Cantilever erection machine and cantilever erection method

Abstract

To provide an overhang erection machine and an overhang erection method capable of reducing the space protruding from under a bridge girder. [Solution] A cantilever erection machine 100 moves forward in the cantilever direction X according to the progress of cantilever erection of a bridge girder G, and supports a formwork P and a work scaffolding 10 for forming the bridge girder G on a main frame 20. The cantilever erection machine 100 is equipped with a support beam 40 that supports the formwork P, a protective floor 30 that is located below the formwork P and protects the space V under the girder by catching objects falling from above, and a protective beam 31 that supports the protective floor 30. The protective beam 31 is located above the lower limit level L of the support beam 40.

Description

[Technical Field]

[0001] The present invention relates to a cantilever erection machine and a cantilever erection method. [Background technology]

[0002] When constructing a bridge that crosses an in-service road, etc., a construction method is required that does not interfere with the construction gauge of the road, etc. Therefore, when the distance between the space under the girders of a bridge constructed using the cantilever erection method and the construction gauge boundary line is small, it is particularly necessary to use a cantilever erection machine (also called a Wagen) that protrudes as little as possible from under the girders so as not to interfere with the construction gauge.

[0003] In the past, there was a cantilever erection machine that eliminated the lower work platform installed below the support beam of the base slab formwork, including the support beam for that lower work platform, and instead installed the side scaffolding of the newly constructed bridge girder directly onto the support beam of the base slab formwork (for example, Patent Document 1).

[0004] However, with conventional cantilever erection machines, it was necessary to install a protective floor suspended directly below the support beam of the base slab formwork, instead of the lower work platform that served to prevent objects from falling from above and the leakage of curing water after concrete was poured.As a result, even if the lower work platform installed below the support beam was eliminated, the protective floor could still interfere with the construction gauge below the girder. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-235687 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a cantilever erection machine and a cantilever erection method that can reduce the space protruding from under the bridge girder. [Means for solving the problem]

[0007] (1) A cantilever erection machine according to one aspect of the present invention is a cantilever erection machine that moves forward in the cantilever direction according to the progress of cantilever erection, and supports the formwork and working scaffolding for forming the bridge girder with a main frame, and is equipped with a support beam that supports the formwork, a protective floor that is located below the formwork and protects the space under the girder by catching objects falling from above, and a protective beam that supports the protective floor, and the protective beam is located above the lower limit level of the support beam. (2) In the above (1), the protection beam may be supported at the side of the support beam. (3) In the above (1) or (2), the protection beam may be supported by being stretched across the sides of the adjacent first and second support beams. (4) In the above (1) or (2), the support beam may extend along the underside of the bridge girder in the width direction of the bridge girder, and the protective beam may extend along the underside of the bridge girder in the projection direction. (5) In (1) or (2) above, the protective beam located at the forefront or rearmost position in the projection direction may have one end at the forefront or rearmost position suspended from the main frame and the other end supported by the support beam. (6) In the above (1) or (2), the protection beam may be supported by the support beam via a hinge. (7) In the above (6), the hinge may have a pin and an elongated hole through which the pin is inserted. (8) A cantilever erection method according to one embodiment of the present invention includes a support beam erection step in which a support beam that supports a formwork is suspended and supported by the main frame of a cantilever erection machine fixed to a bridge girder, and a protective beam erection step in which a protective beam that supports the protective floor from below is spanned between the sides of adjacent support beams. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a cantilever erection machine and a cantilever erection method that can reduce the space protruding from under the bridge girder. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a side view of the cantilever erection machine. [Figure 2] FIG. 2 is a view taken along the arrow A in FIG. [Figure 3] FIG. 2 is a view taken along the arrow B in FIG. [Figure 4] FIG. 2 is a detailed view of part C in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Embodiment) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a side view of the cantilever erection machine 100. Fig. 2 is a view as seen from the arrow A in Fig. 1. Fig. 3 is a view as seen from the arrow B in Fig. 1. Fig. 4 is a detailed view of part C in Fig. 1. Note that, hereinafter, parts having common functions may be given the same reference numerals or symbols. Hereinafter, the starting side of cantilever erection on the bridge girder G, the side of the existing erection block, may be referred to as the rear, and the ending side of cantilever erection, the side of the newly erected erection block, may be referred to as the front.

[0011] As shown in Figures 1 to 3, a cantilever erection machine 100 according to the embodiment can be used for cantilever erection of bridge girders G of PC bridges (also called cantilever construction method). The cantilever erection machine 100 moves forward in the cantilever direction X according to the progress of cantilever erection of the bridge girders G, and supports the formwork P for forming the bridge girders G and the working scaffolding 10 with a main frame 20. The cantilever erection machine 100 is also called a wagon or mobile formwork support.

[0012] The bridge girder G is, for example, a main girder constituting a PC bridge. The main girder may be, for example, a so-called box girder having a box-shaped cross section including an upper deck and a bottom deck.

[0013] The main frame 20 is the main structure that makes up the cantilever erection machine 100, and is a frame structure that cantilevers from the part (column capital) of the existing bridge girder G that was just constructed, and extends in a cantilever manner to the cantilever block G1 of the bridge girder G that is to be newly constructed. The main frame 20 is made of, for example, steel. The main frame 20 supports the weight and live load of the working scaffolding 10, formwork P, and protective floor 30. The main frame 20 may suspend and support the scaffolding beams 11 that support the working scaffolding 10 from below, the support beams 40 that support the formwork P from below, and the protective beams 31 that support the protective floor 30 from below, each using PC steel bars or the like.

[0014] The formwork P is a mold for forming concrete, made up of multiple facing materials, that bears the weight of the fresh concrete until it hardens. The formwork P may be, for example, concrete formwork plywood. The formwork P includes a bottom formwork for forming the bottom surface of the bridge girder G, and a side formwork for forming the side surface of the bridge girder G. The weight of the formwork P and the load acting on the formwork P are supported by being suspended from the main frame 20 via the support beams 40.

[0015] The work scaffold 10 is a lightweight structure that includes, for example, a tread plate (step plate) with a substantially horizontal upper surface for workers to walk on and shaft members that support the tread plate. The work scaffold 10 may be a so-called frame scaffold or a single-pipe scaffold. The entire work scaffold 10 may be supported from below by a scaffold beam 11 that is suspended from the main frame 20 of the cantilever erection machine 100. The lower end of the scaffold beam 11 is located above the lower limit level L of the support beam 40 (the height of an imaginary plane consisting of the plane connecting the lower ends of adjacent support beams 40, the forward horizontal plane, and the rear horizontal plane; details will be described later). This allows the lower end of the cantilever erection machine 100 to be the lower end of the support beam 40. Therefore, the cantilever erection machine 100 can be prevented from protruding below the lower limit level L that connects the lower ends of the support beams 40.

[0016] The cantilever erection of bridge girders G for PC bridges is generally performed in the following manner. First, a foundation is constructed on the ground at the construction site. Column bases are constructed on the foundations. The bridge girder G (column capital), which will become the top of the column base, is constructed. Next, the cantilever erection machine 100 is fixed to the existing bridge girder G (column capital). The cantilever erection machine 100 suspends and supports a formwork P that matches the shape of the cantilever block G1, which will be the portion of the bridge girder G that will be constructed and cantilevered from the existing bridge girder G (column capital). The formwork P includes a bottom formwork for forming the bottom deck slab of the bridge girder G. The cantilever erection machine 100 also suspends and supports a work scaffold 10 for constructing the cantilever block G1. Next, reinforcing bars, sheathing, etc. are placed within the formwork P, and concrete is poured. After the poured concrete reaches a predetermined strength, the prestressing steel attached to the cantilever block G1 is tensioned to introduce prestress into the cantilever block G1. After that, the cantilever erection machine 100 is moved to the end of the bridge girder G under construction and fixed to the existing cantilever block G1, and the adjacent cantilever block G2 is constructed in the same way. By repeating these steps, the bridge girder G is extended to the planned length.

[0017] In this way, the cantilever erection machine 100 moves forward according to the progress of the cantilever erection of the bridge girder G, and suspends and supports the formwork P and work scaffolding 10 for forming the bridge girder G. This allows the formwork P and work scaffolding 10 to be supported from the ground, leaving a space V below the girder, allowing work to be done in mid-air to construct the cantilever blocks G1, G2, ... in sequence. However, since the support beam 40 that supports the formwork P or the work scaffolding 10 from below is located at the lower level (height) of those equipped on the cantilever erection machine 100, care must be taken not to interfere with the construction gauge D below the girder.

[0018] Incidentally, when cantilever erecting the bridge girders G of a PC bridge, it is necessary to install a protective floor 30 below the formwork P and work scaffolding 10 in order to prevent objects from falling from above and leakage of curing water after concrete is poured. Therefore, the cantilever erection machine 100 is equipped with a protective floor 30 below the formwork P and work scaffolding 10 that covers the formwork P and work scaffolding 10 from below so as to encompass and be larger than the horizontal projection plane of the formwork P and work scaffolding 10.

[0019] The protective floor 30 may be, for example, a protective beam 31 covered with boards such as plywood for concrete formwork, or the protective beam 31 may be covered with a flexible sheet material such as a PVC protective sheet (civil engineering sheet).

[0020] The upper and / or lower surfaces of the protective floor 30 are preferably aligned with the bottom surfaces of the bridge girders G or the formwork P. This allows the lower part of the cantilever erection machine 100 to protrude as little as possible into the space V under the girders.

[0021] The protective floor 30 may be placed on the protective beams 31. In other words, the protective beams 31 may support the protective floor 30 from below.

[0022] The protective beams 31 may be configured in a lattice pattern with vertical beams 31X extending in the projection direction X and horizontal beams 31Y supported on the vertical beams 31X and extending in the width direction Y. This allows for more reliable support of the protective floor 30 placed on the protective beams 31. The top surface of the protective floor 30 does not have to be horizontal.

[0023] Like the support beam 40, the protective beam 31 is located at a lower level among the beams provided on the cantilever erection machine 100, so care must be taken not to interfere with the construction gauge D below the girder.

[0024] As such, care must be taken to ensure that the support beams 40 and protective beams 31 that constitute the cantilever erection machine 100 do not interfere with the construction gauge D below the girder. Therefore, the cantilever erection machine 100 is equipped with the support beams 40 that support the formwork P, the protective floor 30 that is located below the formwork P and protects the space V below the girder by catching objects falling from above, and the protective beams 31 that support the work scaffolding 10 and the protective floor 30. The protective beams 31 of the cantilever erection machine 100 are located above the lower limit level L of the support beams 40. Here, as shown in FIG. 1 , the lower limit level L is the height of an imaginary plane that is composed of a plane connecting the lower ends of adjacent support beams 40, a forward horizontal plane that extends horizontally forward from the lower end of the forward-most support beam 40 (second support beam 40B) in the cantilever direction X, and a rearward horizontal plane that extends horizontally rearward from the lower end of the rearmost support beam 40 (first support beam 40A) in the cantilever direction X. For example, above the forward horizontal plane, the protection beam 31 that protrudes further forward than the foremost support beam 40 is located above the lower limit level L. Also, above the rear horizontal plane, the protection beam 31 that protrudes further rearward than the rearmost support beam 40 is located above the lower limit level L. This allows the lower end of the support beam 40 to be at the lowest level of the cantilever erection machine 100. Therefore, the cantilever erection machine 100 can reduce the space occupied by the cantilever erection machine 100 that protrudes from under the bridge girder G. Furthermore, even at a construction site with severe conditions where the construction gauge D is set high, the cantilever erection machine 100 can be prevented from interfering with the construction gauge D.

[0025] It is preferable that the protection beam 31 is supported by the side portion 42 of the support beam 40. This allows the support beam 40 of the formwork P to also support the protection beam 31 (longitudinal beam 31X), simplifying the structure of the cantilever erection machine 100 and allowing the lower end of the support beam 40 to be at the lowest level in the cantilever erection machine 100. Therefore, the cantilever erection machine 100 can reduce the space protruding from below the bridge girder G. It also prevents the cantilever erection machine 100 from interfering with the construction gauge D. In particular, if the support beam 40 is an H-shaped steel with a horizontal flange and a vertical web, the end of the protection beam 31 can be accommodated in the space between the web and the flange. This allows the protection beam 31 to be reliably supported, resulting in a cantilever erection machine 100 with a simple structure.

[0026] The protection beam 31 is supported by being stretched across the side portions 42 of the adjacent first support beam 40A and second support beam 40B. This allows the support beam 40 of the formwork P to also support the protection beam 31, simplifying the structure of the cantilever erection machine 100, and the lower end of the support beam 40 can be at the lowest level of the cantilever erection machine 100. Therefore, the cantilever erection machine 100 can reduce the space that protrudes from below the bridge girder G. Furthermore, the cantilever erection machine 100 can be prevented from interfering with the construction gauge D.

[0027] As shown in FIG. 4 , the protection beam 31 may be supported on the support beam 40 via a hinge 31H. The hinge 31H may have a pin 31P and an elongated hole 31Q through which the pin 31P is inserted. The pin 31P inserted into the elongated hole 31Q is rotatably guided relative to the elongated hole 31Q, and movement in the extension direction of the elongated hole 31Q is restricted. This allows the protection beam 31 to be rotatably supported on the support beam 40, and even if the inclination angle of the protection beam 31 relative to the horizontal direction changes as the cantilever installation progresses, the attachment positions of the support beam 40 and the protection beam 31 can be adjusted in response to the change. The hinge 31H may be provided at either end of the protection beam 31, or at both ends. The hinge 31H may be provided on either the adjacent first support beam 40A or second support beam 40B, or on both. Either the pin 31P or the elongated hole 31Q may be provided in the support beam 40, and the other may be provided in the protection beam 31. The pin 31P or the elongated hole 31Q may be provided at either end of the protection beam 31. The pin 31P or the elongated hole 31Q may be provided at both ends of the protection beam 31. The pin 31P or the elongated hole 31Q may be provided in a support portion 31J provided on the side portion 42 of the support beam 40.

[0028] The support beam 40 extends in the width direction Y of the bridge girder G along the underside of the bridge girder G (bottom deck slab). The protection beam 31 extends in the projection direction X of the bridge girder G along the underside of the bridge girder G (bottom deck slab). This allows the support beam 40 and protection beam 31 to form a lattice-like structure. The protection beam 31 can be placed along the bottom surface of the bridge girder G. Therefore, even if the level of the underside of the bottom deck increases as the cantilever erection of the bridge girder G progresses and the girder height decreases, the levels of the support beam 40 and protection beam 31 can be raised accordingly. As a result, the cantilever erection machine 100 can minimize the space protruding from below the bridge girder G. This also prevents the cantilever erection machine 100 from interfering with the construction gauge D.

[0029] The support beam 40 supports the scaffold beam 11 from below. The support beam 40 may also serve as the scaffold beam 11. In other words, the support beam 40 may support the work scaffold 10 and formwork P from below. As shown in FIG. 1, when the adjacent first support beam 40A and second support beam 40B are at different levels, the support beam 40 may support the scaffold beam 11 via a height adjustment device 41 in order to level the scaffold beam 11.

[0030] The support beam 40 may include a support portion 31J that supports the beam via a hinge 31H. Specifically, as shown in FIG. 4 , the first support beam 40A may include a first support portion 31J1 that supports the protection beam 31 via a first hinge 31H1. The second support beam 40B may include a second support portion 31J2 that supports the protection beam 31 via a second hinge 31H2. This allows the protection beam 31 to be rotatably supported relative to the first support beam 40A and the second support beam 40B, and the attachment position of the support beam 40 and the protection beam 31 can be adjusted. Therefore, as the girder height decreases as the cantilever installation progresses, the angle of the protection beam 31 can be adjusted by rotating it. In this way, the posture of the protection beam 31 (the angle between the extension direction of the protection beam 31 and the horizontal direction) can be changed according to the inclination of the bottom surface of the bridge girder G, and the protection beam 31 can be aligned with the bottom surface of the bridge girder G. Therefore, with the cantilever erection machine 100, it is possible to minimize the space protruding from under the bridge girder G. Furthermore, it is possible to prevent the cantilever erection machine 100 from interfering with the construction gauge D.

[0031] 1 , the protection beam 31 located at the foremost or rearmost position in the projection direction X may have one end at the foremost or rearmost position suspended from the main frame 20, and the other end supported by the support beam 40. In particular, the protection beam 31 located at the foremost position in the projection direction X may have one end at the foremost position suspended from the main frame 20 via a front horizontal member 52 (horizontal member 50) provided above the lower end of the protection beam 31, and the other end located closer to the center in the projection direction X may be supported by a second support beam 40B (support beam 40) via a hinge 31H. Furthermore, the protection beam 31 located at the rearmost position in the projection direction X may have one end at the rearmost position suspended from the main frame 20 via a rear horizontal member 51 (horizontal member 50) provided above the lower end of the protection beam 31, and the other end located closer to the center in the projection direction X may be supported by a first support beam 40A (support beam 40) via a hinge 31H. This allows the protective beam 31 to minimize the space protruding below the girder, and can be aligned along the bottom surface of the bridge girder G, and can be installed extending further forward or rearward than the support beam 40 located at the forefront or rearward end in the projection direction X.

[0032] (Extended installation method) Hereinafter, the cantilever erection method using the cantilever erection machine 100 according to this embodiment will be described using cantilever erection of bridge girders G of a PC bridge as an example.

[0033] (1) First, the foundation is constructed on the ground at the construction site. Next, the column base is constructed on the foundation, and the existing bridge girder G (column capital) is constructed on the column base.

[0034] (2) Next, the cantilever erection machine 100 is fixed to the existing bridge girder G (column capital or existing cantilever block).

[0035] (3) The support beam 40 supporting the formwork P is suspended by the main frame 20 of the cantilever erection machine 100 fixed to the existing bridge girder G (column capital or existing cantilever block) (support beam erection step).

[0036] (4) The work scaffolding 10 for constructing the cantilever blocks is assembled, and the work scaffolding 10 is suspended and supported by the main frame 20 of the cantilever erection machine 100, which is detachably fixed to the existing bridge girder G (column capital). At this time, the work scaffolding 10 and the scaffold beams 11 supporting the work scaffolding 10 are positioned so that they are above the lower limit level L connecting the lower ends of the support beams 40 of the formwork P (the height of the surface connecting the lower ends of adjacent support beams 40).

[0037] (5) The formwork P for constructing the cantilever blocks is assembled, and the formwork P is suspended and supported by the main frame 20 of the cantilever erection machine 100 (beam erection step S1). In detail, a beam 40 is placed, suspended and supported from the main frame 20, and extends in the width direction Y, and the formwork P is supported by the beam 40 from below.

[0038] (6) The protection beams 31 that support the protective floor 30 from below are placed between the side portions 42 of the adjacent support beams 40 (protection beam erection step S2). In detail, support portions 31J with slotted holes 31Q are attached to the support beams 40 by welding, bolting, or the like. Then, the protection beams 31 that support the protective floor 30 from below are attached to the support portions 31J by inserting the pins 31P provided on the protection beams 31 into the slotted holes 31Q to form hinges 31H, and the protection beams 31 are placed between the adjacent support beams 40. The protective floor 30 is then placed on top of the protection beams 31. Here, the positions of the pins 31P relative to the slotted holes 31Q are adjusted as appropriate. This allows the protection beams 31 to be positioned (inclined) along the bottom surface of the bridge girder G in accordance with the level of the bottom surface of the bridge girder G, which increases as the cantilever erection progresses.

[0039] (7) Next, reinforcing bars, sheathing, prestressing steel, etc. are placed inside the formwork P, and concrete is poured. After the poured concrete reaches a predetermined strength, the prestressing steel attached to the protruding block is tensioned to introduce prestress into the protruding block.

[0040] (8) After that, the cantilever erection machine 100 is sequentially moved to the end of the bridge girder G under construction. At this time, if the cross-sectional shape of the newly constructed cantilever block changes, the installation position of the formwork P will change. For this reason, the level of the support beam 40 that bears the load of the formwork P is adjusted to match the installation position of the formwork P. For example, if the girder height of the newly constructed cantilever block is smaller than the girder height of the existing cantilever block and the level of the underside of the newly constructed cantilever block is higher than the level of the underside of the existing cantilever block, the support beam 40 is moved upward and the level of the support beam 40 is adjusted, for example, by pulling up the PC steel rod that suspends the support beam 40, in order to install the formwork P to match the level of the underside of the newly constructed cantilever block. Here, even if the positional relationship between the first support beam 40A and the second support beam 40B changes due to differences in the levels of the first support beam 40A and the second support beam 40B, the protective beam 31 is supported via hinges 31H having elongated holes 31Q, so the change in the positional relationship between the first support beam 40A and the second support beam 40B can be absorbed by changing the inclination angle of the protective beam 31 and the attachment position to the support beam 40. This allows the protective beam 31 to be positioned above the lower limit level L connecting the lower ends of the support beams 40, and the lower limit level L can be raised as high as possible depending on the shape of the newly constructed support block. Then, the cantilever erection machine 100 is fixed to the existing cantilever block that was constructed just before, and the adjacent new cantilever block is constructed in the same manner.

[0041] (9) By repeating these steps, the bridge girder G is extended to the planned length.

[0042] In this way, the work scaffolding 10, formwork P, and protective beams 31 supporting the protective floor 30 are positioned above the lower end of the support beam 40, thereby reducing the space in which the cantilever erection machine 100 protrudes from below the bridge girders G. Therefore, the cantilever erection method for the bridge girders G of a PC bridge can be carried out safely using the cantilever erection machine 100 while avoiding interference with the construction gauge D below the girders.

[0043] The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0044] In addition, the components in the above-described embodiments may be replaced with known components as appropriate without departing from the spirit of the present invention. Furthermore, the above-described modifications may be combined as appropriate without departing from the spirit of the present invention.

[0045] The cantilever erection machine 100 according to the embodiment moves forward in the cantilever direction X in accordance with the progress of the cantilever erection of the bridge girder G, and supports the formwork P and work scaffolding 10 for forming the bridge girder G on a main frame 20. The cantilever erection machine 100 is equipped with a support beam 40 that supports the formwork P, a protective floor 30 that is located below the formwork P and protects the space V under the girder by catching objects falling from above, and a protective beam 31 that supports the protective floor 30. The protective beam 31 is located above the lower limit level L of the support beam 40. This reduces the space protruding from under the bridge girder G. Therefore, even at a construction site with severe conditions where the construction gauge D is set high, the cantilever erection machine 100 can avoid interfering with the construction gauge D during cantilever erection of the bridge girder G.

[0046] The cantilever erection method according to the embodiment includes a support beam erection step S1 in which the support beams 40 that support the formwork P are suspended by the main frame 20 of the cantilever erection machine 100 fixed to the bridge girder G, and a protection beam erection step S2 in which the protection beams 31 that support the protective floor 30 from below are spanned between the side portions 42 of adjacent support beams 40. This makes it possible to reduce the space that protrudes from below the bridge girder G. Therefore, even at a construction site with severe conditions where the construction gauge D is set high, it is possible to prevent the cantilever erection machine 100 from interfering with the construction gauge D during cantilever erection of the bridge girder G. [Explanation of symbols]

[0047] 100 Overhang erection machine 10 Working scaffolding 11 Scaffolding beam 20 Mainframe 30 Protective floor 31 Guard beam 31H hinge 31H1 First hinge 31H2 Second hinge 31J Support part 31P pin 31Q long hole 31X Longitudinal beam 31Y horizontal beam 40 Support beam 40A First beam 40B 2nd support beam 41 Height adjustment tool 42 Side 50 Cross beam 51 Rear horizontal member 52 Front cross member D Building limits G Bridge girder G1, G2, G3 extension blocks L Lower limit level P formwork V space under girder X Extrusion direction Y width direction

Claims

1. A cantilever erection machine that moves forward in the cantilever direction according to the progress of cantilever erection of a bridge girder and supports a formwork and a work scaffold for forming the bridge girder with a main frame, A support beam for supporting the formwork; a protective floor located below the formwork and configured to receive objects falling from above and protect the space under the girder; a protection beam supporting the protective floor; The protection beam is located above the lower limit level of the support beam. Overhang erection machine.

2. The protection beam is supported by the side of the support beam. The cantilever erection machine according to claim 1.

3. The protection beam is supported by being stretched across the side portions of the adjacent first and second support beams. The cantilever erection machine according to claim 1 or 2.

4. The support beam extends in the width direction of the bridge girder along the underside of the bridge girder, The protection beam extends in the overhang direction along the underside of the bridge girder. The cantilever erection machine according to claim 1 or 2.

5. The protective beam located at the front or rear end in the projection direction is suspended from the main frame at one end and supported by the support beam at the other end. The cantilever erection machine according to claim 1 or 2.

6. The protection beam is supported on the support beam via a hinge. The cantilever erection machine according to claim 1 or 2.

7. The hinge has a pin and a long hole through which the pin is inserted. The cantilever erection machine according to claim 6.

8. a support beam erection step in which a support beam supporting the formwork is suspended and supported by a main frame of a cantilever erection machine fixed to the bridge girder; and a protection beam erection step for bridging the protection beams that support the protective floor from below between the side portions of the adjacent support beams. Overhang installation method.

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