Demolition method of reinforced concrete arch bridge lower structure

Abstract

The invention relates to a demolition method of a reinforced concrete arch bridge substructure, which comprises the following steps: arranging a spandrel transport flatcar on a main arch ring, adopting a cable crane and the spandrel transport flatcar for cooperative construction, and segmenting the arch bridge substructure according to the structurally usable size of a demolition component and the maximum hoisting weight of the cable crane. And the cable crane lifts the cut block sections to the on-arch transport flatcar, and the cut block sections are transferred to arch feet through the on-arch transport flatcar. On one hand, synchronous construction of cutting and transporting can be achieved, the dismantling efficiency is improved, the cable crane does not need to walk with loads, and the construction safety is high, on the other hand, by means of the characteristic that the spandrel transporting flatcar is high in carrying capacity, dismantling of large segments of an arch bridge lower structure can be achieved, and secondary utilization of dismantled components is facilitated.

Description

Technical Field

[0001] The present invention relates to the field of bridge demolition construction, and particularly relates to a method for demolishing the lower structure of a reinforced concrete arch bridge. Background Art

[0002] Some early-built reinforced concrete arch bridges need to be demolished and rebuilt because they cannot meet the growing traffic demand. During the demolition process, in order to reduce environmental pollution and considering that some structures still have a certain strength and are of secondary utilization value, large-section demolition is preferably adopted.

[0003] Reinforced concrete arch bridges can be structurally divided into an upper structure and a lower structure. The upper structure is the bridge span structure that directly bears the loads of vehicles and pedestrians, and the lower structure includes the main arch ring and the arch-column on the arch, which are used to support the upper structure. At present, the entire span of the upper structure of the arch bridge can be demolished by a bridge erecting machine, and the lower structure is often demolished by a cable crane. For each demolished block, it is lifted to the arch foot by the cable crane and then lowered onto a ground transportation vehicle for transportation. However, the lifting capacity of the cable crane is limited, especially the safety is poor when the load moves, and the lower structure can only be cut into smaller blocks for demolition, which cannot meet the requirements of large-section demolition of reinforced concrete arch bridges, and the moving speed is slow, resulting in an extended construction period. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for demolishing the lower structure of a reinforced concrete arch bridge to meet the requirements of large-section demolition of the lower structure of the arch bridge, improve the construction efficiency, and ensure the construction safety.

[0005] The technical solution of the present invention is as follows:

[0006] A method for demolishing the lower structure of a reinforced concrete arch bridge, characterized by comprising the following steps:

[0007] (1) Construction preparation:

[0008] (11) After the demolition of the upper structure of the arch bridge is completed, use the main side-span junction pier as a retaining wall to install a small-tonnage tower crane.

[0009] (12) Use the tower crane to install a cable crane pylon on the junction pier, and use the abutment as the rear anchor to erect a cable crane on the pylon; install an arch frame section support under the arch foot section of the main arch ring.

[0010] (13) Lay flat car tracks on the top surface of the main arch ring. First, lay two sections of flat car tracks from the two arch feet to the first arch-column on the arch closest to the arch feet, and install arch transportation flat cars on the two sections of tracks respectively.

[0011] (2) Demolish the arch-columns on the arch:

[0012] (21) Design the segmentation of the upper-arch columns according to the size of the concrete blocks that can be structurally utilized and the maximum lifting capacity of the cable crane, and sequentially number the segmented blocks;

[0013] (22) The two upper-arch transport flatcars respectively drive along the track to the side of the first upper-arch column closest to them;

[0014] (23) According to the segmentation design of the upper-arch columns, use a wire saw to cut the upper-arch columns in sequence, and use the cable crane to lift the cut blocks onto the upper-arch transport flatcars, transport them to the arch feet through the upper-arch transport flatcars, and then transfer them to the ground transport vehicles by a crawler crane and transport them to the designated location;

[0015] (24) After the demolition of the first upper-arch column is completed, extend and lay the flatcar track on the top surface of the arch ring to the lower part of the next upper-arch column, and sequentially demolish all the upper-arch columns from the arch feet to the mid-span according to the methods in steps (22) to (23) above;

[0016] (3) Demolish the main arch ring:

[0017] (31) Use the cable crane tower as the buckling tower, install the buckling cables for the inclined cable buckling of the main arch ring and carry out tensioning;

[0018] (32) Use the cable crane to demolish the closure segment of the main arch ring, and transfer the closure segment to the arch feet through the upper-arch transport flatcar;

[0019] (33) The cable crane and the upper-arch transport flatcar cooperate to sequentially demolish the cantilever segments of the main arch ring from the mid-span to the arch feet, and demolish the corresponding buckling cables and the flatcar track of the cantilever segments;

[0020] (34) Use the crawler crane to demolish the arch foot segment of the main arch ring;

[0021] (4) Finally, use the tower crane to demolish the cable crane, the tower and the arch foot segment support, and complete the demolition of the lower structure of the reinforced concrete arch bridge.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. By pre-segmenting and designing the lower structure of the reinforced concrete arch bridge and then directly disassembling it into structurally utilizable blocks, the secondary treatment work of solid waste is reduced, and environmental pollution is lowered;

[0024] 2. The cable crane is only responsible for lifting the cut blocks onto the upper-arch transport flatcars, and uses the upper-arch transport flatcars to replace the cable crane to transport the demolished blocks. On the one hand, synchronous construction of cutting and transportation can be realized, improving the demolition efficiency. On the other hand, the cable crane does not need to travel under load, and the construction safety is high;

[0025] 3. The upper-arch transport flatcar has a strong carrying capacity, which is conducive to realizing the demolition of large segments of the lower structure of the arch bridge;

[0026] 4. When the transport flat car travels upward on the arch, it is unloaded, and when it travels downward, it is loaded. When traveling downward, it mainly relies on its own gravity, requiring a low power for the power system and being easy to operate.

[0027] 5. The cable-stayed buckle hanging is adopted as the support system for the cantilever demolition of the arch bridge, which is safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of the construction preparation state of the present invention;

[0029] Figure 2 is a schematic cross-sectional structure diagram of the transport flat car on the arch;

[0030] Figure 3 is a schematic side view structure diagram of the transport flat car on the arch;

[0031] Figure 4 is Figure 2 the enlarged view at A in

[0032] Figure 5 is Figure 3 the enlarged view at B in

[0033] Figure 6 is a schematic diagram of a way to divide the cutting blocks of the column on the arch;

[0034] Figure 7 is a schematic diagram of the state when the cable crane and the transport flat car on the arch cooperate to demolish the first column on the arch;

[0035] Figure 8 is a schematic diagram of the state when the cable crane and the transport flat car on the arch cooperate to demolish the subsequent columns on the arch;

[0036] Figure 9 is a schematic diagram of the state when the cable crane and the transport flat car on the arch cooperate to demolish the closure section of the main arch ring;

[0037] Figure 10 is a schematic diagram of the state when the cable crane and the transport flat car on the arch cooperate to demolish the cantilever of the main arch ring;

[0038] Figure 11 is a schematic diagram of the demolition state of the arch foot section of the main arch ring. DETAILED DESCRIPTION OF THE INVENTION

[0039] The specific construction method of the present invention is as follows:

[0040] (1) Construction preparation:

[0041] (11) As shown in Figure 1 and Figure 2 andFigure 3 As shown, after the upper structure of the arch bridge is demolished, the small-tonnage tower crane 2 is installed using the main side-span transition pier 1 as a retaining wall.

[0042] (12) The cable-suspended crane tower 3 is installed on the transition pier using the tower crane, and the cable-suspended crane 5 is erected on the tower using the abutment 4 as the back anchor; the arch frame segment support 7 is installed under the arch foot section of the main arch ring 6.

[0043] (13) The flat car track 8 is laid on the top surface of the main arch ring 6. First, two sections of flat car tracks from the two arch feet to the first upper-arch column 9 closest to the arch feet are laid, and the upper-arch transport flat cars 10 are respectively installed on the two sections of flat car tracks.

[0044] As Figure 2 、 Figure 3 shown, in the specific implementation of the present invention, the running wheels 101 of the upper-arch transport flat car 10 can adopt a gear structure, driven and braked by an electric motor, and the flat car track 8 is provided with teeth 81 meshing with the gear of the running wheel of the transport flat car. Due to the certain slope at the top of the main arch ring, the above-mentioned gear-type running wheel and tooth-type track matching structure can prevent the upper-arch transport flat car from automatically sliding on the track.

[0045] Both sides of the flat car track 8 can be respectively anchored to the main arch ring 6 by anchor bolts 11.

[0046] The top surfaces of the front and rear ends of the frame of the upper-arch transport flat car 10 can be respectively provided with limit beams 102 to prevent the loaded objects on the vehicle from slipping.

[0047] To prevent the derailment of the running wheels, annular anti-derailment limit plates 1011 can be respectively extended in the direction perpendicular to the wheel axle on both sides of the running wheels 101 of the upper-arch transport flat car, and the anti-derailment limit plates 1011 on both sides of the running wheels are respectively located on both sides of the flat car track 8.

[0048] (2) Demolish the upper-arch columns:

[0049] (21) The upper-arch columns are divided and designed according to the size of the concreted blocks that can be structurally utilized and the maximum lifting weight of the cable-suspended crane, and the divided block segments are sequentially numbered; Figure 6 Shown is a schematic diagram of a division design method for the upper-arch columns. The upper-arch columns 9 are horizontally divided into multiple segments, and each segment is divided into 7 large block segments 91 according to its chamber side plates and webs.

[0050] (22) As Figure 7 、 Figure 8 shown, the two upper-arch transport flat cars 10 respectively travel along the track to the side of the first upper-arch column 9 closest to them;

[0051] (23) According to the segmentation design of the upper-arch columns, use a wire saw to cut the upper-arch columns in sequence, and use a cable crane 5 to lift the cut block segments onto the upper-arch transport flatbed 10, transport them to the arch foot through the upper-arch transport flatbed, and then transfer them to a ground transport vehicle by a crawler crane 12 and transport them to the designated location;

[0052] (24) After the demolition of the first upper-arch column is completed, extend and lay the flatbed track on the top surface of the arch ring to below the next upper-arch column, and demolish all the upper-arch columns in sequence from the arch foot to the mid-span according to the methods in steps (22) to (23) above;

[0053] (3) Demolish the main arch ring:

[0054] (31) As Figure 9 、 Figure 10 shown, use the cable crane tower 3 as a buckling tower, install the stay cables 13 for obliquely pulling and buckling the main arch ring 6 and carry out tensioning;

[0055] (32) Use the cable crane 5 to demolish the closure section of the main arch ring 6 and lift it onto the upper-arch transport flatbed, and transfer it to the arch foot through the upper-arch transport flatbed 10;

[0056] (33) The cable crane and the upper-arch transport flatbed cooperate to demolish the cantilever segments of the main arch ring in sequence from the mid-span to the arch foot, and demolish the corresponding stay cables and flatbed tracks of the cantilever segments;

[0057] (34) Use the crawler crane 12 to demolish the arch-foot section segments of the main arch ring;

[0058] (4) Finally, use the tower crane 2 to demolish the cable crane, the tower and the arch-foot section supports to complete the demolition construction of the lower structure of the reinforced concrete arch bridge.

Claims

1. A method for dismantling a reinforced concrete arch bridge substructure, characterized in that: The following steps are involved: (1) Construction preparation: (11) After the arch bridge superstructure is dismantled, the main side span junction pier is used as a buttress to install a small tonnage tower crane; (12) Use a tower crane to install a cable pylon on the junction pier, and use the abutment as a rear anchor to set up a cable pylon on the pylon; install an arch frame bracket under the arch foot section of the main arch ring; (13) Laying flat car tracks on the top surface of the main arch ring. First, laying two sections of flat car tracks from the two arch feet to the first arch column closest to the arch foot, and installing arch transport flat cars on the two sections of tracks respectively; (2) Removal of the arch columns: (21) The arch columns are divided and designed according to the size of the concrete blocks that can be structurally utilized and the maximum lifting weight of the cable crane, and the divided blocks are numbered sequentially; (22) The two arch transport flat cars respectively travel along the track to the first arch column closest to them; (23) According to the segmentation design of the arch columns, the arch columns are cut in sequence using a rope saw, and the cut blocks are lifted onto the arch transport flat car by a cable crane, transported to the arch foot by the arch transport flat car, and then transferred to the ground transport vehicle by a crawler crane and transported to the designated location; (24) After the first arch column is removed, extend the flat car track on the top of the arch ring to the bottom of the next arch column, and remove all the arch columns from the arch foot to the middle of the span in sequence according to the method of steps (22) to (23) above; (3) Removal of the main arch ring: (31) Using the cable suspension tower as the buckle tower, install the buckle cables of the main arch ring and tension them; (32) Use a cable crane to remove the closure section of the main arch ring, and transfer the closure section to the arch foot via a transport flat car on the arch; (33) The cable crane cooperates with the arch transport flat car to remove the cantilever segments of the main arch ring from the mid-span to the arch foot, and removes the buckle cables and flat car tracks corresponding to the cantilever segments; (34) Use crawler crane to dismantle the arch foot section of the main arch ring; (4) Finally, the tower crane is used to dismantle the cable hanger, cable tower and arch foot bracket to complete the dismantling of the reinforced concrete arch bridge substructure.

2. The method for dismantling the lower structure of a reinforced concrete arch bridge according to claim 1, characterized in that: The running wheels of the arch transport flat car are gear structures, the running wheels are driven and braked by a motor, and the flat car track is provided with latch teeth that mesh with the running wheel gears of the transport flat car.

3. The method for dismantling the lower structure of a reinforced concrete arch bridge according to claim 1, characterized in that: Both sides of the flat car track are anchored on the main arch ring by anchor bolts respectively.

4. The method for dismantling the lower structure of a reinforced concrete arch bridge according to claim 1, characterized in that: Limiting beams are respectively arranged on the top surfaces of the front and rear ends of the frame of the arch transport flat car to prevent the loaded objects on the car from sliding off.

5. The method for dismantling the lower structure of a reinforced concrete arch bridge according to claim 1, characterized in that: Annular anti-derail limit plates are respectively extended from both sides of the running wheel of the arch transport flat car in a direction perpendicular to the wheel axle, and the anti-derail limit plates on both sides of the running wheel are respectively located on both sides of the flat car track.

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