JPH07109081B2 - Expansion joint removal method for expansion joints of concrete bridges - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for removing expansion joint play materials for concrete bridges.

[0002]

2. Description of the Prior Art Many short-span girder bridges that are in service have expansion joints, and each time the vehicle passes through the expansion joints, there is vibration and impact, which makes the traveling performance poor. In addition, neighboring residents are complaining about noise and vibration. Therefore, by connecting short-span girders into continuous girders, work is being done to improve runnability and reduce noise and vibration. When constructing a short span girder bridge, a Styrofoam plate is usually inserted between the expansion joint girders at the time of construction, and this is used as a temporary template for the girder concrete of the next span (transverse girder).
Is being placed. Since the expansion and contraction of the girder will not be affected even after the bridge is completed, the general method is to leave the Styrofoam plate as it is.

In order to make a short span girder into a continuous girder, the styrofoam plate in the play part is removed and cleaned, concrete or mortar is filled in the play, and both side main girders are made of PC steel through each cross girder. There is a method of tightening and integrating with a rod. However, the space between expansion joints is as narrow as 30 to 50 mm, and the height is as high as 1 m. In the lateral direction, the bridge width is 10 m.
It is a huge plate-like shape that is continuous in the vicinity, and is firmly attached to the transverse girder concrete on one side, so it is not easy to completely remove it. Conventionally, the above-mentioned styrofoam has been scraped off from one end with a scraping rod, or it has been taken to dissolve it by applying styrofoam-dissolving oil such as gasoline, but it takes time and labor to remove it, and it must be removed completely and completely. I couldn't.

[0004]

As described above, it is difficult and inefficient to remove and clean the Styrofoam of the interstitial material of the expansion joint, and the residue is likely to remain. In developing a construction method to improve this, the following six plans were examined. It is (1) wire sawing method (using wire with diamond for breaking concrete) (2) melting by chemicals, (3) melting by heating wire, (4) continuous perforation by drill, (5) manual scraping, (6) high pressure water It is a jet. In conclusion, the high-pressure water jet was judged to be optimal from the equipment, labor, required time, and difficulty level, and the development of a method for removing the expansion joint interlocking material by this was caught as the subject of this invention.

[0005]

The method for removing expansion joint play material of a concrete bridge of the present invention is a method for removing foam plastic of the play material existing in the expansion joint of each main girder connection portion of the concrete bridge. , The through-holes before and after sandwiching the foamed plastic, through holes that horizontally penetrate the cross-beam to reach the foamed plastic, have an inner diameter into which the L-shaped injection nozzle for high-pressure water can be inserted, and the foamed plastic removal capability of the injection nozzle Drill the required number of holes at adjacent intervals where the ranges overlap,
After removing the foamed plastic in the range centered on each through-hole by the high-pressure water jet nozzle that has reached the foamed plastic through each through-hole, the removal operation occurred from the outer end of each expansion joint. It is characterized in that a lance pipe that can be extended and extended is inserted almost horizontally into the gap and the remaining foamed plastic is removed by an injection nozzle attached to the tip of the lance pipe. It is also proposed that the foamed plastic is allowed to remain without removing only its uppermost layer.

[0006]

[Function] Conventionally, the foamed plastic has been successively removed from the outer end of the expansion joint to proceed to the center. On the other hand, according to the present invention, a through hole is formed in a transverse beam that sandwiches the foamed plastic, and the direction of the L-shaped injection nozzle inserted in this is rotated to collapse the foamed plastic in the arc-shaped range centered on the hole. , Usually drop down. If the through holes are arranged so that the performance ranges of the injection nozzles are overlapped with each other, or if the through holes are blown down, the arc-shaped cavity can be connected to the entire length of the joint clearance. This allows the lance pipe to be inserted from the outer end of the joint to the central portion of the joint or the outer end on the opposite side. At the tip of the lance pipe, replace any nozzle such as a straight nozzle or L-shaped nozzle,
By attaching and spraying high-pressure water, the remaining foamed plastic can be completely removed and cleaned. In addition, if only the top layer of foamed plastic is left without being removed, high-pressure water will not be ejected onto the road surface of the bridge, enabling repairs without stopping road traffic.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 9 and 10 are explanatory views of the elevation surface and the lower surface of a main girder connection portion in which an expansion joint is modified into a continuous joint according to the present invention. A is a bridge pier, 1 is a main girder, 2 is a horizontal girder, 3 is a main girder connection part where the expansion joint is changed to a continuous joint, and the PC girders 4 are tightening the lateral girders 2 on both sides thereof. The most troublesome work in the above-mentioned repair work is the work of removing the foam plastic of the play material interposed in the expansion joint. An embodiment in which the present invention is applied to the removing work will be described with reference to FIGS.

The method of the present invention will be roughly described. As a first step, a horizontal girder through hole 5 is horizontally drilled in a concrete horizontal girder 2 sandwiching a foamed plastic P to be removed, and an L-shaped injection nozzle 6 is provided therein. Is inserted and the direction of the injection port is rotated to blow out the foamed plastic P in an arc shape. In this way, when the arc-shaped cavities are connected horizontally to reach the entire length of the cross beam 2, the lance pipe 7 is passed from the outer end of the joint 3 to the connected cavities as the second stage, and the injection nozzle 7a at the tip thereof is used to form the plastic foam. The remaining portion of P is removed. As shown in FIG. 9, the horizontal girder 2 of this embodiment has a recess 8 on the lower surface of the girder. Therefore, as shown in FIG. 3, the L-shaped injection nozzle 6 is inserted and rotated to form an arc-shaped cavity. 9 was made, and then an L-shaped nozzle 6 was passed through the transverse beam through hole 5 to make an arc-shaped cavity 9 '. If the removal work is performed in this order, it is easy to collapse the foamed plastic from the lower side to the lower side, and the high-pressure water pump operates at a pressure of 210 (kg / kg).
cm ² ), water volume of 50 (l / min) and output of 35 PS are sufficient. The diameter of the through hole 5 in this embodiment is 75 m.
m, the hole diameter is suitable for both the L-shaped nozzle 6 and the PC steel material 4.

If the depression 8 on the lower surface of the cross girder as in this embodiment is not provided, the experiment could not be conducted, but the injection pressure was 1000.
Since it can be increased to (kg / cm ² ), it is considered that the foamed plastic can be blown down by using only the L-shaped nozzle from the transverse beam through hole 5. However, if the lower through-hole instead of the recess 8 is formed at an appropriate position, not only a small-capacity pump will suffice, but also the nozzle can be handled easily. If the mortar was in the gap between the seams of the foamed plastic plate, it could be crushed although it took some time. When proceeding with the repair work without stopping the road surface passage, not all the foamed plastic intervening in the expansion joint is removed, but the upper layer portion P ′ is left like a ceiling wall having a thickness of 30 to 40 cm as shown in FIG.
In this way, when the upper layer portion P'is left, the L-shaped nozzle 6 inserted in the through hole 5 is directed downward from the horizontal direction and is not directed upward. The remaining upper part may be broken down by the lance pipe 7 from the outer end of the joint to leave a ceiling wall with a required thickness. In this way, not only does high-pressure water not blow out onto the road,
Do not heal the rubber at the seams. Even if such a foamed plastic layer remains, there is no problem in strength due to the integration of a sufficient area thereunder.

FIG. 6 shows a basic type of the L-shaped injection nozzle 6,
FIG. 7 shows, as an applied type, an example in which the disk-shaped nozzle 6a at the tip is used to eject in all directions. FIG. 8 shows an example of the lance pipe 7, which can be jetted in a free direction by the nozzle 7a whose tip can be exchanged, and the length can be extended by the connecting pipe 10. As described above with reference to one embodiment, the construction method of the present invention is, after all, after forming the through hole in the cross beam and inserting the L-shaped injection nozzle therein to remove the foamed plastic sandwiched between the cross beams. The lance pipe is put into the generated gap from the outer end of the joint to remove the remaining portion cleanly, and it is free for a site engineer to add various measures according to the implementation conditions without changing the gist of the lance pipe. In this embodiment, as shown in the drawing, since the transverse beam through holes 5 are also used for fastening and unifying with the PC steel material 4, the position thereof is determined by the strength design, but it is not limited to such an arrangement. Even if the through holes 5 that are not used later remain, there is no problem in strength.

[0011]

EFFECTS OF THE INVENTION The present invention is most preferable among all conceivable construction methods for removing and cleaning the foamed plastic in the expansion joint, which has been the most difficult work in the work of modifying the expansion joint of a short span girder bridge into a continuous girder. It paved the way for construction by high-pressure water injection. The foamed plastic fixed on the concrete surface of the girder is the L-shaped injection nozzle inserted from the through hole of the girder,
It could not be removed because the jet flow escaped over the fixed part. However, the remaining part could be easily removed by striking a jet perpendicular to the concrete surface with various nozzles inserted along the seam and changing the injection direction. In addition, the area that was difficult to remove from the through-hole through holes was completely removed by the lance pipe, and the entire surface could be cleaned.
Further, if the foamed plastic is removed by leaving only the upper layer, the work can be carried out without stopping the road surface passage, and an embodiment in which strength is not hindered as a continuous girder even if only the upper layer is not replaced with mortar is also presented.

[Brief description of drawings]

FIG. 1 is an explanatory view of a vertical section of an embodiment of the present invention.

FIG. 2 is a plan sectional view of FIG.

3 is an explanatory side view of FIG.

FIG. 4 is an explanatory diagram after completion of FIG.

FIG. 5 is an explanatory vertical sectional view of the expansion joint before application of the present invention.

FIG. 6 is a diagram illustrating an example of an L-shaped jet nozzle.

FIG. 7 is an explanatory diagram of an application example of an L-shaped nozzle.

FIG. 8 is an explanatory view of an example of a lance pipe.

[Fig. 9] An elevation view of the concrete bridge after the repair.

FIG. 10 is a bottom view of FIG.

[Explanation of symbols]

 5 Transverse beam through hole 6 L-shaped injection nozzle 7 Lance pipe

Claims (1)

[Claims] 1. A method of removing foam plastic of an interstitial material interposed in expansion joints of main girder connection parts of a concrete bridge, wherein the cross girder is horizontally penetrated to the cross girders before and after sandwiching the foamed plastic. The through holes reaching the foamed plastic with an inner diameter into which the L-shaped jet nozzle for high-pressure water can be inserted, and at a required interval at adjacent intervals where the range of the foamed plastic removal capability of the jet nozzle overlaps, and through each of the through holes. With the high-pressure water jet nozzle that reaches the foamed plastic, after removing the foamed plastic in the range centered on each through-hole, it is possible to extend from the outer end of each expansion joint to the gap created by the removal work. Insert a lance pipe almost horizontally and remove the remaining foamed plastic by the injection nozzle attached to the tip of the concrete bridge Expansion joint free material removal method.