Self-anchored suspension bridge span navigable hole steel box girder construction method

Abstract

The present application relates to a kind of self-anchored suspension bridge span navigable hole steel box girder construction method, belong to bridge construction technical field, comprising the following steps: S1, erecting temporary support, and setting up anti-collision pier near the temporary support of navigable hole;S2, floating crane section erection push segment steel box girder, utilize walking type pusher to carry out the push of steel box girder push segment;S3, hoist the both ends of steel box girder section installation corbel;S4, utilize floating crane self-transportation barge to hoist steel box girder section, through hinged anchor, beam section is moved to the above of to-be-installed position, floating crane drops beam section to beam bottom higher than the top of beam drop pad 20cm;S5, three-way jack lifts to contact with the bottom of corbel, remove the connection between hoist steel box girder section and lifting appliance, and floating crane exits work;S6, utilize three-way jack to adjust the relative position of joint seam between beam section, use temporary locking device to lock joint, carry out beam section welding seam construction, so that beam section is welded into whole;The present application is especially suitable for the construction of self-anchored suspension bridge across temporary channel, with practicality.

Description

A construction method for steel box girders spanning navigation channels in a self-anchored suspension bridge Technical Field

[0001] This invention belongs to the field of bridge construction technology, specifically relating to a construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel. Background Technology

[0002] Self-anchored suspension bridges have relatively low geological requirements because they do not require the main cable to be anchored to rocks or large anchorages, making them an increasingly competitive option for urban landmark bridges.

[0003] The stiffening girder of a self-anchored suspension bridge needs to bear and balance the tension of the main cable, so the construction sequence differs from that of a ground-anchored suspension bridge ("cable first, then girder"), and is usually "girder first, then cable." Construction methods for the stiffening girder include the incremental launching method, the scaffolding method, and the cable-stayed method. Because the main span of a self-anchored suspension bridge crosses a temporary waterway, it needs to meet navigation requirements, making the scaffolding method unsuitable. Furthermore, the incremental launching method requires high stiffness of the temporary piers, leading to high costs and a greater risk of ship collisions in areas with large main pier spans or deep water. The cable-stayed method requires the erection of cable-stayed towers, affecting the construction period and increasing costs. Therefore, for construction spanning ultra-large span temporary waterways, it is necessary to develop a construction method for the steel box girder of a self-anchored suspension bridge crossing a navigation channel using a double-suspended bracket method to reduce construction difficulty and costs. Summary of the Invention

[0004] To address the aforementioned problems in the existing technology, this invention provides a construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel, comprising the following steps:

[0005] S1: Two temporary support groups are erected along the same straight line, with a certain distance between them, forming a navigation channel between them; each temporary support group includes several temporary supports, which are set at equal intervals on the ground, and anti-collision piers are set on the two temporary supports near the two ends of the navigation channel.

[0006] S2: Several jacking sections of steel box girders are erected in sections on top of temporary support groups by floating cranes, and the jacking sections of steel box girders are jacked towards the navigation road using walking jacking devices;

[0007] S3: Install brackets at both ends of the lifted steel box girder segment;

[0008] S4: Use a floating crane to lift the steel box girder segment from the self-propelled beam transport vessel, and move the steel box girder segment to the position to be installed by using a hinged anchor. The floating crane then lowers the steel box girder segment to the bottom of the beam, which is 20cm higher than the top of the beam-dropping pad.

[0009] S5: The three-way jack is raised to contact the bottom of the bracket and support the steel box girder segment. The connection between the steel box girder segment and the floating crane is released, the floating crane is withdrawn from work, and the three-way jack is lowered to the bracket supported on the lowering pad block on the top of the jacking section of the steel box girder.

[0010] S6: Use three-way jacks to precisely adjust the relative position of the joint between the jacking section steel box girder and the hoisting steel box girder, lock the joint with a temporary locking device, and carry out the welding construction between the beam segments to weld the beam segments into a whole.

[0011] S7: After the three-way jack is raised to the point where the beam support block can just be removed, the beam support block is removed, then the three-way jack is lowered, and finally the bracket is removed.

[0012] This solution provides a construction method for steel box girders in self-anchored suspension bridges spanning navigation channels. This addresses the problem that existing self-anchored suspension bridges cannot utilize the scaffolding method when their main span crosses a navigation channel, due to navigation requirements. Furthermore, this solution utilizes floating cranes to erect cantilevered steel box girders within the navigation channel, replacing the channel jacking method, thereby reducing the stiffness requirements of temporary scaffolding and lowering construction costs and difficulty.

[0013] Furthermore, this solution utilizes a combination of three-way jacks and corbels to achieve rapid and precise adjustment of the relative position of the joint between the jacking section steel box girder and the lifting section steel box girder, thus expediting the joint work between the jacking section steel box girder and the lifting section steel box girder and further improving the efficiency and speed of the work.

[0014] The objective of this invention can be achieved through the following technical solutions:

[0015] A construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel, characterized by the following steps:

[0016] S1: Two temporary support groups are erected along the same straight line, with a certain distance between them, forming a navigation road between them; each temporary support group includes several temporary supports, which are equally spaced on the ground, and anti-collision piers are installed on the two temporary supports near the two ends of the navigation road.

[0017] S2: Several jacking sections of steel box girders are erected in sections on top of the temporary support group by floating cranes, and the jacking sections of steel box girders are jacked towards the navigation road using walking jacking devices;

[0018] S3: Install brackets at both ends of the lifted steel box girder segment;

[0019] S4: The floating crane is used to lift the steel box girder segment from the self-carrying beam vessel, and the steel box girder segment is moved to the position to be installed by the hinged anchor. The floating crane lowers the steel box girder segment to the bottom of the beam, which is 20cm higher than the top of the beam-dropping pad.

[0020] S5: The three-way jack is raised to contact the bottom of the bracket and support the steel box girder segment. The connection between the steel box girder segment and the floating crane is released, the floating crane is withdrawn from work, and the three-way jack is lowered to the bracket supported on the beam-dropping pad block on the top of the jacking section of the steel box girder.

[0021] S6: Use the three-way jacks to precisely adjust the relative position of the joint between the jacking section steel box girder and the lifting steel box girder, then use a temporary locking device to lock the joint, and then carry out the welding construction between the beam segments to weld the beam segments into a whole.

[0022] S7: After the three-way jack is raised to the point where the beam support block can just be disengaged, the beam support block is removed, then the three-way jack is lowered, and finally the bracket is disassembled.

[0023] As a preferred technical solution of the present invention, in S1, the anti-collision pier adopts an orange-red warning color to serve as a warning and to protect the safety of the construction process.

[0024] As a preferred embodiment of the present invention, in S2, the distance from the temporary support near the navigation channel to the closure section steel box girder is less than or equal to 1 / 3 of the length of the single-segment jacking section steel box girder.

[0025] As a preferred technical solution of the present invention, in S3, two corbels should be arranged at the junction of the beam segments; corbels are symmetrically arranged on the beam surfaces at both ends of the lifting steel box girder segment, and support legs A and B are also provided at both ends of the corbels. Support legs A and B correspond to the positions of the transverse diaphragm and web of the steel box girder. Lifting lugs are provided at support leg B to connect the corbel to the steel box girder; a three-way jack and a beam-dropping pad are provided on the beam surface at the cantilever front end of the jacking section steel box girder corresponding to the transverse diaphragm and web, respectively used to adjust the position of the lifting steel box girder segment and support the lifting steel box girder segment.

[0026] As a preferred embodiment of the present invention, the corbel is located directly above the web of the steel box girder, and the center point of the lifting lug pin hole is on the same horizontal line as the web of the steel box girder.

[0027] As a preferred technical solution of the present invention, in S4, after the beam transport barge is anchored and positioned, the floating crane is pulled by the hinged anchor to the position where the beam segment is directly below the hook of the floating crane. After the floating crane takes the beam, it exits the barge. Then the floating crane continues to hinge anchor until the design position is reached, thus completing the installation of the steel box girder segment.

[0028] As a preferred embodiment of the present invention, in S4, the lifting points are arranged at the corresponding positions of the transverse diaphragms of the steel box girder, avoiding the positions of the top plate ribs.

[0029] In a preferred embodiment of the present invention, in step S5, the drop beam pad serves as a temporary support for the steel box girder during installation, and its top is equipped with a rubber pad. The three-way jack is used to adjust the position of the steel box girder and can assist in adjusting the relative position of the joints between steel box girder segments; its top is also equipped with a rubber pad.

[0030] As a preferred embodiment of the present invention, in S6, the temporary locking device should preferably be prefabricated in the factory along with the steel box girder components. During the hoisting and erection of the steel box girder segments, the spatial position of the top, bottom, and web plates between the segments is controlled by the temporary locking device. Only after the position of the steel box girder reaches the required accuracy can the precision-rolled threaded steel bars and installation bolts be installed and tensioned.

[0031] As a preferred technical solution of the present invention, in S6, the welding of the beam segment is easily affected by temperature. The work should be carried out on one end of the beam segment when the temperature is low, and the other end should be welded after one end is completed.

[0032] The beneficial effects of this invention are as follows:

[0033] This solution provides a construction method for steel box girders in self-anchored suspension bridges spanning navigation channels. This addresses the problem that existing self-anchored suspension bridges cannot utilize the scaffolding method when their main span crosses a navigation channel, due to navigation requirements. Furthermore, this solution utilizes floating cranes to erect cantilevered steel box girders within the navigation channel, replacing the channel jacking method, thereby reducing the stiffness requirements of temporary scaffolding and lowering construction costs and difficulty.

[0034] Furthermore, this solution utilizes a combination of three-way jacks and corbels to achieve rapid and precise adjustment of the relative position of the joint between the jacking section steel box girder and the lifting section steel box girder, thus expediting the joint work between the jacking section steel box girder and the lifting section steel box girder and further improving the efficiency and speed of the work. Attached Figure Description

[0035] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the accompanying drawings.

[0036] Figure 1 is a construction flowchart of the present invention;

[0037] Figure 2 is a schematic diagram of construction step S1 of the present invention;

[0038] Figure 3 is a schematic diagram of construction step S2 of the present invention;

[0039] Figure 4 is a schematic diagram of construction step S3 of the present invention;

[0040] Figure 5 is a schematic diagram of construction step S4 of the present invention;

[0041] Figure 6 is a schematic diagram of construction steps S5 to S6 of the present invention;

[0042] Figure 7 is a schematic diagram of construction step S7 of the present invention;

[0043] Figure 8 is a schematic diagram of the cow leg of the present invention.

[0044] Explanation of main symbols

[0045] In the diagram: 1. Temporary support; 2. Anti-collision pier; 3. Pushing section of steel box girder; 4. Lifting section of steel box girder; 5. Corbel; 6. Floating crane; 7. Three-way jack; 8. Beam lowering pad. Detailed Implementation

[0046] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided.

[0047] Please refer to Figures 1-8. This embodiment provides a construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel, including the following steps:

[0048] S1: Two temporary support groups are erected along the same straight line, spaced at a certain interval, forming a navigation channel between them. Each temporary support group includes several temporary supports 1, which are equally spaced on the ground. Anti-collision piers 2 are installed on the two temporary supports 1 closest to the two ends of the navigation channel. The navigation channel in this scheme facilitates the passage of ships at sea through the self-anchored suspension bridge, improving traffic flow. As a connecting space between the two sides of the self-anchored suspension bridge, the navigation channel makes traffic flow more convenient, meeting the passage needs of large ships and solving the connectivity obstacle between the two sides of the self-anchored suspension bridge. Furthermore, the purpose of installing anti-collision piers 2 is: 1. As a boundary or protection of the bridge, they can prevent ships, vessels, or other water vehicles from accidentally colliding with the bridge piers or bridge structure, thereby effectively protecting the integrity and stability of the bridge. Anti-collision piers 2 can absorb and disperse impact forces, reducing the impact on the bridge and lowering the risk of damage. 2. Installing anti-collision piers 2 can provide navigation guidance for ships in the water, ensuring that ships maintain an appropriate course and navigation safety when passing under the bridge. The presence of crash barriers 2 serves to remind ship operators to maintain a sufficient safe distance, avoiding direct contact with the bridge structure and reducing the occurrence of accidents. Thirdly, crash barriers 2 can reduce damage to the bridge structure from accidental collisions, extending the bridge's service life. By installing crash barriers 2, the frequency of repairs and maintenance can be reduced, maintenance costs lowered, and the long-term benefits of the bridge improved. In conclusion, the installation of crash barriers 2 plays a crucial role in the construction of self-anchored suspension bridges, protecting the bridge structure, ensuring navigational safety, and extending the bridge's service life. It is an effective measure to prevent potential collision accidents and ensure the safe and stable operation of the bridge.

[0049] S2: Several jacking sections of steel box girder 3 are erected in segments on top of the temporary support assembly using floating cranes 6. Walking-type jacking devices are then used to push the jacking sections of steel box girder 3 towards the navigation channel. It should be noted that the walking-type jacking devices are used to gradually move the jacking sections of steel box girder 3 towards the navigation channel. This allows for the erection of the suspension bridge segment by segment, ensuring the continuity and accuracy of the construction. Furthermore, in this scheme, the jacking section steel box girder 3 is placed on top of the temporary support group using a floating crane 6. Then, the jacking section steel box girder 3 is jacked by a walking jacking device, causing it to move along the setting direction of the temporary support group and gradually approach the direction of the navigation road. Next, another jacking section steel box girder 3 is placed on top of the temporary support group using the floating crane 6, and the connection between the two jacking section steel box girder 3 is welded. The jacking section steel box girder 3 is then jacked by a walking jacking device, causing it to move along the setting direction of the temporary support group and gradually approach the direction of the navigation road. This process is repeated until the jacking section steel box girder 3 extends beyond one end of the temporary support group.

[0050] S3: Install brackets 5 at both ends of the lifting steel box girder segment 4; brackets 5 can provide support for the steel box girder, ensuring the stability and safety of the steel box girder.

[0051] S4: Using the floating crane 6, the steel box girder segment 4 is lifted from the self-propelled beam transport vessel. The steel box girder segment is moved to the position above the installation location by means of the hinged anchor. The floating crane 6 lowers the steel box girder segment to the bottom of the beam, which is 20cm higher than the top of the beam lowering pad 8, to provide space for subsequent adjustments and construction.

[0052] S5: The three-way jack 7 is raised to contact the bottom of the corbel 5 and supports the steel box girder segment. The connection between the steel box girder segment and the floating crane 6 is released, the floating crane 6 is withdrawn from work, and the three-way jack 7 is lowered to the corbel 5 and supported on the beam-dropping pad 8 on the top of the jacking section of the steel box girder 3, ensuring the stability and accurate position of the steel box girder segment.

[0053] S6: Use the three-way jack 7 to precisely adjust the relative position of the joint between the jacking section steel box girder 3 and the hoisting steel box girder, then use a temporary locking device to lock the joint, and then carry out the welding construction between the beam segments to weld the beam segments into a whole.

[0054] S7: After the three-way jack 7 is raised to the point where the beam support block 8 can just be disengaged, the beam support block 8 is removed. Then, the three-way jack 7 is lowered, and finally, the corbel 5 is dismantled, completing the installation process of the steel box girder. The purpose of this step is to remove temporary supports and related equipment, preparing for subsequent acceptance and navigation.

[0055] This solution provides a construction method for steel box girders in self-anchored suspension bridges spanning navigation channels, solving the problem that existing self-anchored suspension bridges cannot use the scaffolding method when the main span crosses a navigation channel due to navigation requirements. Furthermore, this solution utilizes floating cranes (6) to erect cantilevered steel box girders on the navigation channel, replacing the channel jacking method, thereby reducing the stiffness requirements of the temporary scaffolding (1) and lowering construction costs and difficulty.

[0056] In addition, this solution uses a combination of three-way jacks 7 and brackets 5 to quickly and accurately adjust the relative position of the joint between the jacking section steel box girder 3 and the lifting section steel box girder, thus expediting the joint work between the jacking section steel box girder 3 and the lifting section steel box girder and further improving the efficiency and speed of the work.

[0057] Furthermore, in S1, crash barriers 2 are painted in orange-red as a warning color to ensure safety during construction. The orange-red color design of crash barriers 2 is intended to provide safety warnings at the construction site. Orange-red is a conspicuous color that easily attracts attention. By placing crash barriers 2 near both ends of the temporary support assembly along the navigable road and using orange-red markings, passing vehicles and pedestrians can be effectively alerted to the construction area, preventing traffic accidents or other unforeseen incidents. This helps protect the safety of construction workers and passing vehicles, ensuring the smooth progress of the construction process.

[0058] Furthermore, in S2, the distance from the temporary support 1 near the navigation channel to the closure section steel box girder is less than or equal to 1 / 3 of the length of the single-segment jacking section steel box girder 3. This setting is to prevent the jacking section steel box girder 3 from extending too far into the navigation channel and causing it to overturn.

[0059] Furthermore, in S3, the corbel 5 consists of a corbel beam and a corbel support point, and two corbels 5 should be arranged at the junction of beam segments. Corbels 5 are symmetrically arranged on both ends of the lifting steel box girder segment 4. The lifting steel box girder is equipped with supports A and B, and supports A and B are also provided at both ends of the corbel 5. Supports A and B correspond to the positions of the transverse diaphragms and web of the steel box girder. Lifting lugs are provided at support B to connect the corbel 5 to the steel box girder. It should be noted that the structure of the steel box girder in this scheme is consistent, similar to the structure of existing I-beams. The transverse diaphragms of the steel box girder in this scheme are similar to the steel plate structures at the top and bottom of an I-beam, while the web of the steel box girder is a vertical steel plate structure in the middle of the I-beam connected to the top and bottom. This arrangement allows the corbels 5 in this scheme to stably drag the steel box girder without causing it to sway. Three-way jacks 7 and beam-lowering blocks 8 are installed on the cantilever front end beam surface of the jacking section steel box girder 3, corresponding to the diaphragm and web, respectively, to adjust the position of the lifting steel box girder segment 4 and support the lifting steel box girder segment 4; the corbel 5 is composed of corbel beams and corbel supports. To ensure the balance and stability of the lifting steel box girder segment 4, two corbels 5 should be arranged at the beam segment junction. Specifically, corbels 5 need to be symmetrically arranged on the beam surfaces at both ends of the lifting steel box girder segment 4. This means that there will be a corbel 5 support point on the beam surface at each end. Among them, support legs A and support legs B correspond to the positions of the diaphragm and web of the steel box girder, respectively. In addition, lifting lugs will be installed at the position of support leg B to connect the corbel 5 to the steel box girder. This ensures that the corbel 5 can be firmly connected to the steel box girder, providing support and stability. In addition, corresponding arrangements are also required on the beam surface at the cantilever front end of the jacking section steel box girder 3. Three-way jacks 7 and beam-lowering pads 8 will be installed here to adjust the position of the lifted steel box girder segment 4 and support it. This design arrangement ensures the balance and stability of the lifted steel box girder segment 4 during construction, guaranteeing the smooth progress of the project.

[0060] Furthermore, the installation position of the lifting lug at support leg B can be adjusted according to the actual situation, ensuring that the corbel 5 is directly above the web of the steel box girder, and that the center point of the lifting lug pin hole is on the same horizontal line as the web of the steel box girder. During processing, the lifting lug position must be accurately installed according to the actual beam surface and actual cross slope, and pre-assembly should be performed to prevent errors. The installation position of the lifting lug can be adjusted according to the actual situation to ensure that the corbel 5 is directly above the web of the steel box girder, and that the center point of the lifting lug pin hole is on the same horizontal line as the web of the steel box girder. During processing, the lifting lug position needs to be accurately installed according to the actual beam surface and actual cross slope. This means that the specific shape and inclination of the beam surface, as well as the size and direction of the cross slope, need to be considered. Based on these actual conditions, appropriate pre-assembly operations should be performed to prevent errors. Through precise installation of the lifting lug and pre-assembly operations, the position and connection stability of the corbel 5 during construction can be ensured, avoiding problems caused by positional deviations. This ensures the quality and safety of the project.

[0061] Further, in S4, after the beam-carrying barge is anchored and positioned, the floating crane 6 is pulled to a position where the beam segment is directly below its hook using a hinged anchoring method. The floating crane 6 then removes the beam from the barge and continues hinged anchoring until it reaches the designed position, completing the installation of the steel box girder segment. After the beam-carrying barge is anchored and positioned, hinged anchoring is first used to position the floating crane directly below the beam segment by securing the anchor ropes. Then, the hook of the floating crane 6 is used to lift the beam segment and move it off the barge. After this step, the floating crane 6 continues hinged anchoring to move the beam segment to the designed position, completing the installation of the steel box girder segment. Throughout the process, anchoring and hinged anchoring are crucial operational steps. Anchoring and positioning ensure the barge remains stably in the designated position, providing a foundation for subsequent operations. Hinged anchoring ensures that the floating crane 6 can accurately move to directly below the beam segment for lifting, while also controlling the position of the floating crane 6 to move the beam segment to the predetermined designed position. Through the above operational procedures, the installation of the steel box girder segment can be achieved. This method can effectively improve construction efficiency, ensure safety and quality, and ensure that beam segments are installed accurately in the designated positions.

[0062] Furthermore, in S4, the lifting points are positioned corresponding to the transverse diaphragms of the steel box girder, avoiding the top ribs. Positioning the lifting points corresponding to the transverse diaphragms ensures the stable lifting and correct installation of the beam segment. During lifting operations, the top ribs must be avoided to prevent unnecessary damage or impact. The accuracy of the lifting point placement is crucial for the safe lifting and installation of the beam segment. By positioning the lifting points corresponding to the transverse diaphragms of the steel box girder, the lifting force can be transferred to the appropriate location on the beam segment structure, avoiding unnecessary loads and stress concentrations on other parts. In addition, the weight and center of gravity of the beam segment must be considered when arranging the lifting points to ensure balance and stability during the lifting process. Simultaneously, the selection and arrangement of the lifting points must comply with relevant design codes and standards to improve the safety and reliability of the lifting operation. In summary, in S4, the lifting points should be positioned corresponding to the transverse diaphragms of the steel box girder, avoiding the top ribs, to ensure the safe lifting and correct installation of the beam segment.

[0063] Furthermore, in S5, the drop beam pad 8 serves as a temporary support for the steel box girder during installation, and its top is equipped with a rubber pad. The three-way jack 7 is used to adjust the position of the steel box girder and can assist in adjusting the relative position of the joints between the steel box girder segments. Its top is also equipped with a rubber pad. The drop beam pad 8 and the three-way jack 7 are auxiliary tools used in the installation process of the steel box girder. The drop beam pad 8 is a temporary support used to support the steel box girder and distribute the load, ensuring that the beam segments can be stably installed in the predetermined position. Its top is usually equipped with a rubber pad to reduce pressure concentration on the bottom of the steel box girder and improve the stability of the support. The three-way jack 7 is an adjustment tool used to adjust the position of the steel box girder to achieve precise adjustment of the relative position of the joints between the beam segments. It can make fine adjustments in both the horizontal and vertical directions, making the installation of the steel box girder more accurate and precise. Similarly, the top of the three-way jack 7 is also equipped with a rubber pad to protect the surface of the steel box girder from damage. When using the beam-dropping pads 8 and the three-way jacks 7, they need to be configured and arranged reasonably according to the specific situation. At the same time, it is essential to ensure that the selection, installation, and use of these auxiliary tools comply with relevant design specifications and standards to ensure the safe and reliable installation of the steel box girder. In summary, in S5, the beam-dropping pads 8 and the three-way jacks 7 are auxiliary tools used for the installation of steel box girders. The beam-dropping pads 8 act as temporary support points, and the three-way jacks 7 are used to adjust the relative positions of the joints between beam segments. Both are equipped with rubber pads on their tops to improve the stability of support and adjustment.

[0064] Furthermore, in S6, the temporary locking device should preferably be prefabricated in the factory along with the steel box girder components. During the hoisting and erection of steel box girder segment 4, the spatial position of the top, bottom, and web plates between the segments is controlled using the temporary locking device. Only after the steel box girder's position reaches the required accuracy can the fine-rolled threaded steel bars and bolts be installed and tensioned. The temporary locking device is typically prefabricated in the factory along with the steel box girder components. When hoisting and erecting steel box girder segments, the spatial position of the top, bottom, and web plates between the segments is controlled using the temporary locking device. Further installation work can only proceed after the steel box girder's position reaches the required accuracy. The purpose of the temporary locking device is to maintain the stability of the steel box girder segments and ensure that they do not shift or deform during installation. This is crucial for subsequent steel bar tensioning and bolt installation, as these processes require precise segment positioning. Once the steel box girder segment's position reaches the required accuracy, the tensioning of the fine-rolled threaded steel bars can begin. Fine-rolled threaded steel bars are typically used to increase the strength and load-bearing capacity of the steel box girder. The installation of bolts is to reinforce the connections of the steel box girder, ensuring a tight and reliable connection between the beam segments. It is important to note that temporary locking, rebar tensioning, and bolt installation must be carried out in accordance with design specifications and standards, and construction safety requirements must be strictly adhered to. This ensures that the installation process of the steel box girder meets requirements and ultimately achieves the expected structural performance and service requirements. In summary, in S6, temporary locking devices are typically fabricated together with the steel box girder components to control the spatial position between beam segments. Tensioning of the precision-rolled threaded rebar and installation of bolts can only proceed after the steel box girder's position has reached the required accuracy. During these tasks, relevant specifications and standards must be followed to ensure construction safety and structural quality.

[0065] Furthermore, in S6, beam segment welding is susceptible to temperature effects. Therefore, it is recommended to select one end of the beam segment for welding during a day when the temperature is lower, and then continue welding the other end after completing that end. Beam segment welding is a process easily affected by temperature. To ensure welding quality and safety, it is suggested to select one end of the beam segment for welding during a day when the temperature is lower, and then continue welding the other end after completing that end. The reason for choosing to weld beam segments during a day with lower temperatures is that the lower ambient temperature helps to reduce the heat-affected zone generated during welding, thereby reducing the probability of welding deformation and stress concentration. Lower temperatures also provide better welding conditions, making the welding process more stable and controllable. By welding beam segments in stages, sufficient quality control of each part of the weld can be ensured. Weld one end first, and wait for that end to completely cool and solidify before continuing to weld the other end. This avoids the heat-affected zone and thermal stress accumulation caused by simultaneous welding, which is beneficial to the stability and quality of the weld. In addition to selecting appropriate temperature conditions and adopting a staged welding method, the following points should also be noted to ensure the quality and safety of beam segment welding:

[0066] 1. Ensure that welding operations comply with relevant specifications and standards, including the selection of welding equipment and the adjustment of current and voltage.

[0067] 2. Ensure that the welding tools and materials are of good quality and have undergone thorough preparation and inspection to prevent welding defects.

[0068] 3. During the welding process, it is important to control factors such as welding speed, welding temperature, and welding deformation to ensure welding quality and structural stability.

[0069] 4. After welding is completed, non-destructive testing and quality inspection of the weld should be carried out in a timely manner to ensure the quality and reliability of the welding.

[0070] In summary, for S6, to ensure the welding quality of beam segments and avoid welding deformation, it is recommended to select one end of the lifted beam segment for welding during a day when the temperature is lower, and to continue welding the other end only after completing one end. At the same time, it is important to control welding conditions and take necessary quality control measures to ensure the reliability of the welding process and the safety of the structure.

[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel, characterized in that, Includes the following steps: S1: Construct two temporary support groups along the same straight line, with a certain distance between them, forming a navigation channel between them; each temporary support group includes several temporary supports, which are equally spaced on the ground, and anti-collision piers are installed on the two temporary supports near the two ends of the navigation channel; S2: Several jacking sections of steel box girders are erected in sections on top of the temporary support groups using a floating crane, and the jacking sections of steel box girders are jacked towards the navigation channel using a walking jacking device; S3: Install brackets at both ends of the lifted steel box girder sections; S4: Use the floating crane to lift the steel box girder sections from the beam transport vessel, and move the steel box girder sections above the installation position using hinged anchors, the floating crane... S5: Lower the steel box girder segment until the bottom of the girder is 20cm higher than the top of the girder support block; S6: The three-way jacks are raised to contact the bottom of the bracket and support the steel box girder segment, the connection between the steel box girder segment and the floating crane is released, the floating crane is withdrawn from work, and the three-way jacks are lowered until the bracket is supported on the girder support block at the top of the jacking section of the steel box girder; S7: The three-way jacks are used to precisely adjust the relative position of the joint between the jacking section of the steel box girder and the lifting steel box girder, and then the joint is locked with a temporary locking device. Then the weld joint construction between the girder segments is carried out to weld the girder segments into a whole; S8: The three-way jacks are raised until the girder support block can just be detached, then the girder support block is removed, then the three-way jacks are lowered, and finally the bracket is disassembled.

2. The construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel according to claim 1, characterized in that: In S1, the crash barriers are made of orange-red warning color to serve as a warning and to protect the safety of the construction process.

3. The construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel according to claim 1, characterized in that: In S2, the distance from the temporary support near the navigation channel to the closure section steel box girder is less than or equal to 1 / 3 of the length of the single-segment jacking section steel box girder.

4. The construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel according to claim 1, characterized in that: In S3, two corbels should be arranged at the junction of the beam segments; corbels are symmetrically arranged on the beam surfaces at both ends of the lifting steel box girder segment, and support legs A and B are also provided at both ends of the corbels. Support legs A and B correspond to the positions of the transverse diaphragm and web of the steel box girder. Lifting lugs are provided at support leg B to connect the corbel to the steel box girder; three-way jacks and beam lowering pads are set on the beam surface at the cantilever front end of the jacking section of the steel box girder corresponding to the transverse diaphragm and web, respectively, for adjusting the position of the lifting steel box girder segment and supporting the lifting steel box girder segment.

5. A construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel according to claim 4, characterized in that: The corbel is located directly above the web of the steel box girder, ensuring that the center point of the lifting lug pin hole is on the same horizontal line as the web of the steel box girder.

6. The construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel according to claim 1, characterized in that: In S4, after the beam transport barge is anchored and positioned, the floating crane is pulled by hinged anchoring until the beam segment is directly below the floating crane hook. After the floating crane takes the beam, it exits the barge. Then the floating crane continues to hinge anchor until it reaches the designed position, completing the installation of the steel box girder segment.

7. The construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel according to claim 1, characterized in that: In S4, the lifting points are located at the corresponding positions of the transverse diaphragms of the steel box girder, avoiding the positions of the top plate ribs.

8. A construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel according to claim 1, characterized in that: In S5, the drop beam pad is used as a temporary support for the steel box girder during installation, and a rubber pad is provided on its top; the three-way jack is used to adjust the position of the steel box girder and can assist in adjusting the relative position of the joints between the steel box girder segments, and a rubber pad is provided on its top.

9. A construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel according to claim 1, characterized in that: In S6, the temporary locking device should be fabricated in the factory together with the steel box girder components. When hoisting and erecting the steel box girder segments, the spatial position of the top, bottom and web plates between the segments is controlled by the temporary locking device. The fine-rolled threaded steel bars and bolts can only be installed and tensioned after the position of the steel box girder has reached the required accuracy.

10. A construction method for a self-anchored suspension bridge steel box girder spanning a navigation channel according to claim 1, characterized in that: In S6, the welding of beam segments is easily affected by temperature. It is advisable to select one end of the beam segment for operation when the temperature is low on a day, and continue welding the other end after one end is completed.

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