Bridge structure

Abstract

To improve the durability of bridge slabs.SOLUTION: A bridge structure 10 includes an unbalanced load resistant layer 20 that is disposed under slabs 18 of a bridge 12 on which a road surface 18a is provided. The bridge structure 10 also includes an embankment layer 22 that is disposed under the unbalanced load resistant layer 20 and made of polyurethane foam or air mortar. The unbalanced load resistant layer 20 can consist, for example, of inorganic fiber layers such as carbon fiber, glass fiber, or metal fiber, or metal layers such as steel, stainless steel, or aluminum.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bridge structure. [Background technology]

[0002] Bridges sometimes require repairs to their decks due to deterioration over time. For example, in the case of hollow decks with hollow spaces, it has been proposed to repair them by filling the hollow spaces with a filler material (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-84459 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, since the repair method of Patent Document 1 cannot be applied to decks with structures different from hollow decks, another method for improving the durability of decks is required.

[0005] The present invention has been proposed in view of the above-mentioned problems associated with the conventional technology, and aims to provide a bridge structure equipped with a deck with improved durability. [Means for solving the problem]

[0006] A first aspect of the bridge structure according to the present invention is a biased load-resistant layer disposed under a deck on which a road surface is provided in the bridge; and a fill layer arranged below the biased load-resistant layer and made of polyurethane foam or air mortar.

[0007] A second aspect of the bridge structure according to the present invention is the bridge structure according to the first aspect, The offset load resistant layer may be joined to the underside of the deck.

[0008] A third aspect of the bridge structure according to the present invention is the first or second aspect, The offset load resistant layer may have a tensile strength in a direction along the lower surface of the deck greater than that of the embankment layer.

[0009] A fourth aspect of the bridge structure according to the present invention is any one of the first aspect, the second aspect, or the third aspect, The uneven load resistant layer may be an inorganic fiber layer or a metal layer. Effect of the Invention

[0010] According to the bridge structure of the present invention, the durability of the deck is improved. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is an explanatory diagram showing a bridge structure according to an embodiment of the present invention. [Diagram 2] FIG. 2 is an explanatory diagram showing a main part of the bridge structure of the embodiment. [Diagram 3] FIG. 2 is an explanatory diagram showing a manufacturing process of the bridge structure of the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, a bridge structure according to the present invention will be described below by way of a preferred embodiment with reference to the accompanying drawings. Note that the embodiments and drawings described below are intended to exemplify a portion of the embodiment of the present invention, and are not intended to be used for the purpose of limiting the present invention to these configurations, and may be modified as appropriate within the scope of the present invention. EXAMPLES

[0013] As shown in FIG. 1, a bridge structure 10 according to the embodiment includes a bridge 12, an unbalanced load resistant layer 20 disposed under a deck 18, and an embankment layer 22 disposed under the unbalanced load resistant layer 20. The bridge 12 of the bridge structure 10 includes a substructure 14 that is a structure supported on the ground such as a pier or abutment, and a deck 18 supported on the substructure 14 via a bridge girder 16. The substructure 14, the deck 18, and the bridge girder 16 are formed of, for example, concrete. The deck 18 includes a road surface 18a. The road surface 18a is a part of a road on which vehicles such as automobiles pass. However, the present invention is not limited to this, and may be applied to other uses, such as a part of a track on which railway vehicles such as trains pass over the road surface 18a.

[0014] The unbalanced load resistant layer 20 is a layer that reinforces the deck 18 in response to a load (hereinafter referred to as an unbalanced load) locally applied from a vehicle traveling on the road surface 18a. An example of an unbalanced load is a vertical load applied to the road surface 18a through one wheel of a vehicle, and is sometimes called a "wheel load". The unbalanced load resistant layer 20 is preferably joined to the lower surface of the deck 18, and directly joining the deck 18 can improve the reinforcing effect of the deck 18 by the unbalanced load resistant layer 20. It is preferable that the entire unbalanced load resistant layer 20 is joined to the deck 18, but this is not limited thereto. For example, a part of the unbalanced load resistant layer 20 may be joined to the deck 18 and the remaining part of the unbalanced load resistant layer 20 may be disposed away from the deck 18, or the deck 18 may be reinforced by the unbalanced load resistant layer 20 via a layer (e.g., a bridge girder 16) disposed between the deck 18 and the unbalanced load resistant layer 20.

[0015] The uneven load resistant layer 20 is preferably disposed over the entire lower surface of the deck 18 (see FIG. 2(a)). This is not limiting, and the uneven load resistant layer 20 may be disposed over only a portion of the lower surface of the deck 18. The uneven load resistant layer 20 is preferably disposed in a concave-convex shape that follows the concave-convex shape of the beams 19 on the lower surface of the deck 18 (see FIG. 2(b)). Furthermore, when the lower surface of the deck 18 has an uneven shape such as the beams 19, the uneven load resistant layer 20 may be disposed in a concave portion of the lower surface of the deck 18 (see FIG. 2(c)), or may be disposed between the beams 19 (convex portions) on the lower surface of the deck 18 (see FIG. 2(d)). The uneven load resistant layer 20 may be disposed under not only the deck 18 but also the deck 18 and the bridge girder 16. The beams 19 may be a structure included in a part of the deck 18, or the beams 19 and the deck 18 may be separate structures.

[0016] It is preferable that the uneven load resistant layer 20 has excellent tensile strength in the direction along the underside of the deck slab 18 (hereinafter referred to as the planar direction). Here, it is preferable that the tensile strength of the uneven load resistant layer 20 in the planar direction is greater than that of the embankment layer 22. In this way, if the tensile strength in the planar direction of the uneven load resistant layer 20 is greater than the tensile strength in the planar direction of the embankment layer 22, the uneven load applied from the deck slab 18 can be appropriately distributed to the embankment layer 22. The thickness of the uneven load resistant layer 20 is not particularly limited, but it is preferable to set the thickness to the minimum thickness that ensures a tensile strength sufficient to reinforce the deck slab 18, as this will reduce the weight.

[0017] Examples of the uneven load resistant layer 20 include single or composite inorganic fibers (including inorganic fillers of short fibers such as needle-shaped fibers) such as carbon fibers, silicon carbide fibers, vinylon, polyamide fibers, aramid fibers, polyester fibers, urethane fibers, olefin fibers, rayon fibers, PBO (poly-p-phenylene benzobisoxazole) fibers, glass fibers, and metal fibers, organic fibers such as cellulose (including organic fillers of short fibers such as needle-shaped fibers), and composites of inorganic fibers or organic fibers and synthetic resins such as CFRP (carbon fiber reinforced plastic) and FRP (fiberglass reinforced plastic). The inorganic fibers and organic fibers may be either woven or nonwoven. Organic materials such as bamboo and cotton may be used for the uneven load resistant layer 20. The uneven load resistant layer 20 may be made of metal such as steel, stainless steel, or aluminum, resin such as polycarbonate or vinyl chloride, or rubber such as NBR (nitrile rubber), CR (chloroprene rubber), EPT (ethylene propylene rubber), SBR (styrene butadiene rubber), FR (fluororubber), SR (silicon rubber), or urethane rubber. The uneven load resistant layer 20 may be made of synthetic resin such as urethane resin or silicone resin. The uneven load resistant layer 20 may be made of a combination of two or more materials, not limited to one material. In particular, when the uneven load resistant layer 20 is an inorganic fiber layer, the tensile strength is excellent, so that the deck slab 18 can be appropriately reinforced, and the weight of the bridge 12 is light, so that an excessive weight increase can be suppressed. When the uneven load resistant layer 20 is a metal layer, the tensile strength is excellent, so that the deck slab 18 can be appropriately reinforced.

[0018] The uneven load resistant layer 20 may be in the form of, for example, a sheet, a net, a plate, a coating, etc. The method of joining the uneven load resistant layer 20 to the deck slab 18 may be, for example, chemical joining using an adhesive or its own adhesiveness, or mechanical joining using bolts or anchors, etc., and may be appropriately selected depending on the constituent material and form of the uneven load resistant layer 20.

[0019] It is preferable that the uneven load resistant layer 20 has good durability such as a long life against repeated uneven loads. In addition, since the uneven load resistant layer 20 may come into contact with water or oil that seeps out from cracks in the deck, it is preferable that the uneven load resistant layer 20 has good water resistance and oil resistance.

[0020] The embankment layer 22 should preferably have a smaller specific gravity than soil. The embankment layer 22 can be made of, for example, polyurethane foam or air mortar. In the case of polyurethane foam, for example, in-situ foamed polyurethane foam that is foamed and hardened at the construction site can be used. Air mortar is a mixture of raw soil (sandy soil), cement, water, and air bubbles, or a mixture of cement, water, and air bubbles, and is also called air-foamed lightweight embankment (FCB). Among these, in-situ foamed polyurethane foam is suitable from the viewpoints of light weight, workability, adhesiveness to the substructure 14, etc. It is preferable that the uneven load resistant layer 20 and the embankment layer 22 are bonded. For example, if polyurethane foam is used as the embankment layer 22, the adhesiveness of the polyurethane foam itself allows the embankment layer 22 and the uneven load resistant layer 20 to be bonded together.

[0021] The bridge structure 10 described above can be manufactured, for example, as follows. There is a bridge 12, which is a bridge on which vehicles can pass over a deck 18. In the bridge 12, a space is provided below the deck 18 supported by the substructure 14. First, an embankment layer 22 is formed in the space below the deck 18 (see FIG. 3(a)). For example, if polyurethane foam is used as the embankment layer 22, polyurethane foam is formed by spraying and foaming a mixture of liquid A (polyol) and liquid B (isocyanate) on-site. This spraying work is repeated from the bottom up, filling the underside of the deck 18 with polyurethane foam. After filling the polyurethane foam to a height where the deck 18 can be reached by hand when standing on it, the polyurethane foam is stood on and the uneven load resistant layer 20 is formed below the deck 18 (see FIG. 3(b)). After forming the uneven load resistant layer 20, polyurethane foam is filled below the uneven load resistant layer 20 to form the embankment layer 22 (see FIG. 3(c)). In this way, a bridge structure 10 is obtained that includes the unbalanced load resistant layer 20 disposed under the deck 18 on which the road surface 18a of the bridge 12 is provided, and the embankment layer 22 disposed under the unbalanced load resistant layer 20. In this manner, the manufacturing method for the bridge structure 10 includes the step of providing the unbalanced load resistant layer 20 under the deck 18 on which the road surface 18a of the bridge 12 is provided, and the step of providing the embankment layer 22 by using polyurethane foam or air mortar to overlap the underside of the unbalanced load resistant layer 20.

[0022] In the above-mentioned manufacturing method, the case where the unbalanced load resistant layer 20 and the embankment layer 22 are formed on the existing bridge 12 has been described, but the unbalanced load resistant layer 20 and the embankment layer 22 may be formed when a new bridge 12 is constructed. Also, the unbalanced load resistant layer 20 may be formed first, and the embankment layer 22 may be formed later.

[0023] In the bridge structure 10 of the present disclosure, when an unbalanced load is locally applied to the deck 18 by a vehicle traveling on the road surface 18a, the deck 18 is supported by the tension of the unbalanced load resistant layer 20 arranged under the deck 18. The load can be distributed from the unbalanced load resistant layer 20 to the embankment layer 22. By forming the bridge structure 10, compared to a new deck 18 or a reinforcement material being attached to the deck 18, there is no closure of vehicles or the period of closure is short, the construction period for reinforcing the deck 18 is short, and the cost of repairing the bridge 12 can be made very low. In addition, since large heavy machinery is not required to form the embankment layer 22, the bridge structure 10 can be constructed even in a place where it is difficult for large vehicles to enter. In particular, if the embankment layer 22 is an in-situ foamed polyurethane foam, the embankment layer 22 will adhere to the substructure 14 and the unbalanced load resistant layer 20 due to the adhesiveness peculiar to the polyurethane foam. As a result, the load applied to the embankment layer 22 from the road surface 18a via the uneven load resistant layer 20 can be distributed to the substructures 14, 14 standing on the left and right, and by supporting the load of the road surface 18a integrally by the embankment layer 22 and the substructure 14, deformation of the embankment layer 22 can be suppressed and the deck slab 18 can be properly supported.

[0024] In the above-mentioned example, the unbalanced load resistant layer 20 is disposed only on the underside of the deck 18, but the unbalanced load resistant layer 20 may be disposed on the upper side of the deck 18. In this case, the unbalanced load resistant layer 20 may be disposed between the deck 18 and the pavement such as asphalt that constitutes the road surface 18a. [Explanation of symbols]

[0025] 12 Bridge, 18 Deck, 18a Road surface, 20 Uneven load-bearing layer, 22 Embankment layer

Claims

1. a biased load-resistant layer disposed under a deck on which a road surface is provided in the bridge; and a fill layer arranged below the unbalanced load-resistant layer and made of polyurethane foam or air mortar. A bridge structure comprising:

2. The bridge structure according to claim 1 , wherein the offset load resistant layer is joined to the underside of the deck.

3. The bridge structure according to claim 1 , wherein the offset load resistant layer has a tensile strength in a direction along the lower surface of the deck that is greater than that of the embankment layer.

4. The bridge structure according to claim 1 , wherein the uneven load resistant layer is an inorganic fiber layer or a metal layer.

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