A combined gantry crane for demolishing the upper structure of a navigable bridge and a demolition method

Abstract

The present invention belongs to the technical field of the construction of the superstructure of a navigable bridge, and particularly relates to a combined gantry crane for demolishing the superstructure of a navigable bridge and a demolition method. A combined gantry crane for demolishing the superstructure of a navigable bridge includes a straight-leg gantry crane, an inclined-leg gantry crane, a leg track, a long-leg track, and an inclined-leg track. Straight-leg gantry crane straight legs and long legs are respectively provided at the lower parts of both ends of the straight-leg gantry crane. The bottom of the straight-leg gantry crane straight leg is movably connected to the leg track, and the bottom of the long leg is movably connected to the long-leg track. Straight-leg gantry crane straight legs and inclined legs are respectively provided at the lower parts of both ends of the inclined-leg gantry crane. The bottom of the straight-leg gantry crane straight leg of the inclined-leg gantry crane is movably connected to the leg track, and the bottom of the inclined leg is movably connected to the inclined-leg track. The combined gantry crane of the present invention has a simple force structure and is convenient to use. During the demolition process of the superstructure of a navigable bridge with limited space, it can reduce the interference with navigation, reduce the number of navigation conversions, significantly speed up the construction progress, and greatly reduce the input cost.

Description

Technical Field

[0001] The invention belongs to the technical field of the construction of the superstructure of a navigable bridge, and particularly relates to a combined gantry crane for demolishing the superstructure of a navigable bridge and a demolition method. Background Technique

[0002] After years of operation, the technical state of a navigable bridge continuously deteriorates. When it can no longer meet the requirements for safe operation, it is necessary to reconstruct a new bridge at the old bridge site and build widened bridges on both sides. Since the main span of the old bridge needs to ensure navigation, it is impossible to directly use a trestle to complete the demolition and construction of the old bridge. Moreover, after the expansion, the bridge needs to be upgraded from a two-way six-lane to a two-way ten-lane. During the reconstruction, it is necessary to ensure the passage of two-way six-lanes. Therefore, the widened parts need to be completed on both sides of the old bridge first, and then the in-situ demolition and new construction of the old bridge are carried out. This will result in limited working space for waterborne lifting equipment (such as a floating crane), and it is impossible to directly perform vertical lifting on both sides of the widened bridge.

[0003] At present, the conventional construction methods for demolishing the superstructure of an old navigable bridge include the construction method of manual cutting and hoisting by a truck crane, the construction method of demolishing by a bridge erecting machine, and the construction method of demolishing by a gantry crane, etc. The construction method of manual cutting and hoisting by a truck crane requires setting up a beam transportation channel on the bridge deck. This method is applicable to sections with broad sites, low requirements for traffic maintenance, and low demolition difficulty. The construction method of demolishing by a bridge erecting machine takes a long time for conversion, so it is applicable to the situation where the span of the navigable hole is large and the mileage of bridge demolition is long. The construction method of demolishing by a gantry crane requires setting the track on the foundation, and there are no influencing factors such as navigation or existing lines within the bridge range. Therefore, it is applicable to sections with fewer influencing factors within the bridge piers and spans. If manual cutting and hoisting by a truck crane are adopted, it will affect the driving safety of the newly widened bridges on both sides of the old navigable bridge. At the same time, the span of the old navigable bridge is small, and the investment cost for using a bridge erecting machine is high and the construction period is long. The conventional gantry crane track needs to be laid longitudinally along the entire length of the bridge, and it is impossible to ensure navigation. Therefore, the above three methods cannot be used for demolishing the superstructure of the old navigable bridge. Summary of the Invention

[0004] Aiming at the above problems, the purpose of the invention is to provide a combined gantry crane for demolishing the superstructure of a navigable bridge and a demolition method. The combined gantry crane of the invention has simple force-bearing structure and is convenient to use. During the demolition process of the superstructure of a navigable bridge with limited space, it can reduce the interference to navigation, reduce the number of navigation conversions, significantly accelerate the construction progress, and greatly reduce the input cost.

[0005] The technical solution of the present invention lies in: a combined gantry crane for demolishing the upper structure of a navigable bridge, including a straight-leg gantry crane, an inclined-leg gantry crane, a leg track, a long leg track, and an inclined leg track. The lower parts of both ends of the straight-leg gantry crane are respectively provided with a straight-leg gantry crane straight leg and a long leg. The bottom of the straight-leg gantry crane straight leg is movably connected to the leg track, and the bottom of the long leg is movably connected to the long leg track. The lower parts of both ends of the inclined-leg gantry crane are respectively provided with an inclined-leg gantry crane straight leg and an inclined leg. The bottom of the inclined-leg gantry crane straight leg is movably connected to the leg track, and the bottom of the inclined leg is movably connected to the inclined leg track.

[0006] An anti-pressure beam is arranged on the inclined leg track, and a plurality of anchoring steel bars are arranged on the anti-pressure beam. The anti-pressure beam is detachably connected to the inclined leg track through the anchoring steel bars.

[0007] The straight-leg gantry crane straight leg of the straight-leg gantry crane has the same structure as the inclined-leg gantry crane straight leg of the inclined-leg gantry crane.

[0008] A method for demolishing the upper structure of a navigable bridge, using the combined gantry crane for demolishing the upper structure of a navigable bridge as described above, includes the following steps:

[0009] S1: Demolish the upper structure of the non-navigable section of the navigable bridge by using a straight-leg gantry crane, specifically including demolishing the hanging beams to be demolished in the non-navigable section and demolishing the T-shaped structures to be demolished in the non-navigable section;

[0010] S2: Demolish the upper structure of the navigable section of the navigable bridge by using an inclined-leg gantry crane, specifically including demolishing the hanging beams to be demolished in the navigable section and demolishing the T-shaped structures to be demolished in the navigable section.

[0011] In the step S1, when demolishing the upper structure of the non-navigable section of the navigable bridge by using a straight-leg gantry crane, the specific steps are as follows:

[0012] S11: Install the straight-leg gantry crane. Lay the leg track on the box girders of the widened sections of the newly built widened bridges on both sides of the navigable bridge, and lay the long leg track at the gap position of the central isolation belt of the navigable bridge. After assembling the straight-leg gantry crane, the bottom of the straight-leg gantry crane straight leg is movably connected to the leg track, and the bottom of the long leg is movably connected to the long leg track;

[0013] S12: Demolish the hanging beams to be demolished in the non-navigable section. The straight-leg gantry crane walks to the designated demolition position. After the connection between the hanging beams to be demolished in the non-navigable section and the T-shaped structures to be demolished in the non-navigable section is cut by a wire saw, two groups of straight-leg gantry cranes synchronously lift the entire hanging beam to be demolished in the non-navigable section, and then the hanging beam to be demolished in the non-navigable section is horizontally moved to the beam transportation channel, and the beam is carried by a beam transportation vehicle to the designated position. Repeat this step to complete the demolition of the entire hole of the hanging beams to be demolished in the non-navigable section;

[0014] S13: Demolish the T-structure to be demolished in the non-navigable section. Divide the T-structure to be demolished in the non-navigable section longitudinally and transversely according to the hoisting capacity. Two sets of straight-leg gantry cranes symmetrically and synchronously demolish on both sides of the pier top. After demolition, the T-structure to be demolished in the non-navigable section is transported to the designated position by a beam transporter. Repeat this step to demolish the T-structure to be demolished in the non-navigable section.

[0015] In step S2, a slant-leg gantry crane is used to demolish the upper structure of the navigable section of the navigable bridge. The specific steps are as follows:

[0016] S21: Install the slant-leg gantry crane. Lay the slant-leg track above the support of the T-structure to be demolished in the navigable section. After assembling the slant-leg gantry crane, the bottom of the straight leg of the slant-leg gantry crane can be movably connected to the leg track, and the bottom of the slant leg can be movably connected to the slant-leg track through an anchor steel bar and a counterweight beam.

[0017] S22: Demolish the hanging beam to be demolished in the navigable section. Move the slant-leg gantry crane to the designated demolition position. After the connection between the hanging beam to be demolished in the navigable section and the T-structure to be demolished in the navigable section is cut by a wire saw, two sets of slant-leg gantry cranes synchronously lift the entire hanging beam to be demolished in the navigable section. Then, the hanging beam to be demolished in the navigable section is horizontally moved to the beam transport channel and transported to the designated position by a beam transporter. Repeat this step to complete the demolition of the hanging beam to be demolished in the navigable section of the navigable hole.

[0018] S23: During the demolition construction of the T-structure to be demolished in the navigable section, divide the T-structure to be demolished in the navigable section longitudinally and transversely according to the hoisting capacity of the slant-leg gantry crane. The slant-leg gantry crane is on the navigable hole side of the pier top, and the straight-leg gantry crane is on the non-navigable hole side of the pier top. The straight-leg gantry crane and the slant-leg gantry crane symmetrically and synchronously demolish. After demolition, the T-structure to be demolished in the navigable section is transported to the designated position by a beam transporter. Repeat this step to demolish the T-structure to be demolished in the navigable section of the navigable bridge.

[0019] In step S21, when installing the slant-leg gantry crane, the straight-leg gantry crane already installed in step S11 can be used to convert the leg support to a slant-leg gantry crane on the outside of the pier top of the navigable hole. The specific process is as follows: The straight-leg gantry crane moves to the outside of the pier top of the navigable hole. Lay the slant-leg track above the support of the T-structure to be demolished in the navigable section. Install the slant leg, anchor steel bar and counterweight beam on the slant-leg track. Then, demolish the long leg in the central isolation belt to complete the conversion of the leg support system of the straight-leg gantry crane and complete the installation of the slant-leg gantry crane.

[0020] For the slant-leg gantry crane in step S21, when the gantry of the slant-leg gantry crane is running with no load, release the anchor steel bar, use the counterweight beam to offset the forward inclination force of the temporary slant leg, and use a jack to realize the movement of the gantry. When in the hoisting condition, lock the anchor steel bar and release the counterweight beam to prevent the gantry crane from tilting forward.

[0021] When hanging beams to be demolished in non-navigable sections in step S1 and when hoisting hanging beams to be demolished in navigable sections in step S2, water drills should be used to drill holes at both ends of the hanging beams to be demolished in non-navigable sections and the hanging beams to be demolished in navigable sections respectively as hoisting holes. Four hoisting holes should be set for each hanging beam to be demolished. Before the hanging beam to be demolished is cut, the steel wire rope passes through the hoisting holes to bundle the beam body from the bottom.

[0022] The technical effects of the present invention are as follows: 1. The inclined-leg gantry crane adopted in the present invention can be converted into an inclined-leg gantry crane by a straight-leg gantry crane outside the pier top of the navigable hole, with simple and convenient operation. During the demolition of the upper structure of a navigable bridge with limited space, the number of equipment is reduced, the construction progress can be significantly accelerated, and the input cost can be greatly reduced; 2. The present invention uses an inclined-leg gantry crane to complete the demolition construction of the upper structure of the navigable section of a navigable bridge within the navigable hole range, which can reduce the interference to navigation, reduce the number of navigation conversions, and accelerate the construction progress; 3. The present invention uses a straight-leg gantry crane for the demolition of the upper structure of the non-navigable section of a navigable bridge and an inclined-leg gantry crane for the demolition of the upper structure of the navigable section of a navigable bridge, without the need to use large-scale equipment, is less affected by the external environment, is not affected by navigation or existing lines within the bridge range, can effectively reduce the occupation of the construction site, and ensure the passage of the original road during construction.

[0023] The following will be further described with reference to the drawings. Description of the Drawings

[0024] Figure 1 It is a construction flow chart for the demolition of the hanging beam to be demolished in the non-navigable section of a combined gantry crane for the demolition of the upper structure of a navigable bridge according to an embodiment of the present invention.

[0025] Figure 2 It is a construction flow chart for the demolition of the non-navigable T-structure to be demolished in the upper structure of a combined gantry crane for the demolition of the upper structure of a navigable bridge according to an embodiment of the present invention.

[0026] Figure 3 It is a schematic diagram of the leg conversion of a combined gantry crane for the demolition of the upper structure of a navigable bridge according to an embodiment of the present invention.

[0027] Figure 4 It is a construction flow chart for the demolition of the hanging beam to be demolished in the navigable section of a combined gantry crane for the demolition of the upper structure of a navigable bridge according to an embodiment of the present invention.

[0028] Figure 5 It is a construction flow chart for the demolition of the navigable T-structure to be demolished in the upper structure of a combined gantry crane for the demolition of the upper structure of a navigable bridge according to an embodiment of the present invention.

[0029] Reference Signs: 1 - straight-leg gantry crane, 2 - inclined-leg gantry crane, 3 - straight support leg of straight-leg gantry crane, 4 - long support leg, 5 - inclined support leg, 6 - support leg track, 7 - long support leg track, 8 - inclined support leg track, 9 - anchoring steel bar, 10 - counterweight beam, 11 - beam transportation passage, 12 - beam transporter, 13 - hanging beam to be demolished in non-navigable section, 14 - T-shaped structure to be demolished in non-navigable section, 15 - widening section, 16 - straight support leg of inclined-leg gantry crane, 17 - hanging beam to be demolished in navigable section, 18 - T-shaped structure to be demolished in navigable section. Detailed Implementation Manner

[0030] Embodiment 1

[0031] As Figures 1 to 5 shown, the technical solution of the present invention lies in: a combined gantry crane for demolishing the upper structure of a navigable bridge, including a straight-leg gantry crane 1, an inclined-leg gantry crane 2, a support leg track 6, a long support leg track 7, and an inclined support leg track 8. At both lower ends of the straight-leg gantry crane 1, there are respectively provided a straight support leg 3 of the straight-leg gantry crane and a long support leg 4. The bottom of the straight support leg 3 of the straight-leg gantry crane is movably connected to the support leg track 6, and the bottom of the long support leg 4 is movably connected to the long support leg track 7. At both lower ends of the inclined-leg gantry crane 2, there are respectively provided a straight support leg 16 of the inclined-leg gantry crane and an inclined support leg 5. The bottom of the straight support leg 16 of the inclined-leg gantry crane is movably connected to the support leg track 6, and the bottom of the inclined support leg 5 is movably connected to the inclined support leg track 8.

[0032] During the actual use process, when the present invention uses the straight-leg gantry crane 1 to complete the demolition construction of the upper structure of the non-navigable section of the navigable bridge, the straight-leg gantry crane 1 includes a straight support leg 3 of the straight-leg gantry crane and a long support leg 4. The bottom of the straight support leg 3 of the straight-leg gantry crane is movably connected to the support leg track 6, and the bottom of the long support leg 4 is movably connected to the long support leg track 7. As Figure 1 shown, when demolishing the hanging beam to be demolished in the non-navigable section, the straight-leg gantry crane 1 walks to the designated demolition position. After the connection between the hanging beam 13 to be demolished in the non-navigable section and the T-shaped structure 14 to be demolished in the non-navigable section is cut by a wire saw, the two groups of straight-leg gantry cranes 1 synchronously lift the entire hanging beam 13 to be demolished in the non-navigable section. Then, the hanging beam 13 to be demolished in the non-navigable section is horizontally moved to the beam transportation passage 11, and the beam is carried to the designated position by the beam transporter 12. Repeat this step to complete the demolition of the entire span of the hanging beam 13 to be demolished in the non-navigable section. As Figure 2 shown, when demolishing the T-shaped structure 14 to be demolished in the non-navigable section, the T-shaped structure 14 to be demolished in the non-navigable section is longitudinally and horizontally divided according to the lifting capacity. The two groups of straight-leg gantry cranes 1 symmetrically and synchronously demolish on both sides of the pier top. The demolished T-shaped structure 14 to be demolished in the non-navigable section is carried to the designated position by the beam transporter 12. Repeat this step to demolish the T-shaped structure 14 to be demolished in the non-navigable section. As Figure 4As shown in the figure, when the hanging beam 17 to be demolished in the navigation section is demolished, the inclined-leg gantry crane 2 travels to the designated demolition position. After the connection between the hanging beam 17 to be demolished in the navigation section and the T-structure 18 to be demolished in the navigation section is cut by a wire saw, the two groups of inclined-leg gantry cranes 2 synchronously lift the entire hanging beam 17 to be demolished in the navigation section. Then, the hanging beam 17 to be demolished in the navigation section is horizontally moved to the beam transportation channel 11, and the beam is transported to the designated position by the beam transportation vehicle 12. Repeat this step to complete the demolition of the hanging beam 17 to be demolished in the navigation hole. As Figure 5 shown, during the demolition construction of the T-structure 18 to be demolished in the navigation section, the T-structure 18 to be demolished in the navigation section is longitudinally and horizontally divided according to the lifting capacity of the inclined-leg gantry crane 2. The inclined-leg gantry crane 2 is on the side of the navigation hole at the pier top, and the straight-leg gantry crane 1 is on the side of the non-navigation hole at the pier top. The straight-leg gantry crane 1 and the inclined-leg gantry crane 2 are symmetrically and synchronously demolished. After demolition, the T-structure 18 to be demolished in the navigation section is transported to the designated position by the beam transportation vehicle 12. Repeat this step to demolish the T-structure 18 to be demolished in the navigation section of the navigation bridge.

[0033] The present invention uses a straight-leg gantry crane for demolishing the upper structure of the non-navigation section of a navigation bridge and an inclined-leg gantry crane for demolishing the upper structure of the navigation section of a navigation bridge. It does not require large-scale equipment, is less affected by the external environment, is not affected by navigation or existing lines within the bridge range, can effectively reduce the occupation of the construction site, and ensure the passage of the original road during construction. The present invention uses an inclined-leg gantry crane to complete the demolition construction of the upper structure of the navigation section of a navigation bridge within the navigation hole range, which can reduce navigation interference, reduce the number of navigation conversions, and speed up the construction progress.

[0034] Embodiment 2

[0035] Preferably, on the basis of Embodiment 1, in this embodiment, a counterweight beam 10 is provided on the inclined support leg track 8, and a plurality of anchoring steel bars 9 are provided on the counterweight beam 10. The counterweight beam 10 is detachably connected to the inclined support leg track 8 through the anchoring steel bars 9.

[0036] During actual use, when the inclined-leg gantry crane 2 is in the no-load walking condition of the gantry frame, the anchoring steel bars 9 are released, and the counterweight beam 10 is used to offset the forward inclination force of the temporary inclined support leg 5, and a jack is used to realize the walking of the gantry frame; during the lifting condition, the anchoring steel bars 9 are locked and the counterweight beam 10 is released to prevent the gantry crane from tilting forward. By adopting the design of the counterweight beam 10 + anchoring steel bars 9, the inclined support leg track 8 is simple, safe, and convenient to use.

[0037] Embodiment 3

[0038] Preferably, on the basis of Embodiment 1, in this embodiment, the straight support leg 3 of the straight-leg gantry crane 1 has the same structure as the inclined support leg 16 of the inclined-leg gantry crane 2.

[0039] During actual use, the straight-leg portal crane straight support leg 3 of the straight-leg portal crane 1 of the present invention has the same structure as the inclined-leg portal crane straight support leg 16 of the inclined-leg portal crane 2. The straight-leg portal crane 1 can be used to perform leg conversion outside the pier top of the navigation hole, turning it into an inclined-leg portal crane 2. During the conversion process, the straight-leg portal crane straight support leg 3 of the straight-leg portal crane 1 directly becomes the inclined-leg portal crane straight support leg 16, which is convenient and fast, and the original equipment can be used without replacement.

[0040] Embodiment 4

[0041] A method for demolishing the upper structure of a navigable bridge, using the combined portal crane for demolishing the upper structure of a navigable bridge as described above, includes the following steps:

[0042] S1: Use the straight-leg portal crane 1 to demolish the upper structure of the non-navigable section of the navigable bridge, specifically including demolishing the to-be-demolished hanging beam 13 of the non-navigable section and demolishing the to-be-demolished T-structure 14 of the non-navigable section;

[0043] S2: Use the inclined-leg portal crane 2 to demolish the upper structure of the navigable section of the navigable bridge, specifically including demolishing the to-be-demolished hanging beam 17 of the navigable section and demolishing the to-be-demolished T-structure 18 of the navigable section.

[0044] In the step S1, when using the straight-leg portal crane 1 to demolish the upper structure of the non-navigable section of the navigable bridge, the specific steps are as follows:

[0045] S11: Install the straight-leg portal crane 1. Lay the support leg track 6 on the box girder of the widened section 15 of the newly built widened bridge on both sides of the navigable bridge, and lay the long support leg track 7 at the gap position of the central isolation belt of the navigable bridge. After assembling the straight-leg portal crane 1, the bottom of the straight-leg portal crane straight support leg 3 can be movably connected to the support leg track 6, and the bottom of the long support leg 4 can be movably connected to the long support leg track 7. When building the newly built widened bridge on both sides of the navigable bridge, the widened section 15 at the top of the widened bridge can ensure the movement of the straight-leg portal crane 1 after laying the support leg track 6, which is convenient for demolishing the navigable bridge. At the same time, the widened section 15 also ensures the normal passage of vehicles on both sides of the navigable bridge during the demolition and reconstruction of the navigable bridge;

[0046] S12: Demolish the to-be-demolished hanging beam 13 of the non-navigable section. As Figure 1 shown, the straight-leg portal crane 1 walks to the designated demolition position. After the connection between the to-be-demolished hanging beam 13 of the non-navigable section and the to-be-demolished T-structure 14 is cut by a wire saw, the two groups of straight-leg portal cranes 1 synchronously lift the entire to-be-demolished hanging beam 13 of the non-navigable section, and then the to-be-demolished hanging beam 13 of the non-navigable section is horizontally moved to the beam transportation channel 11, and the beam is carried to the designated position by the beam transportation vehicle 12. Repeat this step to complete the demolition of the entire span of the to-be-demolished hanging beam 13 of the non-navigable section;

[0047] S13: Demolish the to-be-demolished T-structure 14 of the non-navigable section. As Figure 2As shown in the figure, the non-navigable section of the T-structure to be demolished 14 is divided longitudinally and transversely according to the hoisting capacity. Two groups of straight-leg gantry cranes 1 symmetrically and synchronously demolish on both sides of the pier top. After demolition, the non-navigable section of the T-structure to be demolished 14 is carried by the beam transport vehicle 12 to the designated position. Repeat this step to demolish the non-navigable section of the T-structure to be demolished 14;

[0048] In step S2, the upper structure of the navigable section of the navigable bridge is demolished by the inclined-leg gantry crane 2. The specific steps are as follows:

[0049] S21: Install the inclined-leg gantry crane 2. Lay the inclined-leg track 8 above the support of the T-structure to be demolished 18 in the navigable section. After assembling the inclined-leg gantry crane 2, the bottom of the straight leg 16 of the inclined-leg gantry crane can be movably connected to the leg track 6, and the bottom of the inclined leg 5 can be movably connected to the inclined-leg track 8 through the anchor steel bar 9 and the counterweight beam 10;

[0050] S22: Demolish the hanging beam 17 to be demolished in the navigable section. As Figure 4 shown, move the inclined-leg gantry crane 2 to the designated demolition position. After the connection between the hanging beam 17 to be demolished in the navigable section and the T-structure to be demolished 18 in the navigable section is cut by the wire saw, the two groups of inclined-leg gantry cranes 2 synchronously lift the entire hanging beam 17 to be demolished in the navigable section. Then, move the hanging beam 17 to be demolished in the navigable section horizontally to the beam transport channel 11 and carry the beam to the designated position by the beam transport vehicle 12. Repeat this step to complete the demolition of the hanging beam 17 to be demolished in the navigable section of the navigable hole;

[0051] S23: When demolishing the T-structure 18 to be demolished in the navigable section, as Figure 5 shown, divide the T-structure 18 to be demolished in the navigable section longitudinally and transversely according to the hoisting capacity of the inclined-leg gantry crane 2. The inclined-leg gantry crane 2 is on the navigable hole side of the pier top, and the straight-leg gantry crane 1 is on the non-navigable hole side of the pier top. The straight-leg gantry crane 1 and the inclined-leg gantry crane 2 symmetrically and synchronously demolish. After demolition, the T-structure 18 to be demolished in the navigable section is carried by the beam transport vehicle 12 to the designated position. Repeat this step to demolish the T-structure 18 to be demolished in the navigable section of the navigable bridge.

[0052] When installing the inclined-leg gantry crane 2 in step S21, the straight-leg gantry crane 1 already installed in step S11 can be used to make a leg conversion on the outside of the navigable hole pier top to become the inclined-leg gantry crane 2. As Figure 3 shown, the specific process is as follows: The straight-leg gantry crane 1 walks to the outside of the navigable hole pier top. Lay the inclined-leg track 8 above the support of the T-structure to be demolished 18 in the navigable section. Install the inclined leg 5, the anchor steel bar 9 and the counterweight beam 10 on the inclined-leg track 8. Then, demolish the long leg 4 in the central isolation belt to complete the leg system conversion of the straight-leg gantry crane 1 and complete the installation of the inclined-leg gantry crane 2.

[0053] For the inclined-leg gantry crane 2 in step S21, when the gantry crane is in the no-load traveling condition, the anchoring steel bars 9 are released, the counterweight beam 10 is used to counteract the forward tilting force of the temporary inclined support leg 5, and the gantry is moved by using a jack; when in the hoisting condition, the anchoring steel bars 9 are locked and the counterweight beam 10 is released to prevent the gantry crane from tilting forward.

[0054] When hoisting the non-navigable section hanging beam to be demolished 13 in step S1 and the navigable section hanging beam to be demolished 17 in step S2, water drills should be used to drill holes at both ends of the non-navigable section hanging beam to be demolished 13 and the navigable section hanging beam to be demolished 17 respectively as hoisting holes. Four hoisting holes are set for each hanging beam to be demolished. Before the hanging beam to be demolished is cut, the wire rope passes through the hoisting holes to bind the beam body in a bottom-up manner.

[0055] In summary, the combined gantry crane and method for demolishing the upper structure of a navigable bridge provided by the present invention do not require large-scale equipment, are less affected by the external environment, are simple and fast to install and convert, have simple and clear structural forces, are convenient to operate and use, and are safe in construction. During the demolition process of the upper structure of a navigable bridge with limited space, it can ensure construction safety, significantly accelerate the construction progress, and greatly reduce the input cost, providing useful reference for similar constructions.

[0056] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A method for demolishing the superstructure of a navigable bridge, characterized in that: Use a combined gantry crane for demolishing the superstructure of a navigable bridge. The combined gantry crane for demolishing the superstructure of a navigable bridge includes a straight-leg gantry crane (1), an inclined-leg gantry crane (2), a leg track (6), a long leg track (7), and an inclined leg track (8). At the lower parts of both ends of the straight-leg gantry crane (1), there are respectively a straight-leg gantry crane straight leg (3) and a long leg (4). The bottom of the straight-leg gantry crane straight leg (3) is movably connected to the leg track (6), and the bottom of the long leg (4) is movably connected to the long leg track (7). At the lower parts of both ends of the inclined-leg gantry crane (2), there are respectively an inclined-leg gantry crane straight leg (16) and an inclined leg (5). The bottom of the inclined-leg gantry crane straight leg (16) is movably connected to the leg track (6), and the bottom of the inclined leg (5) is movably connected to the inclined leg track (8). An anti-pressure beam (10) is arranged on the inclined leg track (8), and a plurality of anchoring steel bars (9) are provided on the anti-pressure beam (10). The anti-pressure beam (10) is detachably connected to the inclined leg track (8) through the anchoring steel bars (9). The straight-leg gantry crane straight leg (3) of the straight-leg gantry crane (1) has the same structure as the inclined-leg gantry crane straight leg (16) of the inclined-leg gantry crane (2). The method for demolishing the superstructure of a navigable bridge includes the following steps: S1: Use the straight-leg gantry crane (1) to demolish the superstructure of the non-navigable section of the navigable bridge, specifically including the demolition of the to-be-demolished hanging beam (13) in the non-navigable section and the demolition of the to-be-demolished T-structure (14) in the non-navigable section; S2: Use the inclined-leg gantry crane (2) to demolish the superstructure of the navigable section of the navigable bridge, specifically including the demolition of the to-be-demolished hanging beam (17) in the navigable section and the demolition of the to-be-demolished T-structure (18) in the navigable section.

2. The method for demolishing the superstructure of a navigable bridge according to claim 1, characterized in that : In the step S1, when using the straight-leg gantry crane (1) to demolish the superstructure of the non-navigable section of the navigable bridge, the specific steps are as follows: S11: Install the straight-leg gantry crane (1). Lay the leg track (6) on the box girder of the widened section (15) of the newly built widened bridge on both sides of the navigable bridge, and lay the long leg track (7) at the gap position of the central isolation belt of the navigable bridge. After assembling the straight-leg gantry crane (1), the bottom of the straight-leg gantry crane straight leg (3) is movably connected to the leg track (6), and the bottom of the long leg (4) is movably connected to the long leg track (7); S12: The non-navigable section hanging beam (13) to be dismantled is dismantled, and the straight-leg gantry crane (1) moves to the designated dismantling position. After the rope saw cuts the connection between the non-navigable section hanging beam (13) and the non-navigable section T-structure (14) to be dismantled, the two groups of straight-leg gantry cranes (1) simultaneously lift the entire non-navigable section hanging beam (13), and then move the non-navigable section hanging beam (13) to be dismantled horizontally to the beam transport channel (11), and the beam is transported to the designated position by the beam transport vehicle (12), and then re-mounted. Repeat this step to complete the removal of the hanging beam (13) to be removed in the non-navigable section of the entire hole; S13: Remove the T-structure (14) to be removed in the non-navigable section. Divide the T-structure (14) to be removed in the non-navigable section into blocks in the longitudinal and transverse directions according to the lifting capacity. Two groups of straight-leg gantry cranes (1) symmetrically and synchronously remove the T-structure (14) to be removed in the non-navigable section on both sides of the pier top. After the removal, the T-structure (14) to be removed in the non-navigable section is carried to a designated position by a beam transport vehicle (12). Repeat this step to remove the T-structure (14) to be removed in the non-navigable section.

3. The method for demolishing the superstructure of a navigable bridge according to claim 1, characterized in that: In step S2, the upper structure of the navigation section of the navigation bridge is dismantled using a slanted-leg gantry crane (2), and the specific steps are as follows: S21: Install the inclined leg gantry crane (2), lay the inclined leg track (8) above the support of the T-structure (18) to be dismantled in the navigation section, and after assembling the inclined leg gantry crane (2), the bottom of the straight leg (16) of the inclined leg gantry crane can be movably connected to the leg track (6), and the bottom of the inclined leg (5) can be movably connected to the inclined leg track (8) through the anchor steel rod (9) and the counter-pressure beam (10); S22: The navigation section hanging beam (17) to be removed is removed. The inclined leg gantry crane (2) is moved to the designated removal position. After the rope saw cuts the connection between the navigation section hanging beam (17) to be removed and the navigation section T-structure (18) to be removed, the two sets of inclined leg gantry cranes (2) simultaneously lift the entire navigation section hanging beam (17) to be removed. The navigation section hanging beam (17) to be removed is then moved horizontally to the beam transport channel (11). The beam is carried to the designated position by the beam transport vehicle (12). This step is repeated to complete the removal of the navigation section hanging beam (17) to be removed. S23: During the dismantling construction of the T-structure (18) of the navigation section to be dismantled, the T-structure (18) of the navigation section to be dismantled is divided into blocks in the longitudinal and transverse directions according to the lifting capacity of the inclined leg gantry crane (2). The inclined leg gantry crane (2) is located on the navigation hole side of the pier top, and the straight leg gantry crane (1) is located on the non-navigation hole side of the pier top. The straight leg gantry crane (1) and the inclined leg gantry crane (2) are dismantled symmetrically and synchronously. After being dismantled, the T-structure (18) of the navigation section to be dismantled is carried to a designated position by a beam transport vehicle (12). This step is repeated to dismantle the T-structure (18) of the navigation section of the navigation bridge to be dismantled.

4. The method for demolishing the superstructure of a navigable bridge according to claim 3, characterized in that: The slanted leg gantry crane (2) is installed in step S21. The straight leg gantry crane (1) installed in step S11 can be converted into a slanted leg gantry crane (2) by performing a leg conversion on the outside of the navigation hole pier top. The specific process is as follows: the straight leg gantry crane (1) moves to the outside of the navigation hole pier top, and a slanted leg track (8) is laid above the support of the T-structure (18) to be dismantled in the navigation section. The slanted legs (5), anchoring steel rods (9) and counter-pressure beams (10) are installed on the slanted leg track (8). Then, the long legs (4) of the central dividing strip are removed, and the leg system conversion of the straight leg gantry crane (1) is completed, and the installation of the slanted leg gantry crane (2) is completed.

5. The method for demolishing the superstructure of a navigable bridge according to claim 3, characterized in that: For the inclined-leg gantry crane (2) in step S21, when the gantry crane is in the no-load traveling condition, release the anchoring steel bars (9), use the counterweight beam (10) to offset the forward tilting force of the temporary inclined support leg (5), and use a jack to realize the traveling of the gantry crane; when in the hoisting condition, lock the anchoring steel bars (9) and release the counterweight beam (10) to prevent the gantry crane from tilting forward.

6. The method for demolishing the superstructure of a navigable bridge according to claim 1, characterized in that: When hoisting the non-navigable section of the hanging beam to be demolished (13) in step S1 and the navigable section of the hanging beam to be demolished (17) in step S2, water drills should be used to drill holes at both ends of the non-navigable section of the hanging beam to be demolished (13) and the navigable section of the hanging beam to be demolished (17) respectively as hoisting holes. Four hoisting holes should be set for each hanging beam to be demolished, and the wire ropes should be used to bundle the beam body from the bottom through the hoisting holes before the hanging beam to be demolished is cut.

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