JP2009062772A - Construction method and structure for reinforcing concrete structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a construction method and a structure for reinforcing a concrete structure which enable a polymer cement-based coating material to be protected from a collision of driftwood, boulder stones, etc., without increasing an inhibition ratio of a cross-sectional area of a river, in the concrete structure reinforcing method for embedding and fixing a reinforcing bar into the surface of the concrete structure arranged in flowing water and for coating the surface with the polymer cement-based coating material. <P>SOLUTION: In the construction method for reinforcing the concrete structure, the reinforcing bar is embedded and fixed into the surface of a column 2 of a bridge pier 1 arranged in the flowing water, and coating layers 3 are formed by coating the surface with the polymer cement-based coating material. Only the coating layer 3a at the upstream side of the flowing water is more thickly formed than the other coating layer 3b. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a reinforcing method and a reinforcing structure for a concrete structure in which reinforcing bars are embedded and fixed in a concrete structure disposed in flowing water such as an existing concrete pier and the surface is covered with a polymer cement-based coating material.

  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.

  In order to solve such problems, the present inventor has proposed a concrete structure reinforcing method described in Patent Document 1. In this method of reinforcing a concrete structure, a groove for fitting the reinforcing rod is formed on the surface portion of the concrete structure, and after inserting the reinforcing rod into the groove, the inner surface of the groove and the reinforcing rod A wedge-shaped anchor is driven into the gap to restrain the reinforcing rod, and a resin is injected into the gap to fix the reinforcing rod, and the surface is covered with a polymer cement-based coating material.

Japanese Patent No. 3778638

  However, in the bridge pier reinforced by the above-mentioned concrete structure reinforcement method, drifted wood, rolling stones, etc. flowing from the upstream during flooding may collide with the pier and damage the thickened polymer cement-based coating material. The thicker the polymer cement coating, the more effective it is for impacts such as driftwood and rolling stones, but the larger the cross-section, the greater the inhibition rate of the river volume will not meet the standard value. .

  Therefore, in the present invention, in a reinforcing method for a concrete structure in which reinforcing bars are embedded and fixed on the surface of a concrete structure disposed in running water and the surface is covered with a polymer cement-based coating material, the river volume inhibition rate is increased. An object of the present invention is to provide a reinforcing method and a reinforcing structure for a concrete structure capable of protecting a polymer cement-based coating material caused by a collision with driftwood, a boulder, or the like.

  The concrete structure reinforcing method of the present invention is a concrete structure in which reinforcing bars are embedded and fixed on the surface of a concrete structure disposed in flowing water, and the surface is covered with a polymer cement-based coating material to form a coating layer. In this reinforcing method, only the coating layer on the upstream side of running water is formed thicker than the other coating layers.

  According to the present invention, only the coating layer on the upstream side of the running water is formed thicker than the other coating layers, so even if the coating layer on the upstream side of this running water is formed thick, the change in the width of the concrete structure relative to the river width does not change. There is no impact on the volume inhibition rate. Moreover, since the coating layer of the upstream of the flowing water which the driftwood, the rolling stone, etc. which flow from the upstream at the time of flooding collide is formed thick, it is strong with respect to an impact. Furthermore, since only the coating layer on the upstream side of the flowing water is formed thicker than the other coating layers, an increase in the weight of the pier can be minimized.

  Here, it is desirable to form the coating layer on the upstream side of running water including a reinforcing material in the polymer cement-based coating material. In order to include a reinforcing material in the polymer cement-based coating material, for example, it is effective to mix metal short fibers or install a metal reinforcing material in the polymer cement-based coating material. Thereby, the intensity | strength of the coating layer of the upstream of flowing water can be raised, and also it becomes strong with respect to the impact at the time of collisions, such as a driftwood and a rolling stone.

  Further, in the concrete structure reinforcement method of the present invention, an induced joint is formed at the changing point of the joint portion between the surface of the coating layer along the flow of the flowing water and the coating layer on the upstream side of the flowing water, and the impact joint is formed in the induced joint. It is desirable to fill the absorbent material. When only the coating layer on the upstream side of the running water is made thicker than the other coating layers, there is a stress imbalance at the changing point of the joint between the surface of the coating layer along the flow of the running water and the coating layer on the upstream side of the running water. Therefore, it is possible to improve the stress distribution with the shock absorbing material and prevent cracking of the coating material by forming the induced joint at this change point and filling the induced joint in the induced joint. it can.

  Further, the coating layer on the upstream side of the flowing water can be formed by providing an impact absorbing material on the polymer cement-based coating material after coating with the polymer cement-based coating material. As a result, the impact caused by the collision of driftwood, rolling stones and the like flowing from the upstream during flooding can be directly absorbed by the impact absorbing material, and the impact on the polymer cement-based coating material can be reduced.

(1) Reinforcement of concrete structures that are resistant to impacts when drifted wood, rolling stones, etc. flowing from the upstream collide with water by forming only the upstream coating layer thicker than other coating layers. A structure is obtained, and damage to the polymer cement-based coating material covering the reinforcing bar can be prevented. In addition, since the thickening is only the coating layer upstream of the flowing water, there is no effect on the river volume inhibition rate due to the thickening, and the polymer cement coating by the collision of driftwood or boulders without increasing the river volume inhibition rate The material can be protected. Furthermore, since only the coating layer on the upstream side of the running water is increased, an increase in the weight of the pier can be minimized.

(2) By forming a coating layer on the upstream side of running water including a reinforcing material in the polymer cement-based coating material, the strength of the coating layer on the upstream side of running water can be increased. A reinforced structure of a concrete structure that is strong against impact at the time of collision can be obtained.

(3) An induced joint is formed at the changing point of the joint portion between the surface of the coating layer along the flow of the flowing water and the coating layer upstream of the flowing water. When only the upstream coating layer is thicker than the other coating layers, it induces stress imbalance at the changing point of the joint between the surface of the coating layer along the flowing water and the upstream coating layer It can be improved by the impact absorbing material in the joint, and further cracking of the coating material can be prevented.

(4) Driftwood that flows from the upstream at the time of flooding by forming the coating layer on the upstream side of running water with a polymer cement-based coating material and then forming an impact absorbing material on the polymer cement-based coating material It is possible to directly absorb an impact caused by a collision of a stone or a boulder by the impact absorbing material, to reduce an impact on the polymer cement-based coating material, and to prevent damage to the polymer cement-based coating material.

  FIG. 1 is a plan sectional view of a reinforced concrete pier constructed by a concrete structure reinforcement method according to an embodiment of the present invention, FIG. 2 is an enlarged view of a portion A in FIG. 1, and FIG. 3 is an enlarged view of a portion B in FIG. 4 is a longitudinal sectional view of FIG.

  In FIG. 1, a pier 1 has a reinforcing covering layer 3 formed on a side surface of a column portion 2 of an existing pier made of reinforced concrete. The pier 1 is disposed in the river water, and the column portion 2 has an oval cross section that is long in the flow direction of the river and short in the direction perpendicular to the flow direction. It has a rounded rectangular cross section consisting of parallel lines of equal length and two arcs.

  As shown in FIGS. 3 and 4, main bars 4 a are arranged inside the column part 2 in the axial direction of the column part 2, that is, in the vertical direction. 4b is a girdle. A groove 5 is formed on the side surface of the column portion 2 in the same direction as the main reinforcing bar 4a outside the main reinforcing bars 4a, and a reinforcing vertical reinforcing bar 6 is fitted inside the groove 5. The vertical reinforcing bar 6 is embedded and fixed in the groove 5 by filling the inside of the groove 5 with a resin 7 made of an epoxy resin and curing it.

  Further, on the outside of the vertical reinforcing bar 6, a band 8 is constructed by flare welding 9, and the reinforcing covering layer 3 is formed on the outside thereof. The reinforcing coating layer 3 is made of polymer cement mortar as a polymer cement-based coating material. The polymer cement mortar is a kind of resin concrete, and is a mortar composed of cement, sand, polymer, and the like. As the polymer, latex of SBR type, natural type or acrylic type is used.

  As shown in FIG. 2, the reinforcing coating layer 3 is coated only on the coating layer 3a coated on the upstream arc portion, and on the other arcuate portion on the downstream side and the surface along the flow direction. It is formed thicker than the layer 3b. Moreover, the upstream coating layer 3a is formed so as to increase in thickness toward the upstream side, and the thickness is about 100 mm at the thickest portion. In addition, the thickness of the coating layer 3b is about 14 mm.

  In addition, an induction joint 10 is formed at a change point (boundary between the arc portion and the surface along the flow direction) P of the joint portion between the covering layer 3a and the covering layer 3b, that is, the curvature R of the column portion 2 having an oval cross section. The induction joint 10 is filled with a shock absorbing material 11 such as a sealing material or a buffer material excellent in water resistance and weather resistance.

  In the above configuration, the vertical reinforcing bar 6 is fixed in a state of being fitted in the groove 5 formed in the side surface portion of the column portion 2. Moreover, since the resin 7 made of epoxy resin is interposed between the vertical reinforcing bars 6 and the grooves 5, even when the column portion 2 is bent and deformed by a horizontal load at the time of an earthquake, the column portion 2 The distortion force due to the deformation is transmitted to the vertical reinforcing bar 6 through the resin 7 in the groove 5.

  That is, since the vertical reinforcing bar 6 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 direction reinforcing bar 6 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 6 are constrained and sealed inside the groove 5 by the resin 7, they do not float from the groove 5.

  In addition, in this pier 1, only the upstream coating layer 3a is formed thicker than the other coating layers 3b, so that it is strong against impacts when drifted wood, rolling stones, etc. flowing from upstream collide with water. Further, damage to the reinforcing coating layer 3 made of a polymer cement-based coating material that covers the vertical reinforcing bars 6 and the band reinforcing bars 8 is prevented. Further, since the thickening of the reinforcing covering layer 3 is only the covering layer 3a upstream of the flowing water, there is no influence on the river volume inhibition rate due to the thickening, and the driftwood and the boulders are not increased without increasing the river volume inhibition rate. It is possible to protect the reinforcing covering layer 3 by collision such as the above. Furthermore, in this pier 1, since only the coating layer 3a on the upstream side of running water is thickened, an increase in the weight of the pier 1 can be minimized.

  Moreover, in this pier 1, the induction joint 10 is formed in the change point P of the joint part of the coating layer 3a of an upstream side, and the coating layer 3b of the surface along the flow of flowing water, The impact-absorbing material 11 is formed in this induction joint 10. , The stress imbalance at the changing point P due to the fact that only the upstream coating layer 3a is formed thicker than the other coating layers 3b is improved by the shock absorber 11 in the induction joint 10. Therefore, cracking of the polymer cement-based coating material is further prevented.

Next, with reference to FIGS. 1 to 4, the construction procedure of the reinforcing covering layer 3 will be described.
First, the entire surface of the column portion 2 of the pier 1 to be reinforced is made rough by chipping or sand blasting. A water jet may be used.

  Next, a concrete cutter (not shown) is applied to the side surface of the column part 2 in a direction parallel to the main reinforcement 4a arranged in the column part 2 as shown in FIGS. 3 and 4 (vertical direction). A cut having a width of about 50 mm and a depth of about 50 mm is made, and the concrete inside the cut is suspended by an electric pick to form a groove 5. Concrete dust adhering to the groove 5 is removed and cleaned by a method such as high-pressure washing.

  Next, the vertical reinforcing bars 6 are fitted into the grooves 5 and iron or wooden wedges (not shown) are driven in a staggered arrangement on both sides of the gap between the vertical reinforcing bars 6 and the grooves 5. Then, the vertical reinforcing bar 6 is restrained, and then embedded and fixed with a resin 7 made of an epoxy resin. The wedge is extracted after the resin 7 is cured, or buried with the resin 7.

  Next, the reinforcing bars 6 are attached in the direction perpendicular to the vertical reinforcing bars 6 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 6 with a binding wire (not shown) previously attached to the vertical reinforcing bar 6. After tying, the ends of the band 8 are flare welded 9 to form continuous bars. In addition, although the band 8 may be a deformed reinforcing bar conventionally used, it is desirable that the surface is subjected to rust prevention treatment. The binding wire is preferably made of stainless steel.

  Next, the reinforcing coating layer 3 is formed on the surface of the column part 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. At this time, as shown in FIG. 2, the polymer cement-based coating material is coated only on the coating layer 3a to be coated on the upstream arc portion and on the other arc portion and the surface along the flow direction. It is applied so as to be thicker than the coating layer 3b and thicker toward the upstream side. It is desirable that the polymer cement-based coating material is applied carefully so that no floating occurs between the layers.

  In order to further increase the strength of the upstream coating layer 3a, a reinforcing material may be included in the polymer cement-based coating material. In order to include a reinforcing material in the polymer cement-based coating material, for example, metallic short fibers such as stainless steel are mixed in the polymer cement-based coating material, or a metal reinforcing material such as stainless steel is installed. Thereby, the intensity | strength of the coating layer 3a of the upstream of flowing water can be raised, and also it becomes strong with respect to the impact at the time of collision, such as a driftwood and a rolling stone.

  The thickness exposed on the surface of the column portion 2 of the coating layer 3b other than the coating layer 3a 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. In addition, since the winding thickness can be greatly reduced, the amount of polymer cement-based coating material used can be reduced by about 2/3 compared to the conventional polymer mortar winding method, and construction costs can be significantly reduced. is there.

  Next, another embodiment of the method for reinforcing a concrete structure of the present invention will be described. FIG. 5 is a plan sectional view of a reinforced concrete bridge pier constructed by a concrete structure reinforcement method according to another embodiment of the present invention, and FIG. 6 is an enlarged view of part C of FIG.

  In FIG. 5, the reinforcing piercing layer 22 having the same thickness is formed on the pier 20 over the entire side surface of the column portion 21 of the existing pier made of reinforced concrete with a polymer cement-based coating material. However, an impact absorbing material 23 made of rubber or the like is provided on the reinforcing coating layer 22 on the upstream side of running water. That is, on the upstream side of the flowing water, a double coating layer is configured by overlapping the reinforcing coating layer 22 and the shock absorbing material 23, so that the other reinforcing coating layer 22 other than the upstream side is configured. Is also formed thick.

  In addition, the impact-absorbing material 23 is formed in a crescent-shaped cross section so as to become thicker toward the upstream side, like the above-described coating layer 3a. As shown in FIG. 6, the shock absorber 23 is fixed to the column portion 21 made of reinforced concrete through the reinforcing coating layer 22 by a concrete anchor 24. The head of the concrete anchor 24 is sealed in the shock absorbing material 23 by a sealing material 25.

  As described above, when the coating layer on the upstream side of the flowing water is coated with the polymer cement-based coating material, the impact absorbing material 23 is provided on the reinforcing coating layer 22 made of the polymer cement-based coating material. Even so, the impact caused by the collision of driftwood, rolling stones, etc. flowing from the upstream at the time of flooding can be directly absorbed by the impact absorbing material 23, so the impact on the underlying polymer cement coating material is reduced. Thus, it is possible to prevent damage to the polymer cement-based coating material.

  Although not shown, it is also possible to adopt a configuration in which a rubber shock absorber 23 similar to that shown in FIG. 5 is provided on the covering layer 3a shown in FIG. Further, in the pier 1 shown in FIG. 1, when the flow of the river is relatively gentle and there is no possibility of cracking of the polymer cement-based coating material, the induction joint 10 and the shock absorbing material 11 can be omitted. It is.

  The concrete structure reinforcing method and the reinforcing structure of the present invention are not limited to seismic reinforcement against horizontal loads during earthquakes acting on concrete piers, but the reinforcement of the concrete girder under the bridge and the reinforcement of other concrete structures. Useful for. In particular, it is suitable for reinforcement of a pier installed in a river with a possibility of water discharge.

It is a plane sectional view of the pier made from reinforced concrete constructed by the reinforcement method of the concrete structure in the embodiment of the present invention. It is the A section enlarged view of FIG. It is the B section enlarged view of FIG. It is a longitudinal cross-sectional view of FIG. It is a plane sectional view of the pier made from reinforced concrete constructed by the reinforcement method of the concrete structure in another embodiment of the present invention. It is the C section enlarged view of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bridge pier 2 Column part 3 Reinforcement coating layer 3a, 3b Cover layer 4a Main reinforcement 4b Band reinforcement 5 Groove 6 Vertical reinforcement reinforcement 7 Resin 8 Band reinforcement 9 Flare welding 10 Induction joint 11 Shock absorber 20 Bridge pier 21 Column 22 Reinforcement Coating layer 23 Shock absorber

Claims (8)

In the reinforcement method for concrete structures in which reinforcing bars are buried and fixed on the surface of the concrete structure disposed in running water, and the surface is coated with a polymer cement-based coating material to form a coating layer.
A method for reinforcing a concrete structure, wherein only the coating layer on the upstream side of the flowing water is formed thicker than the other coating layers.   The method for reinforcing a concrete structure according to claim 1, wherein the coating layer on the upstream side of the flowing water is formed by including a reinforcing material in the polymer cement-based coating material.   An induction joint is formed at a change point of a joint portion between the surface of the coating layer along the flow of the flowing water and the coating layer on the upstream side of the flowing water, and a shock absorbing material is filled in the induction joint. The method for reinforcing a concrete structure according to claim 1 or 2.   The coating layer on the upstream side of the flowing water is formed by providing an impact absorbing material on the polymer cement-based coating material after coating with the polymer cement-based coating material. A method for reinforcing a concrete structure according to any one of the above. A reinforcing structure of a concrete structure in which reinforcing bars are embedded and fixed on the surface of a concrete structure disposed in flowing water, and the surface is covered with a polymer cement-based coating material to form a coating layer,
A reinforcing structure for a concrete structure, wherein only the coating layer on the upstream side of the flowing water is thicker than the other coating layers.   The reinforcing structure for a concrete structure according to claim 5, wherein the coating layer on the upstream side of the flowing water includes a reinforcing material in the polymer cement-based coating material.   An induction joint is provided at a change point of a joint portion between the surface of the coating layer along the flow of the flowing water and the coating layer on the upstream side of the flowing water, and a shock absorbing material is provided in the induction joint. Item 7. A reinforcing structure for a concrete structure according to item 5 or 6.   The coating layer on the upstream side of the flowing water includes a first coating layer coated with the polymer cement-based coating material, and a second coating layer formed on the first coating layer with a shock absorbing material. The reinforcing structure for a concrete structure according to any one of claims 5 to 7, which is configured.

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