A method for demolishing the substructure of a reinforced concrete arch bridge

Abstract

This invention relates to a method for dismantling the substructure of a reinforced concrete arch bridge. An arch-mounted transport flatcar is installed on the main arch ring, and a cable crane is used in conjunction with the flatcar for construction. The substructure is segmented according to the reusable dimensions of the dismantled components and the maximum lifting capacity of the cable crane. The cable crane lifts the cut segments onto the arch-mounted transport flatcar, which then transports them to the arch foot. This invention allows for simultaneous cutting and transportation, improving dismantling efficiency. Furthermore, the cable crane does not travel under load, ensuring high construction safety. Additionally, the high carrying capacity of the arch-mounted transport flatcar allows for the dismantling of large segments of the arch bridge substructure, facilitating the secondary reuse of the dismantled components.

Description

Technical Field

[0001] This invention relates to the field of bridge demolition construction, and specifically to a method for demolishing the substructure of a reinforced concrete arch bridge. Background Technology

[0002] Some early reinforced concrete arch bridges are unable to meet the growing traffic demands and need to be demolished and rebuilt. During the demolition process, to minimize environmental pollution and considering that some structures still possess strength and have secondary use value, large-segment demolition is employed whenever possible.

[0003] Structurally, reinforced concrete arch bridges can be divided into superstructure and substructure. The superstructure is the bridge span structure, directly bearing the loads of vehicles and pedestrians, while the substructure includes the main arch ring and the columns supporting the superstructure. Currently, the superstructure of arch bridges can be dismantled in its entirety using a bridge erecting machine, while the substructure is often dismantled using cable cranes. Each segment is lifted by a cable crane to the arch foot and lowered onto a ground transport vehicle for removal. However, cable cranes have limited lifting capacity, and their safety is poor, especially when moving under load. This means that the substructure can only be cut into smaller segments for dismantling, which cannot meet the requirements for dismantling large segments of reinforced concrete arch bridges. Furthermore, the slow movement speed leads to extended construction periods. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by providing a method for demolishing the substructure of a reinforced concrete arch bridge, which meets the requirements for demolishing large segments of the substructure of an arch bridge, improves construction efficiency, and ensures construction safety.

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

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

[0007] (1) Construction preparation:

[0008] (11) After the superstructure of the arch bridge is demolished, the main side span junction pier is used as a buttress to install a small-tonnage tower crane;

[0009] (12) Use tower cranes to install cable pylons on the junction piers, and use the abutments as rear anchors to erect cable pylons on the pylons; install arch frame support below the arch foot section of the main arch ring;

[0010] (13) Lay flatcar tracks on the top surface of the main arch ring. First, lay two sections of flatcar tracks from the two arch feet to the first arch column closest to the arch feet. Install arch transport flatcars on the two sections of tracks respectively.

[0011] (2) Remove the supporting columns on the arch:

[0012] (21) The arch columns are divided according to the size of the concrete blocks that can be structurally utilized and the maximum lifting weight of the cable crane, and the dividing blocks are sequentially numbered.

[0013] (22) The two transport flatcars on the arches travel along the tracks to the nearest first arch column;

[0014] (23) According to the design of the arch column, the arch column is cut in sequence using a wire saw, and the cut sections are lifted onto the arch transport flatcar by a cable crane. The sections are then transported to the arch foot by the arch transport flatcar, and then transferred to the ground transport vehicle by a crawler crane and transported to the designated location.

[0015] (24) After the first arch column is removed, the flatbed track on the top surface of the arch ring is extended and laid to the bottom of the next arch column. All arch columns are removed sequentially from the arch foot to the middle of the span according to the above steps (22) to (23).

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

[0017] (31) Use the cable-stayed tower as a tie tower, install the tie cable of the main arch ring and tension it;

[0018] (32) The main arch ring closure section was dismantled using a cable crane, and the closure section was transferred to the arch foot by a flatcar on the arch.

[0019] (33) The cable crane and the flatcar on the arch work together to remove the cantilever segments of the main arch ring from the middle of the span to the arch foot, and remove the corresponding fastening cables and flatcar tracks of the cantilever segments.

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

[0021] (4) Finally, the cable crane was used to dismantle the cable crane, the tower and the arch foot support to complete the demolition of the reinforced concrete arch bridge substructure.

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

[0023] 1. By pre-designing the substructure of the reinforced concrete arch bridge into segmented sections that can be structurally utilized, the secondary treatment of solid waste is reduced, thus lowering environmental pollution.

[0024] 2. The cable crane is only responsible for lifting the cut sections onto the arch transport flatcar. The arch transport flatcar replaces the cable crane in transporting the dismantled sections. On the one hand, cutting and transportation can be carried out simultaneously, improving dismantling efficiency. On the other hand, the cable crane does not have to move under load, so the construction safety is high.

[0025] 3. The flatbed trucks used for transporting goods on the arch have a strong carrying capacity, which is conducive to the dismantling of large sections of the substructure of the arch bridge;

[0026] 4. The transport flatcar is unloaded when moving up on the arch and loaded when moving down. It mainly relies on its own weight when moving down, so the power requirements of the power system are low and the operation is simple.

[0027] 5. The use of inclined cable-stayed suspension as the support system for the cantilever dismantling of the arch bridge is safe and reliable. Attached Figure Description

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

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

[0030] Figure 3 This is a side view of the structure of the transport flatcar on the arch;

[0031] Figure 4 yes Figure 2 The enlarged view at point A shows a schematic diagram of the elevation structure of the transport flatcar wheels and the flatcar tracks on the arch.

[0032] Figure 5 yes Figure 3 The enlarged view at point B shows a side view of the structure of the transport flatcar wheels and the flatcar track on the arch.

[0033] Figure 6 This is a schematic diagram of a method for dividing the columns on an arch into segments;

[0034] Figure 7 This is a schematic diagram showing the dismantling of the first arch support column in conjunction with a cable crane and an arch transport flatcar.

[0035] Figure 8 This is a schematic diagram showing the dismantling of subsequent arch-mounted columns in conjunction with a cable crane and an arch-mounted transport flatcar.

[0036] Figure 9 This is a schematic diagram showing the dismantling of the main arch closure section using a cable crane and an arch-mounted transport flatcar.

[0037] Figure 10 This is a schematic diagram showing the dismantling of the main arch ring cantilever in conjunction with a cable crane and a flatbed transport vehicle on the arch.

[0038] Figure 11 This is a schematic diagram showing the dismantling status of the main arch foot section. Detailed Implementation

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

[0040] (1) Construction preparation:

[0041] (11) such as Figure 1 , Figure 2 , Figure 3 As shown, after the superstructure of the arch bridge was demolished, the main side span junction pier 1 was used as a support wall to install a small tonnage tower crane 2;

[0042] (12) Use a tower crane to install cable pylon 3 on the junction pier, and use the abutment 4 as the rear anchor to erect cable pylon 5 on the pylon; install arch frame support 7 below the arch foot section of the main arch ring 6;

[0043] (13) Lay flatcar tracks 8 on the top surface of the main arch ring 6. First, lay two sections of flatcar tracks from the two arch feet to the first arch column 9 closest to the arch feet. Install arch transport flatcars 10 on the two sections of flatcar tracks respectively.

[0044] like Figure 2 , Figure 3 As shown, in a specific implementation of the present invention, the traveling wheels 101 of the arch-mounted transport flatcar 10 can adopt a gear structure, driven and braked by a motor. The flatcar track 8 is provided with locking teeth 81 that mesh with the gears of the traveling wheels of the transport flatcar. Since the top of the main arch ring has a certain slope, the above-mentioned gear-type traveling wheels and locking tooth-type track structure can prevent the arch-mounted transport flatcar from automatically sliding down the track.

[0045] The flatcar track 8 can be anchored to the main arch ring 6 on both sides using anchor bolts 11.

[0046] Limiting beams 102 can be respectively installed on the top surfaces of the front and rear ends of the frame of the arch transport flatcar 10 to prevent the load on the car from slipping off.

[0047] To prevent the traveling wheels from derailing, annular anti-derailment limiting plates 1011 can be extended from both sides of the traveling wheels 101 of the arch-mounted transport flatcar in a direction perpendicular to the wheel axle. The anti-derailment limiting plates 1011 on both sides of the traveling wheels are located on both sides of the flatcar track 8.

[0048] (2) Remove the supporting columns on the arch:

[0049] (21) The arch columns are divided according to the size of the concrete blocks that can be structurally utilized and the maximum lifting weight of the cable crane, and the dividing blocks are sequentially numbered. Figure 6 The diagram shows a design for the segmentation of the arch support column 9. The arch support column 9 is divided into multiple segments laterally, and each segment is divided into 7 large blocks 91 according to its box side plate and web plate.

[0050] (22) such as Figure 7 , Figure 8 As shown, the two transport flatcars 10 on the arches travel along the tracks to the side of the first arch column 9 that is closest to them;

[0051] (23) According to the design of the arch column, the arch column is cut in sequence using a wire saw, and the cut sections are lifted onto the arch transport flatcar 10 by cable crane 5. The sections are then transported to the arch foot by the arch transport flatcar, and then transferred to the ground transport vehicle by crawler crane 12 and transported to the designated location.

[0052] (24) After the first arch column is removed, the flatbed track on the top surface of the arch ring is extended and laid to the bottom of the next arch column. All arch columns are removed sequentially from the arch foot to the middle of the span according to the above steps (22) to (23).

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

[0054] (31) such as Figure 9 , Figure 10 As shown, the cable-stayed tower 3 is used as the anchor tower, and the anchor cable 13 of the main arch ring 6 is installed and tensioned.

[0055] (32) Use cable crane 5 to remove the closure section of the main arch ring 6 and lift it onto the arch transport flatcar, and then transfer it to the arch foot via the arch transport flatcar 10.

[0056] (33) The cable crane and the flatcar on the arch work together to remove the cantilever segments of the main arch ring from the middle of the span to the arch foot, and remove the corresponding fastening cables and flatcar tracks of the cantilever segments.

[0057] (34) Use crawler crane 12 to dismantle the arch foot segment of the main arch ring;

[0058] (4) Finally, tower crane 2 was used to dismantle the cable crane, tower and arch foot support to complete the demolition of the reinforced concrete arch bridge substructure.

Claims

1. A method of dismantling a reinforced concrete arch bridge substructure, characterized in that, Includes the following steps: (1) Construction preparation: (11) After the superstructure of the arch bridge is demolished, a small-tonnage tower crane will be installed using the main side span junction pier as a buttress. (12) Use tower cranes to install cable pylons on the junction piers, and use the abutments as rear anchors to erect cable pylons on the pylons; install arch frame support below the arch foot section of the main arch ring; (13) Lay flatcar tracks on the top surface of the main arch ring. First, lay two sections of flatcar tracks from the two arch feet to the first arch column closest to the arch feet, and install arch transport flatcars on the two sections of tracks respectively. The traveling wheels of the arch-mounted transport flatcar are gear-structured, driven and braked by a motor, and the flatcar track is equipped with locking teeth that mesh with the gears of the traveling wheels of the transport flatcar. (2) Remove the columns on the arch: (21) The arch columns are divided according to the size of the concrete blocks that can be structurally utilized and the maximum lifting weight of the cable crane, and the dividing blocks are sequentially numbered. (22) The two transport flatcars on the arches travel along the tracks to the nearest first arch pillar; (23) According to the design of the arch column, the arch column is cut in sequence using a wire saw, and the cut sections are lifted onto the arch transport flatcar by a cable crane. The sections are then transported to the arch foot by the arch transport flatcar, 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, the flatbed track on the top surface of the arch ring is extended and laid to the bottom of the next arch column. All arch columns are removed sequentially from the arch foot to the middle of the span according to the above steps (22) to (23). (3) Remove the main arch ring: (31) Use the cable-stayed tower as a tie tower, install the tie cable of the main arch ring and tension it; (32) The main arch ring closure section was dismantled using a cable crane, and the closure section was transferred to the arch foot by a flatcar on the arch. (33) The cable crane and the flatcar on the arch work together to remove the cantilever segments of the main arch ring from the middle of the span to the arch foot, and remove the corresponding fastening cables and flatcar tracks of the cantilever segments; (34) Use a crawler crane to dismantle the arch foot segment of the main arch ring; (4) Finally, the cable crane was used to dismantle the cable crane, the tower and the arch foot support to complete the dismantling of the reinforced concrete arch bridge substructure.

2. The method of claim 1, wherein: The flatcar track is anchored to the main arch ring on both sides using anchor bolts.

3. The method of claim 1, wherein: The top surfaces of the front and rear ends of the frame of the arch-mounted transport flatcar are respectively equipped with limiting beams to prevent the load on the car from slipping off.

4. The method of claim 1, wherein: The traveling wheels of the arch-mounted transport flatcar have annular anti-derailment limiting plates extending from both sides in a direction perpendicular to the wheel axle. The anti-derailment limiting plates on both sides of the traveling wheels are located on both sides of the flatcar track.

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