JP2018091052A - Method of removing existing concrete from bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of removing existing concrete from a bridge capable of safely and efficiently removing concrete for reinforcement from the underside of a floor slab without damaging the floor slab.SOLUTION: A method for removing existing concrete from a bridge used: a track rail 62; a slide stage 63 installed slidably in the longer direction of the track rail; a guide pole installed on the slide stage; a motor 65; and a wall cutter 61 comprised of a cutter blade 66. The wall cutter 61 is supported in a posture that allows the cutter blade 66 to be rotated along an under surface 52a of a floor slab 52. A horizontal incision is formed along the boundary part between the under surface 52a of the floor slab 52 and a concrete for reinforcement 53. Then, a vertical incision is formed on the concrete for reinforcement 53, and a partial mass of the concrete for reinforcement 53 is separated from the floor slab 52, and removed from the bridge.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of removing existing concrete, and more particularly, to a method of removing reinforcing concrete attached to the lower surface of a bridge deck.

  As shown in FIG. 3 (cross-sectional view along the transverse direction of the conventional bridge 51), in the bridge 51 such as a road bridge or an elevated road, the lower surface of the floor slab 52 is used for the purpose of supplementing the rigidity of the floor slab 52. In some cases, a work for placing the reinforcing concrete 53 is performed. When it becomes necessary to remove the reinforcing concrete 53, a cutting device called a wall cutter (or a wall saw) has been conventionally used, and the reinforcing concrete 53 is removed from the floor slab by the wall cutter. The method of subdividing the state with the state attached to the lower surface of 52, and peeling off the subdivided concrete lump from the lower surface of the floor slab 52 is implemented.

  As shown in FIG. 4 (a perspective view showing a basic configuration of a general wall cutter 61), the wall cutter is attached so as to be slidable in the longitudinal direction with respect to the track rail 62. Slide stage 63, a guide pole 64 erected on the slide stage 63, a motor unit 65 supported so as to be movable along the guide pole 64, and an output shaft (rotation shaft) of the motor unit 65 ) And the cutter blade 66 attached thereto.

  The wall cutter 61 is a device that can form a cut with a desired depth linearly over a desired length. For example, when the surface to be cut of the concrete housing 54 is an upward horizontal surface as shown in FIG. 5, a track is formed by drilling from the surface to be cut into the concrete housing 54 and embedding anchor bolts 67 (concrete anchors). In a state where the rail 62 is fixed on the surface to be cut and the cutter blade 66 is rotated, the motor unit 65 is indicated by a solid line from an upper position (a position farthest from the slide stage 63) indicated by a broken line in FIG. When it is lowered toward a lower position (position closest to the slide stage 63), the cutter blade 66 enters the inside (downward) while cutting the concrete housing 54.

  After the cutter blade 66 reaches the desired depth position in the concrete housing 54, the slide stage 63 is moved in the longitudinal direction of the track rail 62 while the height position of the motor portion 65 is fixed. A straight cut along the longitudinal direction of 62 can be formed at a desired depth and a desired length.

  Conventionally, when removing the reinforcing concrete 53 on the lower surface of the floor slab 52 using the wall cutter 61, first, the track rail 62 shown in FIG. 4 is placed on the bottom surface of the reinforcing concrete 53 shown in FIG. A vertical cut 55 extending from the bottom surface of the reinforcing concrete 53 to the immediate vicinity of the lower surface of the floor slab 52 is fixed by being fixed in a direction opposite to that shown in FIG. As shown in (bottom view of the bridge 51 shown in FIG. 3), the reinforcing concrete 53 is formed in a grid pattern (a plurality of bridges 51 at a predetermined interval in the bridge axis direction and the transverse direction). While being attached to the lower surface of the plate 52, one side is subdivided into blocks having a size of about 1 to 2 m.

  Next, the crushed pieces of the reinforcing concrete 53 are strongly pulled downward by using a jack or the like fixed on the lower side, and are peeled off one by one from the lower side of the floor slab 52. Work was being carried out.

JP 2004-148692 A

  However, as shown in FIG. 7 (1), the reinforcing concrete 53 has an upper end side embedded in the floor slab 52 and a lower end side fixed to the reinforcing concrete 53 via an anchor reinforcing bar 56. When the embedded reinforcing reinforcing bar 56 is pulled out from the floor slab 52 when the mass of the reinforcing concrete 53 is to be peeled off from the floor slab 52 by force, the embedded anchor reinforcing bar 56 is pulled out from the floor slab 52 as shown in FIG. As shown in 2), the floor slab 52 is partially damaged, for example, the surrounding concrete (a part 52 ′ of the floor slab) falls off the floor slab 52 together with the anchor reinforcing bar 56 to form a recess 52 ″. In this case, an operation of filling the recess 52 ″ with mortar and repairing it is necessary.

  Further, when a strong adhesive for concrete is interposed between the floor slab 52 and the reinforcing concrete 53, when the lump of the reinforcing concrete 53 is peeled off from the floor slab 52, as shown in FIG. Part of the reinforcing concrete 53 ′ remains on the lower surface of the floor slab 52, or part of the floor slab 52 ′ falls out in close contact with the reinforcing concrete 53, so that a recess 52 ″ is formed on the lower surface of the floor slab 52. (In this case, irregularities are formed on the lower surface of the floor slab 52). In this case, the work for repairing the recess 52 "or the residue on the lower surface of the floor slab 52 (part of the reinforcing concrete) 53 ′) is required to be removed.

  In addition, when pulling the subdivision of the reinforcing concrete 53 downward, the tensile force applied to the reinforcing concrete 53 is gradually increased, which exceeds the adhesion between the floor slab 52 and the reinforcing concrete 53. Sometimes, it becomes possible to peel the reinforcing concrete 53 from the floor slab 52, but it is unknown when the tensile force exceeds the adhesion force. The concrete mass will fall suddenly, which is extremely dangerous.

  The present invention is intended to solve such a problem in the prior art, and does not damage the floor slab safely, and eliminates the need for removing the residue on the bottom surface of the floor slab and repairing the recess. Therefore, it aims at providing the removal method of the existing concrete of a bridge which can remove concrete for reinforcement from the lower side of a floor slab efficiently.

  The method of removing the existing concrete of the bridge according to the present invention includes a straight track rail, a slide stage attached so as to be slidable in the longitudinal direction with respect to the track rail, and a guide pole erected on the slide stage And removing the existing concrete of the bridge using a wall cutter comprising a motor unit supported so as to be movable along the guide pole and a cutter blade attached to the output shaft of the motor unit The wall cutter is supported in such a posture that the cutter blade can be rotated along the lower surface of the floor slab, and a horizontal cut is formed at the boundary portion between the lower surface of the floor slab and the reinforcing concrete. After forming the horizontal cut or before forming it, the wall cutter will Cut to form vertical to over preparative separates the partial mass of reinforcing concrete floor plate, is characterized in that removal from the bridge.

  In this method, while the cutter blade is rotated, the motor portion is gradually brought closer to the end surface of the reinforcing concrete, and while cutting the uppermost portion of the reinforcing concrete, the lower surface of the floor slab and the reinforcing concrete When the cutter blade enters the inside of the boundary, and when the cutting edge of the cutter blade reaches the desired depth, the slide stage is moved in the longitudinal direction of the track rail, so that the boundary between the lower surface of the floor slab and the reinforcing concrete In the part, it is preferable to form a horizontal cut.

  In addition, the beam material is supported on the lower side of the reinforcing concrete in the direction in which the longitudinal direction coincides with the transverse direction of the bridge, a frame is fixed on the support material, and a bracket having a vertical surface is further mounted on the bridge. A large number of them are arranged and fixed at predetermined intervals in the cross direction, and the wall cutter track rail is fixed to the vertical surfaces of these brackets so that the mounting surface is vertical and the longitudinal direction matches the cross direction of the bridge. Thus, it is preferable to support the wall cutter in a posture in which the cutter blade can be rotated along the lower surface of the floor slab.

  Furthermore, it is preferable to support the wall cutter in such a posture that the frame can be fixed on the beam member via a height adjusting bolt and the cutter blade can be rotated along the lower surface of the floor slab.

  According to the method for removing existing concrete from a bridge according to the present invention, it is not necessary to pull a heavy concrete block strongly downward as in the case of the conventional method, so that the removal work can be performed safely.

  Further, in the conventional method, there is a problem that irregularities are formed on the bottom surface of the floor slab due to the forcible withdrawal of the anchor reinforcing bar or due to the adhesive force by the adhesive. According to the removal method, such a problem can be suitably avoided, and the work for repairing the bottom surface of the floor slab and the removal of the residue become unnecessary, and also when fixing the track rail of the wall cutter to the concrete frame. Anchor bolt installation work (drilling work, fixing work, etc.) becomes unnecessary, and the removal work can be carried out efficiently.

  Furthermore, in the conventional method, as the adhesion between the floor slab and the reinforced concrete increases, a large facility is required as a means for peeling the reinforced concrete. However, in the removal method according to the present invention, the floor slab and the reinforcement are required. The reinforced concrete can be separated and removed without being affected by the magnitude of the adhesion with the concrete.

  In addition, when the stand is fixed on the beam material via the height adjusting bolt, each height adjusting bolt is used even when the lower surface of the floor slab is inclined in either direction. The height and inclination of the gantry, bracket, and track rail can be adjusted by appropriately adjusting the height of the gantry, bracket, and track rail. As a result, the wall cutter is rotated in an appropriate posture (the cutter blade is rotated along the lower surface of the floor slab). Can be supported).

FIG. 1 is an explanatory view of a method for removing existing concrete from a bridge according to the present invention, and is a view showing a vertical section along a bridge axis direction of a floor slab 52 and reinforcing concrete 53 to be removed. is there. FIG. 2 is an explanatory view of a method for removing the existing concrete of the bridge according to the present invention, and a vertical section along the transverse direction of the floor slab 52 (direction perpendicular to the direction of the bridge axis) and the reinforcement to be removed. It is a figure which shows the end surface 53a etc. of the concrete 53 for construction. FIG. 3 is a cross-sectional view of the conventional bridge 51 along the transverse direction. FIG. 4 is a perspective view showing a basic configuration of a general wall cutter 61. FIG. 5 is an explanatory diagram of a general method of using the wall cutter 61 shown in FIG. FIG. 6 is an explanatory view of a conventional method for removing the reinforcing concrete 53, and is a bottom view of the bridge 51 shown in FIG. FIG. 7 is an explanatory view of a conventional method for removing the reinforcing concrete 53, and is a cross-sectional view of the floor slab 52 and the reinforcing concrete 53. FIG. 8 is an explanatory diagram of a conventional method for removing the reinforcing concrete 53, and is a cross-sectional view of the floor slab 52 and the reinforcing concrete 53.

  Hereinafter, an embodiment of a method for removing existing concrete from a bridge according to the present invention will be described with reference to the accompanying drawings. FIG.1 and FIG.2 is explanatory drawing of the removal method which concerns on this invention. More specifically, FIG. 1 is a diagram showing a reinforcing concrete 53 to be removed and a vertical cross section along the bridge axis direction of the floor slab 52, and FIG. 2 is a transverse direction of the floor slab 52. It is a figure which shows the end surface 53a etc. of the vertical cross section along (the direction orthogonal to a bridge axis direction) and the concrete 53 for reinforcement used as removal object.

  In the removal method according to the present embodiment, as shown in FIGS. 1 and 2, first, the cutter blade 66 can be rotated along the lower surface 52a of the floor slab 52 (directly below the lower surface 52a of the floor slab 52). The wall cutter 61 is supported so that the plane of rotation of the cutter blade 66 is parallel to the lower surface 52a of the floor slab 52 at the position.

  Specifically, the beam member 11 is supported by using a bracket or the like fixed to a bridge pier on the lower side of the reinforcing concrete 53 in a direction in which the longitudinal direction coincides with the crossing direction of the bridge. The mount 13 is fixed via bolts for adjusting the height (tilt) (the bolts 12 for adjusting the height), and a number of L-shaped brackets 14 are arranged at predetermined intervals in the crossing direction of the bridge. The track rail 62 of the wall cutter 61 is fixed to the vertical surface 14 a of the L-shaped bracket 14.

  As shown in FIGS. 1 and 2, the track rail 62 has a vertical mounting surface (abutment surface) and a vertical surface 14a of the L-shaped bracket 14 with the longitudinal direction coinciding with the transverse direction of the bridge. Is attached to. Accordingly, the slide stage 63 of the wall cutter 61 (and the motor unit 65, the cutter blade 66, etc. connected thereto) is supported in a slidable state in the crossing direction of the bridge.

  Further, as the beam member 11, it is preferable to support two I-shaped steels in parallel with a gap therebetween as shown in FIG. 1, but the shape is not limited to this, and the supporting member has sufficient load bearing performance. A steel material having a box cross section that is resistant to torsional deformation and the like can also be used as the beam material 11.

  In this way, when the wall cutter 61 is supported in a posture in which the cutter blade 66 can be rotated along the lower surface 52a of the floor slab 52, the motor unit 65 is moved in FIG. Move horizontally from the right position (the position farthest from the end face 53a of the reinforcing concrete 53) to the left position (the position closest to the end face 53a of the reinforcing concrete 53) indicated by the broken line. Go. Then, the cutter blade 66 enters the inside of the boundary portion between the lower surface 52 a of the floor slab 52 and the reinforcing concrete 53 while cutting the uppermost portion of the reinforcing concrete 53.

  When the cutting edge of the cutter blade 66 reaches the deepest portion (the position of the chain line C in FIG. 1), the slide stage 63 is moved in the longitudinal direction of the track rail 62 (the crossing direction of the bridge) while the position of the motor portion 65 is fixed. ). Then, at the boundary portion between the lower surface 52a of the floor slab 52 and the reinforcing concrete 53, a horizontal incision (incision having a width from the end surface 53a to the alternate long and short dash line C shown in FIG. 1) is crossed across the bridge. It can be formed in the direction as long as necessary.

  Since the lower surface 52a of the floor slab 52 is not necessarily horizontal, as described above, "horizontal" in the case of "cutting in the horizontal direction" means "horizontal" in a strict sense. However, it is used here to mean “parallel to the lower surface 52a of the floor slab 52”.

  When forming the horizontal cuts in this way, not only the uppermost part of the reinforcing concrete 53 but also the anchor reinforcing bars 56 shown in FIG. 1 (the upper end side is embedded in the floor slab 52 and the lower end side is placed in the reinforcing concrete 53. Can also be cut off. For this reason, as in the conventional method shown in FIG. 7 (2), when the anchor reinforcing bar 56 is pulled out, a situation in which surrounding concrete (a part 52 ′ of the floor slab) falls off together with the anchor reinforcing bar 56 is preferable. The lower surface 52a of the floor slab 52 can be finished smoothly. Moreover, since the subsequent repair work etc. become unnecessary, removal work can be implemented efficiently.

  Furthermore, by forming a horizontal cut at the top of the reinforcing concrete 53, irregularities (52 ", 53 ') are formed on the lower surface of the floor slab 52 as in the conventional method shown in FIG. In addition, the lower surface 52a of the floor slab 52 can be finished smoothly, repair work of the floor slab 52 and residue removal work can be omitted, and the removal work can be performed efficiently.

  Further, in the conventional method, as shown in FIG. 5, when the track rail 62 is fixed, a drilling operation into the concrete frame 54, an anchor bolt 67 fixing operation, and the like are necessary. It was necessary to repeat operations such as drilling, fixing the anchor bolt 67, and removal each time, but in this embodiment, drilling work into the concrete housing is not required, and the gantry 13 has an L-shape. When the bracket 14 and the track rail 62 are fixed (or fixed on the beam member 11) and the whole is movable in the direction of the bridge axis or the like, it is equivalent to one span. It is not necessary to attach and detach the track rail 62 for every cutting operation, and the removal operation can be carried out very efficiently.

  Next, the wall cutter 61 is rotated 90 ° from the posture shown in FIG. 1 so that the plane of rotation of the cutter blade 66 is vertical (perpendicular to the lower surface 52a of the floor slab 52 (range of ± 5 °)). The vertical cut is formed in the transverse direction of the bridge at the position of the alternate long and short dash line C shown in FIG. 1 (the position of the innermost part of the horizontal cut). Then, a portion of the reinforcing concrete 53 having a width from the end face 53a to the one-dot chain line C shown in FIG. 1 (partial mass of the reinforcing concrete 53) can be separated from the floor slab 52 and removed from the bridge. be able to.

  In order to support the wall cutter 61 so that the plane of rotation of the cutter blade 66 is vertical, the track rail 62 is placed on the bottom surface of the reinforcing concrete 53 from below (as shown in FIG. It may be fixed (in a direction opposite to the vertical direction), or after adjusting the height position, on the upper surface (horizontal plane) of the gantry 13 shown in FIG. 1, the same direction as shown in FIG. The wall cutter 61 may be fixed in the direction.

  According to the removal method according to the present embodiment, as described above, at the boundary portion between the lower surface 52a of the floor slab 52 and the reinforcing concrete 53, the wall cutter 61 is used to form the horizontal cut and an appropriate Since the reinforcing concrete 53 is removed from the floor slab 52 by forming a vertical cut at the position, the floor slab 52 is not damaged as in the case of the conventional method, and the heavy concrete is also removed. Since it is not necessary to pull the lump strongly downward, the removal operation can be performed safely and efficiently.

  In this embodiment, as described above, the horizontal cut is first formed and then the vertical cut is formed. However, the vertical cut is formed first, and then the horizontal cut is formed. Directional cuts may be formed.

11: Beam material,
12: Bolt for height adjustment,
13: Mount,
14: L-shaped bracket,
14a: vertical plane,
51: Bridge,
52: Floor slab,
52 ': Part of the floor slab,
52 ": recess,
52a: lower surface,
53: Reinforcing concrete,
53 ': Part of the reinforcing concrete,
53a: end face,
54: Concrete frame
55: Cut,
56: Anchor rebar,
61: Wall cutter,
62: Track rail,
63: slide stage,
64: Guide pole,
65: Motor part,
66: Cutter blade,
67: Anchor bolt

Claims (4)

A straight track rail, a slide stage mounted so as to be slidable in the longitudinal direction with respect to the track rail, a guide pole erected on the slide stage, and movable along the guide pole A method of removing the existing concrete of the bridge using a wall cutter constituted by a supported motor part and a cutter blade attached to the output shaft of the motor part,
Support the wall cutter in a posture that allows the cutter blade to rotate along the lower surface of the floor slab, and form a horizontal cut at the boundary between the lower surface of the floor slab and the reinforcing concrete,
After or before this horizontal cut is made, a vertical cut is made in the reinforcing concrete with a wall cutter, and a partial mass of the reinforcing concrete is cut off from the floor slab and removed from the bridge A method of removing existing concrete from a bridge, characterized by:   With the cutter blade rotated, move the motor part gradually toward the end face of the reinforcing concrete and cut the top of the reinforcing concrete into the boundary between the bottom of the floor slab and the reinforcing concrete. When the cutter blade is inserted and the cutting edge of the cutter blade reaches the desired depth, the slide stage is moved in the longitudinal direction of the track rail, so that the horizontal incision is made at the boundary between the bottom of the floor slab and the reinforcing concrete. The method for removing existing concrete from a bridge according to claim 1, wherein:   The beam material is supported on the lower side of the reinforcing concrete so that its longitudinal direction matches the crossing direction of the bridge, and a frame is fixed on it, and a bracket with a vertical surface is mounted on it. By arranging and fixing a large number at predetermined intervals to the vertical surfaces of these brackets, fixing the wall cutter track rail in a direction in which the mounting surface is vertical and the longitudinal direction matches the transverse direction of the bridge, The method for removing existing concrete from a bridge according to claim 1 or 2, wherein the wall cutter is supported in a posture in which the cutter blade can be rotated along the lower surface of the floor slab.   The wall cutter is supported on the beam member in a posture capable of rotating the cutter blade along the lower surface of the floor slab by fixing the frame via a height adjusting bolt on the beam material. The removal method of the existing concrete of the bridge in any one of 1-3.

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