JP2023164070A - Pier repair or reinforcement method and formwork - Google Patents

Abstract

The present invention provides a method for reinforcing or repairing a bridge pier and a formwork that can suppress defects such as cracks and fissures in a reinforcing or repairing filler.
[Solution] A method for repairing or reinforcing a bridge pier erected underwater, in which formwork is placed to cover the repaired or reinforced portion of the pier, and cement-based material is filled between the pier and the formwork. This is a method for reinforcing or repairing a bridge pier, in which a first space that serves as a layer is formed, and a second space that serves as a heat insulating layer is formed between water and the first space.
[Selection diagram] Figure 4

Description

The present invention relates to a method for repairing or reinforcing bridge piers and formwork.

In general, structures inevitably deteriorate and corrode over time. Therefore, countermeasures and maintenance are required.

In structures such as piers and road bridges, piers erected underwater are exposed to harsh natural environments, and deterioration and corrosion become a problem. Corrosion and deterioration of bridge piers are particularly likely to progress significantly in areas near the water surface called the tidal zone and splash zone.

As a countermeasure, efforts have been made to make the material itself corrosion resistant at the design stage, such as painting, coating with FRP (fiber reinforced plastic), and cathodic protection. However, there are problems such as aging of the coating material and ineffective cathodic protection at the water surface boundary, so these measures alone are not sufficient.

On the other hand, as maintenance, there is a method of reinforcing the deteriorated parts themselves. For example, in Prior Document 1, which will be described later, a reinforcing cylinder with a larger diameter is attached to the columnar structure so as to cover the periphery of the deteriorated portion of the columnar structure to be reinforced, and then the outer surface of the columnar structure and the reinforcement A method has been proposed in which a reinforcing filler is filled into the gap formed between the inner surface of the cylinder and the inner surface of the cylinder.

Japanese Unexamined Patent Publication No. 61-270464

However, in the method described in Patent Document 1, a temperature difference occurs between the filled reinforcing filler above the water surface (in the air) and below the water surface (in the water) due to the influence of the external environment. This causes a difference in the degree of shrinkage of the reinforcing filler between the upper and lower sides of the water surface, which causes a problem in that the reinforcing filler is likely to crack and crack.

The present invention has been made in view of these points, and an object of the present invention is to provide a method for repairing a bridge pier and a formwork that can suppress defects such as cracks and fissures in a repair or reinforcing filler.

In order to solve the above-mentioned problems, a first invention is a method for repairing or reinforcing a bridge pier erected underwater, in which a formwork is arranged so as to cover the repaired or reinforced part of the pier, A pier forming a first space serving as a filled layer of cement material between the pier and the formwork, and forming a second space serving as a heat insulating layer between the water and the first space. It is a reinforcement or repair method.

In order to solve the above-mentioned problems, a second invention provides a filling method that can be filled with a cement-based material between the bridge pier and the bridge pier when the bridge pier is placed in the water to cover the repair or reinforcement area. A formwork for forming a layer, the formwork comprising a heat insulating layer between water and the filling layer.

According to the present invention, defects such as cracks and fissures in the repair or reinforcing filler can be suppressed, and bridge piers can be repaired and reinforced with higher quality.

It is a diagram schematically showing a pier type quay. FIG. 2 is a partial cross-sectional view of the formwork (repair formwork) according to the first embodiment of the present invention wrapped around a pier; It is a schematic diagram of the formwork body which constitutes a repair formwork. It is a schematic diagram of the plate body which constitutes a repair formwork. It is a partial sectional view of the state where the repair formwork concerning the 2nd embodiment of the present invention is wrapped around a bridge pier.

Embodiments of the present invention will be described below with reference to the drawings. The explanation will be given in the following order. In addition, in all the figures of the following embodiment, the same reference numerals are given to the same or corresponding parts.
<1. First embodiment>
<2. Second embodiment>
<3. Modified example>
<4. Application example>

<1. First embodiment>
With reference to FIGS. 1 to 4, a method for repairing or reinforcing bridge piers and a formwork according to the present invention will be described.

This embodiment will be explained using a pier type quay as an example.

FIG. 1 is a diagram schematically showing a pier type quay 10. The pier type quay 10 is usually formed by retaining the earth with steel sheet piles, driving piers 11 made of steel pipe piles into the water bottom, and installing and fixing the floorboards 13 on the piers 11 erected in the water. .

The area near the water surface 15 of the pier 11 is always exposed to sea waves. The tidal zone (tidal zone), which is directly exposed to waves due to the ebb and flow of the sea surface, and the splash zone (splash zone), which is exposed to the spray generated when the waves collide with the piers 11, are particularly susceptible to corrosion and deterioration among the piers 11. This is an area where damage is likely to progress, and there is a strong demand for repair.

Next, a method for repairing a bridge pier will be explained with reference to FIGS. 2 to 4. The areas to be repaired are the tidal zone and splash zone of Pier 11.

FIG. 2 is a partial sectional view of the formwork (repair formwork) 20 according to the first embodiment of the present invention wrapped around the pier 11. FIG. 3 is a schematic diagram of a formwork body 30 that constitutes the repair formwork 20. FIG. 4 is a schematic diagram of a plate body 40 that constitutes the repair formwork 20.

[Overview of repair method]

Repair of the pier 11 is performed using a repair formwork 20. More specifically, the repair form 20 is wrapped around the pier 11 so as to cover the corroded area 12 (or deteriorated area) that is to be repaired or reinforced on the pier 11, and the space 50 between the repair form 20 and the pier 11 is The corroded areas 12 are covered and repaired by being filled with mortar M and hardened.

[Structure of repair formwork]
The configuration of the repair formwork 20 will be explained below.

The repair formwork 20 is composed of a formwork body 30 and two plate bodies 40.

The formwork body 30 includes a flexible rectangular sheet-like main body part 32 made of olefin resin such as polyethylene, and fixed parts formed with a predetermined width along the upper and lower (shorter direction) edges of the main body part 32. portion 34 and connecting portions 36 provided along both left and right (longitudinal direction) end edges of the main body portion 32. However, in FIG. 2, the cross section is taken at one end of the formwork 30, so only the other end of the connecting portion 36 is shown in the drawing.

The main body portion 32 has a hollow donut-like structure like a floating ring. This hollow part 33 is provided with an intake port (not shown) through which air A can be injected from the outside, and as described later, this hollow part 33 functions as a heat insulating layer during repair. In addition, although the main body part 32 was constructed as one continuous sheet, it may be constructed by connecting a plurality of parts.

The plate body 40 is a ring-shaped member made of steel, reinforced concrete, wood, or the like, and has a hole 46 formed in the center. More specifically, the plate body 40 is constructed by connecting and fixing a first plate portion 42 having a semicircular arch shape and a second plate portion 44 having the same shape using a member such as a connecting plate (not shown). It becomes ring-shaped. The diameter of the hole 46 of the plate body 40 is set at the design stage to correspond to the diameter of the pier 11.

Further, the first plate portion 42 is provided with a through hole 43 .

[How to install repair formwork]
Next, a method for installing the repair formwork 20 on the pier 11 will be explained.

When installing the repair formwork 20, first determine the position where the repair formwork 20 can cover the corroded area 12 of the pier 11, and then install the first plate at the positions corresponding to the upper and lower ends of the repair formwork 20, respectively. The plate body 40 is arranged so that the pier 11 is sandwiched between the section 42 and the second plate section 44.

The fixing portion 34 of the frame body 30 is wrapped around the side surface of the arranged plate body 40 via a sealing member (not shown). A wire 35 is inserted into the fixing part 34, and by tightening the wire 35 using a load tightening machine or the like, the repair formwork 20 is fastened and fixed to the pier 11 and positioned.

Furthermore, air is injected into the hollow portion 33 of the repair formwork 20. As a result, the hollow portion 33 expands, and the repair formwork 20 deforms into a balloon shape.

[Repair method]
Next, a method for repairing the pier 11 will be explained.

With the repair formwork 20 positioned on the pier 11, mortar M is filled through the through-holes 43 of the plate body 40 on the lower side (bottom side). The mortar M flows into the space 50 formed between the repair formwork 20 and the pier 11, and the space 50 (first space) functions as a filling layer and is gradually filled with mortar M from the water bottom side. It will be done.

As the mortar M gradually accumulates upward, the seawater 60 that filled the space 50 of the repair formwork 20 is pushed up by the inflowing mortar M and flows through the through hole 43 provided in the upper plate body 40. It is discharged to the outside of the repair formwork 20. As a result, the space 50 is filled with repair mortar M.

The repair formwork 20 also functions as a curing until the mortar M hardens. As the mortar M hardens, the corroded area 12 is covered and the pier 11 is repaired.

[Effect]
Previously, there was a temperature difference between the part of the filled mortar that was in the air and the part that was in water due to the influence of the external environment, which caused a difference in the degree of shrinkage when the mortar hardened. There was a problem that cracks and fissures were more likely to occur. However, by using the method or repair formwork of the present invention as described above, the hollow part 33 (second space) corresponding to the outer layer functions as a heat insulating layer, so that the mortar M filled in the space 50 corresponding to the inner layer , temperature differences due to the influence of the external environment are less likely to occur. This makes it difficult for defects such as cracks to occur in the mortar M, allowing for higher quality repairs.

In addition, Mortar M takes time to harden at low temperatures, but by forming a heat insulating layer on the outer layer, the temperature of Mortar M becomes difficult to drop, especially during cold seasons, and the curing time is shortened, which shortens the construction period. be able to.

In addition, in this Embodiment, the repair formwork 20 and the abandonment layer (hollow part 33) were comprised integrally, but this may be separate bodies. Furthermore, although the heat insulating layer is one layer, the structure is not limited to this, and a plurality of heat insulating layers may be provided. Further, another space (layer) may be provided between the heat insulating layer and the space 50.

Although cement mortar was used as the filler in this embodiment, other mortar-based materials such as polymer cement mortar and resin mortar may be used. In addition to mortar, other cement-based materials may be used as the filler.

In addition, in recent years, there has been a tendency for pier repair work itself to become larger in scale, such as with the slat construction method, but by using the method or formwork according to the present invention, corroded areas can be repaired in a pinpoint manner. Therefore, the workability is good, and repair work can be carried out on a relatively small scale and at low cost.

<Second embodiment>
[Structure of repair formwork]

FIG. 5 is a partial sectional view of a repair formwork 120 according to a second embodiment of the present invention wrapped around a pier 11. The second embodiment differs from the repair formwork 20 of the first embodiment in that the plate body 40 is not used.

The repair formwork 120 is composed of a formwork body 130. The frame body 130 includes a main body portion 32 including a hollow portion 33 (second space), a fixing portion 34, and a connecting portion 36, as in the first embodiment. The main body part 32 is provided with a mortar M filling port 143 on the lower side (bottom side) and a drain port 144 on the upper side, and the space 50 is directly connected to the repair formwork 120 through the filling port 143 and the drain port 144. communicates with the outside.

[How to install repair formwork]

The repair formwork 120 is fastened and fixed to the pier 11 with a wire 35 with its upper and lower fixing parts 34 wrapped around the pier 11 via a sealing member, and installed in a position to cover the corroded part 12 of the pier 11. be done.

[Repair method]

With the repair formwork 120 fastened and fixed to the pier 11, mortar M is filled into the space 50 formed between the form body 130 and the pier 11 from the filling port 143 on the lower side (bottom side). do.

As the mortar M accumulates from the bottom of the space 50, the seawater 60 filling the space 50 is pushed up by the mortar M and is discharged to the outside of the repair formwork 120 from the drain port 144 of the repair formwork 120. . As a result, the space 50 is filled with repair mortar M, and as the mortar M hardens in this state, the corroded area 12 is covered with the mortar M, and the pier 11 is repaired.

[Effect]

As described above, in the repair method and repair formwork 120 according to the second embodiment, the mortar M can be cured while the hollow portion 33 (second space) functions as a heat insulating layer. Therefore, similar to the first embodiment, defects such as cracks are less likely to occur in the mortar M, making it possible to repair the pier 11 with higher quality. Moreover, the temperature of the mortar M is difficult to fall, and the curing time is shortened, so the construction period is also shortened.

Furthermore, by configuring the repair formwork 120 only with the formwork body 130, the repair formwork 120 can be easily installed on-site, leading to a reduction in construction period.

<3. Modified example>

Although the embodiments of the present invention have been specifically described above, the present invention is not limited to the above-described embodiments, and various modifications can be made based on the technical idea of the invention.

Although the embodiment has been described using an example in which the structure to be repaired is a pier-type quay, the structure is not limited to a pier-type quay. The present invention can also be used when repairing structures other than pier-type quays, such as piers, bridges, and viaducts.

Further, although the embodiment has been described using an example of repairing deteriorated or corroded parts of a bridge pier, the present invention can also be applied to the case of reinforcing a bridge pier.

Further, the shape of the pier is not limited to a cylindrical shape, and the present invention can be applied to a prismatic or other shape. Similarly, the shape of the repair formwork and plate body is also an example, and the shape can be changed according to the shape of the pier.

In addition, a method of injecting air into the hollow part was adopted as a method of forming the heat insulating layer, but the heat insulating layer may also be formed by using a fiber-based heat insulating material such as glass wool or cellulose fiber. .

Further, in the first embodiment, the two upper and lower plate bodies 40 of the repair formwork 20 are the same, but plates of different shapes may be used as long as they can perform the same function. In particular, regarding the upper plate body 40, the holes 46 are not limited to the specific shape shown in the embodiment, but may take various shapes as long as they can fulfill the function of drainage. It is also possible to construct the repair formwork 20 without using the upper plate body 40.

Moreover, each step of the repair formwork installation method described in the embodiment is merely an example, and does not necessarily have to be performed in the same order.

<4. Application example>

Note that when using the repair method and repair formwork according to the present invention underwater, since the buoyancy is greater than in fresh water, a separate weight is attached to the repair formwork 20 to improve workability during installation. Good too. For example, water may be used as the weight.

Although the embodiments of the present invention and their modifications and applications have been specifically described above, the present invention is not limited to the above-described embodiments and their modifications and applications. Various modifications based on technical ideas are possible.

For example, the configurations, methods, processes, shapes, materials, numerical values, etc. mentioned in the above-mentioned embodiments and their modifications/applications are merely examples, and configurations, methods, processes, shapes, etc. that differ from these as necessary. , materials, numerical values, etc. may also be used.

11... Pier 12... Corroded area (repair or reinforcement area)
20...Repair formwork (formwork)
33...Hollow part (second space)
50...Space (first space)

Claims (5)

A method for repairing or reinforcing a bridge pier erected underwater,
arranging a formwork so as to cover the repaired or reinforced portion of the pier, and forming a first space between the pier and the formwork that will become a filled layer of cement-based material;
forming a second space serving as a heat insulating layer between the water and the first space;
Method of repairing or reinforcing bridge piers. The second space is formed by configuring the formwork in a balloon shape.
The method for repairing or reinforcing a bridge pier according to claim 1. The second space is a heat insulating layer using air.
The method for repairing or reinforcing a bridge pier according to claim 1 or 2. A formwork that forms a filling layer that can be filled with a cement-based material between the pier and the pier when placed to cover a repaired or reinforced part of a pier erected in water,
comprising a heat insulating layer between the water and the packed layer;
Formwork. the heat insulating layer is an air layer;
The formwork according to claim 4.

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