Removal method for concrete deck slabs
The method of cutting concrete slabs perpendicular to the girder axis using a wire saw addresses inefficiencies in existing removal techniques, reducing construction time and labor by allowing simultaneous slab removal and eliminating temporary supports.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- SHIMIZU CORP
- Filing Date
- 2022-05-11
- Publication Date
- 2026-05-15
AI Technical Summary
The existing methods for removing concrete floor slabs from composite girders are time-consuming and labor-intensive, particularly due to the need for chopping off and installing temporary supports, and the process of removing wall parapets is also inefficient.
A method involving a cutting device with an endless loop wire saw to cut the concrete slab perpendicular to the girder axis, allowing for simultaneous removal of the slab above and between girders as a single unit, reducing the need for temporary supports and minimizing wire saw slack by setting the cutting position near the steel girder surface.
This approach significantly reduces construction time and labor by shortening the cutting distance, eliminating the need for temporary supports, and enabling continuous slab removal, thereby enhancing efficiency.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a method for removing a concrete floor slab.
Background Art
[0002] In a composite girder in which a steel girder and a concrete floor slab are joined together with anti-slip measures and integrated, when replacing the concrete floor slab, it cannot be removed by peeling the concrete floor slab from the steel girder by jacking up. Therefore, when replacing the concrete floor slab of the composite girder, the portion of the concrete floor slab directly above the steel girder (the slab above the girder) in the concrete floor slab is cut in the girder axis direction by a cutting device equipped with an endless loop wire saw (see, for example, Patent Document 1).
[0003] The procedure for removing the concrete floor slab in the composite girder is as follows: First, a temporary floor slab support for receiving the cut concrete floor slab is installed, and the portion of the concrete floor slab other than the slab above the girder (the slab between the girders) in the concrete floor slab is cut with a road cutter. Subsequently, the slab above the girder is cut with a wire saw. At this time, since the height of the cutting position varies due to the slack of the wire saw, in order not to damage the steel girder, the slab above the girder is cut at a position, for example, about 5 cm above the upper end of the steel girder, and the portion below the cutting position is chopped off and removed with a water jet device or the like.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, the operation of chopping off and removing the portion below the cutting position of the slab above the girder with a water jet device or the like has problems in that it takes time and labor. In addition, there are problems in that it takes time and labor to install and remove the temporary floor slab support as well.
[0006] The present invention aims to provide a concrete slab removal method that can reduce construction time and labor. [Means for solving the problem]
[0007] To achieve the above objective, the concrete slab removal method according to the present invention is a concrete slab removal method for removing a concrete slab from a composite girder in which a steel girder and a concrete slab are joined, and comprises: a cutting device installation step of installing a cutting device equipped with an endless loop wire saw on the concrete slab; a cutting step of cutting the girder slab directly above the steel girder on the concrete slab with the wire saw from one side to the other in a direction perpendicular to the girder axis, thereby separating it from the steel girder; and a removal step of removing the girder slab and the inter-girder slab between adjacent girder slabs in the direction perpendicular to the girder axis on the concrete slab as a single unit.
[0008] In this invention, the deck slab above the girder is cut with a wire saw in a direction perpendicular to the girder axis, resulting in a shorter cutting distance compared to cutting the deck slab in the direction of the girder axis. This allows for a shorter wire saw engagement length and reduces wire saw slack. As a result, the cutting position with the wire saw can be set near the top surface of the steel girder. Consequently, the chipping process below the wire saw cutting position on the deck slab above the girder can be reduced, leading to a reduction in construction time and labor. In this invention, since the upper deck slab and the inter-girder deck slab can be removed as a single unit, the temporary deck support structure that is required when cutting the inter-girder deck slab before cutting the upper deck slab becomes unnecessary, thus reducing construction time and labor. Furthermore, the wall parapets that are continuous with the concrete slab can also be removed as a single unit with the slabs above and between the girders. By doing so, the process of removing the wall parapets individually becomes unnecessary, further reducing the construction period and labor.
[0009] Furthermore, in the concrete slab removal method according to the present invention, the cutting device installation step includes a through-hole formation step in which a pair of core holes are provided at two positions spaced apart in the girder axis direction on the other side of the girder slab to be cut in the concrete slab, in the direction perpendicular to the girder axis, from the upper end of the concrete slab to the cutting position by the wire saw, and a girder axis perpendicular slit formation step in which a pair of girder axis perpendicular slits are provided extending from each of the pair of core holes in the direction perpendicular to the girder axis, from the upper end of the concrete slab to the cutting position, and the concrete The method may include a girder axis slit forming step, in which a girder axis slit is formed on one side of the girder upper deck to be cut in the concrete deck, in the direction perpendicular to the girder axis, continuous with the pair of girder axis perpendicular slits, extending in the direction of the girder axis and reaching from the lower end of the concrete deck to the cutting position; and a wire saw installation step, in which the wire saw is passed through the core hole on one side in the direction of the girder axis, through the girder axis perpendicular slit the other side in the direction of the girder axis, and through the core hole on the other side in the direction of the girder axis.
[0010] This configuration allows all processes except the girder axial slit formation process to be carried out from above the concrete deck slab, thus simplifying the work. By providing slits in the axial direction of the beam, the vertical deviation of the wire saw and scattering of debris, especially at the start of cutting, can be minimized.
[0011] Furthermore, in the concrete slab removal method according to the present invention, the cutting device may include a pulley installed inside the core hole and a guide member that maintains a constant installation height for the pulley.
[0012] This configuration allows the pulley to be installed inside the core hole below the top surface of the concrete slab. Therefore, when the cutting position with the wire saw is set to a height near the top surface of the steel girder, the wire saw can be stably positioned at the cutting location. Furthermore, because the height of the wire saw is kept constant, it prevents the wire saw from coming into contact with the steel girder.
[0013] Furthermore, in the concrete slab removal method according to the present invention, in the cutting device installation step, the cutting device may be installed at a position where it can cut a plurality of adjacent slabs on the girder that are perpendicular to the girder axis, and in the cutting step, the plurality of adjacent slabs on the girder that are perpendicular to the girder axis may be cut continuously without moving the cutting device.
[0014] By adopting this configuration, the number of steps required to install the cutting device can be reduced, thereby shortening the construction period and reducing labor. Furthermore, because multiple girder slabs are cut continuously without moving the cutting device, the overall wire saw pull-in length is longer compared to cutting each girder slab one by one. However, since each girder slab is cut by the wire saw in a direction perpendicular to the girder axis, the slack in the wire saw that occurs when cutting one girder slab can be reduced compared to when cutting the girder slab in the direction of the girder axis. As a result, the cutting position by the wire saw can be set near the top surface of the steel girder, and the chipping process in the part of the girder slab below the wire saw cutting position can be reduced. [Effects of the Invention]
[0015] According to the present invention, it is possible to reduce construction time and labor. [Brief explanation of the drawing]
[0016] [Figure 1] This is a vertical cross-section of the composite girder. [Figure 2] This is a side view of a cutting device used to cut the deck slab above the girders. [Figure 3] Figure 2 is a plan view. [Figure 4] Figure 2 is a perspective view. [Figure 5] This is a plan view showing the core hole, the slit perpendicular to the girder axis, and the slit in the girder axis direction. [Figure 6] This is a cross-sectional view along line AA in Figure 5. [Figure 7] This is a plan view showing the cutting process. [Figure 8] It is a sectional view taken along line B-B of FIG. 7.
Mode for Carrying Out the Invention
[0017] Hereinafter, a method for removing a concrete floor slab according to an embodiment of the present invention will be described based on FIGS. 1-8. The method for removing a concrete floor slab according to the present embodiment is a method for removing the concrete floor slab 22 from the composite girder 2 in which the steel girder 21 and the concrete floor slab 22 as shown in FIG. 1 are joined and integrated by a displacement preventing member 23. Hereinafter, the direction in which the composite girder 2 extends, that is, the direction in which the steel girder 21 extends is referred to as the girder axis direction (the direction of arrow A in the figure, see FIG. 3). In the present embodiment, the girder axis direction is a substantially horizontal direction. The horizontal direction orthogonal to the girder axis direction is referred to as the girder axis orthogonal direction (the direction of arrow B in the figure).
[0018] A plurality of steel girders 21 are provided at intervals in the direction orthogonal to the girder axis, such as I-beams. The flange width of the steel girder 21, that is, the dimension in the direction orthogonal to the girder axis is, for example, about 500 mm.
[0019] The concrete floor slab 22 is provided on top of a plurality of steel girders 21. The concrete floor slab 22 is provided with a haunch portion 26 that protrudes downward at a portion directly above the steel girder 21. The lower surface of the haunch portion 26 is joined to the upper surface of the steel girder 21. The haunch portion 26 gradually decreases in dimension in the direction orthogonal to the girder axis toward the bottom. The portion of the concrete floor slab 22 that is joined to the steel girder 21 directly above the steel girder 21 is referred to as the on-girder floor slab 24, and the portion that does not overlap the steel girder 21 in the vertical direction and is not directly joined to the steel girder 21 is referred to as the inter-girder floor slab 25.
[0020] As shown in Figures 2 to 4, in the concrete deck removal method, at predetermined spans 29 in the girder axis direction, a cutting device 1 equipped with an endless loop-shaped wire saw 4 is used to separate adjacent girder decks 24, 24 in the direction perpendicular to the girder axis from the steel girder 21, and these girder decks 24, 24 and the inter-girder decks 25 between them are removed as a single unit while remaining connected. For this reason, the inter-girder decks 25 are not separated and removed from the concrete deck 22 before the girder decks 24 are separated from the steel girder 21.
[0021] When separating the girder slab 24 from the steel girder 21, the girder slab 24 is cut at predetermined spans 29 in the girder axis direction, from one side perpendicular to the girder axis to the other. The predetermined span 29 in the girder axis direction when cutting the girder slab 24 is the span in the girder axis direction that the cutting device 1 can cut at once. Hereinafter, the predetermined span 29 in the girder axis direction will be referred to as the cutting span 29.
[0022] The girder slab 24 is cut at a cutting position 27 (see Figures 2 and 4) above the upper surface of the steel girder 21, so as not to damage the steel girder 21 with the wire saw 4. The portion 28 of the girder slab 24 below the cutting position 27 is removed by chipping away with a water jet device or the like. The cutting position 27 is, for example, 2 cm above the upper surface of the steel girder 21. The cutting position 27 is the position where the shear stopper 23 is installed. In the concrete slab removal method according to this embodiment, the shear stopper 23 is cut along with the concrete slab 22.
[0023] In this embodiment, the girder deck 24 is separated from the steel girder 21 by cutting it with the wire saw 4 of the cutting device 1. The wire saw 4 can cut in both the horizontal and vertical directions. In the following description of the cutting device 1, the horizontal direction in which the wire saw 4 can cut is referred to as the front-rear direction (direction of arrow C in Figure 4), and the horizontal direction perpendicular to the front-rear direction is referred to as the width direction (direction of arrow D in Figure 4).
[0024] As shown in Figures 2 and 4, the cutting device 1 has a cutting section 31 and a drive section 32. The cutting section 31 has an endless loop-shaped wire saw 4, a plurality of pulleys 5 around which the wire saw 4 is wound, and a guide frame 6 and a pair of guide members 7 that support the plurality of pulleys 5. The pair of guide members 7, 7 are provided one on each side in the width direction of the guide frame 6. The multiple pulleys 5 include a drive pulley and multiple inner pulleys provided inside the guide frame 6, and an outer upper pulley 53 (see Figure 4, omitted in Figure 2) and an outer lower pulley 54 provided outside the guide frame 6 and supported by a pair of guide members 7, 7. The outer lower pulley 54 corresponds to the "pulley installed inside the core hole" of the present invention.
[0025] The guide frame 6 is connected to the drive unit 32. The drive pulley is connected to the drive unit 32. The drive pulley rotates using the power of the drive unit 32, causing the wire saw 4 to rotate in a circular motion. Some of the multiple inner pulleys are movable in the vertical direction. By moving some of the inner pulleys in the vertical direction, the circulating wire saw 4 can be moved in the cutting direction, and the position of the wire saw 4 can be adjusted. The drive pulley and the multiple inner pulleys are arranged in the same vertical plane oriented in the front-to-back direction, with their respective axes of rotation extending in the front-to-back direction.
[0026] The pair of guide members 7 are rod-shaped members that extend in the vertical direction. Each of the pair of guide members 7 is supported on the guide frame 6 so as to be able to move up and down. The lower end of each guide member 7 is movable below the lower end of the guide frame 6. An outer upper pulley 53 (see Figure 4) is attached to the upper end of each guide member 7. An outer lower pulley 54 is attached to the lower end of each guide member 7.
[0027] The axis of rotation of the outer upper pulley 53 extends in the front-rear direction. The outer upper pulley 53 is positioned in the same vertical plane as the drive pulley and the multiple inner pulleys. The outer upper pulley 53 supported by one guide member 7 in the width direction and the outer upper pulley 53 supported by the other guide member 7 are positioned at the same location and height in the front-rear direction, and are separated in the width direction.
[0028] As shown in Figure 2, the outer lower pulley 54 is rotatably supported around the axis 71 of the guide member 7, which extends vertically with its axis of rotation horizontal. In other words, the outer lower pulley 54 is a swivel pulley. The axis of rotation 541 passing through the center of the outer lower pulley 54 does not intersect with the axis 71 of the guide member 7.
[0029] In this embodiment, the outer lower pulley 54 supported by one guide member 7 in the width direction and the outer lower pulley 54 supported by the other guide member 7 are positioned at the same location and height in the front-rear direction, and separated in the width direction. Note that the outer lower pulley 54 supported by one guide member 7 in the width direction and the outer lower pulley 54 supported by the other guide member 7 may be configured to be positioned at any desired height or position. As described above, the pair of guide members 7 are each supported on the guide frame 6 so as to be able to move up and down. The height of the outer lower pulley 54 can be adjusted by adjusting the height of each of the pair of guide members 7 relative to the guide frame 6. The height of the outer lower pulley 54 can be kept constant by fixing the height of each of the pair of guide members 7 relative to the guide frame 6.
[0030] The wire saw 4 is wrapped around the drive pulley and several inner pulleys inside the guide frame 6, exiting on each side in the width direction of the guide frame 6, and is wrapped around the outer upper pulley 53, extending downward and wrapping around the outer lower pulley 54.
[0031] As the wire saw 4 is pulled backward and passes through the section between one outer lower pulley 54 and the other outer lower pulley 54, it cuts the object to be cut, namely the girder-top slab 24 of the concrete slab 22, from front to back. The cutting portion in the circulating rotation trajectory of the wire saw 4, the section between one outer lower pulley 54 and the other outer lower pulley 54, is referred to as the cutting portion 41.
[0032] As shown in Figure 3, the cutting portion 41 extends forward from each of the pair of outer lower pulleys 54, with the front end portion 42 extending in the width direction in front of the pair of outer lower pulleys 54. The cutting portion 41 has a C-shape that opens to the rear when viewed from above. The cutting portion 41 is mainly cut by the front end portion 42. The cutting portion 41 is positioned in front of the pair of outer lower pulleys 54, and the front end portion 42 moves backward as the cutting progresses.
[0033] As shown in Figures 2 and 3, when the cut portion 41 is positioned in front of the pair of outer lower pulleys 54, the rotation axis 541 of the pair of outer lower pulleys 54 extends in the width direction in front of the axis 71 of the guide member 7 (see Figure 2). As shown in Figures 5 and 6, as the cut portion 41 approaches the pair of outer lower pulleys 54, the pair of outer lower pulleys 54, 54 each rotate around the axis 71 of the guide member 7 (see Figure 5), and their front ends move closer to each other and backward. In this way, the cut portion 41 can be pulled further backward.
[0034] Referring to Figure 4, as described above, when separating the girder slab 24 from the steel girder 21, the girder slab 24 is cut at cutting spans 29, from one side perpendicular to the girder axis to the other. For this reason, the cutting device 1 is installed on the inter-girder slab 25 located on the other side perpendicular to the girder axis of the girder slab 24 to be cut, with its width direction being the same as the girder axis direction and its front-to-back direction being the same as the direction perpendicular to the girder axis. The cutting span 29 corresponds to the width dimension of the front end portion 42 of the cutting portion 41. The cutting span 29 is, for example, about 2.5m to 3m.
[0035] Before installing the cutting device 1 on the concrete slab 22, a pair of core holes 81, 81, a pair of slits 82, 82 perpendicular to the girder axis, and a slit 83 in the girder axis direction are provided in the concrete slab 22 to position the wire saw 4 at the cutting position 27.
[0036] As shown in Figures 2, 3, 7, and 8, the pair of core holes 81, 81 are positioned to overlap with the pair of guide members 7, 7 (see Figure 2) in a plan view from above. The core holes 81 are holes that extend vertically from the upper end of the concrete slab 22 to the height of the cutting position 27, and penetrate or open upward through the inter-girder slab 25. The pair of core holes 81, 81 are provided in pairs, spaced apart in the girder axis direction, corresponding to the pair of guide members 7, 7. The outer lower pulley 54 attached to the lower end of the guide member 7 is inserted into the core hole 81 from above. If the core hole 81 does not penetrate the inter-girder slab 25, the depth of the core hole 81 is set so that the wire saw 4 unwound from the outer lower pulley 54 located inside the core hole 81 can be positioned at the height of the cutting position 27. The core holes 81 are formed from above the concrete slab 22.
[0037] The pair of orthogonal slits 82, 82 are grooves that open upward from the upper end of the concrete slab 22 to the height of the cutting position 27, and extend in the direction perpendicular to the girder axis. The pair of orthogonal slits 82, 82 extend in the direction perpendicular to the girder axis from each of the pair of core holes 81. The pair of orthogonal slits 82, 82 are spaced apart in the direction of the girder axis. The spacing between the pair of orthogonal slits 82, 82 corresponds to the cutting span 29 (see Figure 4) and is approximately the same as the width dimension of the front end portion 42 of the cutting portion 41. The pair of orthogonal slits 82, 82 are formed over the entire direction perpendicular to the girder axis of the concrete slab 22. The concrete slab 22 is divided in the direction of the girder axis by the orthogonal slits 82. The pair of orthogonal slits 82, 82 are formed from above the concrete slab 22.
[0038] The girder axial slit 83 is a groove that opens downward from the lower end of the concrete slab 22 to the height of the cutting position 27, and extends in the girder axial direction. The girder axial slit 83 is provided between a pair of girder axis orthogonal slits 82, 82. One end of the girder axial slit 83 in the girder axial direction is connected to the lower end portion of the girder axis orthogonal slit 82 on the other side in the girder axial direction. The other end of the girder axial slit 83 in the girder axial direction is connected to the lower end portion of the girder axis orthogonal slit 82 on the other side in the girder axial direction. The girder axial slit 83 is provided on one side of the girder slab 24 to be cut in the direction perpendicular to the girder axis. In this embodiment, the girder axial slit 83 is provided near the end of the haunch portion 26 that is continuous with the girder slab 24 to be cut in the direction perpendicular to the girder axis. The girder axial slit 83 is formed from below the concrete slab 22.
[0039] As shown in Figures 2 to 4, the cutting device 1 is installed on the inter-girder slab 25 of the concrete slab 22 with its width direction being the same as the girder axis direction and its front-to-back direction being the same as the direction perpendicular to the girder axis. The guide frame 6 and drive unit 32 of the cutting section 31 are installed on the inter-girder slab 25. The guide member 7 of the cutting section 31 is height-adjusted, and the outer lower pulley 54 attached to its lower end is inserted into the core hole 81. The height of the outer lower pulley 54 is adjusted so that the wire saw 4 wrapped around the outer lower pulley 54 is at the height of the cutting position 27.
[0040] As shown in Figures 2 and 3, the cutting portion 41 of the wire saw 4 is positioned to extend from an outer lower pulley 54 located inside a pair of core holes 81, 81 through a pair of orthogonal slits 82, 82 to one side in the orthogonal direction of the girder axis, and through an axial slit 83 between the one-side ends of the pair of orthogonal slits 82, 82 in the orthogonal direction of the girder axis, extending in the axial direction of the girder axis. When the cutting device 1 is driven, the front end portion 42 of the wire saw 4 is pulled from one side to the other in the orthogonal direction of the girder axis, the portion of the girder slab 24 between the pair of orthogonal slits 82, 82 is cut from one side to the other in the orthogonal direction of the girder axis.
[0041] The method for removing concrete slabs using the cutting device 1 described above will now be explained. As shown in Figures 2 and 3, the cutting device 1 is installed on the concrete slab 22 (cutting device installation step). In the cutting device installation step, the cutting device 1 is installed in a position where it can cut the girder slab 24 (referred to as girder slab 24A, see Figure 4), which is located at one end in the direction perpendicular to the girder axis. In this embodiment, the cutting device 1 is installed on the inter-girder slab 25 (referred to as inter-girder slab 25A, see Figure 4), which is adjacent to the other side of the girder slab 24A in the direction of the girder axis.
[0042] In the cutting device installation process, first, a through-hole formation process is performed in which a pair of core holes 81, 81 are made in the concrete slab 22, a girder axis orthogonal slit formation process is performed in which a pair of girder axis orthogonal slits 82, 82 are made, and a girder axis slit formation process is performed in which a girder axis slit 83 is made. The formation of a pair of core holes 81,81, a pair of slits 82,82 perpendicular to the girder axis, and a slit 83 in the girder axis direction may be performed for each cutting span 29, or it may be performed simultaneously for the entire concrete slab 22 or for multiple cutting spans 29. If the formation of a pair of core holes 81,81, a pair of slits 82,82 perpendicular to the girder axis, and a slit 83 in the girder axis direction is performed for each cutting span 29, it may be performed for each girder slab 24 being cut, or it may be performed to correspond to multiple girder slabs 24.
[0043] Next, the cutting device 1 is installed on the girder slab 25A, and the wire saw 4 is installed by passing it through the core hole 81 on one side in the girder axis direction, through the slit 82 perpendicular to the girder axis on the same side in the girder axis direction, through the slit 83 perpendicular to the girder axis on the other side in the girder axis direction, and through the core hole 81 on the other side in the girder axis direction. The cutting portion 41 of the wire saw 4 is positioned about 2 cm above the top surface of the steel girder 21.
[0044] The cutting device 1 is driven to cut the girder deck slab 24A from one side perpendicular to the girder axis to the other side, as shown in Figures 5 and 6 (cutting process). During the cutting process, the anti-slip stopper 23 located at the cutting position 27 is also cut by the wire saw 4.
[0045] Referring to Figure 4, the cutting device 1 is moved to a position where it can cut the adjacent girder slab 24 (referred to as girder slab 24A) on the other side of the girder slab 24A that has been cut in the direction perpendicular to the girder axis (cutting device installation process). In this embodiment, the cutting device 1 is installed on the inter-girder slab 25 (referred to as inter-girder slab 25B) adjacent to the other side of the girder slab 24B in the direction of the girder axis.
[0046] The cutting device 1 is driven to cut the girder deck slab 24B from one side perpendicular to the girder axis to the other side (cutting process). The intermediate portion of the inter-girder slab 25B, which is continuous with the cut upper girder slab 24B in the direction perpendicular to the girder axis, is cut with a road cutter or the like across the entire girder axis direction of the cutting span 29. This divides the inter-girder slab 25B in the direction perpendicular to the girder axis. The portion 251 of the inter-girder slab 25B on one side of the cut portion in the girder axis direction is integrated with the upper girder slab 24B.
[0047] The two upper deck slabs 24A and 24B cut from the steel girder 21, the inter-girder deck slab 25A between them, and the portion 251 on one side of the cut portion in the girder axis direction of the inter-girder deck slab 25B are removed as a single unit (removal process).
[0048] Similarly, in adjacent areas perpendicular to the girder axis within the same cutting span 29, the cutting device 1 is installed, and the girder slab 24 is cut from the steel girder 21 and removed together with the girder slab 24 and the inter-girder slab 25. The concrete slab 22 is removed in the same manner in the adjacent cutting span 29. After the concrete slab 22 is removed, the portion 28 of the girder slab 24 below the cutting position 27 is removed by chipping away at it using a water jet device or the like.
[0049] According to the concrete deck removal method of this embodiment, the deck slab 24 is cut with a wire saw 4 in a direction perpendicular to the girder axis, resulting in a shorter cutting distance compared to when the deck slab 24 is cut in the direction of the girder axis. In this embodiment, the dimension of the deck slab 24 in the direction perpendicular to the girder axis is approximately 500 mm, the same as the flange width dimension of the steel girder 21. When the deck slab 24 is cut in the direction of the girder axis, it is common to cut about 2 m. This allows the length of the wire saw 4 to be retracted to be shortened, and the slack in the wire saw 4 can be reduced. As a result, the cutting position 27 by the wire saw 4 can be set near the upper surface of the steel girder 21. Consequently, the chipping process for the portion 28 below the cutting position 27 by the wire saw on the girder deck slab 24 can be reduced, leading to a reduction in construction time and labor. According to the concrete deck slab removal method of this embodiment, the girder deck slab 24 and the inter-girder deck slab 25 can be removed as a single unit. Therefore, when cutting the inter-girder deck slab 25 prior to cutting the girder deck slab 24, the temporary deck slab support structure that would normally be installed is not required, thus reducing the construction period and labor. Furthermore, the wall parapet (not shown) that is continuous with the concrete slab 22 can also be removed together with the girder slab 24 and the inter-girder slab 25. By doing so, the process of removing the wall parapet individually can be eliminated, further reducing the construction period and labor.
[0050] Furthermore, in the concrete deck removal method according to this embodiment, all steps except the girder axial slit formation step, which involves creating the girder axial slit 83 in the cutting device installation step, can be performed from above the concrete deck slab 22, thus simplifying the work. The girder axial slit 83 is provided to minimize vertical displacement and scattering of the wire saw 4, especially at the start of cutting.
[0051] Furthermore, in this embodiment, the height of the outer lower pulley 54 can be kept constant by fixing the height of each of the pair of guide members 7 relative to the guide frame 6. With this configuration, the height of the wire saw 4 is kept constant. Therefore, when the cutting position 27 by the wire saw 4 is set to a height near the top surface of the steel girder 21, that height is maintained, preventing the wire saw 4 from coming into contact with the steel girder 21. Furthermore, the guide member 7 allows the outer lower pulley 54 to be installed inside the core hole 81 below the upper surface of the concrete slab 22, enabling the wire saw 4 to be stably positioned at a cutting height near the upper surface of the steel girder 21.
[0052] Although embodiments of the concrete slab removal method according to the present invention have been described above, the present invention is not limited to the above embodiments and can be modified as appropriate without departing from its spirit. For example, in the above embodiment, a haunch portion 26 is provided on the girder deck slab 24, but the haunch portion 26 does not necessarily have to be provided. In the above embodiment, the cutting position 27 of the concrete slab 22 is the position where the shear stopper 23 is provided, and the wire saw 4 cuts both the concrete slab 22 and the shear stopper 23. Alternatively, the cutting position 27 may be set to a height above the shear stopper 23, so that the wire saw 4 does not cut the shear stopper 23. In the above embodiment, the outer lower pulley 54 positioned in the core hole 81 has an adjustable installation height by the guide member 7, so it is possible to select whether the cutting position 27 is at the position of the slip-prevention stopper 23 or at a position above the slip-prevention stopper 23.
[0053] The cutting device 1 may have a configuration other than that described above, as long as it is equipped with a wire saw 4. In the above embodiment, the outer lower pulley 54 positioned in the core hole 81 is a swivel pulley, but it does not have to be a swivel pulley. The core hole 81 may be provided with a pulley whose rotation axis extends horizontally (vertical pulley) and a pulley whose rotation axis extends vertically (horizontal pulley), configured to pull the cutting portion 41 of the wire saw 4 closer to the user.
[0054] The outer lower pulley 54 is supported by the guide member 7, but the configuration in which the outer lower pulley 54 is supported may be other than that described above. The height of the guide member 7 is adjustable relative to the guide frame 6, but it may also be fixed in a way that does not allow for height adjustment relative to the guide frame 6.
[0055] Furthermore, in the concrete deck removal method, during the cutting device installation process, the cutting device 1 is installed on one side of the deck slab 24 to be cut that is perpendicular to the girder axis, and during the cutting process, the deck slabs 24 to be cut are cut one by one. In contrast, in the cutting device installation process, the cutting device 1 may be installed at a position where it can cut multiple adjacent girder slabs 24 in the direction perpendicular to the girder axis, and in the cutting process, multiple adjacent girder slabs 24 in the direction perpendicular to the girder axis may be cut continuously without moving the cutting device 1. This configuration reduces the number of steps required to install the cutting device, thereby shortening the construction period and reducing labor.
[0056] Furthermore, since multiple girder slabs 24 are cut continuously without moving the cutting device 1, the total length of wire saw 4 is longer compared to when girder slabs 24 are cut one by one. However, since each girder slab 24 is cut by the wire saw 4 in a direction perpendicular to the girder axis, the slack in the wire saw 4 that occurs when cutting one girder slab 4 can be reduced compared to when the girder slab 24 is cut in the direction of the girder axis. As a result, the cutting position 27 by the wire saw 4 can be set near the upper surface of the steel girder 21, and the chipping process for the portion 28 below the cutting position 27 on the girder slab 24 can be reduced. [Explanation of Symbols]
[0057] 1 cutting device 2 composite digits 4 Wire saw 5 Pulley 6 Guide Frames 7 Guide member 21 Steel girder 22 Concrete slab 24,24A,24B Girder deck slab 25, 25A, 25B Inter-girder floor slab 27 Cutting position 54 Outer lower pulley 81 Core holes 82-slot slits orthogonal to the axis 83-digit axial slit
Claims
1. In a concrete deck removal method for removing a concrete deck from a composite girder in which a steel girder and a concrete deck are joined, A cutting device installation step involves installing a cutting device equipped with an endless loop wire saw on the aforementioned concrete floor slab, A cutting step of separating the upper deck slab of the concrete deck slab, which is directly above the steel girder, from the steel girder by cutting it with the wire saw from one side in a direction perpendicular to the girder axis to the other side, A removal process in which the above-ground deck slab and the inter-girder deck slab between adjacent above-ground deck slabs in the direction perpendicular to the girder axis in the concrete deck slab are removed as a single unit, It has, In the cutting device installation process, A through-hole formation step is to provide a pair of core holes extending from the upper end of the concrete slab to the cutting position by the wire saw at two positions spaced apart in the direction of the girder axis, on the other side of the girder slab to be cut in the direction perpendicular to the girder axis, in the concrete slab, the other side of the girder slab perpendicular to the girder axis, A girder axis orthogonal slit forming step, in which a pair of girder axis orthogonal slits are formed extending from each of the pair of core holes in a direction perpendicular to the girder axis and from the upper end of the concrete slab to the cutting position, A girder axis slit forming step is provided in the concrete deck slab, on one side in the direction perpendicular to the girder axis of the deck slab to be cut, a girder axis slit that is continuous with the pair of girder axis perpendicular slits and extends in the direction of the girder axis, from the lower end of the concrete deck slab to the cutting position, A wire saw installation step involves passing the wire saw through the core hole on one side in the girder axis direction, through the slit perpendicular to the girder axis on one side in the girder axis direction, through the slit perpendicular to the girder axis on the other side in the girder axis direction, and through the core hole on the other side in the girder axis direction. It has, The cutting device is A pulley installed inside the core hole, A guide member to which the pulley is attached, It has, The pulley is a concrete floor slab removal method in which the pulley can move vertically by raising and lowering the guide member.
2. In the cutting device installation step, the cutting device is installed at a position where it can cut multiple adjacent girder deck slabs in the direction perpendicular to the girder axis. The concrete slab removal method according to claim 1, wherein in the cutting step, a plurality of adjacent slabs on the girder in the direction perpendicular to the girder axis are cut continuously without moving the cutting device.