Hollow deck repair method and hollow deck

Abstract

To improve quality of a hollow floor slab.SOLUTION: When repairing a hollow floor slab 16 in a bridge 10, a plurality of through holes 28 communicating with a cavity part 24 of the hollow floor slab 16 are formed in the longitudinal direction of the cavity part 24. Next, a foam material M is injected from a nozzle 30 inserted into the through hole 28 toward one side in the longitudinal direction in the cavity part 24. Repeatedly, the foam material M is ejected in one direction in the length direction in the cavity part 24 from a nozzle 30 inserted into another through hole 28 located at the other side in the length direction in the cavity part 24 than in the previous through hole 28. Thus, the cavity part 24 is filled with the foam F obtained by foaming the foam material M to repair the hollow floor slab 16.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a method for repairing a hollow deck in a bridge and to a hollow deck. [Background technology]

[0002] Hollow decks are widely used in bridges because they are lightweight. By pouring concrete into a large number of cylindrical formwork, a cylindrical cavity is formed inside the concrete of the hollow deck.

[0003] In hollow slabs, the concrete above the cavity may lack strength due to construction issues such as improper installation of the cylindrical formwork or improper filling of the concrete. Furthermore, the asphalt or other paving surfaces installed on the hollow slab are replaced periodically. During replacement, the concrete above the cavity is scraped away, reducing the concrete's strength. In such cases, the hollow slab must be repaired.

[0004] One proposed method for repairing hollow decks involves drilling multiple filling holes along the longitudinal direction of the hollow section of the hollow deck, from the upper pavement surface downward toward the hollow section, inserting a static mixer through these holes, and allowing urethane liquid to drip from the static mixer (see Patent Document 1). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-84459 Summary of the Invention [Problem to be solved by the invention]

[0006] In the method of Patent Document 1, the foam is filled from around the static mixer, so the static mixer adheres to the foam, and the static mixer must be cut off and left inside the foam. As a result, foreign matter remains inside the foam, which can deteriorate the quality.

[0007] The present invention has been proposed in consideration of the above-mentioned problems associated with the conventional technology in order to solve them in an appropriate manner, and aims to provide a high-quality hollow deck repair method and hollow deck. [Means for solving the problem]

[0008] In order to overcome the above problems and achieve the intended purpose, the hollow deck repair method according to the present invention comprises: A plurality of through holes leading to a hollow portion of the hollow deck of the bridge are formed in the longitudinal direction of the hollow portion, A foam material is sprayed from a nozzle inserted into the through hole toward one longitudinal direction of the hollow portion; a nozzle inserted into a through-hole positioned on the other side of the cavity in the longitudinal direction of the cavity, the nozzle injecting a foam material toward one side of the cavity in the longitudinal direction; The gist is that the hollow portion is filled with a foam obtained by foaming the foam material.

[0009] In order to overcome the above problems and achieve the intended purpose, the hollow deck slab according to the present invention is A cover portion that closes a through hole leading to a hollow portion of a hollow deck in a bridge; a foam filled in the hollow portion and the through hole, The gist is that the nozzle for supplying the foam does not remain in the hollow deck. [Effects of the Invention]

[0010] According to the hollow deck slab repair method of the present invention, quality can be improved. The hollow deck slab according to the present invention is of good quality. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a cross-sectional view showing a hollow deck according to an embodiment of the present invention. [Figure 2] FIG. 2 is a partially cutaway perspective view of the hollow deck of the embodiment. [Figure 3] FIG. 10 is an explanatory diagram showing the repair process of the embodiment. [Figure 4] FIG. 10 is an explanatory diagram showing the repair process of the embodiment. [Figure 5] FIG. 10 is an explanatory diagram showing the repair process of the embodiment. [Figure 6] FIG. 10 is an explanatory diagram showing the repair process of the embodiment. [Figure 7] FIG. 10 is an explanatory diagram showing the repair process of the embodiment. [Figure 8] FIG. 10 is an explanatory diagram showing the repair process of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Next, a method for reinforcing a hollow deck and a hollow deck according to the present invention will be described below with reference to preferred embodiments and the accompanying drawings. In the following description, the direction of the road width in a bridge is referred to as the lateral direction, and the direction in which the road extends in a bridge is referred to as the longitudinal direction. [Example]

[0013] The bridge 10 shown in Figures 1 and 2 is an example of an RC (reinforced concrete) deck bridge spanning a river flowing through a mountain valley. The bridge 10 includes a hollow deck 16 mounted on main girders 14 supported by piers 12 (which may be abutments) rising from the ground. The main girders 14 are arranged in parallel and spaced apart laterally across the bridge 10. Cross girders (not shown) extend laterally between adjacent main girders 14. The main girders 14 and cross girders are typically made of concrete or steel, but in the example, H-shaped steel is used. A road surface 20 made of asphalt or the like is provided on the upper surface of the hollow deck 16. Fall prevention measures, such as side walls and parapets 22 (in the example), are provided on the side edges of the hollow deck 16.

[0014] As shown in Figures 1 and 2, the hollow deck 16 has a cavity 24 formed by a cylindrical formwork. In the hollow deck 16 of the embodiment, multiple longitudinally extending cavities 24 are arranged side by side. The cavity 24 after repair, as described below, is filled with a foam F. As the foam F, polyurethane foam, olefin foam such as polyethylene or polypropylene, or polystyrene foam can be used alone or in combination, with rigid foams having high compressive strength being preferred. Furthermore, a closed-cell structure is preferred as the cell structure of the foam F because it is watertight. From the standpoint of economy and other factors, it is preferable to use a so-called foamed-in-place polyurethane foam, in which polyurethane foam is formed on-site by mixing liquid A (polyol) and liquid B (isocyanate).

[0015] The foam F has a density of, for example, 20 kg / m 3 ~60kg / m 3 It is preferable to use a lightweight foam within the range of 1.0 to 1.5 times the compressive strength of the foam F. In addition, it is preferable that the foam F has a high compressive strength, since this allows the hollow deck slab 16 to be reinforced after repair.

[0016] 3 to 8, a method for repairing a hollow deck 16 in which foam F is filled into the cavity 24 will be described. First, the reinforced concrete 26 surrounding the cavity 24 in the hollow deck 16 is drilled using a drill bit, core drill, or the like to form through-holes 28 that lead from the surface of the hollow deck 16 to the cavity 24. The through-holes 28 may be formed in the vertical direction from the top surface of the hollow deck 16 or in the horizontal direction from the side surface of the hollow deck 16. However, in the embodiment, the through-holes 28 are formed so as to penetrate the reinforced concrete 26 in the vertical direction from the bottom surface of the hollow deck 16 to the cavity 24. Forming the through-holes 28 from the bottom surface of the hollow deck 16, as in the embodiment, is preferable because it eliminates the need to excavate the pavement of the road surface 20 and reduces the impact on traffic.

[0017] The size of the through holes 28 need only be such that a nozzle 30 (FIG. 3(c)) for injecting the foam material M can pass through them, and the through holes 28 can have a diameter of, for example, about 32 mm. Furthermore, the size of the through holes 28 is preferably smaller than the reinforcing bar pitch of the reinforced concrete 26. If the through holes 28 are smaller than the reinforcing bar pitch of the reinforced concrete 26, cutting of the rebar during the formation of the through holes 28 can be reduced.

[0018] As shown in FIG. 3(b), a plurality of through holes 28 are formed spaced apart in the longitudinal direction of the cavity 24. In the following description, one longitudinal side of the cavity 24 is referred to as the "front," and the other longitudinal side of the cavity 24 is referred to as the "rear." In the embodiment, filling of the foam F begins from the front side of the cavity 24 and ends at a position in the cavity 24 that is rearward of the filling start position (see FIGS. 4 to 7). The filling start position of the foam F is not limited to the closed end of the cavity 24, and may be set at a location in the hollow deck 16 that requires repair, such as a midpoint in the cavity 24.

[0019] In this embodiment, in addition to the foam material supply holes 28 (referred to as supply holes 28A1-28A4 when specifically distinguished), confirmation holes 28 (referred to as confirmation holes 28B when specifically distinguished) are formed corresponding to the front and rear sides of the cavity 24. The spacing between the supply holes 28A1-28A4 is not particularly limited, but can be set to, for example, approximately 1.5 m to 3.0 m. The spacing between the supply holes 28A1-28A4 can be set in relation to the fluidity of the foam F (foam material M), the amount and filling speed of the foam material M, and the like. For example, if the foam F has fluidity in relation to the amount and filling speed of the foam material M, such that the foam material M expands approximately 2 m from the time it is sprayed until it foams and solidifies, the spacing between the supply holes 28A1-28A4 should be approximately 2 m. Furthermore, the first supply hole 28A1 located at the frontmost side in the hollow portion 24 may be provided approximately 2 m behind the position where the filling of the foam F in the hollow portion 24 starts.

[0020] Nozzle 30 is inserted through first supply hole 28A1, which is located at the frontmost side of cavity 24, and the tip of nozzle 30 is placed inside cavity 24. Foam material M is sprayed toward the front side of cavity 24 from nozzle 30, which is connected to a supply device (not shown) via a hose (see FIG. 4(a)). At this time, the spray position of foam material M may be changed in stages so that foam material M is sprayed far from first supply hole 28A1 through which nozzle 30 passes (a position far from nozzle 30) and then sprayed near first supply hole 28A1 through which nozzle 30 passes (a position close to nozzle 30).

[0021] The nozzle 30 can spray the foam material M in a direction (one of the longitudinal directions) intersecting the penetration direction of the through-hole 28, for example, by having a hook-shaped tip (in the embodiment) or by providing a horizontal spray hole. The supply of the foam material M to the cavity 24 is sufficient as long as it can spray the foam material M at a distance from the through-hole 28 through the nozzle 30. A method that can spray the foam material M farther than the fluidity of the foam F (approximately 2 m in the embodiment) is preferred. For example, an impingement mixing method can be used, which can spray the liquid foam material M obtained by impinging and mixing the base agent and the curing agent under high pressure in the nozzle 30. The foam material M can be sprayed continuously or intermittently from the nozzle 30, but intermittent spraying of the foam material M is preferred because it is less likely to cause workplace problems such as dripping of the foam material M.

[0022] The foam material M injected into the cavity 24 foams and expands, filling the cavity 24 from the front side with foam F (see FIG. 4(b)). At this time, excess air can be released through the confirmation hole 28B located in front of the first supply hole 28A1 through which the nozzle 30 passes. The degree of filling with foam F can also be confirmed through the confirmation hole 28B. For example, the degree of filling with foam F can be easily confirmed visually by checking whether foam F enters the confirmation hole 28B or whether foam F leaks out from the confirmation hole 28B. After a predetermined amount of foam material M is injected, the nozzle 30 is removed from the first supply hole 28A1 (see FIG. 4(c)). It is recommended that the nozzle 30 be retracted from the cavity 24 before the foam F reaches the first supply hole 28A1. Since the size of the cavity 24 is known, the amount of foam material M to be supplied and the timing at which the foam F reaches the first supply hole 28A1 can be easily calculated.

[0023] Next, the nozzle 30 is inserted through the second supply hole 28A2 located behind the first supply hole 28A1, and the tip of the nozzle 30 is inserted inside the cavity 24. The foam material M is sprayed from the nozzle 30 toward the front of the cavity 24 (see FIG. 5(a)). The sprayed foam material M expands and fills the cavity 24 from the front, following the foam F previously filled (see FIG. 5(a)). At this time, excess air can be released through the first supply hole 28A1 located in front of the second supply hole 28A2 through which the nozzle 30 passed. The degree of filling with foam F can also be confirmed through the first supply hole 28A1. After a predetermined amount of foam material M has been sprayed, the nozzle 30 is removed from the second supply hole 28A2 (see FIG. 5(b)).

[0024] In this manner, the nozzles 30 are inserted into the supply holes 28A1-28A4 in order, and the foam material M is sprayed toward the front of the cavity 24 from the nozzles 30 inserted into each of the supply holes 28A1-28A4 (see FIGS. 4-7(a)). As a result, the foam material M sprayed into the cavity 24 foams and expands, filling the cavity 24 sequentially from the front with foam F. At this time, excess air can be released through the confirmation hole 28B located behind the fourth supply hole 28A4 through which the nozzle 30 passed. After a predetermined amount of foam material M is sprayed from the nozzle 30 inserted into the cavity 24 from the fourth supply hole 28A4, the nozzle 30 is removed from the fourth supply hole 28A4 (see FIG. 7(b)). It can be confirmed that the hollow portion 24 has been filled with foam F by the foam F entering the fourth supply hole 28A4 and the confirmation hole 28B located behind the fourth supply hole 28A4, or by the foam F leaking out from the confirmation hole 28B.

[0025] Next, any foam F that has leaked out through the through holes 28 is removed. Then, the through holes 28 are closed with the lids 32 (see FIG. 8). The lids 32 are preferably made of a material that can eliminate factors that adversely affect the foam F, such as light and water. The lids 32 may be made of, for example, a coating of resin applied to the foam F exposed in the through holes 28, mortar or a sealant that closes the through holes 28, or a resin or metal member attached to the through holes 28, either alone or in combination.

[0026] In the repair method described above, the foam material M is sprayed forward from the nozzle 30 inserted into the supply holes 28A1-28A4 by sequentially shifting the insertion positions of the supply holes 28A1-28A4 toward the rear. This allows the foam F to be filled sequentially from the front to the rear of the cavity 24, thereby reducing the likelihood of air pockets forming in the cavity 24 after repair. Since air pockets are thus less likely to form in the foam F of the hollow deck 16, the quality of the hollow deck 16 can be improved. Furthermore, since it is only necessary to form relatively small holes 28 large enough for the nozzle 30 to pass through, the impact on the reinforced concrete 26 that constitutes the hollow deck 16 can be minimized. Furthermore, this method avoids large-scale repair work, simplifies restoration work on the holes 28 after repair, and allows repairs to be completed in a short period of time. Furthermore, because the nozzle 30 is removed before the foam F reaches the nozzle 30, adhesion between the nozzle 30 and the foam F can be avoided, and there is no need to leave the nozzle 30 in the foam F. In this way, the nozzle 30, which would become a foreign object, does not remain in the foam F of the hollow deck 16, and the quality of the hollow deck 16 can be improved.

[0027] In the repair method described above, the foam material M is foamed and solidified inside the cavity 24 to form the foam F, and therefore the adhesive force specific to the foam F acts between the wall surface of the cavity 24 and the foam F. In this way, the foam F is firmly adhered to the wall surface of the cavity 24, and the hollow deck slab 16 can be reinforced by the foam F.

[0028] As described above, the supply of foam material M begins from first supply hole 28A1, which is located rearward of confirmation hole 28B, which is located at the front of hollow portion 24. In this way, by starting the supply of foam material M from first supply hole 28A1, which is located on the other side of the length of hollow portion 24 than confirmation hole 28B, which is located at the farthest end on one side of the length of hollow portion 24, air can be released from confirmation hole 28B when filling with foam F, and the degree of filling with foam F can be easily confirmed by confirmation hole 28B.

[0029] By changing the position where the foam material M is sprayed from a position far from the nozzle 30 to a position close to the nozzle 30, the foam F can be filled in order from the front side to the rear side of the cavity 24.

[0030] As described above, the supply of foam material M is terminated at fourth supply hole 28A4, which is located forward of confirmation hole 28B, which is located at the rear of hollow portion 24. In this way, by terminating the supply of foam material M at fourth supply hole 28A4, which is located on one side of confirmation hole 28B, which is located at the end furthest on the other side of the length of hollow portion 24, air can be released through confirmation hole 28B when filling with foam F, and the degree of filling with foam F can be easily confirmed through confirmation hole 28B.

[0031] By repairing as described above, the hollow deck 16 has a cover 32 that closes the through hole 28 leading to the cavity 24 of the hollow deck 16, and foam F filled into some or all of the cavity 24 and the through hole 28. Furthermore, the nozzle 30 that supplies the foam F does not remain in the hollow deck 16. In this way, since the nozzle 30, which would be a foreign object, does not remain in the foam F of the hollow deck 16, the quality of the hollow deck 16 can be improved. Furthermore, as described above, air pockets are unlikely to form in the cavity 24 filled with foam F, and the cavity 24 is appropriately filled with foam F, so the foam F effectively provides functions such as reinforcement, which also improves the quality of the hollow deck 16.

[0032] (Example of change) The present invention is not limited to the above-mentioned items, but may be, for example, as follows: Note that the present invention is not limited to the specific descriptions of the examples and the following modified examples. (1) In the embodiment, confirmation holes are provided on both sides of the hollow portion in the longitudinal direction, but this is not limitative, and one or both of the confirmation holes may be omitted. (2) The foam material may be sprayed using a spray gun. [Explanation of symbols]

[0033] 10 Bridge, 16 Hollow deck, 24 Cavity, 28 Through hole, 30 Nozzle, 32 Cover, M Foam material, F Foam

Claims

1. A plurality of through holes leading to a hollow portion of the hollow deck of the bridge are formed in the longitudinal direction of the hollow portion, A foam material is sprayed from a nozzle inserted into the through hole toward one longitudinal direction of the hollow portion; a nozzle inserted into a through-hole positioned on the other side of the cavity in the longitudinal direction of the cavity, the nozzle injecting a foam material toward one side of the cavity in the longitudinal direction; The hollow portion is filled with a foam obtained by foaming the foam material. A method for repairing a hollow deck slab, characterized by:

2. A method for repairing a hollow deck as described in claim 1, in which the supply of the foam material is started from the through hole located on the other side of the length of the hollow portion rather than the through hole located at the end furthest on one side of the length of the hollow portion.

3. 3. A method for repairing a hollow deck according to claim 1 or 2, wherein the position where the foam material is sprayed is changed from a position far from the nozzle to a position close to the nozzle.

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