpendicular to the vertical reinforcing bars 8 arranged in the vertical direction inside the side surface of the column part 2, that is, in the horizontal direction. . The attachment is performed by binding the vertical reinforcing bar 8 with a binding wire (not shown) previously attached to the vertical reinforcing bar 8. After binding, as shown in FIG. 1 (b), the ends of the band 10 are flare welded 11 to form continuous bars. Note that the reinforcing bar 10 may be a conventionally used deformed reinforcing bar, but it is desirable to perform a rust prevention treatment on the surface. The binding wire is preferably made of stainless steel.

(S108) Protective Coating Work Next, as shown in FIG. 3C, the reinforcing coating layer 3 is formed on the surface of the column portion 2. The reinforcing coating layer 3 is formed by first applying a polymer paste base reinforcing coating material having antirust performance and then applying a polymer cement coating material. The coating method is brushing or spraying for the base reinforcing coating material, and iron coating or spraying for the polymer cement-based coating material.
(S109) Finishing material application process Finally, a finishing material is apply | coated on the coating layer 3 for a reinforcement.

  The reinforcing covering layer 3 can be formed by a method of forming a mold and winding up cement mortar in addition to the above covering material. At this time, it is desirable that the surface of the pillar portion 2 is roughened by chipping or the like in advance. In addition, when forming the coating layer 3 for reinforcement by RC winding method, after forming a formwork, high fluidity concrete is laid.

  The thickness of the reinforcing covering layer 3 formed in this way exposed on the surface of the column portion 2 is about 1/8 of the conventional RC winding method and about 1/3 of the polymer mortar winding method. It is possible to reinforce bridge piers that are restricted by inhibition. Further, since the winding thickness can be greatly reduced, the amount of the coating material used can be reduced by about 2/3 as compared with the conventional polymer mortar winding method, and the construction cost can be greatly reduced.

  As described above, in the pier made of reinforced concrete in the present embodiment, the groove portion 5 into which the vertical reinforcing bar 8 is fitted is formed on the surface portion of the column portion 2, and the vertical reinforcing bar 8 is fitted into the groove portion 5 and fixed. As a result, the reinforcing layer including the vertical reinforcing bar 8 is bitten into the column 2, and the vertical reinforcing bar 8 is pulled while following the displacement of the column 2 even when the column 2 is distorted. Since the stress is exerted, there is no gap between the reinforcing layer and the concrete.

  For this reason, the further integration of the vertical reinforcing bar 8 and the column part 2 is achieved, and the reinforcing effect can be maintained over a long period of time. Further, since the vertical reinforcing bars 8 are fitted in the grooves 5 in the surface portion of the column part 2, the thickness of the reinforcing covering layer 3 can be extremely reduced, and the amount of material used can be reduced. As a result, the amount of material used can be reduced, and the increased weight and construction cost accompanying reinforcement can be reduced and the construction period can be shortened.

  Further, in the reinforcing method in the present embodiment, when the fixing hole 7 is drilled in the footing part 1 of the pier, the spindle part 22 and the core bit 21 of the special core drill 20 can be stored in the side part on the footing part 1 and the motor part. 23, a recess 6 having a size that cannot be accommodated is cut, and the spindle portion 22 and the core bit 21 excluding the motor portion 23 of the special core drill 20 are accommodated in the cut recess 6 so as to be contained in the footing portion 1. Since the fixing hole 7 is drilled in the vertical direction, it does not interfere with the existing reinforcing bars of the existing concrete structure.

  In particular, in this reinforcement method, since the depth of the recess is 50 mm or less, the possibility of interfering with the existing reinforcing bar of the existing concrete structure is eliminated, and it is necessary to pay attention to the interference with the existing reinforcing bar when cutting the recess 6. The workability at the time of cutting the recesses is improved.

  Further, in this reinforcing method, after embedding the vertical reinforcing bar 8, the upper end portion of the vertical reinforcing bar 8 is constrained in the groove part 5 by the temporary fixing bracket 13 having a length straddling the groove part 5, and the resin 9 is cured. By doing so, it is possible to prevent the upper end portion of the vertical reinforcing bar 8 embedded in the recess from dripping or protruding when the resin 9 is cured, and the workability at the time of resin curing is improved.

  Further, after the vertical reinforcing bar 8 is fitted into the groove 5, a wedge 12 is driven into the gap between the inner surface of the groove 5 and the vertical reinforcing bar 8 to restrain the vertical reinforcing bar 8, and the resin 9 is put into the gap. By injecting and fixing the vertical reinforcing bar 8, it is possible to form a reinforcing layer that efficiently exhibits the tensile strength against concrete regardless of the accuracy of the fitting dimension between the vertical reinforcing bar 8 and the groove 5. It is. Further, by interposing the resin 9 between the column portion 2 and the vertical reinforcing bar 8, no shearing force is generated on the vertical reinforcing bar 8, and no shear force breakage occurs. Further, since the resin 9 also acts as a repair material for cracks generated in the column portion 2, the reinforcing effect of the column portion 2 is further improved.

  The concrete structure reinforcement method of the present invention is useful not only for seismic reinforcement against horizontal loads during earthquakes acting on concrete piers, but also for reinforcement of the concrete underside of bridge concrete girders and other concrete structures. is there. In particular, it is suitable for reinforcing a bridge pier that has a limited increase in winding thickness or a bridge pier that needs to reduce the increased weight.

(A) is a partial plane sectional view of the pier made from a reinforced concrete constructed by the reinforcement method of a concrete structure in an embodiment of the invention, and (b) is a partial side sectional view. It is a flowchart of the reinforcement construction method of the concrete structure in embodiment of this invention. It is explanatory drawing which shows the general construction procedure of the reinforcement construction method of the concrete structure in embodiment of this invention. It is an expansion perspective view of the recessed part formed in a pillar part. It is a figure which shows the state which drills a fixing hole with a special core drill, Comprising: (a) is a plane sectional view, (b) is a side sectional view. (A) is an enlarged view of the upper end part of the groove part of a pillar part, (b) is AA sectional drawing of (a), (c) is BB sectional drawing of (a). It is a figure which shows the example which drills a fixing hole in the diagonal direction using the drill for rock drilling in the footing part of the existing pier.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Footing part 2 Pillar part 3 Reinforcement coating layer 4a Main reinforcement 4b Band reinforcement 5 Groove part 6 Recess 7 Fixing hole 8 Vertical reinforcement reinforcement 9 Resin 10 Band reinforcement 11 Flare welding 12 Wedge 13 Temporary fixing metal 14 Concrete anchor 20 Special core drill 21 Core bit 22 Spindle part 23 Motor part 24 Rotation transmission mechanism 25 Support part 26 Vertical axis

Claims (2)

A concrete structure reinforcement method in which a groove portion is cut in a vertical direction on a side surface portion of a concrete structure, a vertical reinforcing bar is embedded in the groove portion, and a resin is injected and fixed.
A step of cutting a concave portion having a size that is connected to the groove portion and can accommodate a spindle portion of a core drill and a core bit attached to the spindle portion but cannot accommodate a motor portion, on a side surface portion on a footing portion of a concrete structure; ,
Accommodating the spindle part and core bit of the core drill in which the spindle part is offset from the motor part in the recess, and drilling the fixing hole vertically in the footing part;
A vertical reinforcing bar is embedded from the inside of the groove part into the concave part and the fixing hole, and the upper end part of the vertical reinforcing bar is constrained in the groove part by a strip plate material having a length straddling the groove part. A method for reinforcing a concrete structure, including a step of injecting and fixing the resin by curing .   The method for reinforcing a concrete structure according to claim 1, wherein the depth of the concave portion is 50 mm or less.

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