Bracket steel support and method for building overhung structure

Abstract

To provide a bracket steel support which enables construction of an overhung portion even if the construction limit is extremely close to the side surface of a column part.SOLUTION: A bracket steel support 1 is used for constructing an overhung portion 11 that overhangs in the width direction from the top of a pier 10. The bracket steel support 1 includes a bracket 2 that overhangs outward in the width direction from a side surface 10A of the pier 10, and a tension member 3 that fixes the bracket 2 to the pier 10. The bracket 2 has a support member 21 that extends in the vertical direction along the side surface 10A of the pier 10, and a beam member 22 that extends outward in the width direction from the support member 21. The tension member 3 is provided so as to penetrate the pier 10 and the support member 21 in the width direction while maintaining a tensile stress, thereby pressing the support member 21 against the side surface 10A of the pier 10.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a bracket support and a method for constructing a protrusion that protrudes in the width direction from the upper part of a column. [Background technology]

[0002] A formwork support for forming a pier beam section that protrudes in the width direction at the tip (top) of a pier is known (Patent Document 1). This support comprises a lower chord member that protrudes outward in the width direction from the pier, an upper chord member that extends approximately horizontally above the lower chord member, and a connecting member that connects the lower chord member and the upper chord member in a truss shape. In addition, a holding section for holding the support is constructed on the side of the pier. By making the support a truss structure, deformation can be reduced even if the support protrudes significantly outward in the width direction. As a result, it is said that the pier beam section can be formed using the support even when the construction limit of a road or the like is close to the bottom of the pier beam section (the side of the pier) and a column-type support cannot be constructed on the side of the pier. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2000-336619 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned technology requires an area (space) on the side of the pier to construct the retaining part. However, for example, when the pier is constructed in a place adjacent to a river or on a steep slope, it is not possible to secure an area (space) for constructing the retaining part. In such cases, it becomes difficult to construct the retaining part and shoring, and it is sometimes impossible to form the pier beam part (projection part).

[0005] In consideration of the above circumstances, the present invention provides a bracket support and an overhang construction method that make it possible to construct an overhang even when the construction limit is extremely close to the side of the column. [Means for solving the problem]

[0006] The present invention is a bracket support used when constructing a protrusion that protrudes in the width direction from the top of a column, and comprises at least one bracket that protrudes outward in the width direction from a side surface of the column, and at least one tension member that fixes the bracket to the column, wherein the bracket has a support member that extends in the vertical direction along the side surface of the column, and a beam member that extends outward in the width direction from the support member, and the tension member is arranged to penetrate the column and the support member in the width direction while maintaining tensile stress, thereby pressing the support member against the side surface of the column.

[0007] In this case, it is preferable that the cable structure further includes at least one auxiliary tension member that is fixed to the column portion, penetrates an upper portion of the support material in the width direction, and temporarily supports the support material on the column portion.

[0008] In this case, the brackets may be arranged in parallel in a longitudinal direction perpendicular to the width direction when viewed in a plane, and may further include a plurality of upper girder members that are erected in the longitudinal direction on the beam members of the plurality of brackets and arranged in parallel in the width direction.

[0009] The present invention is a protrusion construction method for constructing a protrusion that protrudes in the width direction from an upper part of a column, and includes an assembly process of assembling at least one bracket that is connected in a crossed state between a support material and a beam material; an installation process of installing the bracket on the column in a position in which the support material is extended in the vertical direction along the side of the column and the beam material is extended from the upper part of the support material outward in the width direction; a shoring construction process of constructing a bracket support in which at least one tension material is arranged to penetrate the column and the support material in the width direction while maintaining tensile stress, thereby pressing the support material against the side of the column and fixing the bracket that protrudes outward in the width direction from the side of the column to the column by the tension material; and a protrusion construction process of constructing the protrusion using the bracket shoring.

[0010] In this case, in the installation step, at least one auxiliary tension member fixed to the column portion may penetrate an upper portion of the support material in the width direction, and the support material may be temporarily supported by the column portion.

[0011] In this case, in the assembly process, multiple brackets are assembled, and in the installation process, multiple brackets are arranged side by side in a longitudinal direction perpendicular to the width direction in a plan view, and in the support construction process, multiple upper girder materials are erected in the longitudinal direction on the beam materials of the multiple brackets and arranged side by side in the width direction.

[0012] In this case, the method may further include a shoring dismantling process for dismantling the bracket shoring after constructing the projection portion in the projection construction process, and the shoring dismantling process may include an equipment installation process for fixing at least one rail extending in a longitudinal direction perpendicular to the width direction in a plan view to the underside of the projection portion and installing at least one trolley that moves along the rail, an unloading process for releasing the tensile stress of the tension material and releasing the fixation of the bracket to the column portion, and a removal process for moving the bracket along the rail in one direction in the longitudinal direction while being suspended by the trolley. Effect of the Invention

[0013] According to the present invention, a projection can be constructed even when the construction gauge is extremely close to the side of the column. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a side view showing a bridge pier or the like to which a bracket support according to one embodiment of the present invention is fixed. [Diagram 2] FIG. 2 is a plan view showing a bridge pier etc. to which a bracket support according to one embodiment of the present invention is fixed. [Diagram 3] 1 is a flowchart illustrating an extension construction method according to an embodiment of the present invention. [Figure 4] FIG. 2 is a front view showing a bracket support structure according to one embodiment of the present invention. [Diagram 5] FIG. 2 is a plan view showing a portion of a bracket support according to one embodiment of the present invention. [Figure 6] 1 is a perspective view showing a portion of a bracket support according to one embodiment of the present invention. [Figure 7] FIG. 2 is a plan view showing a bracket support according to one embodiment of the present invention. [Figure 8] FIG. 2 is a front view showing a bracket support and a formwork support according to one embodiment of the present invention. [Figure 9] FIG. 2 is a front view showing a bracket support, a rail, and the like according to one embodiment of the present invention. [Figure 10] FIG. 2 is a plan view showing a bracket support, a rail, and the like according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, a bracket support 1 and a method for constructing an overhang according to one embodiment will be described with reference to the attached drawings. The bracket support 1 is used, for example, when constructing the substructure of a bridge, specifically, the overhang 11 (see FIG. 4 described later) that overhangs in the width direction from the top of a pier 10. Although details will be described later, the bracket support 1 includes a bracket 2 that overhangs outward in the width direction from a side surface 10A of the pier 10, and a tension member 3 that fixes the bracket 2 to the pier 10. The overhang construction method is a method for constructing the overhang 11 using the bracket support 1. In this specification, the direction in which the overhang 11 overhangs is called the "width direction," and the direction perpendicular to the width direction in a plan view is called the "longitudinal direction." The longitudinal direction is parallel to the bridge axis direction in which the superstructure of the bridge is extended. In addition, "U, Lo" shown in the drawings indicate "upper, lower," and "X, Y" indicate "width direction, longitudinal direction." Furthermore, although terms indicating directions and positions are used in this specification, these terms are used for convenience of explanation and do not limit the technical scope of the present invention.

[0016] First, the bridge pier 10 will be briefly described with reference to Figures 1 and 2. Figure 1 is a side view showing the bridge pier 10, etc. Figure 2 is a plan view showing the bridge pier 10, etc.

[0017] The pier 10 is a part of the substructure of the bridge, and is an example of a column portion as defined in the claims. In Fig. 1 and Fig. 2, as an example, two piers 10 and one abutment 12 are constructed with a gap in the longitudinal direction. A pair of overhangs 11 extend from the top of each pier 10 to both outer sides in the width direction (see Fig. 4 described later), and the superstructure of the bridge (not shown) is constructed on the overhangs 11 to form a bridge having a plurality of spans. In addition, when constructing the piers 10 and the overhangs 11, a pier 13 (work platform) for placing a crane 14, etc. is constructed. The pier 13 extends in the longitudinal direction and also in the width direction toward each pier 10 (see Fig. 2). In addition, each pier 10 is constructed in a place where a column-type support structure cannot be assembled from the ground, such as a place adjacent to a river or on a steep slope. In other words, the construction gauge is assumed to be extremely close to the side surface 10A of the pier 10 directly below the overhanging portion 11. In addition, in this specification, for simplicity of explanation, the explanation will be given mainly focusing on one pier 10.

[0018] [Overhang construction method] The overhang construction method will be described in detail with reference to Figs. 3 to 10. Fig. 3 is a flow chart showing the overhang construction method. Fig. 4 is a front view showing the bracket shoring 1 etc. Fig. 5 is a plan view showing a part of the bracket shoring 1 etc. Fig. 6 is a perspective view showing a part of the bracket shoring 1. Fig. 7 is a plan view showing the bracket shoring 1 etc. Fig. 8 is a front view showing the bracket shoring 1 and formwork shoring 16 etc. Fig. 9 is a front view showing the bracket shoring 1 and rail 30 etc. Fig. 10 is a plan view showing the bracket shoring 1 and rail 30 etc.

[0019] As shown in FIG. 3, the cantilever construction method includes an assembly process S1, an installation process S2, a shoring construction process S3, a cantilever construction process S4, and a shoring dismantling process S5.

[0020] <Assembly process> In the assembly process S1, a plurality of (e.g., eight) brackets 2 are assembled. Although details will be described later, the brackets 2 protrude from both sides in the width direction from both side surfaces 10A of the pier 10 in accordance with a pair of overhanging portions 11, and four brackets 2 are arranged side by side in the longitudinal direction (see Figs. 4 and 5, etc.). Note that, in this specification, for simplicity of explanation, attention is mainly focused on one side in the width direction of the pier 10 (one side surface 10A), and the explanation will be focused on one bracket 2.

[0021] As shown in FIG. 4, the bracket 2 has a support member 21, a beam member 22, and a plurality of (for example, three) diagonal members 23. The support member 21, the beam member 22, and the diagonal members 23 are each made of an H-shaped steel (see FIG. 6). The beam member 22 is formed to be longer (for example, about 13 m) than the planned projection length (length in the width direction (for example, 11 m)) of the projection portion 11. In the assembly process S1, the support member 21 and the beam member 22 are connected in a substantially L-shape (in a crossed state), and the three diagonal members 23 are installed diagonally between the support member 21 and the beam member 22 assembled in a substantially L-shape. The three diagonal members 23 are formed to have different lengths and are arranged in parallel at substantially equal intervals in the vertical direction. In this manner, the bracket 2, which becomes a truss structure, is assembled.

[0022] <Installation process> In the installation step S2, the assembled bracket 2 is installed on the upper part of the pier 10. In the installation step S2, prior to installation of the bracket 2, vertical members 24 (e.g., H-shaped steel) in the same number as the bracket 2 (e.g., eight) are fixed to the side surface 10A of the pier 10 below the planned installation position of the bracket 2 (see FIG. 4). The multiple vertical members 24 are arranged substantially parallel to each other at predetermined intervals in the longitudinal direction, in a posture extending in the up-down direction.

[0023] Next, the bracket 2 is lifted by the crane 14 (see FIG. 1) and installed at the planned installation position of the bracket 2 set on the upper part of the pier 10. Here, a plurality of (e.g., 10 per bracket 2) sheath tubes 4 and a plurality of (e.g., two per bracket 2) auxiliary tension members 5 are embedded in the upper part of the pier 10 (the planned installation position of the bracket 2) (see FIGS. 4 and 5). The sheath tubes 4 and the auxiliary tension members 5 are installed together with the reinforcing bars of the pier 10 before pouring concrete, and are embedded in the pier 10 by pouring concrete. The sheath tubes 4 are provided so as to penetrate the pier 10 in the width direction (see FIG. 5), and both ends of the sheath tube 4 are open on both side surfaces 10A. The ten sheath tubes 4 are arranged in a substantially lattice shape with two columns in the longitudinal direction and five rows in the vertical direction in a side view (see FIG. 6 (eight sheath tubes 4 are shown in FIG. 6)). The two auxiliary tendons 5 are arranged in a line in the longitudinal direction above the two uppermost sheath tubes 4 and protrude outward in the width direction from the side surface 10A (see FIG. 6). The auxiliary tendons 5 are, for example, threaded PC (Prestressed Concrete) steel bars.

[0024] As shown in Fig. 4, in the installation step S2, the bracket 2 is installed on the pier 10 in such a position that the support member 21 is extended in the vertical direction along the side surface 10A of the pier 10 and the beam member 22 is extended outward in the width direction from the upper part of the support member 21. Specifically, the support member 21 of the bracket 2 lifted by the crane 14 is placed on the upper end of the vertical member 24, and the auxiliary tension member 5 fixed to the pier 10 passes through an auxiliary hole (not shown) drilled in the upper part of the support member 21 in the width direction. The bracket 2 is temporarily supported (installed) on the pier 10 by screwing the bolt 5A into the auxiliary tension member 5 (see Fig. 6).

[0025] In this embodiment, when the pier 10 is viewed from one side in the longitudinal direction, a pair of brackets 2 are arranged substantially line-symmetrically with the pier 10 at the center (see FIG. 4). Moreover, a pair of brackets 2 facing each other in the width direction across the pier 10 are arranged in parallel at a predetermined interval in the longitudinal direction in a plan view (see FIGS. 5 and 7). In other words, the eight brackets 2 are arranged substantially in a lattice pattern on both sides of the pier 10 in the width direction in a plan view.

[0026] <Shoring construction process> As shown in FIG. 3, the support construction process S3 includes a tensioning process S31 and an upper girder installation process S32.

[0027] (Tension process) In the tensioning step S31, ten tendons 3 are passed (placed) through the sheath tube 4 via ten support holes (not shown) drilled in the supports 21 of the brackets 2. The tendons 3 are, for example, PC steel bars, and are provided so as to penetrate the pier 10 and the supports 21 of a pair of brackets 2 installed on both sides of the pier in the width direction (see FIG. 5). In the tensioning step S31, a tension force (tensile stress) is applied to the tendons 3 that have penetrated the supports 21 and the pier 10 using a jack (not shown), and in this state, fixing devices 3A are fixed to both ends of the tendons 3 in the width direction (see FIG. 6 (so-called post-tensioning method)).

[0028] As described above, in the tensioning step S31 of the support construction step S3, the tensioning material 3 is provided so as to penetrate the support 21 and the pier 10 in the width direction while maintaining a tensile stress, thereby pressing the support 21 located on both sides in the width direction against both side surfaces 10A of the pier 10. In other words, the tensioning material 3 applies compressive stress inward from both outside sides in the width direction to the pier 10 via the support 21 that sandwich the pier 10 from both sides in the width direction. Then, the bracket support 1 is generally constructed by fixing the bracket 2 protruding outward in the width direction from the side surface 10A of the pier 10 to the pier 10 by the tensioning material 3 (see FIG. 4).

[0029] (Upper girder installation process) Next, in the upper girder installation step S32 of the shoring construction step S3, as shown in Figs. 4 and 7, a plurality of upper girder materials 6 are erected in the longitudinal direction on the beam materials 22 of a plurality of brackets 2, and are arranged side by side at a predetermined interval in the width direction. The upper girder materials 6 are, for example, H-shaped steel, and are formed longer than the longitudinal dimension of the pier 10. The upper girder materials 6 cross the four beam materials 22 arranged side by side in the longitudinal direction, and further extend on both sides in the longitudinal direction. The upper girder materials 6 are lifted by the crane 14, and are arranged and fixed on the plurality of beam materials 22. Note that the bracket shoring 1 may be regarded as including the upper girder materials 6 in addition to the brackets 2 and the tendons 3. Also, a scaffolding board (steel plate) may be installed on the upper girder materials 6, or a second upper girder material may be extended in the width direction (neither is shown).

[0030] <Overhang construction process> In the overhang construction process S4, the overhang 11 is constructed using the bracket support 1. Specifically, as shown in FIG. 8, on the bracket support 1 (beam material 22, upper girder material 6), a peripheral scaffolding 15 is installed so as to surround the planned construction position of the overhang 11, and a form support 16 that holds a reinforced formwork (not shown) is installed. Concrete is then poured into the formwork to construct a pair of overhangs 11 that extend from the top of the pier 10 to both sides in the width direction. The bracket support 1 supports the load of the concrete that forms the overhang 11. Note that the overhang construction process S4 also includes a process of dismantling and removing the peripheral scaffolding 15, form support 16, etc. after the overhang 11 is constructed.

[0031] <Shoring dismantling process> In the shoring dismantling process S5, after the overhang portion 11 is constructed in the overhang construction process S4 (more precisely, after the formwork shoring 16 and the like are removed), the bracket shoring 1 is dismantled. However, since the bracket 2 is located directly below the overhang portion 11, the bracket 2 cannot be lifted by the crane 14, and the bracket shoring 1 cannot be dismantled. Therefore, in the shoring dismantling process S5 of the overhang construction method according to this embodiment, the bracket 2 located directly below the overhang portion 11 is moved to one side in the longitudinal direction, making it possible to lift the bracket 2 by the crane 14.

[0032] 3, the shoring dismantling process S5 includes an equipment installation process S51, an unloading process S52, and a removal process S53. It is assumed that the upper girder material 6 is accumulated on the tip side (outside in the width direction) of the beam material 22 of the bracket 2, and is lifted up and removed by the crane 14.

[0033] (Equipment installation process) In the equipment installation step S51, as shown in Figs. 9 and 10, a plurality of (e.g., two) rails 30 extending in the longitudinal direction are fixed to the underside of the overhanging portion 11, and a plurality of (e.g., two) trolleys 31 moving along the rails 30 are installed. The rails 30 are, for example, H-shaped steel, and are formed to a length that crosses the overhanging portion 11 in the longitudinal direction and further extends from the overhanging portion 11 in one longitudinal direction. The rails 30 are arranged at a predetermined interval in the width direction and are fixed to the underside of the overhanging portion 11 via anchors (not shown). The trolley 31 has a chain block (not shown) for hoisting the bracket 2, and moves laterally on the rails 30 while hoisting the bracket 2. The lateral movement of the trolley 31 and the elevation of the chain block may be electrically operated or manually operated.

[0034] (Unloading process) In the unloading process S52, the tensile stress of the tension member 3 is released, and the bracket 2 is released from the pier 10. Specifically, the fixing device 3A is removed from the tension member 3, and the tension (tensile stress) acting on the tension member 3 is released. This releases the bracket 2 from its fixation, and the bracket 2 is temporarily supported by the two auxiliary tension members 5.

[0035] (Removal process) In the removal step S53, the bracket 2 is moved to one side in the longitudinal direction along the rail 30 while being suspended by the trolley 31. Specifically, the bracket 2 is suspended from the trolley 31 (chain block), the bolt 5A is removed from the auxiliary tension member 5, and the auxiliary tension member 5 is relatively pulled out from the support member 21 of the bracket 2. That is, the bracket 2 is separated from the pier 10. Next, as shown in FIG. 10, the trolley 31 moves the bracket 2 located directly below the overhanging portion 11 to a position offset to one side in the longitudinal direction from the overhanging portion 11. The bracket 2 is exposed to one side in the longitudinal direction of the overhanging portion 11 in a plan view. In this state, the bracket 2 is transferred from the trolley 31 (chain block) to the crane 14, and is lifted up and removed by the crane 14. The upper girder member 6 described above may be removed using the trolley 31 in the same manner as in the removal of the bracket 2. In addition, the tendon 3 is pulled out from the sheath tube 4, and a filler is filled into the sheath tube 4. In addition, the vertical member 24 fixed to the side surface 10A of the pier 10 is removed.

[0036] This completes all the steps of the method for constructing an overhang. Note that the above-described method for constructing an overhang is merely an example, and the order (procedure) may be changed in various ways without departing from the spirit and scope of the technical concept.

[0037] In the bracket support 1 (overhang construction method) according to the present embodiment described above, the support material 21 of the bracket 2 is pressed against the side surface 10A of the pier 10 (column portion) by the tensioned tension material 3. With this configuration, the bracket 2 (support material 21) is firmly fixed to the pier 10 via the tension material 3, so that the settlement (deformation) of the bracket 2 can be suppressed without constructing a structure to support the bracket 2 in a position adjacent to the side surface 10A of the pier 10. As a result, even if the pier 10 is constructed in a place adjacent to a river or on a steep slope and an area (space) for constructing a structure (column-type support) to support the bracket 2 cannot be secured, the formwork support 16 for forming the overhang portion 11 can be reliably held by the bracket support 1. In other words, by using the bracket support 1, it becomes possible to construct the overhang portion 11 even if the construction limit is extremely close to the side surface 10A of the pier 10.

[0038] Moreover, in the bracket support 1 (cantilever construction method) according to this embodiment, the auxiliary tension members 5 fixed to the pier 10 penetrate the upper part of the support 21, temporarily supporting the support 21 on the pier 10. With this configuration, the support 21 is temporarily supported on the pier 10 via the auxiliary tension members 5, so that the subsequent process of tensioning the tension members 3 (support construction process S3) can be stably carried out. Similarly, the process of releasing the tension of the tension members 3 (support dismantling process S5) can also be stably carried out.

[0039] Moreover, in the bracket support 1 (overhang construction method) according to this embodiment, a configuration is adopted in which a plurality of brackets 2 are integrated with a plurality of upper girder materials 6. According to this configuration, it is possible to construct the bracket support 1 that properly holds the formwork support 16 of the overhang portion 11 and the like.

[0040] Furthermore, in the overhang construction method according to this embodiment, when dismantling the bracket support 1, the rail 30 extending in the longitudinal direction is fixed to the underside of the overhang 11, and the trolley 31 is installed so as to be movable along the rail 30. Also, the trolley 31 is configured to move in one direction in the longitudinal direction while suspending the bracket 2. With this configuration, the bracket 2 located directly below the overhang 11 can be moved to a position offset in one direction in the longitudinal direction from the overhang 11. This allows the bracket 2 to be smoothly removed using the crane 14 without interfering with the overhang 11.

[0041] In the bracket support 1 according to this embodiment, four brackets 2 are arranged in parallel in the longitudinal direction, and multiple upper girder members 6 are arranged in parallel in the width direction, but the present invention is not limited to this. It is sufficient that one or more brackets 2 and upper girder members 6 are provided (not shown). Furthermore, the upper girder members 6 are not essential and may be omitted (not shown).

[0042] In addition, in the bracket support 1 according to this embodiment, a pair of brackets 2 are provided in the width direction sandwiching the pier 10, but the present invention is not limited to this. For example, the bracket 2 may be provided on only one side of the pier 10 in the width direction (not shown). In other words, the overhanging portion 11 may be constructed on only one side of the pier 10 in the width direction (not shown).

[0043] In addition, in the bracket support 1 according to the present embodiment, the beam 22 extends from the upper portion of the support 21, and the bracket 2 is formed in a substantially L-shape, but the present invention is not limited to this. For example, the beam 22 may extend from the middle portion of the support 21 in the vertical direction to the outside in the width direction, and the bracket 2 may be formed in a substantially T-shape (not shown). In this case, the diagonal member 23 may be installed between the beam 22 and the support 21 on the lower side of the beam 22, or between the beam 22 and the support 21 on the upper side of the beam 22 (neither is shown). In addition, the diagonal member 23 installed on the upper side of the beam 22 is not limited to an H-shaped steel, and may be, for example, a wire such as a PC steel wire (not shown).

[0044] In addition, in the bracket 2 of the bracket support 1 according to this embodiment, three diagonal members 23 are installed between the support member 21 and the beam member 22, but the present invention is not limited to this. It is sufficient that one or more diagonal members 23 are provided, and for example, one diagonal member 23 may be installed between the support member 21 and the beam member 22 (not shown). Also, for example, when the beam member 22 is short or the vertical load is small, the diagonal member 23 may be omitted (not shown).

[0045] In addition, in the bracket support 1 (cantilever construction method) according to this embodiment, the bracket 2 is fixed to the pier 10 by ten tension members 3, but the present invention is not limited to this. At least one tension member 3 (sheath tube 4) may be provided, and for example, the bracket 2 may be fixed to the pier 10 by one tension member 3 (not shown). In addition, two auxiliary tension members 5 that temporarily hold the bracket 2 are provided, but this is not limited to this, and at least one auxiliary tension member 5 may be provided (not shown). In addition, for example, if the bracket 2 can be temporarily held by suspending it with a crane 14, the auxiliary tension members 5 and vertical members 24 may be omitted (not shown).

[0046] Furthermore, in the bracket support 1 (cantilever construction method) according to this embodiment, a post-tensioning method is adopted as a method for applying tension to the tendons 3, in which the tendons 3 are placed in the sheath pipes 4 embedded in the pier 10 in advance and tension is applied to the tendons 3, but the present invention is not limited to this. For example, a pre-tensioning method may be adopted as a method for applying tension to the tendons 3, in which the tendons 3 to which tension has been applied in advance are placed in the formwork of the pier 10 and the tension is released after concrete is poured.

[0047] In addition, in the cantilever construction method according to this embodiment, multiple rails 30 and multiple trolleys 31 were installed during dismantling, but this is not limited to the above, and it is sufficient that at least one rail 30 and at least one trolley 31 are installed (not shown).

[0048] Furthermore, the bracket support 1 (overhang construction method) according to this embodiment has been applied when the construction limit is extremely close to the side surface 10A of the pier 10 directly below the overhanging portion 11, but the present invention is not limited to this. The bracket support 1 (overhang construction method) according to this embodiment can be applied, for example, even in places where pillar-type supports and the like can be assembled from the ground. The bracket support 1 (overhang construction method) according to this embodiment can provide the effect of shortening the construction period compared to assembling pillar-type supports and the like from the ground.

[0049] Furthermore, the bracket support 1 (overhang construction method) according to this embodiment has been applied to the construction of the overhanging portion 11 overhanging from the top of the pier 10, that is, to the construction of a bridge, but the present invention is not limited to this. The bracket support 1 (overhang construction method) according to this embodiment can be applied to the construction of a structure having a portion overhanging in the width direction from the top of a column installed in an upright position.

[0050] The above embodiment is merely an example of the bracket support and the overhang construction method according to the present invention, and the technical scope of the present invention is not limited to the above embodiment. The present invention may be modified, substituted, or altered in various ways without departing from the spirit of the technical idea, and the claims include all embodiments that may be included within the scope of the technical idea. [Explanation of symbols]

[0051] 1 Bracket support 2 Bracket 3 Tensors 3A Fixture 5 Auxiliary tension material 6 Upper girder material 10 Pier (column) 10A Side 11 Overhang 21 Support material 22 Beam material 30 Rail 31 Trolley

Claims

1. A bracket support used when constructing a protruding portion that protrudes in the width direction from the top of a column, At least one bracket protruding outward in the width direction from a side surface of the column portion; At least one tendon fastening the bracket to the post, The bracket is A support member extending in the vertical direction along the side surface of the column portion; A beam member extending from the support member toward an outer side in the width direction, A bracket support structure characterized in that the tension member is arranged to penetrate the column portion and the support material in the width direction while maintaining a tensile stress, thereby pressing the support material against the side surface of the column portion.

2. The bracket support structure described in claim 1, further comprising at least one auxiliary tension member fixed to the column portion, penetrating an upper portion of the support material in the width direction, and temporarily supporting the support material on the column portion.

3. The brackets are arranged in a plurality of rows in a longitudinal direction perpendicular to the width direction in a plan view, The bracket support structure according to claim 1 or 2, further comprising a plurality of upper girders arranged in the longitudinal direction on the beam members of the plurality of brackets and arranged in parallel in the width direction.

4. A method for constructing a protrusion that protrudes in a width direction from an upper portion of a column, comprising the steps of: an assembly process for assembling at least one bracket in which the support material and the beam material are connected in a crossed state; an installation process of installing the bracket on the column portion in a position in which the support material is extended in the vertical direction along the side surface of the column portion and the beam material is extended from an upper portion of the support material toward the outside in the width direction; a support construction process in which at least one tension member is provided to penetrate the column portion and the support member in the width direction while maintaining a tensile stress, thereby pressing the support member against the side surface of the column portion and constructing a bracket support in which the bracket protruding outward in the width direction from the side surface of the column portion is fixed to the column portion by the tension member; and a projection construction process for constructing the projection portion using the bracket support.

5. The method for constructing an overhang as described in claim 4, characterized in that in the installation process, at least one auxiliary tension member fixed to the column portion penetrates an upper portion of the support material in the width direction, and temporarily supports the support material on the column portion.

6. In the assembly process, a plurality of the brackets are assembled, In the installation step, the brackets are arranged side by side in a longitudinal direction perpendicular to the width direction in a plan view, The cantilever construction method according to claim 4 or 5, characterized in that, in the support construction process, a plurality of upper girders are erected in the longitudinal direction on the beams of the plurality of brackets and arranged side by side in the width direction.

7. The method further includes a support dismantling process for dismantling the bracket support after constructing the overhang portion in the overhang construction process, The support dismantling process includes: an equipment installation process of fixing at least one rail extending in a longitudinal direction perpendicular to the width direction in a plan view to a lower surface of the overhanging portion and installing at least one trolley that moves along the rail; an unloading process of releasing the tensile stress of the tension member and releasing the fixing of the bracket to the column portion; 6. The method for constructing an overhang according to claim 4 or 5, further comprising a removal step of moving the bracket along the rail in one direction in the longitudinal direction while being suspended by the trolley.

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