A method for integrated construction of dismantling and building of a new cable-stayed bridge by dismantling an old simple-supported beam bridge

Abstract

The application relates to a dismantling and building integrated construction method for dismantling an old simply supported beam bridge and building a new cable-stayed bridge, which comprises the following steps: firstly, constructing cable-stayed bridge cable towers on both sides of the old bridge; then, driving a truck crane to the old bridge, symmetrically installing main longitudinal beams of the cable-stayed bridge and installing stay cables from the tower area to the midspan and side span in sections by using the truck crane; after the main longitudinal beams are closed, using the main longitudinal beams as a bearing platform to erect two gantry cranes on the two main longitudinal beams in the transverse direction of the bridge; then, dismantling the old bridge by using the gantry cranes; and finally, hoisting the deck system of the cable-stayed bridge by using the gantry cranes to complete the construction of the new cable-stayed bridge. The application does not need to use large equipment such as a floating crane for dismantling the old bridge, and does not need to erect a cable crane for building the new suspension bridge, so that the construction cost can be greatly reduced, and the bridge dismantling and new bridge building processes are closely connected, so that the construction efficiency can be greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of bridge construction technology and relates to an integrated demolition and construction method for demolishing old simply supported beam bridges and building new cable-stayed bridges. Background Technology

[0002] Simply supported beam bridges are bridges whose superstructure is simply supported on piers at both ends. They are characterized by simple construction, clear stress distribution, and ease of standardized prefabrication, making them the most widely used bridge type among early river-crossing bridges. However, the mid-span bending moment of simply supported beam bridges increases sharply with the span, leading to a significant increase in beam height and self-weight, affecting structural safety. Therefore, their maximum span is generally no more than 50 meters, with correspondingly smaller height and width, resulting in significant limitations on both the traffic capacity on the bridge and the navigation capacity underneath. With the development of society and the economy, some old simply supported beam bridges can no longer meet the growing transportation demands and need to be demolished and rebuilt. Steel cable-stayed bridges are a bridge system composed of towers, main beams, and cable stays. They have advantages such as large span capacity, reasonable stress distribution, and aesthetically pleasing design. Economical spans range from 300 to 1000 meters, and as a self-anchored system, they do not require expensive ground anchor foundations, thus often being the preferred bridge type for new bridges.

[0003] Currently, the conventional construction method for demolishing old bridges and rebuilding new ones is generally to demolish first and then rebuild. This involves completely dismantling the old bridge and then rebuilding the new one on the same site, which results in a long construction period. Moreover, bridge demolition requires the use of large floating cranes, truck cranes, and other equipment, and is significantly affected by hydrological, navigation, and site conditions, leading to low construction efficiency. On the other hand, the construction of new cable-stayed bridges generally adopts the cantilever method, which requires the use of bridge deck cranes or cable cranes to symmetrically assemble precast steel beams from the tower area to both sides, resulting in higher construction costs. Summary of the Invention

[0004] The purpose of this invention is to address the above-mentioned problems by providing an integrated demolition and construction method for demolishing old simply supported beam bridges and building new cable-stayed bridges, so as to improve construction efficiency and reduce construction costs.

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

[0006] A method for integrated demolition and construction of a new cable-stayed bridge by demolishing an old simply supported beam bridge, wherein the new cable-stayed bridge adopts a steel main beam with a greater height and deck width than the old bridge, characterized by the following steps:

[0007] (1) Construct cable-stayed bridge towers on both sides of the old bridge;

[0008] (2) The truck crane is driven to the old bridge and the main longitudinal beam of the cable-stayed bridge is installed symmetrically from the tower area to the middle and side spans. The cable stays are installed between the tower and the main longitudinal beam according to the design position of the cable stays. When the fourth cable stay is installed, the cross beam between the main longitudinal beams is installed using the truck crane.

[0009] (3) After the main longitudinal beams are joined, the main longitudinal beams are used as the load-bearing foundation. Gantry crane tracks are laid on the two longitudinal beams, and two gantry cranes are erected in the transverse direction on the two main longitudinal beams using a truck crane.

[0010] (4) The truck crane exits the old bridge, and two transport vehicles drive from both ends of the old bridge to the old bridge. The transport ship drives to the bottom of the old bridge. The old bridge deck system, bridge panel and pier are symmetrically cut and dismantled from the middle of the old bridge to both ends. The upper components of the old bridge are lifted by the gantry crane and transported to the transport vehicle. The lower components are lifted onto the transport ship and transported away, thus completing the demolition of the old bridge.

[0011] (5) Transport the bridge deck system between the main longitudinal beams of the cable-stayed bridge to the roadbed positions at both ends of the old bridge, move the gantry crane to lift the bridge deck system between the two longitudinal beams, install it symmetrically from the tower area to both sides, and weld it to the main longitudinal beams until the bridge deck system between the main longitudinal beams is fully installed.

[0012] (6) Transport the flange plates of the cable-stayed bridge to the roadbed positions at both ends of the old bridge, move the gantry crane to lift the flange plates onto the bridge, and use the bridge deck crane to lift the flange plates and weld them to the outside of the main longitudinal beam to complete the construction of the new cable-stayed bridge.

[0013] This invention first uses the old bridge as a construction platform to install the main longitudinal beams and cross beams of the suspension bridge. Then, the main longitudinal beams of the suspension bridge after closure are used as a load-bearing platform to install a gantry crane. The gantry crane is then used to dismantle the old bridge and install the suspension bridge deck system. Dismantling the old bridge does not require expensive large equipment such as floating cranes, and building a new suspension bridge does not require large equipment such as cable cranes. This can significantly reduce construction costs. Moreover, the dismantling and construction of the new bridge are closely linked, which can greatly improve construction efficiency.

[0014] This invention is also applicable to the demolition and reconstruction of old rigid frame bridges and continuous beam bridges. Attached Figure Description

[0015] Figure 1 This is a construction flowchart of the present invention;

[0016] Figure 2 This is a schematic diagram of the longitudinal structure of a newly built cable-stayed bridge, where a mobile crane is used to install the main longitudinal beams of the bridge on the old bridge.

[0017] Figure 3 This is a schematic diagram of the plan structure of a new cable-stayed bridge being installed by a mobile crane on an old bridge;

[0018] Figure 4 This is a schematic diagram of the transverse structure of a newly built cable-stayed bridge, showing a truck crane installing the main longitudinal beams of the old bridge onto the old bridge.

[0019] Figure 5 This is a schematic diagram of the longitudinal structure of the old bridge being demolished using a gantry crane on the main longitudinal beam.

[0020] Figure 6This is a schematic diagram of the transverse structure of the old bridge, which is demolished using a gantry crane on the main longitudinal beam.

[0021] Figure 7 This is a schematic diagram of the transverse bridge structure for installing the bridge deck system between the main longitudinal beams using a gantry crane on the main longitudinal beams;

[0022] Figure 8 This is a schematic diagram of the transverse structure of the cable-stayed bridge after construction is completed. Detailed Implementation

[0023] The method of the present invention will be described below through a specific embodiment and in conjunction with the accompanying drawings. In this embodiment, an old simply supported beam bridge needs to be demolished and a new cable-stayed bridge built on the original site due to its low height and narrow deck. The cable-stayed bridge adopts a steel main beam, the height of which and the width of the deck are both greater than those of the old bridge. Figure 1 This is a construction flowchart; the specific construction methods are as follows:

[0024] (1) such as Figure 2 , Figure 3 , Figure 4 As shown in the figure, cable-stayed bridge towers 1 are constructed on both sides of the old bridge 100; construction should avoid damaging the old bridge structure.

[0025] (2) The truck crane 2 travels to the old bridge 100 and uses the truck crane 2 to install the main longitudinal beam 3 of the cable-stayed bridge symmetrically from the tower area to the middle and side spans. According to the design position of the cable stays, the cable stays 4 are installed between the tower and the main longitudinal beam. When the fourth cable stay is installed, the truck crane is used to install the cross beam 5 between the main longitudinal beams to enhance the stability of the main longitudinal beam.

[0026] (3) such as Figure 5 , Figure 6 As shown, after the main longitudinal beams 3 are joined together, the alignment is adjusted to form a longitudinal beam load-bearing system with sufficient rigidity and overall stability; using the main longitudinal beams as the load-bearing foundation, gantry crane tracks are laid on the two longitudinal beams, and two gantry cranes 6 are erected transversely on the two main longitudinal beams using a truck crane.

[0027] (4) The truck crane exits the old bridge, and two transport vehicles drive from both ends of the old bridge onto the old bridge. The transport ship drives to the bottom of the old bridge. The old bridge deck system, bridge panel and piers are symmetrically cut and dismantled from the middle of the 100-span of the old bridge to both ends. The upper components of the old bridge are lifted by the gantry crane 6 and transported away on the transport vehicles. The lower components are lifted onto the transport ship and transported away, thus completing the demolition of the old bridge.

[0028] (5) such as Figure 7 As shown, the bridge deck system between the main longitudinal beams of the cable-stayed bridge is transported to the roadbed positions at both ends of the old bridge. The gantry crane is moved to lift the bridge deck system 7 between the two longitudinal beams 3 and install it symmetrically from the tower area to both sides. The bridge deck system between the main longitudinal beams is welded to the main longitudinal beams until the bridge deck system 7 between the main longitudinal beams is completely installed.

[0029] (6) For example Figure 8 As shown, the flange plates of the cable-stayed bridge are transported to the roadbed positions at both ends of the old bridge. The gantry crane is moved to lift the flange plates onto the bridge. The bridge deck crane is used to lift the flange plates 8 and weld them to the outside of the main longitudinal beam 3. The bridge deck is then paved and ancillary facilities are installed to complete the construction of the new cable-stayed bridge.

Claims

1. A method for integrated demolition and construction of a new cable-stayed bridge by demolishing an old simply supported beam bridge, wherein the new cable-stayed bridge adopts a steel main beam, the height of which and the width of which are greater than those of the old bridge, characterized in that... Includes the following steps: (1) Construct cable-stayed bridge towers on both sides of the old bridge; (2) The truck crane is driven to the old bridge and the main longitudinal beam of the cable-stayed bridge is installed symmetrically from the tower area to the middle and side spans. The cable stays are installed between the tower and the main longitudinal beam according to the design position of the cable stays. When the fourth cable stay is installed, the cross beam between the main longitudinal beams is installed using the truck crane. (3) After the main longitudinal beams are joined, the main longitudinal beams are used as the load-bearing foundation. Gantry crane tracks are laid on the two longitudinal beams, and two gantry cranes are erected in the transverse direction on the two main longitudinal beams using a truck crane. (4) The truck crane exits the old bridge, and two transport vehicles drive from both ends of the old bridge to the old bridge. The transport ship drives to the bottom of the old bridge. The old bridge deck system, bridge panel and pier are symmetrically cut and dismantled from the middle of the old bridge to both ends. The upper components of the old bridge are lifted by the gantry crane and transported to the transport vehicle. The lower components are lifted onto the transport ship and transported away, thus completing the demolition of the old bridge. (5) Transport the bridge deck system between the main longitudinal beams of the cable-stayed bridge to the roadbed positions at both ends of the old bridge, move the gantry crane to lift the bridge deck system between the two longitudinal beams, install it symmetrically from the tower area to both sides, and weld it to the main longitudinal beams until the bridge deck system between the main longitudinal beams is fully installed. (6) Transport the flange plates of the cable-stayed bridge to the roadbed positions at both ends of the old bridge, move the gantry crane to lift the flange plates onto the bridge, and use the bridge deck crane to lift the flange plates and weld them to the outside of the main longitudinal beam to complete the construction of the new cable-stayed bridge.

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