JP5012355B2 - Underwater structure reinforcement method, underwater structure - Google Patents

Description

  The present invention relates to a method of reinforcing an underwater structure by surrounding the underwater structure with a cylindrical temporary cutoff wall, draining the inside of the temporary partition wall, and placing concrete on the outer periphery of the underwater structure.

  Conventionally, a temporary cutoff wall has been built around an underwater structure such as an existing underwater bridge pier, the inside of this temporary cutoff wall is drained, and reinforced concrete is reinforced and repaired to surround the underwater structure in the temporary cutoff wall. The method of performing is used. At this time, since the hydraulic pressure acts on the temporary cutoff wall from the outer peripheral side, the cutting beam is bridged between the temporary cutting wall and the underwater structure, and the temporary cutting wall is supported from the inside by this cutting beam (for example, Patent Document 1).

When the reinforced concrete is constructed in such a state that the cut beam is bridged, the concrete cannot be placed in a portion corresponding to the cut beam, and a concave portion is formed in the reinforced concrete. Since such a concave portion may become a structural weak point, it is necessary to finish the concrete surface by filling the concave portion with mortar or the like after the concrete is cured.
Japanese Patent Laid-Open No. 2003-232044

  The finishing of the surface of the reinforced concrete is performed in a state where the temporary cutoff wall is supported by a replacement beam having a simple configuration and the cut beam is removed. That is, first, as shown in FIG. 13A, the replacement beams 50 are installed above and below each of the cut beams 20. If a replacement beam 50 having the same configuration as that of the main cutting beam 20 is used, the cost increases. Therefore, a simple beam composed of a log 51 and a universal jack 52 is used.

  Next, as shown in FIG. 13B, the jacks 22 of the respective beam 20 are contracted to remove the beam 20. And mortar is apply | coated to the recessed part 40A formed in the reinforced concrete 40. FIG. Since the mortar cannot be brought into contact with water until it is cured, the temporary cutoff wall 10 stands by in a state of being supported by the replacement beam 50 until the applied mortar is cured.

  After the mortar applied to the recess 40A is cured, water 5 is poured into the temporary cutoff wall 10 until it becomes equal to the external water surface height, as shown in FIG. As a result, the pressure inside and outside the temporary cutoff wall 10 becomes equal, so that the replacement beam 50 can be removed underwater as shown in FIG. 13 (D). And construction is completed by dismantling the temporary cutoff wall 10.

  As described above, in the above method, the temporary cutoff wall 10 is supported by the replacement beam 50 until the water 5 is injected into the interior after the cut beam 20 is removed. However, since the replacement beam 50 has a simple configuration including the log 51 and the universal jack 52 as described above, a structurally unstable state continues for a long period of time.

  The present invention has been made in view of the above problems, and its purpose is to construct a temporary cutoff wall around an underwater structure and to hang a cut beam between the temporary cutoff wall and the underwater structure. This is to prevent the unstable state from continuing for a long time when finishing the portion corresponding to the cut beam of the reinforced concrete cast around the underwater structure in the state.

  The underwater structure reinforcing method according to the present invention surrounds the underwater structure with a cylindrical temporary cutoff wall, and bridges a cutting beam provided with a telescopic mechanism between the underwater structure and the temporary cutoff wall. A method of draining the interior of the temporary cutoff wall and reinforcing an underwater structure in the temporary cutoff wall, the step of additionally striking concrete around the underwater structure, and the hardening of the increased concrete Later, a replacement beam installation step of bridging the replacement beam between the surface of the concrete in the vicinity of the cutting beam and the temporary fastening wall, a cutting beam contraction step of contracting the cutting beam by the extension mechanism, A plate material installation step in which a plate material provided with an injection hole so as to cover a concave portion formed in a portion corresponding to the cutting beam on the concrete surface is brought into contact with the concrete surface; And a mortar filling step for filling the recess with the mortar from the injection hole, and a step for re-installing the beam between the plate member and the temporary fastening wall. And

  In the above method, the method includes a water inflow step for allowing water to flow into the temporary cutoff wall after the cutting beam re-installation step and before the mortar filling step, and in the mortar filling step, A hose may be attached so as to extend to mortar, and the mortar may be filled through the hose.

In the replacement beam installation step, the replacement beam may be bridged and water may be injected into the temporary cutoff wall to the lower side of the cutting beam.
The underwater structure of the present invention is reinforced by the above method.

  According to the present invention, an iron plate in which an injection hole is formed so as to cover the recess can be made to abut against the concrete and the permanent beam can be bridged between the iron plate and the temporary cut wall. It is only necessary to support it with a temporary replacement beam during the mounting of the frame, and the period of structural instability can be shortened.

Hereinafter, an embodiment of the method for reinforcing an underwater structure of the present invention will be described in detail with reference to the drawings, taking as an example the case of repairing a bridge pier.
FIG. 1 shows the temporary cutoff wall 10 constructed around the pier 1 in a front view, and FIG. 2 shows the temporary cutoff wall 10 viewed from the side. In each figure, the left side from the center is an external view, and the right side is a sectional view. 3 is a cross-sectional view taken along the line II ′ in FIG. 1, FIG. 4 is an enlarged view of a portion II in FIG. 1, and FIG. 5 is an enlarged view of a portion III in FIG. FIG. 4 is an enlarged view of a portion IV in FIG. 3. The temporary cut-off wall 10 is constructed so as to surround the pier 1 and is used by draining the internal water in order to repair the bridge pier 1 having an oval cross section standing in water such as a river or the sea. It is.

  The temporary cutoff wall 10 is configured by connecting a plurality of steel panels 11 in the vertical direction and the horizontal direction, and is formed in a rectangular cylindrical shape in plan view. The steel panels 11 are connected by bolting with a water-stopping rubber 12 sandwiched therebetween, ensuring water-stopping at the joint.

  An underwater concrete 30 is placed on the footing 2 of the pier 1 so that the upper surface is horizontal, and the temporary cutoff wall 10 is constructed on the underwater concrete 30. Further, along the lower end of the temporary cutoff wall 10, a mortar 31 is placed from the inside so as to cover the joint portion between the temporary cutoff wall 10 and the underwater concrete 30, whereby the temporary cutoff wall 10 and the underwater concrete 30 are The water-stopping property at the joint is ensured.

When the water inside the temporary cutoff wall 10 is drained, a greater water pressure acts on the temporary cutoff wall 10 from the outer peripheral side. Therefore, a cut beam 20 is provided to connect the temporary cutoff wall 10 and the pier 1. The wall 10 is supported by the cut beam 20 from the inside. The cut beam 20 includes a steel material 21 that is bolted to the temporary fastening wall 10 and a jack 22 that is interposed between the steel material 21 and the bridge 1. The jack 22 is fixed to the bridge 1 via a base metal 23 attached to the pier 1 with an anchor 24.
FIG. 7 is an enlarged view of the base metal 23. As shown in the figure, the pedestal 23 is configured by connecting a pair of plates 23A with a plurality of steel bars 23B, a rebar can be inserted between the plates 23A, and a compression acting between the plates 23A. It is a member that can resist the force by the steel rod 23B.

  Reinforcement of the pier 1 is performed by striking reinforced concrete along the outer periphery of the pier 1 in the temporary cutoff wall 10. That is, first, reinforcing bars are arranged along the outer periphery of the pier 1. At this time, in a portion corresponding to the base metal object 23, a reinforcing bar may be inserted between the plates 23A of the base metal object 23 to be arranged. Next, a mold frame is disposed at a position corresponding to the outer peripheral surface of the reinforced concrete, and a polystyrene foam is disposed so as to surround the base metal 23. Then, the concrete is placed, and after the concrete is hardened, the mold and the polystyrene foam are removed. Through the above steps, the reinforced concrete 40 is constructed along the outer periphery of the pier 1 as shown in FIG. Further, as shown in FIG. 9, by surrounding the base metal object 23 with the polystyrene foam, a recess 40A is formed around the base metal object 23 of the reinforced concrete 40, and the base metal object 23 is exposed in the concave part 40A. It becomes.

As described in the section of the prior art, such a recess 40A becomes a structural weakness of the reinforced concrete 40, and if the pedestal 23 is exposed to the surface, it will be corroded, so After the cast concrete 40 is cured, mortar is applied in the recess 40A so as to cover the base metal 23 from the outer peripheral side, and the recess 40A is finished. In the conventional method, until the mortar applied to the recess 40A formed in the reinforced concrete 40 is cured, the water pressure acting on the temporary cutoff wall 10 must be supported by the replacement beam 50 having a simple configuration. A state of structural instability will continue over time.
Therefore, in the present embodiment, the period of the structurally unstable state is shortened by finishing such a recess 40A by the method described below.

10 and 11 show the steps of finishing the recesses on the surface of the reinforced concrete and disassembling the temporary cutoff wall 10, and FIG. 10 is a diagram for explaining the entire flow. FIG. FIG.
First, as shown in FIGS. 10 (A) and 11 (A), the replacement beam 50 is installed above the first-stage beam 20 from below, and the provisional deadline to the height immediately below the beam 50 is provided. Water 5 is allowed to flow into the wall 10. In the conventional method described above, the replacement beams 50 are installed above and below the cutting beam 10, but when the water 5 flows into the temporary cutting wall 10, the water pressure of the water 5 in the temporary cutting wall 10 is temporarily reduced. Since it acts on the cut-off wall 10 toward the outer periphery, the replacement beam below the cut beam 10 can be omitted.

  Next, as shown in FIG. 11 (B), the bolt that joins the jack 22 of the first stage beam 20 and the base metal 23 is removed, and the jack 22 is contracted. At this time, the water pressure acting on the temporary cutoff wall 10 from the outside is resisted by the water pressure of the replacement beam 50 and the water 5 inside.

  Next, as shown in FIG. 11C, the iron plate 60 in which the inlet 60B and the outlet 60A are formed is added to the surface of the reinforced concrete 40 so as to cover the recess 40A. Then, as shown in FIG. 11 (D), the jack 22 is extended again, and the cut beam 20 is bridged again between the iron plate 60 brought into contact with the surface of the reinforced concrete 40 and the temporary cut wall 10. As a result, the water pressure acting on the temporary cutoff wall 10 can be supported again by the cut beam 20, and the replacement beam 50 is removed in this state. As will be described later, a chain may be attached so as to connect the iron plate 60 and the jack 22 so that the iron plate 60 can be easily recovered when the iron plate 60 is removed. In addition, after the mortar is injected into the recess 40A in the next step, the difference between the internal water pressure and the external water pressure is reduced by increasing the amount of water inside the temporary cutoff wall 10, so that the jack 22 It is better to keep the applied tension small.

  Next, as shown in FIG. 11E, mortar 61 is injected into the recess 40A from the injection port 60B provided in the iron plate 60. At this time, the air in the recess 40A is discharged from the discharge port 60A. The mortar 61 is continuously injected until it overflows from the discharge port 60A. When the mortar 61 overflows from the discharge port 60A, it can be confirmed that the mortar 61 is filled in the recess 40A. Thus, by covering the base metal object 23 with the mortar 61, it is possible to prevent the base metal object 23 from being corroded.

  Next, as shown in FIG. 10 (B), a replacement beam 50 is installed above the second stage beam 20 from below, and water 5 is placed in the temporary cutoff wall 10 to a height just below the beam 20. Inflow.

  Next, in the case of the first-stage beam 20, the jack 22 and the base metal object 23 of the second-stage beam 20 are attached in the same manner as described with reference to FIGS. The bolt to be joined is removed and the jack 22 is contracted. Next, the iron plate 60 in which the inlet 60B and the outlet 60A are formed is added to the surface of the cast concrete 40 so as to cover the recess 40A. Then, the jack 22 is extended again, and the second-stage beam 20 is again bridged between the steel plate 60 brought into contact with the surface of the reinforced concrete 40 and the temporary cutoff wall 10, and the replacement beam 50 is removed. . Then, similarly to the first stage, the mortar 61 is filled into the recess 40A from the inlet 60B provided in the iron plate 60.

  Next, as shown in FIG. 10C, the replacement beam 50 is installed above the uppermost cutting beam 20, and the water 5 is allowed to flow into the temporary cutoff wall 10 to a height immediately below the cutting beam 20. . In the case of the first-stage beam 20, the jack 22 and the base metal object 23 of the uppermost beam 20 are joined in the same manner as described with reference to FIGS. Remove the bolt and shrink the jack 22. Next, the iron plate 60 in which the inlet 60B and the outlet 60A are formed is added to the surface of the cast concrete 40 so as to cover the recess 40A. Then, the jack 22 is extended again, and the second-stage beam 20 is again bridged between the steel plate 60 brought into contact with the surface of the reinforced concrete 40 and the temporary cutoff wall 10, and the replacement beam 50 is removed. . Then, similarly to the first stage, the mortar 61 is filled into the recess 40A from the inlet 60B provided in the iron plate 60. Then, water 5 is poured into the temporary cutoff wall 10 until the water level becomes equal to the outside.

Next, after the mortar 61 filled in each recess 40A is cured, as shown in FIG. 10 (D), the jacks 22 of the cut beams 20 at each step are contracted to remove the cut beams 20 and add concrete. The iron plate 60 is removed from the 40 surface. At this time, as described above, by providing a chain so as to connect the iron plate 60 and the jack 22, it is possible to prevent the iron plate 60 from falling, and the iron plate 60 can be easily collected.
Next, the repair of the pier 1 is completed by dismantling the temporary cutoff wall 10.

  As described above, according to the present embodiment, the iron plate 60 provided with the injection port 60B so as to cover the recess 40A is brought into contact with the reinforced concrete 40, and the mortar 61 is injected from the injection port 60B. Since the temporary cutoff wall 10 only needs to be supported by the replacement beam 50 while the jack 22 is contracted and the iron plate 60 is brought into contact, the structurally unstable period can be shortened.

  In addition, since the mortar 61 is injected into the recess 40 </ b> A covered with the iron plate 60, the water 5 can be injected into the temporary cutoff wall 10 even if the mortar 61 is not cured. In this way, filling the water 5 into the temporary cutoff wall 10 eliminates the pressure difference between the inside and the outside of the temporary cutoff wall 10, so that a stable state is achieved.

  Further, when the jack 22 of the cut beam 20 at each stage is contracted, the water 5 is injected into the temporary fastening wall 10 to a height just below the cut beam 20, so that the replacement beam 50 is placed below the cut beam 20. Even if it is not provided, the temporary cutoff wall 10 can be supported.

  In the above embodiment, the iron plate 60 is brought into contact with the recess 40 </ b> A, the mortar 61 is injected into the inside through the injection port 60 </ b> B of the iron plate 60, and then the water 5 is injected into the temporary cutoff wall 10. However, the present invention is not limited to such an order. For example, as shown in FIG. 12, the hoses 62B and 62A are attached to the inlet 60B and the outlet 60A provided in the iron plate 60, and water 5 is injected into the temporary cutoff wall 10 and then recessed through the hose 62B. It is also possible to inject mortar into 40A.

  Moreover, in the said embodiment, the base metal 23 was attached to the pier 1, and the cut beam 20 was bridged between this base metal 23 and the temporary cutoff wall 10, but it is not restricted to this. The beam 20 may be bridged between the temporary fastening walls 10.

It is a figure which shows the temporary cut-off wall constructed | assembled around the pier in the front view, The left side from the center is an external view, and the right side is sectional drawing. It is a figure which shows the temporary cutoff wall seen from the side, the left side from the center is an external view, and the right side is sectional drawing. It is II 'sectional drawing in FIG. It is an enlarged view of the II section in FIG. It is an enlarged view of the III section in FIG. It is an enlarged view of the IV section in FIG. It is an enlarged view of a base metal fitting. It is a figure which shows the mode of the pier in which the reinforced concrete was constructed. It is a figure which shows the mode of the recessed part constructed | assembled in the reinforced concrete. It is a figure for demonstrating the whole flow which finishes the recessed part of the surface of a reinforced concrete, and disassembles a temporary cut-off wall. It is a figure for demonstrating the operation | work in each cutting beam at the time of dismantling the finishing of the recessed part of the surface of a reinforced concrete, and a temporary cutoff wall. It is a figure which shows a mode that the hose was attached to the injection hole and discharge hole which were provided in the iron plate. It is a figure for demonstrating each process of finishing the surface of the conventional reinforced concrete, and dismantling a temporary cutoff wall.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pier 2 Footing 5 Water 10 Temporary cut-off wall 11 Steel panel 20 Cut beam 21 Steel material 22 Jack 23 Joint metal 30 Underwater concrete 31 Mortar 40 Reinforced concrete 40A Concave 50 Replacement beam 51 Log 52 Universal jack 60 Iron plate 60A Discharge port 60B Inlet

Claims (4)

Surrounding the underwater structure with a cylindrical temporary cutoff wall, spanning a beam provided with a telescopic mechanism between the underwater structure and the temporary cutoff wall, and draining the inside of the temporary cutoff wall, A method of reinforcing an underwater structure within the temporary cutoff wall,
Striking concrete around the underwater structure;
A replacement beam installation step of bridging the replacement beam between the surface of the concrete in the vicinity of the cutting beam and the temporary fastening wall after hardening of the increased concrete;
A beam contraction step for contracting the beam by the extension mechanism;
A plate material installation step of bringing a plate material provided with an injection hole into contact with the concrete surface so as to cover a concave portion formed in a portion corresponding to the cut beam of the concrete surface;
A beam re-installation step of extending the beam by the expansion and contraction mechanism and spanning the beam between the plate member and the temporary fastening wall;
And a mortar filling step of filling the recess with the mortar from the injection hole. A method for reinforcing an underwater structure according to claim 1,
After the beam re-installation step and before the mortar filling step,
A water inflow step for allowing water to flow into the temporary cutoff wall;
In the mortar filling step, a hose is attached to the injection hole so as to extend to the water surface, and the mortar is filled through the hose. A method for reinforcing an underwater structure according to claim 1 or 2,
In the replacement beam installation step,
A method for reinforcing an underwater structure characterized by spanning the replacement beam and injecting water into the temporary fastening wall to a position below the cutting beam.   An underwater structure reinforced by the method according to any one of claims 1 to 3.