JP2000303703A - Widening construction method for concrete-made structure, construction method for temporary receiving frame on bridge, and reinforcing method for bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a widening construction method capable of constructing a widened part by integrating it without applying any construction to lower strength of a drilled hole, etc., on the structure on an outer periphery of the existing columnar concrete- made structure o a bridge pier, etc., a construction method for a temporary receiving frame on a bridge to be used for lifting up a bridge girder at the time of exchanging supports, and a reinforcing method to reinforce a desired portion of the bridge pier. SOLUTION: A temporary receiving frame is constructed on an upper part of a bridge pier by forming a frame body 7 an outer periphery of which is roughly cylindrical by installing plural number of metallic formworks 6 on an outer periphery of a concrete-made structure 1 with intervals between each other interposing partition plates 8 free to contract in clearances between each of the formworks 6, depositing concrete 9 in the frame body 7, winding strands 10 at a plural number of points on the outer periphery of the frame body 7 after the concrete 9 is hardened and maintaining a tensional state by fixing both end parts of the strands crossed with each other by a connector 11 by giving tensional force in the opposite directions to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for widening a concrete structure, and more particularly, to a method for constructing a temporary gantry in a bridge using the widening method and a method for reinforcing a bridge.

[0002]

2. Description of the Related Art In recent years, widening work on expressways and general roads has been carried out in various places with an increase in traffic volume. Also, 2
Roads are being reinforced by a law amendment that allows the passage of heavy vehicles of 5 tons. Along with that, we replaced bridge supports, including viaducts, with ones with greater reaction force,
Bridge piers have also been reinforced. In addition, replacement of bearings with deteriorated or lost functions and reinforcement of piers in bridges are frequently performed sequentially from the end of their useful life, in addition to damage due to the earthquake.

First, in the replacement work of the bearing, there is often no space for installing a jack device for lifting the bridge girder on the upper surface of the pier, and even if the jack device can be installed, it is difficult to replace the bearing. In many cases, the jack device cannot be installed on the upper surface of the bridge pier for some reason.
Therefore, it is necessary to build a temporary gantry around the pier, but the conventional method of constructing the temporary gantry is to use a method of supporting with a vented bridge (venting method), and to install a bracket on the pier. There is a supporting method (bracket method). The venting method involves excavating around the pier, constructing a temporary receiving foundation on the pier foundation, forming a support on the pier by forming a vent, and forming a temporary support base. In the case of standing on a large scale, the construction is large and the cost is very high. On the other hand, the bracket method drills holes in the upper part of the pier, makes a reinforcing bar, and casts concrete to form a temporary support base. However, there is not enough reaction force to replace large bearings. At the same time, there are also problems such as cutting of existing rebar by drilling and noise. In addition, RC reinforced seismic
In some cases, winding has already been performed, and new and old reinforcing bars are densely arranged on the pier itself, making drilling difficult.

[0004] In the pier reinforcement work, the above-mentioned RC winding method of seismic reinforcement is known as a proven method. In this method, steel bars are placed around the pier that needs reinforcement, a space is provided around them, steel plates are placed, and a hardened material with fluidity such as cement or synthetic resin mortar is filled. However, even with this method, the reinforcement strength is not enough.

As a method of tightening a structure from the outer periphery with a PC cable, the SE method is a standard type in Japan. In this method, the PC cable is wound in a U-shape, and both ends are fastened to each other by receiving a reaction force. Therefore, the reaction force is large, and the distance between adjacent PC cables needs to be about 50 mm to 100 mm. On the other hand, there is a method in which a PC cable is wound around the outer periphery of the structure in 5 to 10 turns, one end is fixed to a reaction force receiver, and tension is applied from the other end. If it breaks, it is dangerous because the whole line is loosened.

[0006]

SUMMARY OF THE INVENTION In view of the above situation, the present invention is intended to solve the problem of reducing the strength of a pillar-shaped existing concrete structure such as a hole in the outer periphery of the existing structure. It is possible to integrate the widened part without any construction, and to restrict the movement along the surface of the existing concrete structure mainly to the friction resistance at the joint surface It is an object of the present invention to provide a method for widening a concrete structure which can be achieved by the above method. Then, the widening method of the concrete structure is applied to the upper part of the pier of the bridge, and the constructed widened part is used as a temporary gantry for lifting the bridge girder when replacing the bearing installed on the upper surface of the pier. An object of the present invention is to provide a method for constructing a gantry and a method for reinforcing a bridge in which a widening method is applied to a desired portion of a bridge pier to reinforce the pier.

[0007]

According to the present invention, a plurality of molds are mounted on the outer periphery of a concrete structure to form a frame having a substantially cylindrical outer periphery.
A plurality of contractible partition plates are interposed from the inner surface of each frame to the surface of the concrete structure or the vicinity of the surface and substantially along the generatrix of the outer peripheral surface of the frame, and concrete is inserted into the frame. After the concrete is hardened, the frame is removed, the strands are wound around the outer circumference of the concrete at a plurality of locations along the generating line a plurality of times, and the opposite ends of the crossed strands are tensioned in opposite directions to each other. The widening method for concrete structures was established by fixing and maintaining tension. By this widening method,
The widened portion can be constructed at a desired portion of the existing concrete structure, and the structure can be reinforced.

[0008] A plurality of metal molds are mounted on the outer periphery of the concrete structure at an interval from each other to form a frame body. Alternatively, a plurality of shrinkable partition plates are interposed in a direction near the surface and substantially along the generatrix of the outer peripheral surface of the frame, and after the concrete poured into the frame hardens, the frame is left. It is also possible to tighten the outer periphery with the strand while keeping it.

[0009] In the method of constructing a temporary gantry for a bridge according to the present invention, a plurality of molds are mounted on an upper outer periphery of a concrete pier to form a frame having a substantially cylindrical outer periphery.
A plurality of shrinkable partition plates are interposed from the inner surface of each frame to the surface of the pier or near the surface thereof and substantially along the generatrix of the outer peripheral surface of the frame, and concrete is poured into the frame. After the concrete has hardened, the frame is removed, the strands are wound around the outer periphery of the concrete at a plurality of locations along the generatrix a plurality of times, and both ends of the crossed strands are fixed with connectors by applying opposite tension to each other. It is a matter of maintaining tension. This makes it possible to construct a temporary gantry for lifting the bridge girder above the pier when replacing the bearing installed on the upper surface of the pier of the bridge.

Here, a plurality of metal molds are mounted on the outer periphery of the pier with a space therebetween to form a frame body, and a gap between the respective molds is formed at the surface or near the surface of the pier. In the direction substantially along the generatrix of the outer peripheral surface of the frame body, a plurality of shrinkable partition plates are interposed, and after the concrete poured into the frame body hardens, the frame body is left, It is also possible to tighten the outer circumference with the strand.

[0011] A spacer having a height retaining portion having a width substantially equal to the diameter of the strand is interposed between the bottom surface of the connector and the cast concrete or the frame,
By tightly winding the strand, the tightening force is further increased and the sliding friction resistance at the interface between the pier and the cast concrete is made sufficient.

Further, in the method of reinforcing a bridge according to the present invention, a plurality of molds are mounted on the outer periphery of a concrete pier to form a frame having a substantially cylindrical outer periphery, and the surface of the pier is formed from the inner surface of each frame. Or reaching the vicinity of the surface and in a direction substantially along the generatrix of the outer peripheral surface of the frame, interposing a plurality of contractible partition plates, placing concrete in the frame, and after the concrete is hardened, The frame is removed, the strands are wound multiple times around the concrete circumference along the bus bar multiple times, and the opposite ends of the crossed strands are tensioned in opposite directions, fixed by connectors and maintained in tension. is there. Thereby, it is possible to reinforce the desired portion of the pier of the bridge very strongly.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the accompanying drawings. The method for widening a concrete structure according to the present invention is a method in which a widened portion is firmly integrated on an existing outer periphery of a columnar shape without performing any construction for reducing the strength of a hole or the like in the structure. Although its application range is very wide, in the present embodiment, when replacing the bearing mainly installed on the pier upper surface of the bridge, a temporary gantry for lifting the bridge girder is provided at the upper part of the pier. The construction method of the temporary gantry for the bridge to be constructed will be described in detail. 1 to 3 show a construction method of constructing a temporary gantry on an upper part of a bridge, lifting a bridge girder and replacing a bearing, and FIGS. 4 to 9 show actual construction steps of the temporary gantry. In the figure, reference symbol A is the ground, B is the bridge, 1 is the pier, 2 is the bridge girder, 3 is the bearing, 4 is the temporary gantry, 5
Indicates jack devices.

The structure of the bridge pier 1 in which the present invention is most effective is a truncated pyramid or a truncated cone whose cross-sectional shape is a square or a quadrangle or a circle close to a square, and whose cross-sectional area decreases further upward. There is no particular limitation.
The structure of the bridge B in which the present invention is most effective is a structure in which the gap between the upper surface of the pier 1 and the lower surface of the bridge girder 2 such as a hollow slab bridge, a PC bridge, and a Gerber girder bridge is narrow.

According to the construction method of the temporary gantry for the bridge according to the present invention, the temporary gantry 4 for lifting the bridge girder 2 when the bearing 3 installed on the upper surface of the pier 1 of the bridge B is replaced is mounted on the upper part of the pier 1. It is a construction method to build. Specifically, a plurality of metal molds 6,... Are mounted on the outer periphery of the concrete pier 1 at an interval from each other to form a frame 7 having a substantially cylindrical outer periphery. 6, a shrinkable partition plate 8 is interposed in a direction reaching the surface or the vicinity of the surface of the pier 1 and substantially along the generatrix of the outer peripheral surface of the frame 7 so as to be inserted into the frame 7. After the concrete 9 has been cast and the concrete 9 has hardened, the strands 10 are wound around the outer periphery of the frame 7 a plurality of times at a plurality of locations along the generatrix, and the opposite ends of the crossed strands 10 are tensioned in opposite directions. The temporary support base 4 is constructed by applying the connection, fixing the connector 11 and maintaining the tension.

The strand 10 used here is P
It is also called C steel wire or PC stranded wire.
It can withstand a tension of about 50 ton · f. The connector 11 is connected to the strand 10 wound around the structure in a state where both ends of the strand 10 cross each other.
Are fixed by applying opposite tensions to each other on the same straight line to maintain the tension, and are provided under the trade name Strong Hold Connector.

More specifically, as shown in FIGS. 4 and 5, the steel frame 6 has an arc-shaped side obtained by dividing the outer peripheral surface of a cylindrical frame 7 formed by using the same. A bottom plate 13 is welded to the lower end of the side plate 12, vertical partition plates 14, 14 are welded to both end edges, and a plurality of rib plates 15 are attached to the inner surface of the side plate 12. ,
... are formed by welding vertically and horizontally. In the present embodiment, the frame 7 is composed of four molds 6,. Also, on the outer surface of the side plate 12 of the formwork 6,
A plurality of hooks 16,... Are projected to lock the strands 10,. The partition plate 14
Is not always necessary, and when constructing the frame 7, the position of each mold 6 can be fixed and the adjacent molds 6, 6
The partition plate 14 is unnecessary if the partition plate 8 can be reliably supported therebetween.

.. Are installed on the outer periphery of the upper part of the pier 1 while supporting the form frames 6,.
The partition plate 8 is interposed between the two partition plates 14, 14. In this case, between the bottom plate 13 and the outer surface of the pier 1 and between the bottom plates 13 and 13 of the adjacent formwork 6 and 6,
It is necessary to prevent the formation of gaps so that the fluid concrete to be poured later does not flow out. Therefore, when there is a gap between the molds 6 and 6 and between the mold 6 and the pier 1, the joint material is appropriately filled. In the interior of the frame body 7 configured as described above, an independent space is formed by the partition plates 14,... Or when the partition plates 14 do not exist, by the partition plates 8,.

Here, in the present embodiment, the partition plate 8 is used.
Although a plate made of expanded polystyrene is used, a shrinkable polymer material such as expanded polyethylene or rubber, or an inorganic material that is broken by compression can be used. The case of being broken by this compression is also included in the concept of “shrinkable” in the present invention.

Then, the outer periphery of the frame 7 composed of the molds 6,... Is loosely fastened to the outer periphery of the frame 7 with a small number of strands 10 to maintain its shape. . Here, "loosely tightening" means that the partition plate 8 is tightened with a tension force that is not crushed.

Next, concrete is poured into each space of the frame 7. Concrete 9 after curing and curing
Becomes the receiving surface 17 of the temporary receiving stand 4. The concrete used here is preferably an immediate-hardening concrete which hardens to a predetermined hardness in a short time in order to shorten the construction period. As a property of the concrete, the compressive strength is large, but the tensile strength is small.In general, it is necessary to provide a sufficient curing period for the concrete. It does not need to be completely cured, but only needs to exhibit a predetermined compressive strength. still,
Before placing concrete, it is also preferable to arrange reinforcement appropriately.

Finally, a plurality of strands 10,... Are wound around the outer periphery of the frame body 7 while being engaged with the hooks 16,. The connector 11 is attached to one end of the strand 10 and the other end is connected to the same connector 1.
After inserting the cable through the connector 1, as shown in FIG. 8, a tension jack 18 such as a center hole jack is attached to the projecting portion to apply tension to the strand 10 and maintain the tension with the connector 11. Here, reference numeral 10 </ b> A in the figure indicates an end of the strand 10 penetrating the connector 11. In this way, the frame 7 is tightened from the outer periphery by applying tension to the many strands 10,... And the block of hardened concrete 9 is pressed against the outer surface of the pier 1 with a large normal force. It is. At this time, the partition plates 8,... Are compressed and crushed. That is, the tension of the large number of the strands 10,... Becomes large frictional resistance against the vertical movement of the temporary gantry 4 along the outer surface of the pier 1 by strongly pressing the concrete 9 against the pier 1. is there. In the present embodiment, the partition plates 8,.
Is set at the corner of the pier 1 having a square cross section. In this way, the tension of the strand 10 can be converted into a pressing force in a direction perpendicular to the outer surface of the pier 1 with minimal loss.

In order to further increase the tightening force on the casting concrete 9 and to make the sliding friction resistance at the interface between the pier 1 and the casting concrete 9 sufficient, the strands 10,. It needs to be wound precisely.
For this purpose, the width of the connector 11 is required to be as small as possible, but since the ends 10A, 10A of the strand 10 penetrate the inside, it is necessary to increase the thickness in terms of strength. From strand 10
, Which is about five times the diameter, and it is impossible in principle to reduce the distance between the adjacent strands 10, 10. Therefore, in the present invention, a spacer 19 as shown in FIGS. 10 and 11 is interposed between the bottom surface of the connector 11 and the frame 7 so as to minimize the distance between adjacent strands 10. I can do it. That is, the spacer 19 has a substantially T-shaped cross-section including a holding portion 19A having a width approximately equal to the diameter of the strand 10 and a mounting plate 19B on which the connector 11 is mounted.

The procedure for densely winding the strand 10 using the spacer 19 is as follows.
The strand 10 is wound in order along the generatrix of the frame 7. First, it is assumed that the first strand 10 is wound, and the second and third strands 10 are wound close to the strand 10. The height maintaining portion 19A of the spacer 19 is brought close to or in contact with the first strand 10 and lightly welded to the frame 7, and the connector 11 is disposed on the upper surface of the mounting plate 19B. At 10, both ends 10A, 10A of the second strand 10 are tightened by the connector 11 as usual. Then, the third strand 10 is made to approach or come into contact with the second strand 10, and the holding portion 19A of the spacer 19 and the mounting plate 19B are placed.
In the state of being hooked on the concave portion formed by the above, the tension is applied by the connector 11 placed on the spacer 19 installed in the same manner as described above at another location in the circumferential direction of the frame 7 (see FIG. 12).

The normal pressing force (abdominal pressure) of the strand 10 to which the tension is applied by the tension jack 18 is applied.
Is very important in actual construction, and a method for measuring the abdominal pressure is shown in FIG. For this purpose, two load cells 20 and 20 and a gantry 21 arranged so as to straddle them are used. At the center of the gantry 21, there is a through hole 21A through which the strand 10 penetrates, and on both sides thereof, there are steps 21B, 21B for accommodating the load cells 20, 20, respectively. Then, the specific strand 10 is passed through the through hole 21A of the gantry 21, and the load cell 2 disposed at the upper and lower positions of the
The strand 10 is tensioned while suspended at 0,20. Then, the load cells 20, 20 interposed between the gantry 21 and the frame 7 are compressed, and the pressing force (belly pressure) can be measured from the output of the load cells 20, 20. In this manner, the hydraulic pressure of the tension jack 18 is associated with the pressing force (abdominal pressure) measured by the load cells 20, 20.
The tension caused by the other strands 10 can be managed by the hydraulic pressure of the tension jack 18.

In the above-described embodiment, after the concrete 9 cast in the frame 7 has hardened, the outer periphery thereof is tightened with the strands 10 while the frame 7 is left. After the body 7 is removed, a method of directly tightening the cast concrete 9 is generally used.

That is, in the method of constructing a temporary gantry for a bridge according to the present invention, a plurality of molds 6 are mounted on the upper outer periphery of a concrete pier 1 to form a frame 7 having a substantially cylindrical outer periphery. A plurality of shrinkable partition plates 8 are interposed in a direction extending from the inner surface of each frame 7 to the surface of or near the surface of the pier 1 and substantially along the generatrix of the outer peripheral surface of the frame 7. Concrete 9 is poured into the body 7 and the concrete 9
After the hardening, the frame 7 is removed and the concrete 9
.. Are wound a plurality of times around a plurality of locations along the generatrix on the outer periphery, and the opposite ends of the crossed strands 10 are given tensions in opposite directions to each other and are fixed by the connector 11 to maintain the tensioned state. It is good. In this case, the mold 6 does not need to be made of metal at all, and can be made of wood or synthetic resin.

Here, in the case where the cast concrete 9 is directly tightened with the strands 10 after removing the frame 7, the strands 10 are wound tightly around the outer circumference of the cast concrete 9 as shown in FIG. The spacer 22 shown in FIG. 15 is used. The spacer 22 has a holding portion 22A having a width approximately equal to the diameter of the strand 10 and a mounting plate 22B on which the connector 11 is mounted. The H-shaped section has a base plate 22C for preventing the pressing force from concentrating and for holding the spacer 22 itself.

The spacer 22 clamps a part of the base plate 22C between the first strand 10 and the cast concrete 9 before the tension, and then holds the strand 10 in tension. After that, the connector 1 is attached to the mounting plate 22B.
The method for tensioning the second strand 10 by placing the 1 is as described above. Then, the third strand 10 is moved to the height holding portion 22A of the spacer 22, the mounting plate 22B, and the base plate 22.
C is hooked on the recess formed.

As described above, on the receiving surface 17 of the concrete 9 of the temporary receiving stand 4 constructed on the upper part of the pier 1, directly on the leveling concrete molded to be horizontal, and further on the receiving surface of the concrete 9 Are stacked on the steel plate installed on the steel plate 17 so as to have an appropriate height, the jack device 5 is left standing thereon, and the bridge girder 2 is lifted by the jack device 5. You do it. Here, in the present embodiment, the reaction force is 1900 ton class and the weight is 1
Lifting force is 600t to replace 7ton bearing 3
Four jack devices 5 are used. Incidentally, the jack device 5 used in the present embodiment is a wedge-shaped jack device (Japanese Patent No. 17698812) invented earlier by Nonaka of the present inventor.
No., Japanese Patent No. 2099537, Japanese Patent No. 257002
No. 4,944,492), a wedge-shaped driving member and a wedge-shaped pressure-receiving member are slidably laminated on each other on an inclined surface, and the wedge-shaped driving member is horizontally driven by push-pull means such as a hydraulic jack. The lifting device lifts the heavy structure by raising the wedge-shaped pressure receiving member. However, in the present invention, the structure of the jack device 5 is not limited.
After the bearing 3 is replaced, the temporary support base 4 is removed, but may be left as it is to reinforce the pier 1.

In addition to the method of placing the concrete 9 in the frame 7 as described above, the frame 7 may be made of a steel structure having high rigidity and a large contact area with the pier 1, and Strand 1 without casting
0 may directly press the frame 7 against the outer surface of the pier 1.

In the method of constructing a temporary support base for a bridge according to the present invention, once the temporary support base 4 has been constructed, it is possible to open the road underneath, and at the top end of the pier 1 from the bearing 3 via the jack device 5,. As the reaction force is transferred to the temporary support 4
It has the excellent features that the burden on the base of the pier 1 is small, and the problems such as the noise caused by drilling holes in the pier 1 and the cutting of existing reinforcing bars, which are seen in the conventional method, are eliminated.

Although the present invention has been described based on the construction method of the temporary gantry for a bridge, the present invention is also applied to a general widening method for expanding the outer shape of a desired portion of a concrete structure such as the pier 1. Not only can it be applied, but it can also be applied to a reinforcing method for reinforcing a desired portion of a concrete structure such as the pier 1.

[0034]

According to the method for widening a concrete structure, the method for constructing a temporary gantry in a bridge, and the method for reinforcing a bridge according to the present invention, the following remarkable effects can be obtained.

According to the widening method of the concrete structure according to the first and second aspects, it is possible to easily expand the outer shape of a desired portion of the existing concrete structure,
Moreover, the concrete poured into the frame or the expanded portion formed by the concrete and the frame is firmly pressed against the outer surface of the concrete structure and fixed.

According to the construction method of the temporary receiving stand in the bridge according to the third, fourth and fifth aspects, once the temporary receiving stand is constructed, the road can be opened under the road, so that the traffic stop or the traffic is stopped. In addition to minimizing the period of inconvenience to local residents due to regulations, it also eliminates problems such as noise caused by drilling holes in the piers and cutting of existing reinforcing bars found in the conventional bracket method. Large-scale foundation work as in the construction method and a large amount of steel material for venting are not required.In addition, in the work of lifting the bridge girder with the jack device installed on the temporary support stand and replacing the bearing, the jack device is installed from the bearing at the top end of the pier. Since the reaction force is transferred to the temporary support base via the pier, there is an excellent advantage that the burden on the base of the pier is small.

According to the bridge reinforcing method according to the sixth, seventh and eighth aspects, it is possible to easily and firmly reinforce the desired portion of the pier.

[Brief description of the drawings]

FIG. 1 is a simplified explanatory view showing a state of performing a replacement work of a bearing by using a method of constructing a temporary gantry in a bridge of the present invention.

FIG. 2 is an enlarged side view of a main part of the same.

FIG. 3 is an enlarged omitted plan view of a main part.

FIG. 4 is a perspective view of a main part showing a state in which a formwork is being installed on an upper part of a pier in a process of constructing a temporary gantry on a pier.

FIG. 5 is a perspective view of a main part showing a state in which a frame is formed by a plurality of molds in a process of constructing a temporary gantry on a pier.

6A and 6B show the relationship between the frame body and the pier, wherein FIG. 6A is a longitudinal sectional view taken along a direction perpendicular to a side surface of the pier, and FIG. 6B is a longitudinal sectional view taken along a plane including a corner of the pier. It is.

FIG. 7 is a perspective view of a main part showing a state in which concrete is poured into a frame in a process of constructing a temporary gantry on a pier.

FIG. 8 is a main part showing a state in which a frame is fastened with a strand using a tension jack in a process of constructing a temporary support base on a pier.

FIG. 9 is a plan view of a main part showing a state in which a frame is fastened with strands in a process of constructing a temporary gantry on a pier.

FIG. 10 is a perspective view of a spacer for tightly winding a strand around the outer periphery of a frame.

FIG. 11 is a partial cross-sectional view of a state where a strand is tightly wound using a spacer.

FIG. 12 is a partial side view of the same.

13A and 13B show a method for measuring abdominal pressure due to strand tension, wherein FIG. 13A is a plan view, FIG. 13B is a side view, and FIG. 13C is a rear view.

FIG. 14 is a perspective view of a spacer for tightly winding a strand around an outer periphery of a cast concrete.

FIG. 15 is a partial cross-sectional view of a state in which a strand is tightly wound using a spacer.

[Explanation of symbols]

 Reference Signs List A Ground B Bridge 1 Bridge pier 2 Bridge girder 3 Bearing 4 Temporary gantry 5 Jack device 6 Formwork 7 Frame 8 Partition plate 9 Concrete 10 Strand 11 Connector 12 Side plate 13 Bottom plate 14 Partition plate 15 Rib plate 16 Hook 17 Receiving surface 18 Tension jack 19 Susa 20 Load cell 21 Mount 22 Susa 23 Sandle

Claims (8)

[Claims] 1. A concrete structure having a plurality of molds mounted on an outer periphery thereof to form a frame having a substantially cylindrical outer periphery, and extending from the inner surface of each frame to the surface of the concrete structure or near the surface. And, in a direction substantially along the generatrix of the outer peripheral surface of the frame, a plurality of contractible partition plates are interposed, concrete is poured into the frame, and after the concrete is hardened, the frame is removed, The concrete is characterized in that the strand is wound a plurality of times around a plurality of points along the generatrix on the outer periphery of the concrete, and the opposite ends of the crossed strands are fixed by a connector by applying opposite tensions to each other and maintained in a tensioned state. Widening method for structures. 2. A concrete structure, wherein a plurality of metal molds are mounted on an outer periphery of the concrete structure at an interval from each other to form a frame body. After a plurality of shrinkable partition plates are interposed in a direction reaching the surface or near the surface and substantially along the generatrix of the outer peripheral surface of the frame, the concrete poured into the frame hardens, and then the frame is 2. The method for widening a concrete structure according to claim 1, wherein the outer periphery of the concrete structure is tightened with the strands while leaving a gap. 3. A method of constructing a temporary gantry for lifting a bridge girder on an upper part of a pier when replacing a bearing installed on an upper surface of a pier of a bridge, wherein a plurality of concrete piers are provided on an outer periphery of an upper part of the concrete pier. The mold is attached to form a frame having a substantially cylindrical outer periphery, and shrinks from the inner surface of each frame to the surface or near the surface of the pier and substantially along the generatrix of the outer peripheral surface of the frame. A possible plurality of partition boards are interposed, concrete is poured into the frame, and after the concrete has hardened,
The frame body is removed, the strands are wound around a plurality of locations along the generatrix on the outer periphery of the concrete a plurality of times, and the opposite ends of the crossed strands are provided with tension in opposite directions to each other and fixed by a connector to maintain the tension. The construction method of the temporary support stand in the bridge characterized by the following. 4. A frame body is formed by mounting a plurality of metal molds around the pier at an interval from each other,
A plurality of shrinkable partition plates are interposed in the gap between the formwork to reach the surface of the pier or in the vicinity of the surface and substantially along the generatrix of the outer peripheral surface of the frame body. 4. The method according to claim 3, wherein the outer periphery of the concrete body is tightened with the strands while the frame is left after the concrete is hardened. 5. A spacer having a height retaining portion having a width approximately equal to the diameter of the strand is interposed between the bottom surface of the connector and the cast concrete or the frame body, and the strand is densely packed. The method for constructing a temporary mounting frame for a bridge according to claim 3 or 4, which is wound. 6. A method for reinforcing a desired portion of a bridge pier of a bridge, wherein a plurality of molds are mounted on an outer periphery of a concrete pier to form a frame having a substantially cylindrical outer periphery, and the inner surface of each frame is provided. From there, a plurality of contractible partition plates are interposed in a direction substantially along the generatrix of the outer peripheral surface of the frame body to or near the surface of the pier, and concrete is poured into the frame body. After curing, the frame is removed, the strands are wound around the concrete at multiple locations along the generatrix multiple times, the opposite ends of the crossed strands are given opposite tensions, fixed by connectors, and maintained in tension. A bridge reinforcement method characterized by the following. 7. A frame body is formed by mounting a plurality of metal molds on the outer periphery of the pier at intervals.
A plurality of shrinkable partition plates are interposed in the gap between the formwork to reach the surface of the pier or in the vicinity of the surface and substantially along the generatrix of the outer peripheral surface of the frame body. 7. The method of reinforcing a bridge according to claim 6, wherein after the set concrete is hardened, the outer periphery thereof is tightened with the strands while leaving the frame body. 8. A spacer having a height retaining portion having a width approximately equal to the diameter of the strand is interposed between the bottom surface of the connector and the cast concrete or the frame body, and the strand is compacted. The method for reinforcing a bridge according to claim 6 or 7, wherein the bridge is wound.