JP4087978B2 - Method for forming tendon fixing body - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forming a tension member fixing body by adding concrete so as to protrude from the surface of each concrete member in a structure in which a plurality of existing concrete members are juxtaposed, such as a bridge.
[0002]
[Prior art]
In a prestressed concrete member, generally a tension material is arrange | positioned in a concrete member, and prestress is provided to concrete by the tension | tensile_strength introduced into this tension material. However, a tension material for introducing prestress into concrete may be disposed outside the concrete member. For example, when prestressed concrete girders formed by pre-tensioning or post-tensioning as shown in Fig. 1 are placed between piers or between piers and abutments, and the girders on both sides are connected to form continuous girders. In some cases, a tension material is arranged outside the girder as a so-called out cable. This is because a tension member for resisting a large bending moment generated on a pier when a continuous girder is used cannot be arranged in a concrete member, and is arranged as an out cable along the girder.
Moreover, when it is necessary to reinforce a girder in a bridge that is already in service, a tension member may be arranged outside the girder and prestress may be additionally introduced.
[0003]
In such a case, it is necessary to form the tension material fixing body for transmitting the reaction force of the tension material to the concrete member so as to be integrated with the existing concrete girder.
A method for forming such a tension member fixing body (fixing bracket) is described in Japanese Patent Application Laid-Open No. 8-158315. In this method, as shown in FIG. 6A, first, through holes are provided in a plurality of concrete girders 101, and tension is introduced into a tension member 102 inserted through the through holes. And as shown in FIG.6 (b), while placing concrete 103 in the shape of a block in the position which touches the side surface of each girder, it embeds and integrates a part of tension material 102 into which the said tension | tensile_strength was introduce | transduced. . After the concrete 103 is hardened, as shown in FIG. 6C, the tendon material 102 protruding from the side surface of the placed concrete is cut. As a result, the tension of the tension material 102 is transmitted to the hardened concrete block, and acts to strongly press the hardened concrete block, that is, the tension material fixing body 103, against the side surface of the concrete girder 101. Therefore, the tension member fixing body is firmly integrated with the girder.
[0004]
[Problems to be solved by the invention]
However, the above-described method for forming a tension member fixing body (fixing bracket) has the following problems.
When existing concrete members (for example, girders) are large in size and the interval between the parallel concrete members is large, a formwork for placing the concrete of the tension material fixing body is assembled between the concrete members, and each concrete is assembled. Concrete for the fixing body can be placed so as to be independent of the members. However, when the girder height is small like a pretensioned girder and a large number of girder are arranged at small intervals, there is not enough work space between the girder and each girder is for fixing block. The formwork may not be assembled. In addition, when concrete is placed on a tension member fixing body that is independent of each other for a large number of girders, the number of work steps increases, and the efficiency deteriorates.
[0005]
The invention according to the present application has been made in view of the above-described problems, and its purpose is to provide a block-like tension material so as to protrude from each member even when the interval between the plurality of concrete members is narrow. It is an object of the present invention to provide a method for forming a tension member fixing body that can efficiently form a fixing body and can be firmly integrated with a concrete member.
[0006]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 is a tension material for fixing a tension material on opposite surfaces of a plurality of parallel concrete members and transmitting a reaction force to the concrete member. A method of forming a fixing body, the method comprising providing a through hole in each of the plurality of concrete members along a straight line substantially perpendicular to the opposing surfaces of the plurality of concrete members, and being continuous with the through holes A step of disposing a tubular member between the plurality of concrete members, and embedding the tubular member between the plurality of concrete members and fixing the fixing member so as to be joined to opposing surfaces of the concrete members on both sides. A step of placing concrete, a step of inserting a tension member through a duct formed by the through-hole and the cylindrical member, and introducing a tension force; A step of filling and curing the material and integrating the lateral tension member with the fixing body concrete; and the fixing body concrete and the lateral tension material at a central portion between opposing surfaces of the plurality of concrete members. The present invention provides a method for forming a tension member fixing body having a step of cutting and separating.
[0007]
In such a method for forming a tension member fixing body, since the concrete to be the fixing body is placed so as to be joined to the concrete members on both sides between the concrete members, it is necessary to assemble the formwork separately for each concrete member. In addition, the formwork can be assembled even when the member interval is narrow. In addition, the fixing concrete fixed to the members on both sides can be cast in a lump, and the working efficiency is improved.
[0008]
After the fixing concrete placed between the concrete members is hardened, a tensioning force is introduced by inserting a lateral tension material through the duct. At this time, the plurality of concrete members are in a state of being connected by fixing concrete placed between them, and even if the concrete member receives a reaction force and introduces a tensile force, the concrete member However, there is no need to reinforce in the lateral direction.
[0009]
Also, after the fixing concrete and the transverse tension material are integrated by introducing the tension to the lateral tension material and injecting grout into the duct, the fixing body concrete and the tension material are placed between the concrete members. By cutting at the portion, the tension force is transmitted to the fixing body concrete near the cutting end by the adhesive force, and this force acts to strongly press the cut fixing body concrete against the existing concrete member surface. Thereby, the cut fixing body concrete is firmly fixed to the concrete members on both sides.
[0010]
At this time, the tension force of the laterally tightened tension member is transmitted to the fixing member concrete by the adhesion force with the fixing member concrete. Therefore, it is desirable to use a tension member having a large adhesion force. In addition, the cut tendon is short in length, and a material having a large elongation is desirable in order to effectively press the fixing body concrete against the concrete member surface. For this reason, it is desirable to use a non-metallic fiber bundled in a rod shape as described in claim 4 and having a node-like or spiral convex portion on the peripheral surface.
[0011]
Nonmetallic fibers are, for example, aramid fibers, carbon fibers, glass fibers, and the like. Except for a part of the carbon fiber, these materials generally have a smaller elastic coefficient than that of the PC steel, and a large elongation occurs when a tensile force is introduced. Therefore, prestress is effectively introduced even if it is short. Further, by forming the above-mentioned bundle of non-metallic fibers with a synthetic resin into a rod shape, it is possible to easily form a node-like or spiral convex portion on the peripheral surface. By forming such a convex part, the adhesive force with concrete improves remarkably.
[0012]
The invention according to claim 2 is a method of forming a tension member fixing body for fixing a tension material and transmitting a reaction force to the concrete member on opposite surfaces of a plurality of concrete members arranged in parallel. A step of providing a through hole in each of the plurality of concrete members along a straight line substantially perpendicular to the opposing surface of the plurality of concrete members; and a lateral direction continuous to the through holes provided in the plurality of concrete members. A step of inserting a tensioning material and introducing a tension force; embedding the lateral tensioning material between the plurality of concrete members and placing fixed body concrete so as to be joined to opposite surfaces of the concrete members on both sides; And the step of integrating with the lateral tension material, and after the fixing body concrete has hardened, the fixing body controller is formed at the center between the opposing surfaces of the plurality of concrete members. There is provided a method of forming a tension member fixing body and a step of cutting and separating the discrete and Yokoshime tendons.
[0013]
In such a method for forming a tension member fixing body, after introducing a tension force to the laterally tightening tension member, concrete of the fixing member is placed and integrated so as to directly embed the tension member. Accordingly, when a tension force is introduced into the lateral tension material, a frame or a frame body that bears the reaction force is required. However, unlike the method according to claim 1, the tubular member prior to the placement of concrete. There is no need to embed. Moreover, it is not necessary to grout this cylindrical member, and the number of work steps can be reduced.
[0014]
2. After the concrete for forming the fixing body has hardened, the fixing body concrete and the tension material integrated between the concrete members are cut to form the fixing body concrete in the same manner as in the method according to claim 1. Fastened and firmly fixed to the member.
[0015]
Further, in this method, the same effect as described in claim 1 can be obtained by using the transverse tension material according to claim 4, and the fixing body concrete is effectively tightened to the existing concrete member to be strong. It can be fixed.
[0016]
The invention according to claim 3 is the method of forming the tension member fixing body according to claim 1 or 2, wherein the step of cutting and separating the fixing body concrete is performed by winding an annular wire saw around the fixing concrete, It is assumed that the wire saw is driven to rotate and cut while introducing tension.
In such a method, even when the interval between the concrete members is narrow, if the wire saw can be wound, the fixing body can be easily and efficiently cut.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the invention according to the present application will be described with reference to the drawings.
FIG. 1 is a schematic side view of a prestressed concrete bridge to which the method for forming a tension member fixing body according to the present invention can be applied.
In this bridge, a plurality of prestressed concrete girders 5 manufactured in a pre-tension system are bridged between the abutments 1 and 4 and the piers 2 and 3 and between the piers 2 and 3, respectively. The girder 5 between both side supports is connected to form a three-girder continuous girder. In order to connect the girder 5 on the piers 2 and 3, as shown in FIG. 2A, a cable 6 is arranged outside the concrete member, and the girder connecting portion is pre-stressed by the tension force introduced into the cable 6. Integrate by introducing stress.
[0018]
In order to fix the cable 6 to the prestressed concrete girder 5 in a state where tension is introduced, a tension material fixing body 7 as shown in FIGS. 2B and 2C is provided.
The tension material fixing body 7 is a concrete block-like member that is added so as to protrude from the side of the prestressed concrete girder 5, that is, from the web portion, and is clamped in a direction perpendicular to the girder by a lateral tension material 8. It is firmly fixed to the girder 5. The cable 6 is inserted into a through-hole provided in the tension material fixing body 7 and fixed to the end surface of the tension material fixing body 7 via a fixing plate 9. As the above-described lateral tension material 8, a material formed by bundling aramid fibers and forming a rod shape with a synthetic resin is used.
[0019]
Next, a method for forming the tension material fixing body 7 will be described with reference to the drawings. In addition, this formation method of a tension material fixing body is one Embodiment of the invention of Claim 1, Claim 3 or Claim 4.
First, as shown in FIG. 3A, a through hole 11 is formed in the web portion of the prestressed concrete girder 5 in a direction perpendicular to the axis. The through holes 11 are provided in all the girders, and the through holes of the respective girders are located on the same straight line.
[0020]
Next, as shown in FIG. 3B, the formwork 12 for placing the fixing body concrete 14 is assembled, and the sheath 13 is disposed so as to be continuous with the through holes between the girders. This sheath 13 is formed by joining strip-shaped steel thin plates in a spiral shape into a cylindrical shape.
[0021]
The above-mentioned formwork 12 is provided continuously between the girders, and the fixing body concrete placed in this formwork is in close contact with the sides of the girders on both sides and becomes a member for connecting the girders. In addition, since the sheath 13 is arranged so as to be continuous with the through hole 11 provided in the beam, this portion becomes a duct penetrating in the lateral direction. Note that a gap 15 is left between the upper surface of the placed concrete and the upper floor slab.
[0022]
After the fixed concrete 14 that has been placed is cured, as shown in FIG. 3 (c), the transverse tension member 8 is inserted into the duct, and a jack (not shown) is attached to one or both ends. Wear and introduce tension. Then, the end portion of the lateral fastening tension member 8 is fixed to the fixing body concrete 14. The tendon is made of aramid fibers bundled in a rod shape with a synthetic resin, and a string-like body is spirally wound around the outer peripheral surface and integrated with the synthetic resin. The portion around which the string-like body is wound becomes a spiral convex portion, which improves the adhesion with concrete.
[0023]
After introducing the tension force to the lateral tension material, grout is injected into the duct and cured to integrate the tension material 8 and the fixing body concrete 14 by adhesion. Then, at the tension end or the fixing end of the tension material, the tension material protruding from the concrete is cut, and the fixing tools 17 at both ends are removed. At the center between the girders, the fixing body concrete 14 is cut together with the tendon 8 as shown in FIG.
[0024]
The fixing concrete 14 is cut using a wire saw 20 as shown in FIG. The wire saw 20 includes a cutting member 21 in which a cutting material, for example, artificial diamond particles are attached to a ring-shaped wire, a driving wheel 22 that circulates the cutting member 21, and the cutting member 21 circulates in a predetermined path. A support wheel 23 that guides the cutting member 21 and a moving wheel 24 that pulls the cutting member 21 outward so that tension is always introduced to the cutting member 21 are provided.
[0025]
In the cutting of the fixing body concrete 14, as shown in FIG. 4A, the cutting member 21 is wound around the fixing body concrete 14, and is wound around the driving wheel 22, the moving wheel 24, and the support wheel 23 and driven around. As a result, as shown in FIG. 4B, the fixing concrete 14 is gradually cut, and accordingly, the moving wheel 24 moves along the support rail 25, and the cutting member 21 is always subjected to a constant tension. It is driven around in the state. Then, as shown in FIG. 4C, the fixing body concrete 14 is cut and separated at the central portion between the girders.
In addition to the above, a wall saw can be used for cutting and separating the fixing body concrete.
[0026]
FIG. 5 is a schematic view showing a method for forming a tension material fixing body according to an embodiment of the invention described in claim 2, claim 3, or claim 4.
In this method, the process of drilling the through hole 11 in the prestressed concrete girder 5 is the same as the method shown in FIG. 3 [FIG. 5 (a)], but after the through hole 11 is provided, A reaction force support frame 31 is attached to the side, and a reaction force is applied to the reaction force support frame 31, and tension is introduced into the laterally tightening tension member 38 inserted through the through hole of each girder [FIG. 5 (b)]. After that, as shown in FIG. 5C, the fixing concrete 33 is placed between the girders and on the side of the outermost girders, and these are integrated by the adhesive force between the concrete and the tension material.
[0027]
The fixing body concrete 33 is placed so as to connect the beams 5 on both sides between the beams. Then, after the concrete has hardened, it is cut at the center between the beams [FIG. 5 (d)]. The fixing concrete 33 can be cut and separated in exactly the same manner as shown in FIG.
In such a method, even if the space between girders is narrow, a strong tension member fixing body can be provided on both sides of the girders.
[0028]
【The invention's effect】
As described above, in the method for forming a tension member fixing body according to the present invention, fixing body concrete is placed between the concrete members so as to be continuous with these opposing surfaces, and is cut and separated at the central portion between the concrete members. Therefore, it is possible to efficiently form an independent tension member fixing body for each concrete member in a narrow space.
In addition, the tension member is integrated with the fixing concrete in a state where tension is introduced to the transverse tension members penetrating a plurality of concrete members, and the transverse tension material is cut and separated together with the fixing member concrete between the concrete members. A tension material fixing body can be firmly tightened and fixed to each concrete member.
[Brief description of the drawings]
FIG. 1 is a schematic view of a prestressed concrete bridge to which a method for forming a tension member fixing body according to the present invention can be applied.
2 is a side view, an enlarged view and a cross-sectional view of a tension member fixing body provided on the prestressed concrete bridge shown in FIG. 1; FIG.
FIG. 3 is a schematic view showing a method for forming a tension material fixing body according to an embodiment of the invention according to claim 1, claim 3 or claim 4;
4 is a schematic view showing a step of cutting fixing body concrete in the method for forming a tension member fixing body shown in FIG. 3; FIG.
FIG. 5 is a schematic view showing a method for forming a tension material fixing body according to an embodiment of the invention according to claim 2, claim 3, or claim 4.
FIG. 6 is a schematic view showing a conventionally known method for fixing a cable fixing body.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,4 Abutment 2,3 Pier 5 Prestressed concrete girder 6 Cable 7 Tension material fixing body 8 Lateral tightening tension material 9 Fixing plate 11 Through-hole 12 Form 13 Sheath 14 Fixing body concrete 15 Gap 17 Fixing tool 20 Wire saw 21 Cutting member 22 Driving wheel 23 Support wheel 24 Moving wheel 25 Support rail 31 Reaction force support frame 33 Fixing body concrete 38 Lateral tightening tension material

Claims (4)

A method of forming a tension material fixing body for fixing a tension material and transmitting a reaction force to the concrete member on opposing surfaces of a plurality of parallel concrete members,
Providing a through hole in each of the plurality of concrete members along a straight line substantially perpendicular to the opposing surfaces of the plurality of concrete members;
Arranging a cylindrical member between the plurality of concrete members so as to be continuous with the through hole;
A step of embedding the tubular member between the plurality of concrete members and placing fixed body concrete so as to be bonded to opposing surfaces of the concrete members on both sides;
Inserting a tensioning material through a duct formed by the through-hole and the cylindrical member, and introducing a tension force;
Filling the duct with a grout material and curing to integrate the lateral tension material with the fixing concrete;
And a step of cutting and separating the fixing body concrete and the lateral tension material at the center between the opposing surfaces of the plurality of concrete members. A method of forming a tension material fixing body for fixing a tension material and transmitting a reaction force to the concrete member on opposing surfaces of a plurality of parallel concrete members,
Providing a through hole in each of the plurality of concrete members along a straight line substantially perpendicular to the opposing surfaces of the plurality of concrete members;
Inserting a continuous tension material through through holes provided in the plurality of concrete members, and introducing a tension force;
Embedding the lateral tension member between the plurality of concrete members, placing the fixing body concrete so as to be joined to opposing surfaces of the concrete members on both sides, and integrating with the lateral tension member;
A tension member fixing body comprising a step of cutting and separating the fixing body concrete and the lateral tension member at a central portion between opposing surfaces of the plurality of concrete members after the fixing body concrete has hardened. Forming method. The step of cutting and separating the fixing body concrete is characterized in that an annular wire saw is wound around the fixing concrete, and is driven to rotate while introducing tension to the wire saw and cut. 3. A method for forming a tension member fixing body according to 2. 3. The transverse tightening material according to claim 1, wherein a non-metallic fiber is bundled into a rod shape, and a nodular or spiral convex portion is provided on a peripheral surface. A method for forming a tendon-fixed body.

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