JP4732310B2 - Repair method for prestressed concrete structures - Google Patents

Description

  The present invention relates to a repair method for a prestressed concrete structure, and more particularly, to a repair method for a prestressed concrete structure in which a compressive force is applied to a frame portion by a tension material to which tension is applied.

  As a structure such as a bridge, a prestressed concrete structure in which a compressive force is applied to a frame portion by a tension material to which tension is applied is frequently used. Since these structures deteriorate due to salt damage, neutralization of concrete, alkali aggregate reaction, etc., structures with a service life of several decades have cracked or peeled off. Repair is necessary. If a prestressed concrete structure is newly installed, such as a bridge change, huge construction costs will be required, and traffic such as bridges will need to be blocked. The negative effects will also increase.

In patent document 1, the following concrete bridge girder repair methods are disclosed. The concrete bridge girder is divided into a plurality of sections by the dividing line in the axial direction of the bridge girder, and a support is installed under the girder of the part other than the specific section to limit the deflection of the bridge girder. In that state, the concrete on the underside of the girder in the specific section is suspended until the main rebar is exposed by the high-pressure water jet, and the portion where the concrete is suspended is restored by spraying the mortar layer.
JP 2003-13411 A

  However, in the repair method disclosed in Patent Document 1, since a support work is installed, the work for repairing bridges and the like becomes a large-scale work, and the work cost and work period become enormous, and the work is supported on rivers and coasts. It may be difficult to install the work directly.

Further, when the support is removed after repairing the concrete, the bridge itself bends downward, and tensile stress is generated in the repaired part, resulting in problems such as separation of the existing part and the repaired part.
Moreover, when the bridge is a prestressed concrete structure, when the main rebar is exposed until it is exposed, part of the tension due to the tension material is released, and after that, repairing by blowing mortar, The tension cannot be recovered by the tendon, and the mechanical strength of the prestressed concrete structure is greatly reduced.

On the other hand, Patent Document 2 discloses a method for cutting a prestressed concrete structure. In this method, the portion adjacent to the cutting position of the prestressed concrete structure is hung, the tension material to be cut is exposed, the intermediate fixing tool is fixed to the exposed tension material, and the tension to which the intermediate fixing tool is fixed. A part of the material is backfilled together with the intermediate fixing tool to construct a fixing base connected to the remaining structure side. Then, the tension material is cut between the fixing base and the cutting position, and the end portion of the cut tension material is fixed to the fixing base with another fixing tool.
Japanese Patent No. 3687930

  The cutting method in Patent Document 2 can be said to be an effective method for cutting a prestressed concrete structure, but cannot be applied to repairing a structure that does not cut the tendon material, and was temporarily repaired with cutting. Even in this case, it is necessary to newly join the tension material between the residual structure and the new structure, which complicates the work process and increases the work cost and work time.

  The problem to be solved by the present invention is to solve the above-described problems, suppress an increase in work cost and work time, and maintain the compressive force on the frame portion due to the tension of the tension material after repair. It is to provide a repair method for a prestressed concrete structure.

In order to solve the above-mentioned problem, in the invention according to claim 1, in the repairing method of the prestressed concrete structure in which the compressive force is applied to the frame portion by the tension material to which tension is applied, at least the repaired portion of the prestressed concrete structure is repaired. In the direction of expanding the repair location for the surrounding housing part, an additional force applying step for applying force along the direction in which the tension of the tendon is applied, and in the state of applying the additional force, and concrete repairing process for repairing a concrete repair point, after the concrete repairing process is completed, possess an additional force releasing step of releasing the additional force, the additional force applying step, by pushing the repaired portion The method of applying an additional force and expanding the repaired part is to push a plurality of fixing means arranged on the structure with a jack so as to sandwich the repaired part. And performing by the gel.

  According to a second aspect of the present invention, in the repair method for a prestressed concrete structure according to the first aspect, the additional force applying step or the additional force releasing step measures deformation or stress at a predetermined location of the prestressed concrete structure. However, it is characterized by adjusting the application or release of the additional force.

In the invention which concerns on Claim 3 , in the repair construction method of the prestressed concrete structure of Claim 1 or 2, it has several fixing means arrange | positioned at this structure so that a repair location may be pinched | interposed, and this repair location is A space holding means is provided between the plurality of fixing means in a state where the repaired portion is spread out to maintain a state where the repaired portion is pushed out.

In the invention which concerns on Claim 4 , in the repair method of the prestressed concrete structure in any one of Claims 1 thru | or 3 , this concrete repair process uses the repair material which is expansible for repair material, It is characterized by the above-mentioned. To do.

In the invention which concerns on Claim 5 , in the repair method of the prestressed concrete structure in any one of Claims 1 thru | or 4 , this additional force cancellation | release process is after the intensity | strength of the repair material used at this concrete repair process was expressed. It is characterized by performing.

In the invention which concerns on Claim 6 , in the repair method of the prestressed concrete structure of Claim 5 , this additional force cancellation | release process expands repair material after the intensity | strength of the repair material used in this concrete repair process was expressed. It is characterized by being carried out gradually according to the amount.

In the invention which concerns on Claim 7 , in the repair method of the prestressed concrete structure in any one of Claim 1 thru | or 6 , strength of this repair material from the stage which fills a repair material in a repair location among this concrete repair process At least the additional force imparting step is performed during the period until the expression of.

According to the invention according to claim 1, in the repair method of the prestressed concrete structure in which the compressive force is applied to the housing part by the tension material to which tension is applied, at least the housing part around the repaired part of the prestressed concrete structure, An additional force applying step for applying a force along the direction in which the tension of the tension material is applied, and repairing the concrete at the repaired portion in a state in which the additional force is applied. Repairing a prestressed concrete structure while maintaining the compressive force on the frame portion due to the tension of the tension material, since the concrete repairing step and the additional force releasing step of releasing the additional force after the concrete repairing step is completed It can be performed with Do Ri, additional force application step in order to impart additional force by pushing the repaired portion, repairs During work, it is possible to easily apply the necessary force to the part where the compressive force to the housing part due to the tension of the tension material is released, and the method of expanding the repaired part is to sandwich the repaired part Since a plurality of fixing means arranged in the structure are expanded by jacking, it does not require large-scale equipment such as conventional support work and can suppress increase in work cost and work time. Doo ing.

  According to the invention of claim 2, the additional force application step or the additional force release step adjusts the application or release of the additional force while measuring deformation or stress at a predetermined location of the prestressed concrete structure. When excessive force is applied to the structure, the structure itself is destroyed, the tension of the tension material is reduced due to insufficient additional force, and further, the additional force is released before the strength of the repair material in the concrete repair process is developed It is possible to repair a prestressed concrete structure that suppresses various problems such as damage to the repaired portion of the steel and maintains an appropriate compressive force on the housing portion at all times.

According to the invention of claim 3 , the plurality of fixing means arranged in the structure so as to sandwich the repaired portion, and in a state where the repaired portion is expanded, the repaired portion is interposed between the plurality of fixing means. In order to arrange space holding means to maintain the expanded state, for example, jacks, pulling means, and further pressing means such as pressing means can be replaced with various means for expanding the repaired area, and the expanded state is stable. Can be maintained. For this reason, it is not necessary to prepare a lot of various means for expanding the repaired portion as described above, and also maintain a safe working environment even when the working ability of the means for expanding during the work is reduced. Is possible.

According to the invention of claim 4 , the concrete repairing process uses an inflatable repairing material as the repairing material, so that the internal stress is generated in the concrete structure itself by the expansion action of the repairing material itself, and the concrete structure frame It is possible to further increase the compression force generated between the portion and the tendon.

According to the invention according to claim 5 , since the additional force release process is performed after the strength of the repair material used in the concrete repair process is expressed, the strength of the repair material is expressed even if the additional force is released. Even after the force is released, the frame part including the repaired part continues to receive a part of the added additional force, resulting in a decrease in compressive force on the repaired part and the surrounding frame part and the tension material. It becomes possible to suppress release of tension.

According to the invention of claim 6 , the additional force releasing step is performed gradually in accordance with the expansion amount of the repair material after the strength of the repair material used in the concrete repair step is expressed. It is possible to release the additional force while always applying a compressive force of a certain level or more to the repaired part and its surrounding parts by linking the increase of internal stress in the body part and the decrease of the additional force. .

According to the invention according to claim 7 , in the concrete repair process, at least an additional force application process is performed from the stage of filling the repair material into the repair site until the strength of the repair material is expressed. The force applied to the housing part in the applying step is maintained even after the repair is completed, and as a result, the same compressive force can be applied to the repaired portion.
Pre-stressed concrete can be applied by applying an additional force application process when applying concrete that has deteriorated in the concrete repair process, thereby reducing the reduction of compressive force and releasing the tension of the tension material around the repaired part. Repair work can be performed while maintaining the mechanical strength of the entire structure. And even after repair, the mechanical strength of the whole prestressed concrete structure can be maintained.

Hereinafter, the present invention will be described in detail using preferred examples.
FIG. 1 is an example showing a repair method for a prestressed concrete structure according to the present invention.
A prestressed concrete structure (hereinafter referred to as a “PC structure”) has a concrete frame portion 1 and a tension material 2, and a tensile tension is applied to the tension material 2. A compressive force, which is an internal stress, is applied to the housing portion 1 by the tension.

  As shown in FIG. 1 (a), when repairing the deteriorated portion 3 as a repaired portion of the PC structure, first, as shown in FIG. 1 (b), the deteriorated portion 3 is removed by a known means such as a high-pressure water jet. As shown by reference numeral 4, the suspension work is performed. In the case where it is not necessary to hang the repaired portion like a crack or the like, and the repairing material only needs to be filled in the cracked portion, naturally the suspending operation is not performed. Next, a fixing means 5 such as an anchor is fixed to the PC structure in order to apply a compressive force to the casing portion 1, particularly the casing portion around the repaired portion, and to apply an additional tension to the tension member 2 (FIG. 1 (c)). The fixing means 5 may be a means for sandwiching the PC structure from the vertical direction or depth direction in the figure in addition to the anchor, and when the force that spreads the PC structure in the horizontal direction in the figure is applied to the fixing means, the stress is applied. There is no particular limitation as long as it is a means that can be effectively transmitted to the PC structure, particularly the tendon.

  Next, as shown in FIG. 1 (d), the fixing means 5 is provided with means for applying a force to push the fixing means 5 such as the hydraulic jack 6, and the force is applied in the directions of arrows a1 and a2. In this additional tension applying step, the pressing force of the jack 6 spreads the periphery of the repaired portion of the concrete structure housing part 1 through the fixing means 5 and applies a compressive force to the housing portion around the repaired portion, resulting in tension. Additional tension is applied to the material 2.

  Next, as shown in FIG. 1 (e), the repair material 7 such as mortar is filled in the repair location in a state where an additional force is applied to the housing portion. Commonly used grout materials for cross-sectional repair, fast-hardening grout materials, and non-shrinkable / non-expandable materials can be used as repair materials. Also, by using inflatable repair materials, it is possible to increase the internal stress in the PC structure due to the expansion action of the repair materials, and in addition to the application of force to the frame part, additional tension to the tension material It is possible to maintain the appropriate compressive force on the housing portion 1 more effectively. Needless to say, in the repair material filling operation, various methods such as spraying as well as mortar and concrete can be employed.

  In the PC structure repair method shown in FIG. 1, in the concrete repairing process, the suspending work is performed before the additional force applying process. By applying the application process as well, repair work is performed while maintaining the compressive force to the frame around the repair site and suppressing the tension release of the tension material and maintaining the mechanical strength of the entire prestressed concrete structure. Can be performed.

  Next, as shown in FIG. 1 (f), after the strength of the repair material used in the concrete repair process is sufficiently developed, the hydraulic jack 6 is removed (additional force release process), and the fixing means 5 is further removed. Then, the repair of the PC structure is completed. Since the strength of the repair material is expressed even if the additional force is released in this way, a part of the added force is continuously applied to the repaired part and the frame part around the repaired part. In addition, it is possible to maintain the compressive force applied to the frame portion around the repaired portion and to suppress the release of the tension of the tendon.

  In addition, when using an expandable material for the repair material, after the strength of the repair material has been developed, the additional force is gradually released along with the amount of expansion of the repair material. It is possible to release the additional force while always applying a certain amount of compressive force to the repaired part and the surrounding part of the repaired part by linking the increase of internal stress in the structural part of the structure and the decrease of the additional force. It becomes possible.

  In addition, when using the means to form and arrange | position a hole in concrete structures, such as an anchor, as the fixing means 5, the hole is filled with repair materials, such as concrete, after the fixing means removal.

In the repair method of the PC structure described above, the method using the jack 6 has been described as a method for expanding the repaired portion. However, as a reference example, the following method may be employed.

As a first reference example, as shown in FIG. 2, a fixing means 8 such as an anchor is arranged on a PC structure, and the fixing means 8 is pulled by a wire 9 or the like in the directions of arrows b1 to b4 shown in FIG. Thus, it is possible to push the repaired portion 4 wide. The fixing means 8 is not limited to the anchor, and means for sandwiching the PC structure as described above can also be used. In the case of repairing a bridge or the like, if there is a place where a tension means such as a wire can be fixed in the middle of the bridge girder, the structure of the structure (such as a convex portion or a concave portion) can be used. .

  The pulling direction of the wire 9 is not particularly limited, but it is possible to select an arbitrary direction from the direction extending in parallel to the repair surface of the structure to the vertical direction. In the case of repairing a bridge or the like, it is possible to set the other end of the wire to be fixed to the pier.

As a second reference example, as shown in FIG. 3, the PC structure is bent by pressing the structure as shown by an arrow C from the side opposite to the repair location 4 of the PC structure, It is also possible to widen the repair location 4. As a pressing method, a known pressurizing means such as a hydraulic press can be employed. The pressurizing means is appropriately fixed to the ground or other parts of the PC structure.
Further, in the case of a PC structure such as a bridge, it is possible to place a heavy object such as a heavy vehicle on the bridge and generate the pressing force C by the weight of the heavy object.

Since the method of expanding the repair location shown in FIG . 1 which is an embodiment according to the present invention and FIG. 2 or 3 which is a reference example does not require large-scale equipment such as a conventional support work, It is simple, and it becomes possible to suppress an increase in work cost and work time. In addition, since repairs can be made in a short period of time, the time until opening of traffic can be shortened, and adverse effects such as traffic congestion can be suppressed.

Next, a method for more appropriately applying and releasing the additional force described above will be described.
Specifically, as shown in FIG. 4, deformation of a PC structure housing portion that occurs around a repaired site due to the application or release of additional force, the development of strength of the repair material, or the expansion of the repair material ( This is a method of controlling an additional force generating means such as a hydraulic jack 6 while measuring changes in internal stress and various changes with sensors 10 and observing the measured values with a monitor 11. In FIG. 4, the operator observes the monitor 11 and adjusts the hydraulic jack 6. However, the signal from the sensor 10 or the monitor 11 is input to a control circuit (not shown), and the hydraulic pressure is determined by the signal from the control circuit. It is also possible to control the additional force generating means such as the jack 6 so as to automatically adjust the force applied to the housing portion around the repaired portion.

  The application of an excessive force or a sudden stress change to the housing portion in the application of additional force leads to the destruction of the PC structure. In addition, even when releasing the additional force, if the additional force is released at a stage where the strength of the repair material does not develop, or if the additional force is released before sufficient expansion is completed while using the inflatable repair material, the repair material will It is difficult to maintain a compressive force on the repaired part and the surrounding part of the repaired part and to apply sufficient tension to the tendon material by being pushed out of the PC structure from the repaired part.

  Further, when using an inflatable repair material, it is preferable to gradually release the additional force while measuring an increase in internal stress due to the expansion action of the repair material, in which case FIG. Such a method of releasing the additional tension while measuring the deformation and stress of the casing portion 1 of the PC structure can be suitably used.

  As the sensor 10 for measuring the deformation and stress of the housing portion of the PC structure, various measuring methods such as a strain gauge, a deflection measuring method, a slot stress method, a stress releasing method, an EM sensor method, and a reinforcing bar cutting method can be used. It is.

  Next, when the present invention is applied to a large structure such as a bridge, as the repaired portion becomes larger, more means for expanding the hydraulic jack or the like are required. In addition, when using equipment with movable parts such as hydraulic jacks, there is a concern that the movable parts may move over time due to a decrease in hydraulic pressure, etc. In order to maintain the compressive force, it is not preferable.

  For this reason, as shown in FIG. 5, after fixing the repaired portion using a hydraulic jack or the like to the fixing means 5 arranged in the structure so as to sandwich the repaired portion, the repaired portion is expanded. Space holding means 20 for maintaining the above is disposed. Thereby, even after removing the hydraulic jack or the like, the space holding means 20 can stably maintain the pushed-up state.

  As the space holding means 20, various members can be used as long as they are members that are durable against a compressive force in a predetermined direction using a steel material or the like and have little change with time. In addition, the portion that comes into contact with the fixing means does not destroy the fixing means, and can appropriately receive the stress transmitted from the fixing means around the repaired portion, such as a flat plate. It is preferable to form in a shape that can ensure a wide contact area.

  According to the repair method for a prestressed concrete structure according to the present invention, a prestressed concrete structure capable of suppressing an increase in work cost and work time and maintaining the compressive force on the frame portion due to the tension of the tension material after the repair. It is possible to provide a repair method for objects.

It is a figure which shows an example of the repair method of the PC structure which concerns on this invention. It is a figure explaining the method of expanding a repair location using the tension means based on the 1st reference example . It is a figure explaining the method based on a 2nd reference example, giving a pressing force from the other side of a repair location, and expanding a repair location. It is a figure explaining a mode that addition or cancellation of additional force is adjusted, measuring a deformation and stress of a frame part of a PC structure. It is a figure explaining the method of maintaining in the state which extended the repair location using the space holding means.

DESCRIPTION OF SYMBOLS 1 Body part 2 of concrete structure Tensile material 3 Deteriorated part 4 Repair location 5, 8 Fixing means 6 Jack 7 Repair material 9 Pulling means 10 Deformation or stress sensor 11 Monitoring means 20 Space holding means

Claims (7)

In the repair method of prestressed concrete structure in which compressive force is applied to the frame part by the tension material to which tension is applied,
An additional force applying step for applying a force along the direction in which the tension of the tension material is applied in a direction in which the repaired portion is expanded with respect to the frame portion around at least the repaired portion of the prestressed concrete structure;
A concrete repairing process for repairing the concrete at the repaired place with the additional force applied,
After the concrete repairing process is completed, it possesses an additional force releasing step of releasing the additional force,
In the additional force application step, an additional force is applied by expanding the repair location,
The method for expanding the repaired portion is a method for repairing a prestressed concrete structure, wherein a plurality of fixing means arranged on the structure are pushed and expanded with a jack so as to sandwich the repaired portion .   2. The method for repairing a prestressed concrete structure according to claim 1, wherein the additional force application step or the additional force release step applies or cancels the additional force while measuring deformation or stress at a predetermined location of the prestressed concrete structure. A repair method for prestressed concrete structures characterized by adjusting the stress. The repair method for a prestressed concrete structure according to claim 1 or 2 , wherein a plurality of fixing means are arranged on the structure so as to sandwich the repaired portion, and the plurality of fixing means are expanded in a state where the repaired portion is expanded. A repair method for a prestressed concrete structure, characterized in that space holding means for maintaining a state in which the repaired portion is expanded is disposed between the fixing means. The repair method for a prestressed concrete structure according to any one of claims 1 to 3 , wherein the concrete repairing step uses an inflatable repair material as the repair material. . The prestressed concrete repair method according to any one of claims 1 to 4 , wherein the additional force releasing step is performed after the strength of the repair material used in the concrete repair step is developed. Repair method for structures. 6. The repair method for a prestressed concrete structure according to claim 5 , wherein the additional force release step is gradually performed according to the expansion amount of the repair material after the strength of the repair material used in the concrete repair step is expressed. Repair method for prestressed concrete structures characterized by In the repair method of the prestressed concrete structure in any one of Claims 1 thru | or 6 , The period until the intensity | strength of this repair material expresses from the step of filling a repair material into a repair location among this concrete repair process at least. A method for repairing a prestressed concrete structure, wherein the additional force application step is performed.

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