Bridge structures and concrete deck replacement methods

Abstract

To enable a concrete floor slab cut and separated from a steel girder to be used for a fixed period by connecting the concrete floor slab and the steel girder of a bridge without damaging the steel girder even after the concrete floor slab and the steel girder are cut and separated.SOLUTION: A bridge structure has a concrete floor slab 104, a steel girder 102 supporting the concrete floor slab 104 from below, and continuous fibers connecting the concrete floor slab 104 to the steel girder 102. The continuous fibers are attached by adhesion to the steel girder 102.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a bridge structure and a concrete deck replacement method, and more particularly to a bridge structure and a concrete deck replacement method that can be suitably used when replacing an existing concrete deck. The bridge structure according to the present invention has a structure for connecting the concrete deck to a steel girder. [Background technology]

[0002] Bridge decks are components that directly support the load of vehicles passing over the bridge, and damage to them due to deterioration over time as bridges age is becoming a problem, leading to an increasing number of cases where existing concrete decks are being replaced with new decks.

[0003] On the other hand, when replacing the existing concrete deck, temporary traffic restrictions are required on the bridge surface, which has an impact on traffic, so shortening the period of traffic restrictions is an issue. In particular, in composite girder bridges, where headed studs or other anti-slip devices are placed on the upper flange of the main girder to join the upper flange of the main girder to the existing concrete deck, it is difficult to easily separate the main girder from the existing concrete deck, and removing the existing concrete deck is time-consuming, making it difficult to shorten the period of traffic restrictions when replacing the existing concrete deck with a new one.

[0004] In response to this, Patent Document 1 describes a technology for recombining the separated steel main girder and concrete slab by cutting the joint between the concrete slab and the steel main girder of a bridge, installing a space-retaining material in the gap that results at the joint, installing post-installed anchors in the concrete slab, installing fastening materials in the main girder, and joining the separated concrete slab and main girder with a combining jig via the post-installed anchors and fastening materials.The technology describes that, because it is possible to form a combined structure of the separated concrete slab and main girder behind the work of cutting the joint while performing the work, it is possible to ensure a period of traffic freedom on the bridge between the time when the concrete slab is cut and separated from the main girder and when it is removed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-25288 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the technology described in Patent Document 1 requires fastening materials to be fixed to the steel main girders by welding or mechanical joining. In the case of welding, welding heat is applied to the steel main girders, causing partial melting of the base material, which can damage the steel main girders. In the case of mechanical joining, through holes must be formed in the webs of the steel main girders, which can also damage the steel main girders.

[0007] The present invention has been made in consideration of the above points, and aims to provide a bridge structure and a concrete deck replacement method that enables the concrete deck that has been cut and separated from the steel girders to be used for a certain period of time by connecting the two without damaging the steel girders, even after the concrete deck and steel girders of the bridge have been cut and separated. [Means for solving the problem]

[0008] The present invention is an invention that solves the above-mentioned problems, and is a bridge structure and a concrete deck replacement method as described below.

[0009] That is, one aspect of the bridge structure according to the present invention is a bridge structure having a concrete deck, steel girders supporting the concrete deck from below, and continuous fibers connecting the concrete deck to the steel girders, wherein the continuous fibers are attached to the steel girders by adhesive.

[0010] Here, "the continuous fiber is attached to the steel girder by adhesive" means that the continuous fiber is connected and fixed to the steel girder only by adhesive, and that there is no part of the continuous fiber that is connected and fixed to the steel girder in any other manner of attachment (for example, mechanical joints such as bolt joints, or welded joints, etc.).

[0011] The continuous fibers may be attached to the underside of the upper flange of the steel girder by adhesive.

[0012] The continuous fibers may be attached to the concrete slab by adhesive.

[0013] The continuous fibers may be fixed to the concrete slab with anchors.

[0014] A portion of the underside of the concrete deck may be formed by a cut surface cut by a wire saw or a wall saw.

[0015] A vertical load transfer member that transfers vertical load from the concrete deck to the steel girder may be arranged in the gap between the underside of the concrete deck and the upper flange of the steel girder.

[0016] The vertical load transfer member may be made of grout material.

[0017] The continuous fibers may be arranged in a sheet-like member with their longitudinal directions aligned in a substantially uniform direction.

[0018] The continuous fibers may be woven into a fabric to form a sheet-like member.

[0019] The sheet-like members may be arranged closely packed in the longitudinal direction of the steel girder without any gaps.

[0020] The sheet-like member may have a predetermined width in the longitudinal direction of the steel girder, and the sheet-like members having the predetermined width may be arranged at a predetermined interval in the longitudinal direction of the steel girder.

[0021] The continuous fibers may be configured such that the central portion in the longitudinal direction is bundled to form a rod shape, and both ends in the longitudinal direction are not bundled but are open fiber portions that can be spread out into a fan shape, and each of the open fiber portions at both ends in the longitudinal direction of the continuous fibers is attached to the concrete deck and the steel girder by adhesive.

[0022] The continuous fibers may be at least one of carbon fibers, aramid fibers, and glass fibers.

[0023] The continuous fibers may be aramid fibers, and the aramid fibers may be configured such that at least a portion of the longitudinal range is not impregnated with resin, and both longitudinal ends thereof are attached to the concrete deck and the steel girder by adhesive.

[0024] The continuous fibers may be bonded using an epoxy resin adhesive or an acrylic resin adhesive.

[0025] One aspect of the concrete deck replacement method of the present invention comprises a separation process in which a portion of an existing concrete deck in a bridge near a steel girder is cut approximately horizontally to separate the existing concrete deck from the steel girder; a replacement process in which the existing concrete deck separated in the separation process is removed and replaced with a new concrete deck; and a connection process in which, between the separation process and the start of the replacement process, the existing concrete deck separated in the separation process is connected to the steel girder, wherein in the connection process, the existing concrete deck and the steel girder are connected by continuous fibers, and the continuous fibers are attached to the steel girder by adhesive.

[0026] The connecting process may include a vertical load transmission member placement process for placing a vertical load transmission member in the gap between the cut surface of the existing concrete deck formed in the separating process and the upper surface of the upper flange of the steel girder.

[0027] The vertical load transfer member may be made of grout material.

[0028] The replacement step may include a disconnection step of disconnecting the connection between the existing concrete deck and the steel girder made in the connection step.

[0029] The cutting step may be a step of peeling the continuous fibers adhered to the steel girder in the connecting step from the existing concrete slab or the steel girder.

[0030] The dividing step may be a step of cutting the continuous fibers connected in the connecting step.

[0031] The separating step and the connecting step may be performed alternately at predetermined distances in the bridge axis direction of the bridge.

[0032] The separating step may be carried out at one portion of the bridge, and at the same time, the connecting step may be carried out at another portion of the bridge adjacent to the one portion in the bridge axis direction of the bridge.

[0033] Here, "another part of the bridge adjacent to the one part in the bridge axis direction" refers to a part that is a certain distance away from the one part in the bridge axis direction, to an extent that it does not affect the implementation of the separation process at the one part of the bridge.

[0034] After the connecting step and before the replacing step, a passing step may be provided in which a vehicle passes over the existing concrete deck slab separated in the separating step. [Effects of the Invention]

[0035] According to the present invention, it is possible to provide a bridge structure and a concrete deck replacement method that make it possible to use the concrete deck that has been cut and separated from the steel girders for a certain period of time by connecting the two without damaging the steel girders even after the concrete deck and steel girders of the bridge have been cut and separated. [Brief explanation of the drawings]

[0036] [Figure 1] FIG. 1 is a vertical cross-sectional view of a bridge structure 10 according to a first embodiment of the present invention, viewed from the bridge axis direction. [Figure 2] 1 is a horizontal cross-sectional view of the bridge structure 10 according to the first embodiment of the present invention, viewed from below (cross-sectional view taken along line II-II in FIG. 1). [Figure 3] 1 is a vertical cross-sectional view of a bridge structure 20 according to a second embodiment of the present invention, viewed from the bridge axis direction. [Figure 4] 1 is a horizontal cross-sectional view of a bridge structure 30 according to a third embodiment of the present invention, viewed from below (a horizontal cross-sectional view of a cross-section at a position similar to the cross-section along line II-II in FIG. 1, viewed from below). [Figure 5] 1 is a horizontal cross-sectional view of a bridge structure 40 according to a fourth embodiment of the present invention, viewed from below (a horizontal cross-sectional view of a cross-section at a position similar to the cross-section along line II-II in FIG. 1, viewed from below). [Figure 6] 10 is a vertical cross-sectional view of a bridge structure 50 according to a fifth embodiment of the present invention, viewed from the bridge axis direction. [Figure 7] 10 is a horizontal cross-sectional view of a bridge structure 60 according to a sixth embodiment of the present invention, viewed from below (a horizontal cross-sectional view of a cross-section at a position similar to the cross-section along line II-II in FIG. 1, viewed from below). [Figure 8] 1 is an enlarged plan view schematically showing a continuous fiber fixing member 62. [Figure 9] 10 is a vertical cross-sectional view of a bridge structure 60 according to a sixth embodiment of the present invention, viewed from the bridge axis direction. [Figure 10] 10 is a horizontal cross-sectional view of a bridge structure 70 according to a seventh embodiment of the present invention, viewed from below (a horizontal cross-sectional view of a cross-section at a position similar to the cross-section along line II-II in FIG. 1, viewed from below). [Figure 11]1 is a vertical cross-sectional view of a bridge 100 to which a concrete deck replacement method using a bridge structure 10 according to a first embodiment is applied, taken in a direction perpendicular to the bridge axis. [Figure 12] A vertical cross-sectional view of the bridge 100 in a direction perpendicular to the bridge axis with the wire saw 200 installed. [Figure 13] Vertical cross-sectional view of the cutting portion above the upper flange 102A of the steel main girder 102 during cutting [Figure 14] A vertical cross-sectional view of the cut portion above the upper flange 102A of the steel main girder 102 after cutting is completed [Figure 15] Vertical cross-sectional view of the bridge 100 in the direction perpendicular to the bridge axis after the fixing process is completed [Figure 16] A vertical cross-sectional view of the upper flange 102A of the steel main girder 102 in the direction perpendicular to the bridge axis, with the separated existing concrete deck 104 jacked up after the fixing process is completed. [Figure 17] A vertical cross-sectional view of the upper flange 102A of the steel main girder 102 in the direction perpendicular to the bridge axis when the separated existing concrete deck 104 is jacked up after the fixing process is completed (when the continuous fiber sheet 12 has been fixed using the anchoring mechanism 22). [Figure 18] A vertical cross-sectional view of the upper flange 102A of the steel main girder 102 in the direction perpendicular to the bridge axis after replacement with the new concrete deck 150 DETAILED DESCRIPTION OF THE INVENTION

[0037] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. A bridge 100 to which the embodiment of the present invention is applied is a plate girder bridge in which the cross section of the steel main girders is I-shaped. However, the application of the bridge structure and concrete deck replacement method according to the present invention is not limited to plate girder bridges, and can be applied to any bridge with steel girders, such as a steel box girder bridge.

[0038] (1) First embodiment FIG. 1 is a vertical cross-sectional view of a bridge structure 10 according to a first embodiment of the present invention, as viewed from the bridge axis direction. FIG. 2 is a horizontal cross-sectional view of the bridge structure 10 according to the first embodiment of the present invention, as viewed from below (cross-sectional view taken along line II-II in FIG. 1). In the horizontal cross-sectional view of FIG. 2, the haunch start point 104A of the existing concrete slab 104 is indicated by a two-dot chain line (this also applies to FIGS. 4, 5, 7, and 10, which show other embodiments). In FIG. 2, the location where the existing concrete slab 104 is cut in a direction perpendicular to the bridge axis when removed is indicated by a dashed line, and the cut length of the existing concrete slab 104 in the bridge axis direction when removed is indicated as a (this also applies to FIGS. 4, 5, 7, and 10, which show other embodiments). The cut length a of the existing concrete slab 104 in the bridge axis direction when removed is usually about 2 m.

[0039] The bridge structure 10 according to the first embodiment is a bridge structure having a continuous fiber sheet 12, and is a bridge structure in which a portion of an existing concrete deck 104 near the steel main girder 102 is cut in a substantially horizontal direction to separate the existing concrete deck 104 from the steel main girder 102, and the separated existing concrete deck 104 is connected to the steel main girder 102 by the continuous fiber sheet 12. In this specification, the existing concrete deck 104 of the bridge 100 is designated by reference numeral 104, but the state after the portion of the existing concrete deck 104 near the steel main girder 102 is cut in a substantially horizontal direction to separate it from the steel main girder 102 may be referred to as the "separated existing concrete deck 104" with the addition of the word "separated."

[0040] The continuous fiber sheet 12 is a sheet-shaped member made by arranging continuous fibers with excellent mechanical properties so that their longitudinal direction is in a substantially constant direction. The continuous fiber sheet 12 is bonded to the underside of the upper flange 102A of the steel main girder 102 and the underside of the separated existing concrete deck slab 104 with a resin-based adhesive so as to bridge the two, and the steel main girder 102 and the separated existing concrete deck slab 104 are connected by bonding via the continuous fiber sheet 12. Specifically, for example, an epoxy resin-based adhesive or an acrylic resin-based adhesive can be used to bond the continuous fiber sheet 12.

[0041] Any continuous fiber that can connect the separated existing concrete deck slab 104 separated from the steel main girder 102 to the steel main girder 102, making the separated existing concrete deck slab 104 safe for vehicle traffic, can be used as the continuous fiber of the continuous fiber sheet 12 (however, the continuous fiber is connected to the steel main girder 102 by adhesive). Specific examples of continuous fibers that can be used as the fiber of the continuous fiber sheet 12 include carbon fiber, aramid fiber, and glass fiber.

[0042] The continuous fibers that make up the continuous fiber sheet 12 are arranged so as to intersect at a predetermined angle with respect to the longitudinal direction of the steel main girders 102 when viewed from below, and in the bridge structure 10 according to the present first embodiment, they are arranged so as to intersect at an angle of approximately 90° with respect to the longitudinal direction of the steel main girders 102 when viewed from below. Also, in the bridge structure 10 according to the present first embodiment, the continuous fiber sheets 12 are arranged closely packed with no gaps in the longitudinal direction of the steel main girders 102, as shown in Fig. 2. Here, the longitudinal direction of the steel main girders 102 refers to the direction in which the steel main girders 102 extend, and normally coincides with the bridge axis direction of the bridge 100.

[0043] The bonding length 12A between the underside of the upper flange 102A of the steel main girder 102 and the continuous fiber sheet 12 (the bonding length in the direction perpendicular to the longitudinal direction of the steel main girder 102 (see Figure 1)) is typically about 10 to 20 cm, with a minimum of 10 cm being ensured. Usually, the continuous fiber sheet 12 is attached to the underside of the upper flange 102A up to the edge of the web 102B of the steel main girder 102.

[0044] Furthermore, the bonding length 12B between the underside of the separated existing concrete deck 104 and the continuous fiber sheet 12 (the bonding length in the direction perpendicular to the longitudinal direction of the steel main girder 102 (see Figure 1)) is typically about 20 to 40 cm, with a minimum of 10 cm being ensured. Usually, the continuous fiber sheet 12 is attached to the underside of the separated existing concrete deck 104 up to or near the starting end 104A of the haunch portion on the underside of the separated existing concrete deck 104.

[0045] Then, verification confirms that the continuous fiber sheet 12 attached so as to span the underside of the upper flange 102A of the steel main girder 102 and the underside of the separated existing concrete deck 104 can resist loads that must be taken into consideration for use, such as horizontal loads during earthquakes, wall parapet collision loads (external force perpendicular to the bridge axis), and vehicle braking loads (external force in the bridge axis direction). Also, in order to ensure the composite action of the main girder and deck slab, verification confirms that it can resist the force required for the composite action of the main girder and deck slab.

[0046] The method for cutting the portion of the existing concrete slab 104 near the steel main girder 102 in the approximately horizontal direction is not particularly limited, but is usually performed by cutting in the approximately horizontal direction using a wire saw or a wall saw. In the first embodiment, the description will be given assuming that the portion of the existing concrete slab 104 near the steel main girder 102 is cut in the approximately horizontal direction using a wire saw.

[0047] The outer diameter of the cutting wire 202 (see FIG. 13) of the wire saw 200 (see FIG. 12) is about 10 to 20 mm, and in order to cut without damaging the steel main girder 102, the cutting wire 202 is usually aimed at a position about 20 to 50 mm above the top surface of the upper flange 102A of the steel main girder 102. As a result, residual concrete 104X with a thickness of about 10 to 40 mm remains on the top surface of the upper flange 102A of the steel main girder 102, and a horizontal gap 104Y (see FIGS. 2 and 14) is created between the top flange 102A of the steel main girder 102 and the underside of the separated existing concrete deck 104.

[0048] A vertical load transfer member 14 is placed in the horizontal gap 104Y. The vertical load transfer member 14 has the role of transferring the weight of the existing separated concrete deck 104 and the like and the load of vehicles passing through it to the steel main girder 102. Any member capable of performing such a role can be used as the vertical load transfer member 14. Specifically, for example, a plate-like member such as a steel plate can be used as the vertical load transfer member 14, and the vertical load transfer member 14 may also be formed by filling it with grout. Examples of grout that can be used include cement-based grout (cement milk, mortar, etc.) and epoxy adhesives. Forming the vertical load transfer member 14 by filling it with grout is preferable because it can be expected to transfer not only vertically downward loads but also horizontal loads and vertically upward loads to a certain extent.

[0049] Furthermore, even if a composite girder is constructed by providing anti-slip devices such as headed studs 106 (see Figure 13) on the upper surface of the upper flange 102A of the steel main girder 102, the cutting wire 202 of the wire saw 200 can simultaneously cut the anti-slip devices such as headed studs 106.

[0050] A step of up to about 100 mm occurs between the underside of the upper flange 102A of the steel main girder 102 and the underside of the separate existing concrete deck slab 104, so a step buffer member 16 is placed to fill the step, as shown in Figure 1. The step buffer member 16 only needs to have the function of temporarily maintaining its shape until the adhesive that bonds the continuous fiber sheet 12 hardens, and specifically, for example, facing wood or polystyrene foam can be used. The step buffer member 16 may also be formed by filling the step with putty or caulking material.

[0051] (2) Second embodiment FIG. 3 is a vertical cross-sectional view of a bridge structure 20 according to a second embodiment of the present invention, as viewed from the bridge axis direction.

[0052] In the bridge structure 10 according to the first embodiment, the continuous fiber sheet 12 is bonded to both the underside of the upper flange 102A of the steel main girder 102 and the underside of the separated existing concrete deck slab 104 with a resin-based adhesive, and the underside of the upper flange 102A of the steel main girder 102 and the underside of the separated existing concrete deck slab 104 are connected via the continuous fiber sheet 12 only with adhesive, but in the bridge structure 20 according to the second embodiment, the end of the continuous fiber sheet 12 on the separated existing concrete deck slab 104 side is fixed to the separated existing concrete deck slab 104 with an anchoring mechanism 22 (post-installed anchors 24, nuts 24A, and angled steel 26). Other points are the same as in the bridge structure 10 according to the first embodiment, and therefore, the same components as in the bridge structure 10 according to the first embodiment are designated by the same reference numerals and, in principle, description thereof will be omitted.

[0053] In the bridge structure 20 according to the second embodiment, as shown in FIG. 3, the continuous fiber sheet 12 is fixed to the underside of the separated existing concrete slab 104 by an anchoring mechanism 22 at a position near the end of the continuous fiber sheet 12 on the side of the separated existing concrete slab 104.

[0054] The anchoring mechanism 22 includes a post-installed anchor 24, a nut 24A, and an L-shaped steel 26. Specifically, the anchoring mechanism 22 fastens the continuous fiber sheet 12 as follows: First, the post-installed anchor 24 is attached to the underside of the separated existing concrete slab 104 at a position near the end of the continuous fiber sheet 12 on the side of the separated existing concrete slab 104. Then, the shank of the post-installed anchor 24 is inserted into a through-hole (not shown) of the L-shaped steel 26, and the L-shaped steel 26 is pressed against the continuous fiber sheet 12 from below. Then, the nut 24A threaded onto the post-installed anchor 24 is tightened, thereby pressing the continuous fiber sheet 12 against the underside of the separated existing concrete slab 104 with the L-shaped steel 26, thereby fixing the continuous fiber sheet 12 to the separated existing concrete slab 104. When fixing the continuous fiber sheet 12 using the anchoring mechanism 22, before attaching the L-shaped steel 26, the continuous fiber sheet 12 is adhered to the underside of the separated existing concrete deck slab 104 with a resin-based adhesive, and in that state the L-shaped steel 26 is pressed against the continuous fiber sheet 12 from below to attach it.

[0055] In the bridge structure 20 according to the second embodiment, the continuous fiber sheet 12 is fixed to the underside of the upper flange 102A of the steel main girder 102 by adhesive bonding, as in the bridge structure 10 according to the first embodiment.

[0056] In the bridge structure 10 according to the first embodiment, the continuous fiber sheet 12 is also fixed to the separated existing concrete deck 104 by bonding with an adhesive. However, even in cases where the continuous fiber sheet 12 cannot be sufficiently fixed to the separated existing concrete deck 104 by bonding with an adhesive alone, the bridge structure 20 according to the second embodiment can achieve sufficient fixing by using an anchoring mechanism 22.

[0057] Both adhesive anchors and metal anchors can be used for the post-installed anchors 24. Multiple post-installed anchors 24 are placed along the longitudinal direction of the steel main girder 102 according to the attachment range of the continuous fiber sheet 12. The placement pitch, diameter and embedment depth of the post-installed anchors 24 can be determined appropriately in the design according to the expected external forces, etc.

[0058] The L-shaped steel 26 is attached to the end of the continuous fiber sheet 12 on the side of the separated existing concrete deck 104, along the longitudinal direction of the steel main girder 102, and in principle, over the entire area where the continuous fiber sheet 12 is arranged. The cross-sectional shape (width, height, thickness) of the L-shaped steel 26 may be determined appropriately in the design depending on the expected external forces, etc. Furthermore, in the bridge structure 20 according to the second embodiment, the L-shaped steel 26 is used as the steel material used for anchoring, but the steel material that can be used for anchoring is not limited to the L-shaped steel, and steel materials such as flat bars may also be used for anchoring.

[0059] (3) Third embodiment FIG. 4 is a horizontal cross-sectional view of a bridge structure 30 according to a third embodiment of the present invention as viewed from below (a horizontal cross-sectional view of a cross section at a position similar to the cross section along line II-II in FIG. 1 as viewed from below).

[0060] In the bridge structure 10 according to the first embodiment, the continuous fiber sheets 12 were arranged closely packed with no gaps in the longitudinal direction of the steel main girders 102, but in the bridge structure 30 according to the third embodiment, the continuous fiber sheets 32 having a predetermined width are arranged discretely with a predetermined interval in the longitudinal direction of the steel main girders 102. Other points are the same as those in the bridge structure 10 according to the first embodiment, and therefore, explanations of other points will, in principle, be replaced by explanations of the bridge structure 10 according to the first embodiment.

[0061] The bridge structure 30 according to the third embodiment is an embodiment in which continuous fiber sheets 32 having a predetermined width are discretely arranged at predetermined intervals along the longitudinal direction of the steel main girder 102, and is an embodiment that can be considered for adoption when, as a result of design calculations, safety can be ensured even if the continuous fiber sheets 12 are arranged with gaps rather than packed closely together along the longitudinal direction of the steel main girder 102.

[0062] In the bridge structure 30 according to the third embodiment, an anchoring mechanism similar to the anchoring mechanism 22 of the bridge structure 20 according to the second embodiment can also be used to fix the position near the end of the continuous fiber sheet 32 ​​on the separated existing concrete slab 104 side to the underside of the separated existing concrete slab 104.

[0063] In addition, in the bridge structure 30 according to the third embodiment, the continuous fibers constituting the continuous fiber sheet 32 ​​are arranged so as to intersect at an angle of approximately 90° with respect to the longitudinal direction of the steel main girder 102 when viewed from below, which is also the same as in the bridge structure 10 according to the first embodiment.

[0064] (4) Fourth embodiment FIG. 5 is a horizontal cross-sectional view of a bridge structure 40 according to a fourth embodiment of the present invention as viewed from below (a horizontal cross-sectional view of a cross section at a position similar to the cross section taken along line II-II in FIG. 1 as viewed from below).

[0065] In the bridge structure 30 according to the third embodiment, the continuous fiber sheets 32 having a predetermined width are discretely arranged at predetermined intervals in the longitudinal direction of the steel main girders 102, and the continuous fibers constituting the continuous fiber sheets 32 are arranged so as to intersect at an angle of approximately 90° with respect to the longitudinal direction of the steel main girders 102 when viewed from below. However, in the bridge structure 40 according to the fourth embodiment, the continuous fiber sheets 42 having a predetermined width (narrower than the continuous fiber sheets 32 of the bridge structure 30 according to the third embodiment) are discretely arranged at predetermined intervals in the longitudinal direction of the steel main girders 102, and the continuous fibers constituting the continuous fiber sheets 42 are arranged so as to intersect at an angle of approximately ±45° with respect to the longitudinal direction of the steel main girders 102 when viewed from below. Since the bridge structure 40 according to the fourth embodiment is otherwise similar to the bridge structure 30 according to the third embodiment, the explanation of the other points will, in principle, be superseded by the explanation of the bridge structure 30 according to the third embodiment.

[0066] In the bridge structure 40 according to the fourth embodiment, the continuous fibers constituting the continuous fiber sheet 42 are arranged so as to intersect at an angle of approximately ±45° relative to the longitudinal direction of the steel main girder 102 when viewed from below, and therefore can be made of a narrower continuous fiber sheet than when arranged so as to intersect at an angle of approximately 90° relative to the longitudinal direction of the steel main girder 102 when viewed from below.

[0067] (5) Fifth embodiment FIG. 6 is a vertical cross-sectional view of a bridge structure 50 according to a fifth embodiment of the present invention, as viewed from the bridge axis direction.

[0068] In the bridge structure 10 of the first embodiment, a step buffer member 16 was placed in the step between the underside of the upper flange 102A of the steel main girder 102 and the underside of the separate existing concrete deck slab 104 to fill the step, but in the bridge structure 50 of the fifth embodiment, no step buffer member 16 is placed, and the step remains as it is between the underside of the upper flange 102A of the steel main girder 102 and the underside of the separate existing concrete deck slab 104.

[0069] The continuous fiber sheet 52 of the bridge structure 50 according to the fifth embodiment is made of aramid fiber. Aramid fiber is a high-strength fiber with excellent toughness and flexibility, and exhibits stable mechanical properties on its own without being compounded with resin or the like. Furthermore, it is difficult for a continuous fiber sheet to change shape after being impregnated with resin due to the hardening of the resin, but the continuous fiber sheet before being impregnated with resin is flexible and can be easily deformed. For this reason, only the bending point 52D of the continuous fiber sheet is not impregnated with resin, and the other parts 52A, 52B, and 52C are impregnated with and hardened with resin, and the composite continuous fiber sheet member is brought to the construction site, and only the bonding part 52A with the underside of the upper flange 102A of the steel main girder 102 and the bonding part 52B with the underside of the separate existing concrete deck 104 are bonded with resin.Even if the central part 52C is not bonded to a step buffer material or the like, the continuous fiber sheet 52 made of aramid fiber will exhibit sufficient mechanical properties to connect the separate existing concrete deck 104 to the steel main girder 102, and therefore it is possible to omit the step buffer material 16 in the bridge structure 50 of this fifth embodiment.

[0070] Other than the points described above, the bridge structure 50 according to the fifth embodiment is similar to the bridge structure 10 according to the first embodiment, and therefore, explanations of points other than those described above will be replaced by explanations of the bridge structure 10 according to the first embodiment.

[0071] (6) Sixth embodiment Figure 7 is a horizontal cross-sectional view of a bridge structure 60 according to the sixth embodiment of the present invention as viewed from below (a horizontal cross-sectional view of a cross-section at a position similar to the cross-section along line II-II in Figure 1 as viewed from below), Figure 8 is an enlarged plan view schematically showing a continuous fiber fixing member 62, and Figure 9 is a vertical cross-sectional view of a bridge structure 60 according to the sixth embodiment of the present invention as viewed from the bridge axis direction.

[0072] In the bridge structures 10, 20, 30, 40, and 50 according to the first to fifth embodiments, the continuous fibers connecting the separated existing concrete deck 104 to the steel main girder 102 constitute a continuous fiber sheet, which constitutes a sheet-like member. However, in the bridge structure 60 according to the sixth embodiment, the continuous fibers connecting the separated existing concrete deck 104 to the steel main girder 102 constitute continuous fiber anchoring members 62 as shown schematically in FIG. 8 . In the bridge structure 60 according to the sixth embodiment, the shafts 62B of the continuous fiber anchoring members 62 are arranged so as to intersect at an angle of approximately 90° with respect to the longitudinal direction of the steel main girder 102 when viewed from below, and the continuous fiber anchoring members 62 are arranged discretely at predetermined intervals in the bridge axis direction. Other than this and related points, the configuration is the same as that of the bridge structure 10 according to the first embodiment. Therefore, the same reference numerals are used for corresponding components, and a description thereof will be omitted in principle.

[0073] The continuous fiber fixing member 62 has spread portions 62A at both ends and a shaft portion 62B in the center. In the spread portion 62A, the continuous fibers are not bundled and can be spread into a fan shape, while in the central shaft portion 62B, the continuous fibers are bundled and are impregnated with a resin that has been hardened, forming a rod shape.

[0074] 7 and 9, in the bridge structure 60 according to the sixth embodiment, the spread portions 62A at both ends of the continuous fiber anchoring member 62 are attached by adhesive to the underside of the upper flange 102A of the steel main girder 102 and the underside of the separated existing concrete deck slab 104, respectively, and the central shaft portion 62B is disposed in the step portion between the underside of the upper flange 102A of the steel main girder 102 and the underside of the separated existing concrete deck slab 104. The central shaft portion 62B of the continuous fiber anchoring member 62 is impregnated with resin and hardened, and is already in a state of fiber-reinforced composite material, and therefore exhibits sufficient mechanical properties in this state. For this reason, if only one spread portion 62A which is an adhesion portion with the lower surface of the upper flange 102A of the steel main girder 102 and the other spread portion 62A which is an adhesion portion with the lower surface of the separated existing concrete deck slab 104 are bonded with resin, the separated existing concrete deck slab 104 can be connected to the steel main girder 102; therefore, in the bridge structure 60 according to the sixth embodiment, the step buffer member 16 can be omitted.

[0075] Specific examples of continuous fibers that can be used for the continuous fiber fixing member 62 include carbon fibers, aramid fibers, and glass fibers.

[0076] Furthermore, for bonding the spread portions 62A at both ends of the continuous fiber fixing member 62, specifically, for example, an epoxy resin adhesive or an acrylic resin adhesive can be used.

[0077] Also in the bridge structure 60 according to the sixth embodiment, the spread portion 62A of the continuous fiber fixing member 62 on the separated existing concrete slab 104 side can be fixed to the underside of the separated existing concrete slab 104 by using an anchoring mechanism similar to the anchoring mechanism 22 of the bridge structure 20 according to the second embodiment.

[0078] (7) Seventh embodiment FIG. 10 is a horizontal cross-sectional view of a bridge structure 70 according to the seventh embodiment of the present invention as viewed from below (a horizontal cross-sectional view of a cross section at a position similar to the cross section along line II-II in FIG. 1 as viewed from below).

[0079] In the bridge structure 60 according to the sixth embodiment, the continuous fiber anchoring members 62 are discretely arranged at a predetermined interval in the longitudinal direction of the steel main girder 102, and the shanks 62B of the continuous fiber anchoring members 62 are arranged so as to intersect at an angle of approximately 90° with respect to the longitudinal direction of the steel main girder 102 when viewed from below, but in the bridge structure 70 according to the seventh embodiment, the continuous fiber anchoring members 62 are discretely arranged at a predetermined interval in the longitudinal direction of the steel main girder 102, and the shanks 62B of the continuous fiber anchoring members 62 are arranged so as to intersect at an angle of approximately ±45° with respect to the longitudinal direction of the steel main girder 102 when viewed from below. Since other points are the same as those of the bridge structure 60 according to the sixth embodiment, the explanation of these other points will, in principle, be superseded by the explanation of the bridge structure 60 according to the sixth embodiment.

[0080] In the bridge structure 70 according to the seventh embodiment, the shaft portion 62B of the continuous fiber fixing member 62 is arranged so that it intersects with the longitudinal direction of the steel main girder 102 at an angle of approximately ±45° when viewed from below, and is therefore more able to resist external forces in the bridge axis direction, such as vehicle braking loads, than when it is arranged so that it intersects with the longitudinal direction of the steel main girder 102 at an angle of approximately 90° when viewed from below.

[0081] (8) Construction procedure for concrete deck replacement method The construction procedure for replacing the existing concrete slab 104 of the bridge 100 with a new concrete slab 150 using the bridge structure 10 according to the first embodiment will be described with reference to FIGS.

[0082] Fig. 11 is a vertical cross-sectional view perpendicular to the bridge axis of a bridge 100 to which the concrete deck replacement method using the bridge structure 10 according to the first embodiment is applied. As shown in Fig. 11, the bridge 100 is a plate girder bridge having four steel main girders 102. Headed studs 106 are provided on the upper surfaces of the upper flanges 102A of the steel main girders 102, resulting in a composite girder structure, but this method can also be applied to non-composite girder structures.

[0083] (Step S1 (separation process)) Fig. 12 is a vertical cross-sectional view of the bridge 100 in a direction perpendicular to the bridge axis with the wire saw 200 installed, Fig. 13 is a vertical cross-sectional view of the cutting portion above the upper flange 102A of the steel main girder 102 during cutting, and Fig. 14 is a vertical cross-sectional view of the cutting portion above the upper flange 102A of the steel main girder 102 after cutting has been completed. Note that in Fig. 13, the main body of the wire saw 200 is omitted, and only the cutting wire 202 is shown.

[0084] As shown in Figure 12, a wire saw 200 is placed below the existing concrete deck 104, and a portion of the haunch of the existing concrete deck 104 near the steel main girder 102 is cut in a substantially horizontal direction. The diameter of the cutting wire 202 of the wire saw 200 is about 10 to 20 mm. In order to cut without damaging the steel main girder 102, the cutting wire 202 is usually aimed at a position about 20 to 50 mm above the top surface of the upper flange 102A of the steel main girder 102. As a result, residual concrete 104X with a thickness of about 10 to 40 mm remains on the top surface of the upper flange 102A of the steel main girder 102, and a horizontal gap 104Y (see Figures 2 and 14) is created above the upper flange 102A of the steel main girder 102 and between the upper flange 102A of the steel main girder 102 and the underside of the separated existing concrete deck 104.

[0085] The work in step S1 (separation process) is carried out below the existing concrete deck 104, and the work in step S1 (separation process) can be carried out while the bridge surface above the existing concrete deck 104 remains open to vehicle traffic.

[0086] (Step S2 (fixing process)) FIG. 15 is a vertical cross-sectional view of the bridge 100 in a direction perpendicular to the bridge axis after the fixing process has been completed.

[0087] Spacers such as steel plates are inserted as vertical load transmission members 14 into the horizontal gap 104Y generated in step S1 (separation process) so that even when vehicles pass over the bridge surface above the separated existing concrete slab 104, excessive bending moment is not generated in the separated existing concrete slab 104. It is preferable to insert spacers such as steel plates as vertical load transmission members each time the length of the horizontal gap 104Y in the bridge axis direction reaches a certain length.

[0088] Instead of inserting a spacer such as a steel plate into the horizontal gap 104Y as a vertical load transmission member, the horizontal gap 104Y may be filled with grout material to form the vertical load transmission member 14. In this case, it is preferable because it can be expected that not only vertically downward loads but also horizontal loads and vertically upward loads can be transmitted to some extent.

[0089] A vertical load transfer member 14 is provided in the horizontal gap 104Y, and a step buffer member 16 is placed in the step between the underside of the upper flange 102A of the steel main girder 102 and the underside of the separated existing concrete deck slab 104. After that, a continuous fiber sheet 12 is bonded to the underside of the upper flange 102A of the steel main girder 102 and the underside of the separated existing concrete deck slab 104 with a resin-based adhesive so as to bridge them, thereby connecting the steel main girder 102 and the separated existing concrete deck slab 104. The continuous fiber sheet 12 is placed so that its continuous fibers intersect the longitudinal direction of the steel main girder 102 at an angle of approximately 90°.

[0090] When attaching the continuous fiber sheet 12, first, the paint on the adhesive surface of the steel main girder 102 (the underside of the upper flange 102A) is removed using a disk sander or similar tool. Dirt and other contaminants are also removed from the adhesive surface of the underside of the separate existing concrete deck slab 104 using a disk sander or similar tool. Then, after a primer is applied to both adhesive surfaces and allowed to dry, a resin-based adhesive is applied to adhere the continuous fiber sheet 12. A resin-based adhesive is also applied to the surface of the adhered continuous fiber sheet 12, and the entire cross section of the continuous fiber sheet 12 is made into a composite material.

[0091] It is difficult for the vertical load transmission member 14 alone to handle external forces perpendicular to the bridge axis, such as horizontal forces during an earthquake and wall parapet collision loads, and external forces in the bridge axis direction, such as vehicle braking loads, so it is advisable to carry out step S1 (separation step) and step S2 (fixing step) alternately at predetermined distances in the bridge axis direction of the bridge 100 so that the length of the horizontal gap 104Y in the bridge axis direction in the area not fixed with the continuous fiber sheet 12 does not exceed a certain length. Alternatively, it is advisable to carry out step S2 (fixing step) simultaneously after step S1 (separation step).

[0092] In step S2 (fixing step), the continuous fiber sheet 12 may be fixed at a position near the end thereof on the separated existing concrete slab 104 side to the underside of the separated existing concrete slab 104 by an anchoring mechanism 22 (see FIG. 3).

[0093] When restricting traffic on the bridge surface above the existing concrete deck 104 that is to be replaced, it is also possible to carry out a long distance cut in the bridge axis direction (cutting the area near the steel main girder 102 of the haunch portion of the existing concrete deck 104 using a wire saw 200) (separation process of step S1) all at once while the traffic restrictions are in place, and then construct the bridge structure 10 in the cut area (step S2 (fixing process)), and then lift the traffic restrictions.

[0094] (Step S3 (concrete floor slab replacement process)) 16 and 17 are vertical cross-sectional views taken at right angles to the bridge axis of the area above the upper flange 102A of the steel main girder 102 in the state where the separated existing concrete deck 104 has been jacked up after the fixing process has been completed, and Fig. 17 shows the case where the continuous fiber sheet 12 has been fixed using the anchoring mechanism 22. Fig. 18 is a vertical cross-sectional view taken at right angles to the bridge axis of the area above the upper flange 102A of the steel main girder 102 in the state where it has been replaced with a new concrete deck 150.

[0095] In this step S3 (concrete deck replacement process), traffic restrictions must be implemented because the separated existing concrete deck 104 fixed in step 2 is to be removed and replaced with a new concrete deck 150, so traffic restrictions are implemented first. If the separated existing concrete deck 104 to be replaced spans the entire cross section in the transverse direction of the bridge 100 (direction perpendicular to the bridge axis), all lanes of the bridge 100 must be closed to traffic; however, if, for example, the separated existing concrete deck 104 to be replaced spans only half of the cross section (only one of the up and down lanes) in the transverse direction of the bridge 100 (direction perpendicular to the bridge axis), it is also possible to close only the relevant lane to carry out the construction.

[0096] After necessary traffic control, the separated existing concrete deck 104 after the fixing process is completed is jacked up. For the jacking up itself, a method generally used in concrete deck replacement work can be used. Specific methods for removing the separated existing concrete deck 104 include, for example, a method in which the adhesive portion between the continuous fiber sheet 12 and the separated existing concrete deck 104 is heated (for example, by applying heat of about 100°C to the adhesive portion using an iron or the like) to peel off the continuous fiber sheet 12, and then the separated existing concrete deck 104 is removed by jacking up (see Figure 16); a method in which the adhesive portion between the continuous fiber sheet 12 and the underside of the upper flange 102A is heated (for example, by applying heat of about 100°C to the adhesive portion using an iron or the like) to peel off the continuous fiber sheet 12, and then the separated existing concrete deck 104 is removed by jacking up; and a method in which the continuous fiber sheet 12 is cut using a tool such as a disc grinder, and then the separated existing concrete deck 104 is jacked up and removed. If the continuous fiber sheet 12 has been fixed using the anchoring mechanism 22 (see Figure 3), the nuts 24A and L-shaped steel 26 are removed from the post-installed anchors 24, the continuous fiber sheet 12 is then peeled off or cut, and jacking is performed to jack up the separated existing concrete slab 104 as shown in Figure 17. Figure 17 shows a situation in which, after the nuts 24A and L-shaped steel 26 are removed from the post-installed anchors 24, the adhesive joint between the continuous fiber sheet 12 and the separated existing concrete slab 104 is heated to peel off the continuous fiber sheet 12, and then the separated existing concrete slab 104 is removed by jacking up.

[0097] After the separated existing concrete slab 104 is jacked up and removed, a new concrete slab 150 is installed. The new concrete slab 150 can be installed using a method that is commonly used in concrete slab replacement work.

[0098] After the new concrete deck 150 is installed, the continuous fiber sheet 12 and adhesive attached to the underside of the upper flange 102A of the steel main girder 102 are removed, and the steel main girder 102 is painted. More specifically, when removing the continuous fiber sheet 12, for example, heat of about 100°C is applied to the adhesive portion using an iron or the like, the continuous fiber sheet 12 is removed, any remaining adhesive is removed using a sander or the like, and then the steel main girder 102 is painted. All of these operations are performed under the new concrete deck 150, so construction can be carried out even when the area has resumed service to vehicle traffic.

[0099] (9) Supplementary information The continuous fiber sheet 12 used in the embodiment described above is a member in which continuous fibers with excellent mechanical properties are aligned in a substantially uniform longitudinal direction to form a sheet, but in the present invention, a member in which continuous fibers are woven into a fabric to form a sheet can also be used. [Explanation of symbols]

[0100] 10, 20, 30, 40, 50, 60, 70...Bridge structure 12, 32, 42, 52...Continuous fiber sheet 12A: Adhesion length between the continuous fiber sheet 12 and the lower surface of the upper flange 102A 12B: Adhesion length between the continuous fiber sheet 12 and the underside of the existing concrete slab 104 14...Vertical load transmission member 16...Step buffer material 22...Anchor mechanism 24...Post-installed anchor 24A...Nut 26…L-shaped steel 52A: Adhesion portion between the continuous fiber sheet 52 and the lower surface of the upper flange 102A 52B: Adhesion portion between the continuous fiber sheet 52 and the underside of the existing concrete floor slab 104 52C…Central part 52D...break point 62...Continuous fiber fixing member 62A…Opening section 62B…Shaft part 100...Bridge 102...Steel main girder 102A...Top flange 102B…Web 104... Existing concrete slab, Separated existing concrete slab 104A...Start of haunch 104X: Remaining concrete 104Y...Horizontal gap 106...headed stud 150...New concrete deck 200...Wire saw 202...Cutting wire a...Cut length along the bridge axis

Claims

1. a separation process of cutting a portion of an existing concrete deck near a steel girder in a substantially horizontal direction to separate the existing concrete deck from the steel girder; a replacement process for removing the existing concrete slab separated in the separation process and replacing it with a new concrete slab; A connecting process of connecting the existing concrete deck separated in the separation process to the steel girder between the separation process and the start of the replacement process; Equipped with A concrete deck replacement method characterized in that, in the connecting step, the existing concrete deck and the steel girder are connected with continuous fibers, and the continuous fibers are attached to the steel girder by adhesive.

2. The concrete deck replacement method described in claim 1, characterized in that the connecting process includes a vertical load transfer member placement process of placing a vertical load transfer member in the gap between the cut surface of the existing concrete deck formed in the separation process and the upper surface of the upper flange of the steel girder.

3. The concrete deck replacement method according to claim 2, wherein the vertical load transfer member is made of grout material.

4. The concrete deck replacement method according to any one of claims 1 to 3, characterized in that the replacement process includes a disconnection process for disconnecting the connection between the existing concrete deck and the steel girder performed in the connection process.

5. The concrete deck replacement method according to claim 4, characterized in that the cutting process is a process of peeling off the continuous fibers adhered to the steel girder in the connecting process from the existing concrete deck or the steel girder.

6. 5. The method for replacing a concrete deck according to claim 4, wherein the dividing step is a step of cutting the continuous fibers connected in the connecting step.

7. The concrete deck replacement method according to any one of claims 1 to 6, characterized in that the separation process and the connection process are performed alternately at predetermined distances in the bridge axis direction of the bridge.

8. A concrete deck replacement method as described in any one of claims 1 to 6, characterized in that the separation process is carried out at one portion of the bridge, and at the same time, the connection process is carried out at another portion of the bridge adjacent to the one portion in the bridge axis direction of the bridge.

9. A concrete deck replacement method according to any one of claims 1 to 8, characterized in that after the connecting process and before the replacing process, a passing process is provided in which a vehicle is passed over the existing concrete deck separated in the separating process.

Images