Strut installation method

Abstract

To provide a strut installation method that enables installation of struts of a timbering when it is difficult to use a crane.SOLUTION: A strut installation method for installing a strut 15 of a timbering 13 of earth retaining walls 11, 11 comprises: a hardware installation process of installing a pair of stool-type hardware 23 which support ends of the strut 15 at a height of wales 17 of the timbering 13 respectively on the pair of wales 17; a guide installation process of installing a guide steel material 27 having a sloped surface 27a that slopes upward toward a height of the stool-type hardware 23; and a strut member moving process of sliding a strut member 19 constituting the strut 15 on the sloped surface 27a from a position lower than the wales 17 and placing both ends 19a, 19a of the strut member 19 on the stool-type hardware 23.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a method for installing a cross beam.

Background Art

[0002] Conventionally, in construction work performed by excavating the ground, a retaining wall is constructed, and in order to support the retaining wall, support works are constructed by means such as bracing and cross beams. For example, in the construction method of Patent Document 1 below, the steel materials constituting the cross beam of the support work are lifted by a crane, moved to a predetermined position, and installed, thereby constructing the cross beam.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when constructing the support work for a retaining wall at a site with headroom restrictions, it may be difficult to secure sufficient crane lifting costs, and it may also be difficult to lift the cross beam and move it to the cross beam installation position. Therefore, an object of the present invention is to provide a method for installing a cross beam of a support work that enables installation of the cross beam when it is difficult to use a crane.

Means for Solving the Problems

[0005] The gist of the present invention resides in the following [1] to [4].

[0006] 〔1〕A method for installing a crossbeam for supporting an earth-retaining wall, the method comprising: a metal fitting installation step of installing a pair of bracket fittings that support an end portion of the crossbeam at a height of a web rise of the support; a guide installation step of installing a guide steel material having an inclined surface that slopes upward toward a position at the height of the bracket fitting; and a crossbeam member movement step of moving a crossbeam member constituting the crossbeam from a position lower than the web rise onto the inclined surface and placing both end portions of the crossbeam member on the bracket fitting.

[0007] 〔2〕The bracket fitting according to 〔1〕 has a horizontal plate portion on which an end portion of the crossbeam member is placed, and a stopper portion that prevents the end portion of the crossbeam member on the horizontal plate portion from further moving forward in the moving direction of the crossbeam member in the crossbeam member movement step.

[0008] 〔3〕In the crossbeam member movement step, a temporary support that protrudes upward from the web rise is attached to the web rise at a position in front of the crossbeam member in the moving direction of the crossbeam member in the crossbeam member movement step relative to the bracket fitting, and the end portion of the crossbeam member is pulled toward the temporary support by a tension device that connects the temporary support and the end portion of the crossbeam member, thereby moving the crossbeam member. The crossbeam installation method according to 〔1〕 or 〔2〕.

[0009] 〔4〕In the guide installation step, an upper end of the guide steel material is attached to the bracket fitting, a lower end of the guide steel material is placed on the ground below the bracket fitting, and after the crossbeam member movement step, the upper end of the guide steel material is removed from the bracket fitting and the guide steel material is removed. The crossbeam installation method according to any one of 〔1〕 to 〔3〕.

Advantages of the Invention

[0010] According to the present invention, it is possible to provide a crossbeam installation method capable of installing a crossbeam for a support even when it is difficult to use a crane.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the method for installing a cut beam according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a view showing a construction site 100 to which the method for installing a cut beam according to this embodiment is applied, and is a cross-sectional view in a cross-section orthogonal to the longitudinal direction of the railway track 101. FIG. 1 shows the state of the construction site 100 after the cut beam 15 of the shoring 13 is installed by the method for installing a cut beam according to this embodiment.

[0013] At this construction site 100, the ground is excavated and construction is carried out below the track 101. During the construction, a temporary structure 103 for supporting the track 101 is constructed and the operation of the railway is continued. The temporary structure 103 includes a construction girder 107 for temporarily supporting the track 101, a cantilever girder 108 for supporting the construction girder 107, and columns 105, 105 for supporting the cantilever girder 108. A pair of earth retaining walls 11, 11 are constructed so as to sandwich the temporary structure 103 in the track width direction, and the space between the earth retaining walls 11, 11 is excavated. The earth retaining walls 11, 11 are constructed, for example, by the method of sheet pile wall with vertical piles.

[0014] At this construction site 100, a portion approximately 2 m below the construction girder 107 is first excavated to form a first-excavated ground surface 109, and the earth-retaining walls 11, 11 facing each other are exposed above the first-excavated ground surface 109. Also, the ground between the struts 105, 105 is secondarily excavated to approximately 2 m further below the first-excavated ground surface 109 to form a second-excavated ground surface 111. Therefore, the crane 9 is introduced onto the second-excavated ground surface 111, and the crane 9 can be operated in a space with an up-and-down width of approximately 4 m between the second-excavated ground surface 111 and the construction girder 107.

[0015] The shoring 13 that supports the earth-retaining walls 11, 11 has the braces 17, 17 and the crossbeam 15. The braces 17, 17 are made of H-shaped steel extending in the longitudinal direction of the track, are provided at the upper parts of the respective earth-retaining walls 11, 11, and are arranged at positions slightly lower than the construction girder 107. The crossbeam 15 is made of H-shaped steel extending in the track-width direction, is sandwiched between the braces 17, 17, and is arranged such that both end faces of the crossbeam 15 face the flanges of the braces 17 respectively. The crossbeam 15 is the crossbeam located at the uppermost stage of the shoring 13 and is located slightly below the construction girder 107.

[0016] Subsequently, with reference to FIGS. 2 to 5, the method for installing the crossbeam of the present embodiment will be described. The method for installing the crossbeam of the present embodiment is executed during the construction of the shoring 13 as described above, and installs the crossbeam 15 at a predetermined crossbeam installation position 14 of the shoring 13. This method for installing the crossbeam starts from a state where the braces 17, 17 are already installed on the earth-retaining walls 11, 11. In the following description, when simply referring to "inside / outside", it means the inside / outside of the excavation space surrounded by the earth-retaining walls 11, 11. Also, when simply referring to "front / rear", etc., the direction deep into the paper in FIGS. 1 and 2 is defined as "front", and the direction towards the front is defined as "rear". The method for installing the crossbeam of the present embodiment includes the following steps to be described.

[0017] (Hardware Installation Step) In the hardware installation process, as shown in FIGS. 2 and 3, seat hardware 23, 23 is installed on the belly rises 17, 17 respectively. Here, the configuration of one belly rise 17 and the seat hardware 23 will be mainly described with reference to FIG. 3, but as shown in FIG. 2, the other belly rise 17 and the seat hardware 23 also have a symmetrical configuration.

[0018] The seat hardware 23 is bolted to the flange 21 inside the belly rise 17 for installation. A general-purpose bracing member made of H-beam is used for the belly rise 17, and bolt holes 22 are provided in the flange 21 of this type of general-purpose H-beam. The seat hardware 23 is bolted to the flange 21 using the bolt holes 22. The seat hardware 23 projects inward from the flange 21 and supports one end of the cross beam 15 (FIG. 1) at the height of the belly rise 17. The seat hardware 23 has a horizontal plate portion 23a and a vertical plate portion 23b. The horizontal plate portion 23a is in the shape of a horizontal rectangular flat plate and places one end of the cross beam 15 on the upper surface. The vertical plate portion 23b is in the shape of a rectangular flat plate and is formed to rise vertically upward from the front edge of the horizontal plate portion 23a.

[0019] Also, the seat hardware 23 has a mounting plate portion 23c that abuts against the flange 21. The mounting plate portion 23c is in the shape of a vertical rectangular flat plate that is orthogonal to both the horizontal plate portion 23a and the vertical plate portion 23b. By bolting the mounting plate portion 23c to the flange 21, the seat hardware 23 is fixed to the belly rise 17. The seat hardware 23 is excellent in strength due to its structure having the horizontal plate portion 23a, the vertical plate portion 23b, and the mounting plate portion 23c that are orthogonal to each other. A general-purpose steel member having such three rectangular flat plate portions 23a, 23b, 23c that are orthogonal to each other may be used as the seat hardware 23.

[0020] (Guide Installation Process) Subsequently, in the guide installation step, guide steel members 27, 27 are installed within the construction site 100. In the present embodiment, a pair of guide steel members 27, 27 exist so as to correspond to each of the pair of seat fittings 23, 23. The upper surface of the guide steel member 27 is a flat plane and forms an inclined surface 27a. The inclined surface 27a slopes upward from the primary excavation ground 109 to the seat fitting 23. The inclined surface 27a extends parallel to the belly rise 17 in plan view and slopes upward toward the front. The guide steel member 27 may be a flat steel member as illustrated in FIG. 3, but may have other shapes as long as it has an inclined surface 27a forming a flat plane. The upper end of the guide steel member 27 is attached to the rear edge portion of the horizontal plate portion 23a of the seat fitting 23 by a predetermined fixing means (not shown) using, for example, a burman or the like. At this time, the inclined surface 27a of the guide steel member 27 is connected to the upper surface of the horizontal plate portion 23a. The lower end of the guide steel member 27 is placed on the primary excavation ground 109, and at this time, the inclined surface 27a of the guide steel member 27 is connected to the primary excavation ground 109.

[0021] (Temporary Placement Step of the Cross Beam Member) Subsequently, in the temporary placement step of the cross beam member, as shown in FIG. 4, a cross beam member 19, which is an H-beam constituting the cross beam 15, is temporarily placed on the ground of the construction site 100. Specifically, the cross beam member 19 is temporarily placed on the primary excavation ground 109 in a direction extending in the track width direction at a position slightly behind the lower end of the guide steel member 27. The primary excavation ground 109 is divided into two in the track width direction with the secondary excavation ground 111 in between, but the cross beam member 19 is placed so as to span each part of the divided primary excavation ground 109. The positions of both end portions 19a, 19a of the cross beam member 19 in the track width direction are respectively adjusted to the positions of the seat fittings 23, 23.

[0022] In the temporary placement process of the cut beam member, for example, the cut beam member 19 is carried into the space below the construction girder 107 at a predetermined location (not shown) behind the position of the construction site 100 shown in FIG. 4 and conveyed in the longitudinal direction of the track. Then, the cut beam member 19 is suspended by the crane 9 (FIG. 1) and temporarily placed on the primary excavation ground 109. Since there is a height difference of about 2 m between the primary excavation ground 109 and the construction girder 107, here, the space with a vertical width of about 2 m can be utilized as the suspension allowance of the crane 9.

[0023] Note that this temporary placement process of the cut beam member may be executed before the above-described guide installation process or before the hardware installation process. Also, the temporary placement process of the cut beam member may be executed in parallel with the guide installation process or the hardware installation process.

[0024] (Cut beam member movement process) Subsequently, in the cut beam member movement process, the cut beam member 19 temporarily placed on the primary excavation ground 109 as described above is moved to the cut beam installation position 14. At this time, the cut beam member 19 is slid upward on the inclined surface 27a of the guide steel material 27 and finally, both ends of the cut beam member 19 are placed on the seat hardware 23, 23. The specific method is as follows.

[0025] First, as shown in FIGS. 3 and 4, at a position in front of the seat hardware 23, a temporary support 31 is attached to the flange 21 of the web 17. The temporary support 31 is a steel material extending vertically and protrudes upward from the web 17. For example, the temporary support 31 is an angle material and is bolted to the inner surface (the surface where the seat hardware 23 is attached) of the flange 21 of the web 17. Since the general-purpose bolt holes 22 of the flange 21 are provided in two upper and lower rows with the position of the web in between, the temporary support 31 is bolted using two bolt holes 22 in the upper row and the lower row. The portion of the temporary support 31 protruding upward from the web 17 is located between the temporary structure 103 and the earth retaining wall 11.

[0026] Next, as shown in Fig. 5(a), the end portion 19a in the track width direction of the cut beam member 19 is connected to the temporary support 31 via the tension device 33. The tension device 33 has a wire 35 and a manual winder 37 that winds the wire 35 by manual lever operation. As the manual winder 37, for example, a lever block (registered trademark) or a chain block may be used. Part or all of the wire 35 may be replaced with a chain.

[0027] A pair of the above-described temporary supports 31 and tension devices 33 are symmetrically provided corresponding to both end portions 19a, 19a in the track width direction of the cut beam member 19, respectively. From this state, when the operator manually operates the pair of manual winders 37, 37 by the same wire winding amount, the end portions 19a, 19a of the cut beam member 19 are pulled toward the temporary supports 31, 31 by the wires 35, 35, respectively. Then, as shown in Fig. 5(b), the end portions 19a, 19a of the cut beam member 19 slide on the inclined surfaces 27a, 27a and move upward in inclination toward the seat fittings 23, 23, and the entire cut beam member 19 moves obliquely upward in parallel toward the cut beam installation position 14. Then, as shown in Figs. 5(c) and 6, when the end portions 19a, 19a of the cut beam member 19 are placed on the horizontal plate portions 23a, 23a of the seat fittings 23, 23, the operation of the manual winders 37, 37 is stopped. The cut beam member 19 is in a state of being supported at both ends by the seat fittings 23, 23. Thus, the movement of the cut beam member 19 to the cut beam installation position 14 is completed. Thereafter, the tension device 33 and the temporary support 31 are removed, the upper end of the guide steel material 27 is removed from the seat fitting 23, and the guide steel material 27 is removed.

[0028] Thereafter, at both end portions 19a, 19a of the cut beam member 19 located at the cut beam installation position 14, the lower flange 19b (Fig. 5(c)) of the cut beam member 19 is bolted to the horizontal plate portion 23a of the seat fitting 23, and mortar is filled between the end face of the cut beam member 19 and the mounting plate portion 23c of the seat fitting 23, thereby constituting the cut beam 15. Thus, the cut beam installation method of the present embodiment is completed and the cut beam 15 is completed.

[0029] The operational effects of the method for installing the cut beam according to the present embodiment described above will be described.

[0030] As shown in FIG. 1, as described above, a construction girder 107 exists slightly above the cut beam installation position 14. Therefore, it is difficult to secure the suspension allowance of the crane 9, and it is difficult to install the cut beam 15 using the crane 9. That is, if an attempt is made to lift the cut beam member 19 with the crane 9 and move it to this cut beam installation position 14, the boom tip of the crane 9 may interfere with the construction girder 107, so it is difficult to use the crane 9. On the other hand, in the method for installing the cut beam of the present embodiment, since the cut beam member 19 is moved from below along the inclined surface 27a to the cut beam installation position 14, the force required for the movement of the cut beam member 19 is relatively small, and it can be executed by equipment simpler than the crane 9. Therefore, even when it is difficult to use the crane 9 due to headroom restrictions, the cut beam 15 can be installed.

[0031] For example, as another method for moving the cut beam member 19 to the cut beam installation position 14, it is also conceivable to lift the cut beam member 19 with a forklift, a lifter, or the like. However, since the equipment becomes too large, it is disadvantageous in terms of labor costs, and the workability at a narrow site cannot be said to be good. On the other hand, in the method for installing the cut beam of the present embodiment, since the cut beam member 19 is moved on the inclined surface 27a of the guide steel material 27, it can be executed by relatively simple equipment such as a tension device 33 including a manual winch 37 or the like. Therefore, it is advantageous in terms of labor costs, and the workability at a narrow site is also good.

[0032] In the cut beam member movement step, a temporary support 31 protruding upward from the belly lift 17 is attached to the belly lift 17 at a position in front of the seat fittings 23, and a tension device 33 connecting the temporary support 31 and the end of the cut beam member 19 is attached. Then, the cut beam member 19 moves by pulling the end of the cut beam member 19 toward the temporary support 31 by operating the tension device 33. According to such a configuration, the cut beam member 19 can be lifted on the inclined surface 27a by a relatively simple mechanism.

[0033] In the construction under the track, it may be prohibited to apply a load to the temporary structure 103 during railway operation. In this case, one end side of the tension device 33 cannot be connected to the temporary structure 103. If it is at night when the railway operation stops, it is possible to apply a load to the temporary structure 103. However, if the installation work of the cut beam 15 is only carried out at night, it is disadvantageous in terms of labor cost and construction period. On the contrary, according to the cut beam installation method of the present embodiment, the temporary support 31 is attached to the web 17 instead of the temporary structure 103, and one end side of the tension device 33 is connected to the temporary support 31. Therefore, it is possible to avoid applying the load of the cut beam member 19 to the temporary structure 103, and the installation work of the cut beam 15 can be carried out during the daytime railway operation. As a result, it is advantageous in terms of labor cost and construction period.

[0034] Here, as another method for moving the cut beam member 19 to the cut beam installation position 14, it is also conceivable to temporarily place the cut beam member 19 vertically below the cut beam installation position 14 and lift it vertically upward to the cut beam installation position 14 by suspending the cut beam member 19 with the tension device 33. However, as described above, it is necessary to avoid connecting one end side of the tension device 33 to the temporary structure 103. Therefore, the temporary support 31 needs to be attached to the web 17. However, there is a hanging hardware 23 at the position where the temporary support 31 should be attached, and the attachment is difficult. In addition, there is also a problem that the cut beam member 19 moving vertically upward interferes with the hanging hardware 23. On the contrary, in the cut beam installation method of the present embodiment, since the cut beam member 19 is pulled upward obliquely on the inclined surface 27a, the temporary support 31 can be appropriately attached to the web 17 at a position horizontally separated from the hanging hardware 23. In addition, the problem that the rising cut beam member 19 interferes with the hanging hardware 23 can also be avoided. Also, compared with the case of pulling the cut beam member 19 vertically upward, the cut beam member 19 can be moved using a tension device 33 with a lower capacity.

[0035] In addition, as shown in FIG. 3, the bracket 23 in the method for installing the cut beam of the present embodiment has a horizontal plate portion 23a on which the end portion 19a of the cut beam member 19 is placed, and a vertical plate portion 23b that rises from the front edge portion of the horizontal plate portion 23a. According to this configuration, after the end portion 19a of the cut beam member 19 reaches the horizontal plate portion 23a in the cut beam member moving step, it is prevented from further moving forward and falling off the horizontal plate portion 23a. That is, the vertical plate portion 23b functions as a stopper portion that prevents the end portion 19a of the cut beam member 19 on the horizontal plate portion 23a from moving further forward. Therefore, the safety of the work in the cut beam member moving step is improved. For example, in the cut beam member moving step, an operation such as operating the manual winder 37 until the end portion 19a of the cut beam member 19 abuts against the vertical plate portion 23b may be performed.

[0036] Note that the stopper portion as described above is not limited to the vertical plate portion 23b that rises vertically from the front edge portion of the horizontal plate portion 23a, and may be, for example, a protrusion that protrudes upward from the front portion of the horizontal plate portion 23a. Further, the mounting plate portion 23c of the bracket 23 may be omitted, and the bracket 23 may be fixed to the flange 21 by another method such as welding. Further, the vertical plate portion 23b of the bracket 23 may be omitted.

[0037] In the guide installation step in the present embodiment, the upper end of the guide steel material 27 is attached to the bracket 23, and the lower end of the guide steel material 27 is placed on the primary excavation ground 109. Therefore, after the completion of the cut beam member moving step, the guide steel material can be easily removed by removing the upper end of the guide steel material 27 from the bracket 23.

[0038] The present invention can be implemented in various forms with various changes and improvements based on the knowledge of those skilled in the art, starting from the above-described embodiments. It is also possible to configure a modified example by using the technical matters described in the above-described embodiments. The configurations of the respective embodiments and the like may be appropriately combined and used.

[0039] For example, in the process of moving the cutting beam member in the embodiment, the cutting beam member 19 is pulled up to the seat fitting 23 on the inclined surface 27a by the tension device 33. However, in the process of moving the cutting beam member, the cutting beam member 19 may be pushed up to the seat fitting 23 on the inclined surface 27a by a predetermined device.

Explanation of Signs

[0040] 11... earth retaining wall, 13... support work, 15... cutting beam, 17... abdominal lift, 19... cutting beam member, 19a... end, 23... seat fitting, 23a... horizontal plate part, 23b... vertical plate part (stopper part), 27... guide steel material, 27a... inclined surface, 31... temporary support, 33... tension device.

Claims

1. A method for installing a cross beam for a retaining wall support, comprising: A fitting installation step of installing a pair of bracket fittings that support the ends of the cross beam at the height of the web rise of the support on a pair of the web rises respectively; A guide installation step of installing a guide steel material having an inclined surface that slopes upward toward the position of the height of the bracket fitting; A cross beam member moving step of moving the cross beam members constituting the cross beam from a position lower than the web rise onto the inclined surface and placing both ends of the cross beam members on the bracket fittings; The cross beam installation method comprising the above steps.

2. The bracket fitting has: A horizontal plate portion on which the end of the cross beam member is placed; A stopper portion that prevents the end of the cross beam member on the horizontal plate portion from moving further forward in the moving direction of the cross beam member in the cross beam member moving step. The cross beam installation method according to Claim 1.

3. In the cross beam member moving step: A temporary support that protrudes upward from the web rise is attached to the web rise at a position in front of the moving direction of the cross beam member in the cross beam member moving step and ahead of the bracket fitting; The cross beam member moves by the end of the cross beam member being pulled toward the temporary support by a tension device that connects the temporary support and the end of the cross beam member. The cross beam installation method according to Claim 1.

4. In the guide installation step, the upper end of the guide steel material is attached to the bracket fitting, and the lower end of the guide steel material is placed on the ground below the bracket fitting; After the cross beam member moving step, the upper end of the guide steel material is removed from the bracket fitting and the guide steel material is removed. The cross beam installation method according to Claim 1.

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