JP2023015912A - How to replace wall balustrades - Google Patents

Abstract

[Problem] To provide a method for replacing a wall railing that can be constructed with minimal traffic restrictions. [Solution] In a wall balustrade replacement method of replacing an existing wall balustrade made of reinforced concrete (RC wall balustrade 10) with a new wall balustrade made of reinforced concrete (PCa wall balustrade 1), a drainage portion 14 of an existing floor slab 11 is provided. After carrying out the process of cutting out the existing draining part, a new draining part preliminary construction process is carried out in which a new draining part 14' is constructed in advance before the removal of the existing wall railing (RC wall railing 10). [Selection diagram] Figure 4

Description

TECHNICAL FIELD The present invention relates to a method for replacing wall balustrades, and more particularly to a method for replacing existing reinforced concrete wall balustrades with PCa wall balustrades made of precast reinforced concrete.

Rigidity designed to prevent vehicles from deviating from elevated bridges and roads to the outside of roads and sidewalks, minimize injuries to vehicle occupants and damage to vehicles, and restore vehicles to the normal direction of travel. When replacing the existing wall balustrade, which is a protective fence, it is necessary to restrict traffic such as vehicles passing on the road. In addition, since shortening the period of traffic regulation leads to restraining economic loss, there is a strong demand for minimizing the period of traffic regulation. In addition, since it leads to a reduction in complaints from road users, it promotes the smooth progress of construction work.

Therefore, in the present invention, when removing the existing wall balustrade from the part facing the floor slab upper surface and floor slab side wall balustrade, the floor slab side part is removed in advance, and the floor slab upper surface is removed later. However, it was decided to install a new wall balustrade. It is possible to minimize traffic congestion due to traffic regulations because the removal work of the side of the floor slab (drainage part) can be done without traffic restrictions or with minimal traffic restrictions (lane restrictions, road shoulder restrictions, etc.) Because it becomes In particular, on the side of the floor slab, which is the drainage part, there are horizontal tightening fixtures, horizontal tightening PC steel materials, and reinforcing bars from the main girder, so it is necessary to carefully remove them. . The removal work of the side of the floor slab, which requires a lot of time and care, can be done without traffic restrictions or with minimal traffic restrictions, thus minimizing traffic congestion caused by traffic restrictions. becomes possible.

On the other hand, in Patent Document 1, the ground guard 5 is sequentially provided on the side of a plurality of girder blocks 2 from one side in the overhang direction, and the ground guard 5 is provided sequentially from one side in the overhang direction. A wall balustrade block 7 is fixedly installed by inserting a fixing bar 3 through an insertion hole to a girder block 2, and a plurality of wall balustrade blocks 7 are arranged side by side in the bridge axis direction to construct a balustrade. A construction method is disclosed (see claim 1 of patent document 1, paragraphs [0019] to [0028] of the specification, Figs. 1 and 2 of the drawings, etc.).

However, in the bridge construction method described in Patent Document 1, at the time of new construction of a bridge, in order to cover the surroundings of the fixture of the PC steel material that applies prestress to the floor slab with concrete and to process the end, However, it is not applicable to the replacement work of the wall balustrade, and of course, it is not possible to shorten the traffic regulation.

Moreover, in Patent Document 2, a precast concrete gutter 1 is installed on the side opposite to the road surface 10r of the wall balustrade placed on the bridge 10. A method is disclosed (see paragraphs [0026] to [0044] of the specification of Patent Document 2, FIGS. 2 to 5 of the drawings, etc.).

However, the method for installing a precast concrete gutter described in Patent Document 2 is also accompanied by the method for installing a gutter at the time of constructing a new bridge, and the floor slab side is precedently constructed, and the construction of the bridge described in Patent Document 1 As with the method, it was not applicable to replacement work of wall balustrades, and of course, it was not possible to shorten traffic regulations.

JP 2018-178588 A JP 2019-131960 A

SUMMARY OF THE INVENTION Accordingly, the present invention has been devised in view of the above problems, and its object is to provide a method for replacing wall balustrades that can be constructed with minimal traffic restrictions.

A wall balustrade replacement method according to claim 1 is a wall balustrade replacement method for replacing an existing reinforced concrete wall balustrade with a new reinforced concrete wall balustrade. After performing the step of removing the existing draining part, a new draining part precedent construction process is performed in which the new draining part is preliminarily constructed before the existing wall balustrade is removed.

The wall balustrade replacement method according to claim 2 is the wall balustrade replacement method according to claim 1, wherein the step of removing the existing draining portion and the preceding step of constructing the new draining portion include lane control from temporary scaffolding. It is characterized in that it is performed without

The wall balustrade replacement method according to claim 3 is the method for replacing wall balustrades according to claim 1 or 2, wherein embedded reinforcing bars for supporting the newly-established ditching section are performed before performing the newly-established ditching section preceding construction step. An anchor hole drilling step is performed to drill an anchor hole for use.

A wall balustrade replacement method according to claim 4 is the wall balustrade replacement method according to any one of claims 1 to 3, wherein in the wall balustrade installation step of installing the new wall balustrade, precast reinforced concrete It is characterized by installing PCa wall balustrades.

A wall balustrade replacement method according to claim 5 is the wall balustrade replacement method according to claim 4, wherein in the wall balustrade installation step, anchor members having bearing pressure plates attached to both ends through a floor slab are installed. and fixing the PCa wall balustrade.

The wall balustrade replacement method according to claim 6 is the wall balustrade replacement method according to claim 4 or 5, wherein in the wall balustrade installation step, the outer surface of the floor slab and the PCa wall balustrade is coated with carbon. It is characterized by bonding fiber sheets.

According to the inventions according to claims 1 to 6, after scraping off the draining part of the existing floor slab, the new draining part is constructed prior to the removal of the existing wall balustrade, so traffic regulation is minimized. The existing balustrade can be replaced with a new balustrade. In addition, according to the inventions of claims 1 to 6, the work of scraping off and removing the draining part, which needs to be done carefully, can be performed as a work on the scaffolding that does not carry out lane regulations and is outside lane regulations. can. For this reason, it is possible to carefully remove the water draining portion over time without worrying about the regulation time of the lane regulation.

In particular, according to the third aspect of the invention, since the anchor hole drilling step is performed, the next step, the pre-construction step of the newly installed draining portion, can be efficiently performed in a shorter time.

In particular, according to the fourth aspect of the invention, since the PCa wall balustrade is installed, the wall balustrade can be replaced while the curing period required for the concrete to develop a predetermined strength is greatly shortened.

In particular, according to the fifth aspect of the invention, since the PCa wall balustrade is fixed by the anchor member that penetrates the floor slab and has bearing pressure plates attached to both ends, the work for installing the PCa wall balustrade can be further shortened. can.

In particular, according to the sixth aspect of the invention, since the carbon fiber sheet is adhered to the outer surface of the floor slab and the PCa wall balustrade, it is possible to cope with an external force in the direction opposite to the collision load from the outside of the bridge.

FIG. 1 is a vertical view of the RC wall balustrade showing the structure of the existing RC wall balustrade in the direction of the bridge axis. FIG. 2 is a process explanatory diagram for explaining a process of stripping the existing draining part of the method for replacing the wall balustrade according to the embodiment of the present invention. FIG. 3 : is process explanatory drawing which shows the anchor hole drilling process of the replacement method of a balustrade same as the above. FIG. 4 is a process explanatory diagram showing a new water drain section precedent construction process of the method for replacing the wall balustrade same as the above. FIG. 5 : is process explanatory drawing which shows the wall balustrade cutting removal process of the replacement method of a wall balustrade same as the above. FIG. 6 : is process explanatory drawing which shows the wall balustrade installation process of the replacement method of a wall balustrade same as the above.

Hereinafter, one embodiment of a method for replacing a wall balustrade according to the present invention will be described in detail with reference to the drawings.

The wall balustrade replacement method according to the embodiment of the present invention is preferably applied when replacing the existing RC wall balustrade 10 (reinforced concrete wall balustrade) with the PCa wall balustrade 1 (precast reinforced concrete wall balustrade). . FIG. 1 is a vertical sectional view showing the structure of an existing RC wall balustrade as viewed in the bridge axis direction.

First, the structure of the existing RC wall balustrade 10 and its periphery will be briefly described. As shown in FIG. 1, the existing RC wall balustrade 10 is formed with a covering portion 12 along the outer edge of the bridge so as to be higher than the upper surface of the floor slab 11. 11 is protruded above the ground covering portion 12 along the outer edge of the base portion 11 .

In addition, a draining portion 14 is formed on the outer surface of the existing floor slab 11 so that the lower end surface is lower than the general portion 13 of the floor slab 11 . Since the lower end surface of the water draining portion 14 is lower than the lower surface of the general portion 13 , precipitation such as rainwater flows from the upper surface of the floor slab 11 along the side surface and wraps around the lower surface of the general portion 13 . It has a function to reduce reaching

[How to replace wall balustrades]
Next, a method for replacing a wall balustrade according to an embodiment of the present invention will be described with reference to FIGS. 2 to 6. FIG. FIG. 2 is a process explanatory diagram for explaining a process of stripping the existing draining part of the method for replacing the wall balustrade according to the embodiment of the present invention.

(Draining process: scaffolding work outside lane regulations)
First, as shown in FIG. 2, in the method for replacing the wall balustrade according to the present embodiment, an existing draining portion scraping step is performed to scrape off the draining portion 14 corresponding to the outer surface of the existing floor slab 11 . In this step, a temporary scaffolding such as a suspended scaffolding is installed immediately below and outside of the ground protection part 12, and the work is performed as work outside the lane regulation, which is not carried out as work on the scaffolding.

Specifically, in this step, a scraping machine such as an air pick is used to scrape off the draining portion 14 of the floor slab 11 indicated by the hatched portion in FIG. At this time, the outer lower corner portion indicated by the hatched portion of the ground covering portion 12 is also scraped off. This is to secure a space for pouring concrete and a space for inserting a rod-shaped vibrator in the later-described step of installing a draining portion. However, since the floor slab 11 is in service as the main road, care should be taken to keep the scraped portion to a minimum.

In addition, in this step, some unnecessary reinforcing bars of the existing drainage part 14 and the ground covering part 12 after scraping off the concrete are also removed.

As described in the background art, on the side of the floor slab, which is the draining part 14, there are cases where horizontal tightening fixtures and horizontal tightening PC steel materials are arranged, and there are cases where reinforcing bars are arranged from the main girder. It must be removed carefully. However, in the method for replacing the wall balustrade according to the present embodiment, this process is carried out as a work on the scaffolding and as a work outside the lane regulation without lane regulation. becomes possible. For this reason, it is possible to reduce the risk of a serious accident in which the PC steel material is accidentally damaged and cut, and the tension of the prestress is released, causing the PC steel material to protrude.

(Anchor hole drilling process: Scaffolding work outside lane restrictions)
Next, as shown in FIG. 3, in the wall balustrade replacement method according to the present embodiment, an anchor hole drilling step of drilling the horizontal anchor holes 15 for the embedded reinforcing bars that support the newly installed drain section 14'. (see also Figure 4). In addition, in order to reduce lane control work, in parallel with the drilling work of the lateral anchor holes 15, in this step, the vertical through anchor holes 17 through which the anchor members 2 described later are inserted are also drilled. As in the previous process, this process is also carried out as a work on the scaffolding that does not have lane restrictions and is outside lane restrictions. FIG. 3 is a process explanatory diagram showing the anchor hole drilling process of the method for replacing the wall balustrade according to the present embodiment.

Specifically, in this process, since a D16 deformed steel bar is assumed as the embedded reinforcing bar 16, a horizontal anchor hole 15 with a diameter of φ26 mm and a depth of 250 mm is drilled using a core drill or the like equipped with a diamond core bit. pierce. Moreover, as will be described later, an anchor bolt 20 of M24×510 mm is assumed as the anchor member 2 . Therefore, in this process, in parallel with the drilling work of the horizontal anchor holes 15, a core drill or the like is used to penetrate the floor slab 11 from the bottom surface of the floor slab 11 and reach the ground covering portion 12. A through anchor hole 17 is drilled.

In the method for replacing the wall balustrade according to this embodiment, considering the degree of deterioration of the existing bridge, the surrounding concrete may fall off during the drilling of the lateral anchor holes 15. 11 with a floor slab thickness of 220 mm and a one-stage bar arrangement, with one hole drilled near the center of the floor slab thickness. Needless to say, the embedded reinforcing bars 16 may be appropriately set and arranged according to the floor slab thickness of the existing floor slab 11 and the degree of deterioration of the concrete.

(Preceding construction process for the new drainage section: Scaffolding work outside lane regulations)
Next, as shown in FIG. 4, in the method for replacing the wall balustrade according to the present embodiment, a new water draining portion precedent construction process is performed in which the new water draining portion 14 ′ is precedently constructed before the existing RC wall balustrade 10 is removed. conduct. This process, like the previous process and the water draining process, is also performed as a work outside the lane restriction as a work on the scaffolding. FIG. 4 is a process explanatory diagram showing a new draining section precedent construction process of the wall balustrade replacement method according to the present embodiment.

Specifically, an L-shaped D16 deformed steel bar made of a high-adhesion type epoxy resin-coated reinforcing bar as the embedded reinforcing bar 16 is chemically applied to the horizontal anchor hole 15 using a chemical such as a modified vinyl ester resin or an epoxy resin. , and perform the prescribed reinforcement such as distributing reinforcement. After that, secure a predetermined cover thickness of 70 mm or more around the embedded reinforcing bars 16, install a formwork, and fill the time-hardened material while compacting it using a small bar-shaped vibrator B1 or the like to newly drain the water. The part 14' is preliminarily constructed.

At this time, the newly installed water draining part 14' has a small contact surface area with the existing floor slab 11, which is the existing concrete, and is in contact with the existing floor slab 11 on the vertical plane, so that the structure is easy to separate. For this reason, it is preferable to use a material such as polymer cement mortar, which has a small shrinkage rate and excellent adhesion to the existing concrete, as the hardening material to be placed over time.

(Wall balustrade cutting and removal process: lane regulation work)
Next, as shown in FIG. 5 , in the wall balustrade replacement method according to the present embodiment, a wall balustrade cutting and removing step is performed to cut and remove the existing ground guard portion 12 and RC wall balustrade 10 . In this process, in order to remove the RC wall balustrade 10, which is a rigid protective fence, the work is carried out with lane restrictions such as closing some lanes. FIG. 5 is a process explanatory diagram showing a wall balustrade cutting and removing process of the wall balustrade replacement method according to the present embodiment.

Specifically, using a wire saw or a wall saw along the upper surface of the existing floor slab 11, the existing ground covering portion 12 and the RC wall balustrade 10 above the upper surface of the existing floor slab 11 are cut and removed. do.

(Wall railing installation process: lane regulation work)
Next, as shown in FIG. 6, in the wall balustrade replacement method according to the present embodiment, a wall balustrade installation step of installing a new PCa wall balustrade 1 is performed. In this process, as in the previous process, work is carried out with lane restrictions such as closing some lanes. FIG. 6 is a process explanatory diagram showing a wall balustrade installation process of the wall balustrade replacement method according to the present embodiment.

Specifically, the newly installed PCa wall balustrade 1 is brought in and placed along the outer edge of the existing floor slab 11, and the upper and lower penetrating holes drilled in the above-mentioned anchor hole drilling process as scaffolding work outside the lane regulation Anchor bolts 20 are inserted into the anchor holes 17, and the PCa wall balustrade 1 is fixed by bolting with the anchor members 2 penetrating the floor slab 11. - 特許庁In addition, non-shrinkage mortar is filled around the anchor members 2 and between the PCa balustrade 1 and the floor slab 11 as indicated by the shaded areas.

This anchor member 2 is a member based on an anchor bolt 20 made of alloy-plated S45CH and measuring M24×length 510 mm. A bearing pressure plate 21 is attached. This bearing pressure plate 21 is fixed by a locking nut 22 . A high nut 23 made of alloy-plated SGDM is interposed directly below the bearing plate 21 embedded in the PCa wall balustrade 1, and a predetermined distance from the lower end of the PCa wall balustrade 1 to the bearing plate 21 is interposed. is ensured. Around the high nut 23, a grid bar 24 is arranged, which is made by welding round steel bars with a diameter of 6 mm in a mochi net shape and coating with epoxy resin.

Further, in this step, a formwork is installed around the bearing plate 21 below the anchor member 2 installed below the floor slab 11, and the cement grout 25 is filled and solidified. A hole (not shown) is formed in the bearing plate 21 below the anchor member 2 for checking the filling of the non-shrinkable mortar 26 .

A carbon fiber sheet 3 for reinforcement with a basis weight of 200 g/m ² in two directions and a vertical width of 720 mm is newly installed near the lower end of the outer surface of the floor slab 11 in order to block the discharge hole of the non-shrinkable mortar 26 and reinforce it. is adhered over the outer surface of the PCa balustrade 1. This carbon fiber sheet 3 has a function of resisting an external force pushing down the PCa balustrade 1 from the outside to the inside of the bridge.

According to the wall balustrade replacement method according to the embodiment of the present invention described above, the existing RC wall balustrade 10 can be replaced with the PCa wall balustrade 1 with minimal traffic restrictions. Further, according to the method for replacing the wall balustrade according to the embodiment of the present invention, the work of scraping off and removing the draining part 14, which needs to be done carefully, is regarded as the work on the scaffolding, and the lane regulation is not performed. Can be done as outside work. Therefore, according to the method for replacing the wall balustrade according to the embodiment of the present invention, it is possible to carefully remove the water draining portion 14 over time without worrying about the regulation time of lane regulation. Therefore, it is possible to reduce the risk of a serious accident in which the PC steel material is erroneously damaged and cut, and the tension of the prestress is released, causing the PC steel material to protrude.

The method for replacing the wall balustrade according to the embodiments of the present invention has been described in detail above, but the above-described or illustrated embodiments are all specific embodiments for carrying out the present invention. Not too much. Therefore, the technical scope of the present invention should not be construed to be limited by these. In particular, the material and dimensions of each member are given as an example, and needless to say, the design may be changed as appropriate.

1: PCa wall balustrade (new wall balustrade)
2: Anchor member 20: Anchor bolt 21: Bearing plate 22: Locking nut 23: High nut 24: Grid line 25: Cement grout 26: Non-shrinking mortar 3: Carbon fiber sheet 10: RC wall balustrade (existing wall balustrade)
11: Floor slab 12: Undercover part 13: General part (floor slab)
14: Draining section (floor slab)
15: Horizontal anchor hole 16: Embedded reinforcing bar 17: Vertical penetration anchor hole B1: Rod-shaped vibrator

A wall balustrade replacement method according to claim 1 is a wall balustrade replacement method for replacing an existing reinforced concrete wall balustrade with a new reinforced concrete wall balustrade. After performing the step of removing the existing draining portion , and then performing the anchor hole drilling step of drilling the anchor hole for the embedded reinforcing bar that supports the newly installed draining portion, the newly installed draining portion is removed from the existing The method is characterized in that a pre-construction process for a new water draining section, which is pre-constructed before the removal of the wall balustrade, is performed.
A wall balustrade replacement method according to claim 2 is a wall balustrade replacement method for replacing an existing reinforced concrete wall balustrade with a new reinforced concrete wall balustrade. After performing the step of scraping off the existing draining part, the new draining part is precedently constructed before removing the existing wall balustrade, and the wall balustrade for installing the new wall balustrade. In the installation step, the PCa wall balustrade made of precast reinforced concrete is fixed and installed by anchor members having pressure plates attached to both ends through the floor slab.

A wall balustrade replacement method according to claim 3 is the wall balustrade replacement method according to claim 1 or 2 , wherein the step of removing the existing water drain and the preceding construction step of the new water drain are performed from temporary scaffolding to lane regulation. It is characterized by performing without performing

A wall balustrade replacement method according to claim 4 is the wall balustrade replacement method according to claim 2 , wherein in the wall balustrade installation step, a carbon fiber sheet is applied to the outer surface of the floor slab and the PCa wall balustrade. It is characterized by bonding.

According to the inventions of Claims 1 to 4 , after scraping off the draining part of the existing floor slab, the new draining part is constructed prior to the removal of the existing wall balustrade, so traffic regulation is minimized. The existing balustrade can be replaced with a new balustrade. In addition, according to the inventions of claims 1 to 4 , the work of scraping off and removing the draining part, which needs to be done carefully, can be done as a work on the scaffolding that does not carry out lane regulations and is outside lane regulations. can. For this reason, it is possible to carefully remove the water draining portion over time without worrying about the regulation time of the lane regulation.
In addition, according to the first aspect of the invention, since the anchor hole drilling process is performed, the next process, which is the pre-construction process for the new water draining portion, can be efficiently performed in a shorter time.

In particular, according to the second aspect of the invention, since the PCa wall balustrade is installed, it is possible to perform the wall balustrade replacement work while greatly shortening the curing period for the concrete to develop a predetermined strength.
In addition, according to the second aspect of the invention, the PCa wall balustrade is fixed by the anchor member that penetrates the floor slab and has bearing plates attached to both ends, so that the work for installing the PCa wall balustrade can be further shortened. can.

In particular, according to the fourth aspect of the invention, since the carbon fiber sheet is adhered to the outer surface of the floor slab and the PCa balustrade, it is possible to cope with an external force in the direction opposite to the collision load from the outside of the bridge.

Claims (6)

A wall balustrade replacement method for replacing an existing reinforced concrete wall balustrade with a new reinforced concrete wall balustrade,
After performing the existing water draining process to remove the water draining part of the existing floor slab,
A method for replacing a wall balustrade, characterized by performing a pre-construction process for a new water-draining section in which a new water-draining section is constructed prior to removal of the existing wall balustrade. 2. The method for replacing a wall balustrade according to claim 1, wherein the step of removing the existing water drain and the preceding construction step of the new water drain are performed without lane restrictions from temporary scaffolding. 3. The anchor hole drilling step of drilling an anchor hole for an embedded reinforcing bar that supports the newly installed draining portion is performed before performing the new draining portion precedent construction step. How to replace the wall balustrade. The wall balustrade replacement method according to any one of claims 1 to 3, wherein PCa wall balustrades made of precast reinforced concrete are installed in the wall balustrade installation step of installing the new wall balustrade. 5. The method for replacing a wall balustrade according to claim 4, wherein in the wall balustrade installation step, the PCa wall balustrade is fixed by anchor members having bearing pressure plates attached to both ends of the floor slab. 6. The method for replacing a wall balustrade according to claim 4 or 5, wherein, in the wall balustrade installation step, a carbon fiber sheet is adhered to the outer surface of the floor slab and the PCa balustrade.

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