Rotary deck crane for assembling steel box girder section by section and construction method of rotary deck crane

Abstract

The invention discloses a rotary bridge deck crane for steel box girder segmental assembly and a construction method thereof.The rotary bridge deck crane comprises a bearing mechanism, a hoisting mechanism, girder transporting trolleys and steel box girder segments, the two girder transporting trolleys are moved to the position between lower cross beams between rear supporting legs and front supporting legs respectively, the bearing mechanism is integrally jacked up through jacking air cylinders on the girder transporting trolleys, and the steel box girder segments are assembled through the jacking air cylinders; a jacking air cylinder on a beam transporting trolley is driven to enable the whole machine to fall on a bridge floor, a lower beam is lifted through a beam lifting machine on a transverse connection main beam, the beam transporting trolley transports a steel box beam section to the position between a rear supporting leg and a front supporting leg, a steel box beam connecting lifting lug is connected with the steel box beam section, and a moving trolley drives a lifting mechanism to move to the foremost end of the main beam. According to the bridge deck crane, the requirements of all the segments are met, the spatial postures of all the segments are adjusted through hydraulic pressure, hydraulic lifting and hoisting are stable, impact is small, and the safety of the construction process can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of bridge deck cranes, and in particular to a rotating bridge deck crane for assembling steel box beam sections and a construction method thereof. Background Art

[0002] The installation of steel box girders, under floating conditions, is basically carried out by shipping beam sections, which can be assembled using a bridge crane cantilever or installed by configuring a large floating crane to erect bracket sections, or by using a top-pushing method. Existing rotating bridge cranes usually include a bridge crane travel mechanism, a main truss, a bridge crane lifting mechanism, and a rotating hoist. The bottom of the main truss is the bridge crane travel mechanism, the upper part of the main truss is the bridge crane lifting mechanism, and a longitudinal and transverse adjustment mechanism is provided between the main truss and the bridge crane lifting mechanism. A rotating hoist is provided on the top. When the existing rotating bridge deck crane is in use, it is usually necessary to transport the steel box girder to the bottom of the installation bridge position, and then use the bridge deck rotating crane to lift the steel box girder on the beam transport vehicle at the installation bridge position to the bridge deck for assembly. The existing device has high requirements on the construction environment when in use. It is necessary to first level the bottom surface below the construction area so that the beam transport vehicle can pass through and transport the pre-assembled steel box girder, which makes the existing rotating bridge deck crane and construction method still have certain limitations in actual use. Summary of the invention

[0003] The object of the present invention is to provide a rotating bridge crane for assembling steel box girders in sections and a construction method thereof, so as to solve the technical problem that the prior art has high requirements on the construction environment and needs to first level the bottom surface below the construction area so that the beam transport vehicle can pass through and transport the pre-assembled steel box girders, which makes the existing rotating bridge crane and construction method still have certain limitations in actual use.

[0004] The technical problem to be solved by the present invention can be achieved by the following technical solutions:

[0005] A rotating bridge deck crane for steel box girder segment assembly and a construction method thereof, comprising:

[0006] The bearing mechanism comprises a symmetrically arranged main beam, a front support leg being fixedly connected to one side of the bottom surface of the main beam, and a rear support leg being fixedly connected to the other side of the bottom surface of the main beam;

[0007] The lifting mechanism includes a lifting beam, an upper turntable and a lower turntable, the upper turntable and the lower turntable are rotatably connected, moving trolleys are symmetrically distributed and fixedly connected on both sides of the bottom surface of the lifting beam, the symmetrically distributed moving trolleys are respectively arranged on the symmetrically distributed main beams, and a lifting top for lifting operations is arranged on the upper turntable;

[0008] A sling mechanism, which is arranged on the traction end of the lifting top and is provided with a steel box beam segment;

[0009] The beam transport trolley is used to transport the steel box girder segments to be laid.

[0010] As a further solution of the present invention: a cross-connecting main beam is fixedly connected between the symmetrically arranged main beams, a cross-connecting main beam hoist is arranged on the cross-connecting main beam, and two main beams and two moving trolleys are arranged.

[0011] As a further solution of the present invention: a lower longitudinal beam is arranged between the rear support leg and the front support leg arranged on the same main beam, one end of the lower longitudinal beam is fixedly connected to the rear support leg, and the other end of the lower longitudinal beam is fixedly connected to the front support leg, a lower cross beam is fixedly connected between the two front support legs and the two rear support legs, a connecting rod is obliquely arranged between the front support leg, the rear support leg and the main beam, one end of the connecting rod is fixedly connected to the main beam, and the other end of the connecting rod is fixedly connected to the front support leg and the rear support leg.

[0012] As a further solution of the present invention: an oblique brace is arranged between the front supporting leg and the main beam, one end of the oblique brace is fixedly connected to the front supporting leg, and the other end of the oblique brace is fixedly connected to the main beam.

[0013] As a further solution of the present invention: a front support assembly is arranged at the bottom end of the front support leg, and the front support assembly includes a sleeve screw rod and a nut, and the screw rod and the nut are supported above the steel beam partition.

[0014] As a further solution of the present invention: a rear support anchor assembly is arranged at the rear of the lower longitudinal beam, and the rear support anchor assembly includes a support anchor cross beam and a rear support, and support anchors are fixedly connected to both sides of the bottom surface of the support anchor cross beam, and the support anchor cross beam is located directly below the rear support leg.

[0015] As a further solution of the present invention: the lower turntable is slidably arranged on the lifting beam, and a transverse cylinder for laterally adjusting the lower turntable is fixedly connected to the lifting beam, a centering shaft is arranged between the upper turntable and the lower turntable, and the upper turntable and the lower turntable are rotatably connected through the centering shaft, a rotary motor for driving the upper turntable to rotate is arranged on the lower turntable, a fixed frame is fixedly connected to one side of the lower turntable, a rotary motor reducer for decelerating the rotary motor is fixedly installed on the fixed frame, and a steel rope is arranged on the traction end of the lifting top.

[0016] As a further solution of the present invention: the sling mechanism includes a sling beam, on which two cross swing frames are symmetrically arranged and fixedly connected, and the cross swing frames are fixedly connected with steel strand connecting seats, the steel strands are fixedly connected to the steel strand connecting seats, and steel beam connecting ears are fixedly connected on both sides of the bottom surface of the sling beam.

[0017] As a further solution of the present invention: a lifting cylinder is arranged on the beam transport trolley.

[0018] A construction method of a rotating bridge deck crane for assembling steel box beam sections, comprising the following steps:

[0019] Step 1: After the bridge crane is installed at the side span, the lifting mechanism moves to the tail of the main beam, and two beam transport trolleys move to the lower crossbeam between the rear legs and the front legs respectively. The lifting cylinder on the beam transport trolley lifts the entire load-bearing mechanism, thereby moving the entire device to the bridge deck joint;

[0020] Step 2: After the whole machine is moved into position, the lifting cylinder on the beam transport trolley is driven to drop the whole machine onto the bridge deck, the rear support anchor assembly is anchored, the front support assembly is supported, and the beam transport trolley returns;

[0021] Step 3: Remove the lower crossbeam between the rear legs, lift the lower crossbeam through the crossbeam hoist on the cross-connected main beam, transport the steel box beam segment between the rear legs and the front legs with the crossbeam hoist, lower the crossbeam with the crossbeam hoist and reinstall the lower crossbeam;

[0022] Step 4: Connect the steel box girder connecting lugs to the steel box girder segments, use the mobile trolley to drive the lifting mechanism to move to the front end of the main beam, and use the slewing motor to drive the hoisting mechanism to rotate 90 degrees to complete the lifting and installation of the steel box girder segments;

[0023] Step 5: Repeat the above steps to install the steel box girder segment, and connect the front ends of the main beams of the devices on both sides to install the closing section.

[0024] Beneficial effects of the present invention:

[0025] After the side span of the bridge crane of the present invention is installed, the lifting mechanism moves to the tail of the main beam, and the two beam transport trolleys move to the lower cross beam between the rear legs and the front legs respectively, and the load-bearing mechanism is lifted up as a whole by the lifting cylinder on the beam transport trolley, so that the device is moved as a whole to the bridge deck joint. After the whole machine moves into place, the lifting cylinder on the beam transport trolley is driven to drop the whole machine on the bridge deck, the rear support anchoring assembly is anchored, the front support assembly is supported, the beam transport trolley returns, and the lower cross beam between the rear legs is removed, and the lower cross beam is lifted by the cross beam hoist on the cross-connected main beam. The beam transport trolley transports the steel box beam segment between the rear legs and the front legs, and the cross beam The hoist lowers the crossbeam and reinstalls the lower crossbeam, connects the steel box girder connecting lugs to the steel box girder segments, and drives the lifting mechanism to move to the front end of the main beam via the mobile trolley. The slewing motor drives the hoisting mechanism to rotate to complete the hoisting and installation of the steel box girder segments. This bridge deck crane can realize the installation of segmental beams of long-distance cross-river cable-stayed bridges. During the construction process, the segmental beams can be lifted, moved, rotated, lowered and accurately positioned. The lifting points of the hoist can be adjusted over a wide range to meet the requirements of each segment. Hydraulics are used to adjust the spatial posture of each segment. The hydraulic lifting is stable and has little impact, which is conducive to improving the safety of the construction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The present invention will be further described below in conjunction with the accompanying drawings.

[0027] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0028] Figure 2 It is a schematic diagram of the lateral structure of the bearing mechanism of the present invention;

[0029] Figure 3 It is a schematic diagram of the forward structure of the bearing mechanism of the present invention;

[0030] Figure 4 It is a schematic diagram of the forward structure of the lifting mechanism of the present invention;

[0031] Figure 5 It is a schematic diagram of the lateral structure of the lifting mechanism of the present invention;

[0032] Figure 6 It is a schematic diagram of the forward structure of the sling mechanism of the present invention;

[0033] Figure 7 It is a structural schematic diagram of the present invention during the construction of the closing section.

[0034] In the figure: 1. bearing mechanism; 11. main beam; 12. rear support leg; 13. connecting rod; 14. lower longitudinal beam; 15. front support leg; 16. transverse main beam; 17. lower cross beam; 18. diagonal support rod; 2. lifting mechanism; 21. lifting top; 22. rotary motor reducer; 23. transverse cylinder; 24. upper turntable; 25. lower turntable; 26. moving trolley; 27. centering shaft; 3. lifting device mechanism; 31. steel strand connecting seat; 32. cross swing frame; 33. lifting device cross beam; 34. steel beam connecting lifting eye; 4. beam transport trolley; 5. steel box beam segment. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] like Figure 1-Figure 6As shown, a rotating bridge crane for assembling steel box beam sections includes a bearing mechanism 1, a lifting mechanism 2, a hoisting device mechanism 3 and a beam transporting trolley 4. The bearing mechanism 1 includes a symmetrically arranged main beam 11, one side of the bottom surface of the main beam 11 is fixedly connected to a front support leg 15, and the other side of the bottom surface of the main beam 11 is fixedly connected to a rear support leg 12. The lifting mechanism 2 includes a lifting beam, an upper turntable 24 and a lower turntable 25. The upper turntable 24 and the lower turntable 25 are rotatably connected. Moving trolleys 26 are symmetrically distributed and fixedly connected on both sides of the bottom surface of the lifting beam. The symmetrically distributed moving trolleys 26 are respectively arranged on the symmetrically distributed main beam 11. A lifting top 21 for lifting operations is arranged on the upper turntable 24. The hoisting device mechanism 3 is arranged on the traction end of the lifting top 21. The hoisting device mechanism 3 is provided with a steel box beam segment 5. The beam transporting trolley 4 is used to transport the steel box beam segment 5 to be laid.

[0037] In some specific implementations, a transverse main beam 16 is fixedly connected between the symmetrically arranged main beams 11, a transverse beam hoist is provided on the transverse main beam 16, and two main beams 11 and two moving carts 26 are provided.

[0038] A lower longitudinal beam 14 is arranged between the rear supporting leg 12 and the front supporting leg 15 arranged on the same main beam 11, one end of the lower longitudinal beam 14 is fixedly connected to the rear supporting leg 12, and the other end of the lower longitudinal beam 14 is fixedly connected to the front supporting leg 15, a lower cross beam 17 is fixedly connected between the two front supporting legs 15 and the two rear supporting legs 12, and a connecting rod 13 is obliquely arranged between the front supporting leg 15 and the rear supporting leg 12 and the main beam, one end of the connecting rod 13 is fixedly connected to the main beam 11, and the other end of the connecting rod 13 is fixedly connected to the front supporting leg 15 and the rear supporting leg 12.

[0039] A diagonal brace 18 is provided between the front leg 15 and the main beam 11, one end of the diagonal brace 18 is fixedly connected to the front leg 15, and the other end of the diagonal brace 18 is fixedly connected to the main beam 11. By providing the diagonal brace 18, the overall stability of the device during the lifting operation can be ensured.

[0040] A front support assembly is provided at the bottom end of the front support leg 15. The front support assembly includes 4 sets of screw and nut mechanical supports, with a lateral spacing of 1.3m and a center distance of 10.9m on both sides. It is supported above the steel beam partition. Pay attention to the safe distance between the outer front fulcrum and the inclined cable cylinder during walking. The front support assembly adopts a threaded auxiliary structure, and the heavy load is borne by the screw and nut with trapezoidal thread. The bottom is a ball joint structure, which has a good fit with the segment beam surface and can meet the needs of adjusting the slope of this construction.

[0041] A rear support anchor assembly is provided at the rear of the lower longitudinal beam 14. The rear support anchor assembly includes an anchor crossbeam and a rear support. Anchors are fixedly connected to both sides of the bottom surface of the anchor crossbeam. The distance between the front and rear anchors is 2.1m. The anchor crossbeam is located directly below the rear support leg. The rear support is a threaded secondary ball joint structure. The rear anchor is connected to the single plate ear seat of the segment beam through a double plate ear seat, and a pin is used to connect the two anchor points of the segment beam.

[0042] The lower turntable 25 is slidably set on the lifting beam, and a transverse cylinder 23 for laterally adjusting the lower turntable 25 is fixedly connected to the lifting beam. A centering shaft 27 is provided between the upper turntable 24 and the lower turntable 25. The upper turntable 24 and the lower turntable 25 are rotatably connected through the centering shaft 27. A rotary motor for driving the upper turntable 24 to rotate is provided on the lower turntable 25. A fixed frame is fixedly connected to one side of the lower turntable 25, and a rotary motor reducer 22 for reducing the speed of the rotary motor is fixedly installed on the fixed frame.

[0043] A steel strand is provided on the traction end of the lifting top 21, and the sling mechanism 3 includes a sling beam 33, on which two cross swing frames 32 are symmetrically arranged and fixedly connected, and on the cross swing frames 32 are fixedly connected steel strand connection seats 31, the steel strand is fixedly connected to the steel strand connection seats 31, and steel beam connection ears 34 are fixedly connected on both sides of the bottom surface of the sling beam 33.

[0044] In some specific implementations, a lifting cylinder is provided on the beam transport trolley 4 .

[0045] A construction method of a rotating bridge deck crane for assembling steel box beam sections, comprising the following steps:

[0046] Step 1: After the bridge crane is installed at the side span, the lifting mechanism 2 moves to the tail of the main beam 11, and the two beam transport trolleys 4 move to the lower cross beam 17 between the rear legs 12 and the front legs 15 respectively, and the bearing mechanism 1 is lifted as a whole by the lifting cylinder on the beam transport trolley 4, so as to move the device as a whole to the bridge deck splicing position;

[0047] Step 2: After the whole machine is moved into position, the lifting cylinder on the beam transport trolley 4 is driven to drop the whole machine onto the bridge deck, the rear support anchor assembly is anchored, the front support assembly is supported, and the beam transport trolley 4 returns;

[0048] Step 3: Remove the lower cross beam 17 between the rear legs 12, lift the lower cross beam 17 through the cross beam hoist on the cross-connecting main beam 16, transport the steel box beam segment 5 between the rear legs 12 and the front legs 15, lower the cross beam 17 through the cross beam hoist and install the lower cross beam 17 again;

[0049] Step 4: Connect the steel box girder connecting lug 34 to the steel box girder segment 5, the mobile trolley 26 drives the lifting mechanism 2 to move to the front end of the main beam, and the rotary motor drives the hoisting mechanism 3 to rotate 90 degrees to complete the lifting and installation of the steel box girder segment 5;

[0050] Step 5: Repeat the above steps to install the steel box girder segment 5, and connect the front ends of the main beams 11 of the devices on both sides to install the closed section.

[0051] In order to facilitate the understanding of the embodiments of this solution by those skilled in the art, the working principle of this solution is briefly described in combination with specific application scenarios:

[0052] After the side span installation of the bridge crane is completed, the lifting mechanism 2 moves to the tail of the main beam 11, and the two beam transport trolleys 4 move to the lower cross beam 17 between the rear legs 12 and the front legs 15 respectively. The load-bearing mechanism 1 is lifted up as a whole by the lifting cylinder on the beam transport trolley 4, so that the device is moved as a whole to the bridge deck joint. After the whole machine is moved into place, the lifting cylinder on the beam transport trolley 4 is driven to drop the whole machine on the bridge deck, the rear support anchoring assembly is anchored, the front support assembly is supported, the beam transport trolley 4 returns, and the lower cross beam 17 between the rear legs 12 is removed, and the lower cross beam 17 is lifted by the cross beam hoist on the cross-connected main beam 16. The beam transport trolley 4 transports the steel box beam segment 5 to the rear legs 12 and the front legs 15. In the meantime, the beam hoist lowers the lower beam 17 and reinstalls the lower beam 17, connects the steel box beam connecting lug 34 to the steel box beam segment 5, and the mobile trolley 26 drives the lifting mechanism 2 to move to the front end of the main beam. The rotary motor drives the hoist mechanism 3 to rotate 90 degrees to complete the hoisting and installation of the steel box beam segment 5. This bridge deck crane can realize the installation of segment beams of long-distance cross-river cable-stayed bridges. During the construction process, the segment beams can be lifted, moved, rotated, lowered and accurately aligned. The lifting points of the hoist can be adjusted in a wide range to meet the requirements of each segment. Hydraulics are used to adjust the spatial posture of each segment. The hydraulic lifting is stable and has little impact, which is beneficial to improving the safety of the construction process.

[0053] Several embodiments of the present invention are described in detail above, but the embodiments of the present invention are not limited thereto and cannot be considered to limit the scope of implementation of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the patent coverage of the present invention.

Claims

1. A rotating bridge deck crane for steel box girder segment assembly and a construction method thereof, characterized in that: include: The bearing mechanism (1) comprises a symmetrically arranged main beam (11), wherein one side of the bottom surface of the main beam (11) is fixedly connected to a front support leg (15), and the other side of the bottom surface of the main beam (11) is fixedly connected to a rear support leg (12); The lifting mechanism (2) comprises a lifting beam, an upper turntable (24) and a lower turntable (25), wherein the upper turntable (24) and the lower turntable (25) are rotatably connected, moving trolleys (26) are symmetrically distributed and fixedly connected on both sides of the bottom surface of the lifting beam, and the symmetrically distributed moving trolleys (26) are respectively arranged on the symmetrically distributed main beams (11), and a lifting top (21) for performing lifting operations is arranged on the upper turntable (24); A sling mechanism (3), the sling mechanism (3) is arranged on the traction end of the lifting top (21), and a steel box beam segment (5) is arranged on the sling mechanism (3); The beam transport trolley (4) is used to transport the steel box beam segments (5) to be laid.

2. A rotating bridge deck crane for steel box girder segment assembly according to claim 1, characterized in that: A transverse main beam (16) is fixedly connected between the symmetrically arranged main beams (11), a transverse beam hoist is arranged on the transverse main beam (16), and two main beams (11) and two mobile trolleys (26) are each arranged.

3. The rotating bridge deck crane for steel box girder segment assembly according to claim 1, characterized in that: A lower longitudinal beam (14) is arranged between the rear supporting leg (12) and the front supporting leg (15) arranged on the same main beam (11); one end of the lower longitudinal beam (14) is fixedly connected to the rear supporting leg (12); the other end of the lower longitudinal beam (14) is fixedly connected to the front supporting leg (15); a lower cross beam (17) is fixedly connected between the two front supporting legs (15) and the two rear supporting legs (12); a connecting rod (13) is obliquely arranged between the front supporting leg (15) and the rear supporting leg (12) and the main beam; one end of the connecting rod (13) is fixedly connected to the main beam (11); the other end of the connecting rod (13) is fixedly connected to the front supporting leg (15) and the rear supporting leg (12).

4. A rotating bridge deck crane for steel box girder segment assembly and a construction method thereof according to claim 1, characterized in that: An oblique support rod (18) is arranged between the front support leg (15) and the main beam (11), one end of the oblique support rod (18) is fixedly connected to the front support leg (15), and the other end of the oblique support rod (18) is fixedly connected to the main beam (11).

5. The rotating bridge crane for steel box girder segment assembly according to claim 1, characterized in that: A front support assembly is arranged at the bottom end of the front support leg (15), and the front support assembly includes (4) sets of screw rods and nuts, and the screw rods and nuts are supported above the steel beam partition.

6. The rotating bridge crane for steel box girder segment assembly according to claim 1, characterized in that: A rear support anchor assembly is arranged at the rear of the lower longitudinal beam (14), and the rear support anchor assembly comprises a support anchor cross beam and a rear support, and support anchors are fixedly connected to both sides of the bottom surface of the support anchor cross beam, and the support anchor cross beam is located directly below the rear support leg.

7. The rotating bridge crane for steel box girder segment assembly according to claim 1, characterized in that: The lower turntable (25) is slidably arranged on the lifting crossbeam, and a transverse oil cylinder (23) for lateral adjustment of the lower turntable (25) is fixedly connected to the lifting crossbeam. A centering shaft (27) is arranged between the upper turntable (24) and the lower turntable (25), and the upper turntable (24) and the lower turntable (25) are rotatably connected via the centering shaft (27). A rotary motor for driving the upper turntable (24) to rotate is arranged on the lower turntable (25), and a fixed frame is fixedly connected to one side of the lower turntable (25), and a rotary motor reducer (22) for reducing the speed of the rotary motor is fixedly installed on the fixed frame. A steel rope is arranged on the traction end of the lifting top (21).

8. The rotating bridge deck crane for steel box girder segment assembly according to claim 7, characterized in that: The sling mechanism (3) comprises a sling crossbeam (33), on which two cross swing frames (32) are symmetrically arranged and fixedly connected, on which the cross swing frames (32) are fixedly connected steel strand connection seats (31), the steel strands are fixedly connected to the steel strand connection seats (31), and on both sides of the bottom surface of the sling crossbeam (33) are fixedly connected steel beam connection ears (34).

9. The rotating bridge crane for steel box girder segment assembly according to claim 1, characterized in that: A lifting cylinder is arranged on the beam transport trolley (4).

10. A construction method of a rotating bridge deck crane for section assembly of a steel box girder according to any one of claims 1 to 9, characterized in that: The steps include: S1: The bridge crane is installed at the side span, the lifting mechanism (2) moves to the tail of the main beam (11), and the two beam transport trolleys (4) move to the lower cross beam (17) between the rear support legs (12) and the front support legs (15), respectively, and the bearing mechanism (1) is lifted as a whole by the lifting cylinder on the beam transport trolley (4), so that the device is moved as a whole to the bridge deck joint; S2: After the whole machine is moved into position, the lifting cylinder on the beam transport trolley (4) is driven to drop the whole machine onto the bridge deck, the rear support anchoring assembly is anchored, the front support assembly is supported, and the beam transport trolley (4) returns; S3: The lower cross beam (17) between the rear legs (12) is removed, and the lower cross beam (17) is lifted by the cross beam hoist on the cross-connecting main beam (16). The beam transport trolley (4) transports the steel box beam segment (5) between the rear legs (12) and the front legs (15). The cross beam hoist lowers the cross beam (17) and installs the lower cross beam (17) again. S4: Connect the steel box beam connecting lug (34) to the steel box beam segment (5), drive the lifting mechanism (2) to move to the front end of the main beam by the moving trolley (26), and drive the lifting device mechanism (3) to rotate 90 degrees by the rotary motor to complete the lifting and installation of the steel box beam segment (5); S5: Repeat the above steps to achieve the installation of the steel box girder segment (5), and connect the front ends of the main beams (11) of the devices on both sides to achieve the installation of the closed section.

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