JP3687930B2 - Cutting method of existing PC structure - Google Patents

Description

[0001]
[Industrial application fields]
INDUSTRIAL APPLICABILITY The present invention is an existing PC structure such as a PC bridge, and is suitable for application to a case where an unnecessary part is cut in a form that effectively leaves a part of the existing PC structure. About.
[0002]
[Prior art]
In a so-called post-tension type PC structure that introduces pre-stress after the construction of the concrete frame, even if it is attempted to cut and remove part of the PC structure and effectively use the remaining part as a structure, At the time of cutting the material, the prestress introduced by the tension material was dissipated, and it was impossible to reuse it as a structure.
[0003]
[Problems to be solved by the invention]
However, this causes a disadvantage that it is impossible to repair or modify the post-tension type PC structure.
[0004]
In view of the above circumstances, in the post-tension type PC structure, the present invention can cut and remove the remaining portion in a state in which tension is effectively applied to the tension material in the remaining structure. It aims at providing the cutting method of the existing PC structure.
[0005]
[Means for Solving the Problems]
That is, among the present inventions, the first invention is that the existing PC structure (1) in which the compressive force is applied to the housing parts (2, 3) by the tension material (5) to which the tension is applied is moved to a predetermined cutting position. When cutting together with the tendon (5) in (C) and separating and cutting into a remaining structure (1A) and an unnecessary structure to be cut (1B) that are used thereafter, the cutting position of the remaining structure The tension member to be cut is exposed by sandwiching a portion adjacent to the intermediate member, and the intermediate fixing tool (6) is fixed to the exposed tension member, and the tension member to which the intermediate fixing tool is fixed is fixed to the intermediate fixing member. A fixing foundation (9a) partially backfilled with the tool and connected to the residual structure side is constructed, and in this state, the exposed tension material is cut between the fixing foundation and the cutting position. the end of the cut side of the have been tendons, the fixing group Established in this set of swing fittings configured so as to mount the (13), configured then existing PC structure so as to cut at the cutting position.
[0006]
In the present invention, the second invention is configured such that the existing PC structure is a PC bridge, and the fixing foundation is constructed of fast-hardening concrete.
Note that the numbers in parentheses are for the sake of convenience indicating corresponding elements in the drawings, and therefore the present description is not limited to the descriptions on the drawings. The same applies to the “action” column below.
[0007]
[Action]
With the above-described configuration, the first invention of the present invention is the tension on the residual structure (1A) side during the period from when the intermediate fixing device (6) cuts the tendon material (5) to the fixing of the set clothing. It acts to temporarily hold the tension of the material (5). Of the present invention, the second invention acts so that a fast foundation can be constructed in a short time with fast-curing concrete.
[0008]
【Example】
Embodiments of the present invention will be described below with reference to the drawings. 1 is a view showing an example of a PC structure to which the present invention is applied, FIG. 2 is a cross-sectional view taken along the Z2-Z2 section of FIG. 1, FIG. 3 is a front view showing an example of an intermediate fixing tool, and FIG. FIG.
[0009]
As shown in FIGS. 1 and 2, an existing PC structure 1 such as a post-tension type PC bridge to which the present invention is applied has a slab 2 constituting a concrete frame portion and a beam 3 that supports the slab 2. At the intersection of the slab 2 and the beam 3 (therefore, the upper part of the beam 3), as shown in FIG. A plurality of existing PC structures 1 in a form in which a predetermined tension is applied by a known fixing device (not shown) provided at the left and right ends in the drawing (therefore, a compressive force is applied to the concrete frame portion). Are provided in the directions of arrows A and B. In the existing PC structure, the left part in the figure is damaged by an earthquake or the like, or the left part in the figure needs to be cut at the cut surface C of the PC structure 1 in order to reconstruct the left part. On the other hand, as shown in FIGS. 3 and 4, the intermediate fixing tool 6 used for cutting the existing PC structure has a quadrangular columnar main body 7. A fixing hole 7a is formed in the direction of arrows D and E, that is, in the axial direction of the main body 7. As shown in FIG. 4, the main body 7 has two main body pieces 7c and 7d, and the main body pieces 7c and 7d are opposed to the main body pieces 7c and 7d via the joint surfaces 7i and 7i. When assembled in such a manner, the tension member fixing hole 7a is formed, and grooves 7e and 7e having a semicircular cross section are formed in the directions of arrows D and E. Also, the body 7 has a plurality of bolt mounting holes 7f, and the body pieces 7c and 7d are fastened and fixed by bolts and nuts (not shown) with the groove portions 7e and 7e forming the tension material fixing holes 7a as shown in FIG. The main body piece 7c is further provided with a fixing material injection hole 7g for fixing a tension material such as an expansion material and an air vent hole 7h so that the tension material fixing hole 7a communicates with the outside. It has been drilled.
[0010]
Since the existing PC structure 1 etc. has the above-described configuration, the existing PC structure is damaged because the left part in FIG. 1 is damaged by an earthquake or the like, or the left part in the figure is remodeled. When the PC structure 1 is cut at the cutting plane C and separated into a remaining structure 1A to be reused as a structure and a structure to be cut 1B to be removed, it is performed as follows. That is, first, as shown in FIG. 1, concrete at a position on the residual structure side adjacent to the cutting plane C, which is a planned cutting position of the existing PC structure 1, is formed to form a fixing hole 9 and embedded in the interior. The tension material 5 is exposed. When the fixing hole 9 is formed and drilled, the intermediate fixing tool 6 shown in FIGS. 3 and 4 is divided in half, and the main body pieces 7c and 7d are formed so that the groove portions 7e and 7e face each other. Each tendon 5 is swallowed in such a manner that it is disposed in the tendon fixing hole 7a formed by the grooves 7e, 7e. Then, in this state, as shown in FIG. 4, the joint surfaces 7i and 7i of the main body pieces 7c and 7d are brought into contact with each other, and the main body pieces 7c and 7d are connected by bolt nuts (not shown) through the bolt mounting holes 7f. Is integrated.
[0011]
Next, as shown in FIG. 3, the fixing material 10 such as an expansion material is injected into the tension material fixing hole 7 a from the fixing material injection hole 7 g formed in the main body piece 7 c of the intermediate fixing tool 6, and the tension material 5. Are fixed to the intermediate fixing tool 6, and a washer 11 is attached to the right side of each intermediate fixing tool 6 in FIG. 1, and the intermediate fixing tool 6 is temporarily fixed in the fixing hole 9 by an appropriate means. In this state, tension is still applied to the tendon 5 and the compressive force on the concrete constituting the slab 2 and the beam 3 of the PC structure 1 around the fixing hole 9 is locally applied by the fixing hole 9. Is open, but when viewed as a whole structure, due to the tension introduced into the tension member 5 by a known fixing tool provided at the left and right ends of the existing PC structure 1 (not shown) in FIG. The compressive force is effectively applied to the PC structure 1 as prestress.
[0012]
Next, as shown in FIG. 1, the fixing material to be fixed on the left side of the fixing hole 9 in the fixing hole 9, i.e., the residual structure 1 </ b> A on the right side of the cut surface C that remains as a structure after cutting. A part of concrete 12 such as super fast hard concrete is backfilled on the end side, a fixing base 9a is connected to the fixing hole 9 on the right side of FIG. 1 and the intermediate fixing part 6 is connected to the residual structure 1A. It is constructed by embedding it with the washer 11 and the like. The surface on the left side of the fixing base 9a in the figure is formed as a permanent fixing surface 9b in the fixing hole 9 so as to be substantially perpendicular to the directions of arrows F and G as the laying direction of the tendon material 5. In addition, when the super-fast hard concrete whose design strength is expressed in a shorter time than ordinary concrete is used as the concrete 12, the curing time of the concrete is short, and the subsequent work can be started quickly. Therefore, it is effective when the existing PC structure needs to be shortened as much as possible, such as a PC bridge, etc., and it must be used in general as soon as possible.
[0013]
Thus, when the fixing base 9a is formed in the fixing hole 9, the space between the permanent fixing surface 9b of the fixing base 9a and the left side of the fixing hole 9 in the drawing, that is, from the residual structure 1A and the cut surface C is shown in FIG. The tension material 5 still exposed in the space between the structure to be cut 1B on the middle left side is cut at a position K that is separated from the permanent fixing surface 9b by a predetermined fixing distance LX. Then, the tension member 5 that has been cut is released from the position K to the left to-be-cut structure 1B, and the tension that has been applied to the tension member 5 until then is released, but the reclaimed residual structure 1A side is Even if the tendon 5 is cut, the intermediate fixer 6 embedded in the fixing base 9a and the tendon 5 are fixed and fixed, so that the intermediate fixer 6 and the existing PC structure 1 are not shown. The tension state of the tension material 5 on the right side of FIG. 1 is maintained without change by the existing fixing tool provided at the middle right end, and the residual structure 1A portion is the same as before the tension material 5 is cut. A predetermined compressive force is applied, and the residual structure 1A is maintained in a good stress state that is not changed.
[0014]
Next, the end portions of the tension members 5 that have been cut off and remain on the residual structure 1A side in a state of protruding from the permanent fixing surface 9b of the fixing base 9a are fixed to the fixing base 9a using a known fixing tool 13. Fix and fix.
[0015]
When the fixing device 13 is fixed to the residual structure 1A side in this way, the existing PC structure 1 is cut from the cut surface C shown in FIG. 1, and the structure to be cut 1B side is removed to obtain a new structure. Build things. The residual structure 1A is prestressed by the fixing tool 13, the intermediate fixing tool 6 and the existing fixing tool provided at the right end of the existing PC structure 1 (not shown) in spite of the cutting of the tension member 5. Since the state in which is introduced is maintained, it is possible to continue in a good state even after the structure to be cut 1B is removed.
[0016]
【The invention's effect】
As described above, according to the first invention of the present invention, the existing PC structure 1 in which the compressive force is applied to the housing parts such as the slab 2 and the beam 3 by the tension material 5 to which the tension is applied is cut. When cutting together with the tendon 5 at a predetermined cutting position such as the surface C and then separating and cutting the residual structure 1A and the unnecessary structure 1B to be used, the residual structure is placed at the cutting position. The tension material to be cut is exposed by sandwiching adjacent portions, and the intermediate fixing tool 6 is fixed to the exposed tension material, and the tension material with the intermediate fixing tool fixed together with the intermediate fixing tool. The fixing base 9a connected to the residual structure side by refilling the part is constructed, and the exposed tension material is cut between the fixing base and the cutting position in that state, and the tension material of the cut tension material is cut. Set the end of the residual structure side Since the existing PC structure is fixed at the cutting position and then fixed at the cutting position, the intermediate fixing tool is placed on the remaining structure side from the time of cutting the tendon to the fixing of the setting clothes. The tension of the tension material can be temporarily maintained, and in the post-tension type PC structure, the remaining portion is cut and removed in a state in which tension is effectively applied to the tension material in the remaining structure. It becomes possible.
[0017]
According to the second aspect of the present invention, the existing PC structure is a PC bridge, and the fixing foundation is constructed of fast-curing concrete such as super-hard-hardening concrete. It can be built on time, and PC bridges can be used immediately.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a PC structure to which the present invention is applied.
FIG. 2 is a cross-sectional view taken along the Z2-Z2 cross section of FIG.
FIG. 3 is a front view showing an example of an intermediate fixing tool.
4 is a side view of FIG. 3. FIG.
[Explanation of symbols]
1 …… Existing PC structure 1A …… Residual structure 1B …… Cut structure 2 …… Housing part (slab)
3 …… Housing part (beam)
5 …… Tension material 6 …… Intermediate fixing tool 9a …… Fixing base 13 …… This setting dressing (fixing tool)
C: Cutting position (cut surface)

Claims (5)

An existing PC structure in which a compressive force is applied to the housing portion by a tension material to which tension is applied is cut together with the tension material at a predetermined cutting position, and thereafter, a residual structure to be used and an unnecessary structure to be cut are used. When separating and cutting, the tension material to be cut is exposed by sandwiching a portion of the residual structure adjacent to the cutting position, and an intermediate fixing tool is fixed to the exposed tension material, and the intermediate fixing is performed. A part of the tension material to which the tool is fixed is backfilled together with the intermediate fixing tool to construct a fixing base connected to the residual structure side, and in this state, the exposed tension material is fixed to the fixing base and the cutting position. And the end of the cut side of the cut tension material is fixed with the present setting device configured to be mounted on the fixing base, and then the existing PC structure is cut. I will cut at the position Cutting method in existing PC Structures to configure. 2. The method for cutting an existing PC structure according to claim 1, wherein the existing PC structure is a PC bridge, and the fixing foundation is constructed of fast-hardening concrete. The intermediate fixing device is formed on two main body pieces configured to be separable, a bolt nut for fastening and fixing the two main body pieces, and an opposing surface of the two main body pieces. A groove portion that forms a tendon fixing hole when fastened,
    The fixing of the intermediate fixing tool to the tendon material is performed by dividing the two main body pieces into a state where the tendon material is inserted into the tendon material fixing hole, and attaching the two main body pieces to the bolt nut. By fastening and fixing,
    The cutting method of the existing PC structure of Claim 1 or 2 characterized by the above-mentioned. The intermediate fixing tool has a fixing material injection hole that communicates the tension material fixing hole and the outside,
    The tendon fixing hole is formed in such a size that a gap is formed around the tendon when the tendon is inserted,
    After the intermediate fixing device is installed and before the fixing foundation is constructed by backfilling, the fixing material is injected into the gap from the fixing material injection hole to fix the tension material to the intermediate fixing device. To fix,
    The cutting method for an existing PC structure according to any one of claims 1 to 3. The fixing surface of the fixing base on the side close to the set clothing is formed to have an inclination so that the tendon protrudes in a substantially normal direction.
    The cutting method of the existing PC structure of any one of Claims 1 thru | or 4 characterized by the above-mentioned.

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