Wet joint process and system in overpass railway bridge point

Abstract

The invention relates to the technical field of bridge construction, and discloses a wet joint construction technology and system in an overpass railway bridge point, and the technology comprises the steps: respectively tying and hanging two long ropes which can be independently operated on the upper edges of the two ends of a wet joint template; establishing a real-time voice communication link among the bridge floor, the underbridge and the ground; in the railway operation intermission period, the length of the double ropes is adjusted in a differentiated mode, and the space posture and the falling track of the formwork after demolding are actively controlled; personnel under the bridge observe the distance between the formwork and the contact network in real time and feed back the distance, and bridge floor operators dynamically adjust the distance according to the distance, so that obstacle-avoiding lowering of the formwork is achieved; and finally, personnel under the bridge receive the transfer template, and site cleaning and point selling are completed. According to the method, the problems of swinging, rotating and contact net collision risks caused by uncontrollable formwork postures and accidental falling caused by out-of-control are effectively avoided, the construction safety risk is reduced, and the problems of limit invasion and falling in the formwork dismantling process are solved.

Description

Technical Field

[0001] This invention relates to the field of bridge construction technology, specifically to a construction process and system for wet joints within overpass railway bridges. Background Technology

[0002] In railway engineering projects involving highways and bridges crossing existing railways, the removal of wet joint formwork is a high-risk aspect of construction. Traditional wet joint formwork removal mainly employs either the flipping method or direct crane lifting. The flipping method relies on manual prying and flipping of the formwork on the bridge deck, allowing it to fall freely to a collection area below the bridge; the crane method utilizes lifting equipment such as truck cranes to directly lift the formwork from the bridge deck or side. These methods, under normal working conditions, have the advantages of being simple to construct and relatively low in cost, and can complete routine formwork removal operations.

[0003] The existing formwork removal process has the following problems: the formwork is uncontrollable after being removed from the concrete, and is prone to swinging and rotating, which can easily touch the railway contact network, causing power outages and train accidents; the formwork is at risk of falling accidentally, which poses a serious threat to the railway facilities below and train safety.

[0004] Based on the above situation, there is an urgent need for a construction technology and system for wet joints within overpass railway bridges to solve the problems of encroachment and falling during the formwork removal process. Summary of the Invention

[0005] The purpose of this invention is to address the problems of uncontrollable posture of formwork after it detaches from concrete during existing formwork removal processes. These problems include the risk of formwork swaying and rotating, which could easily cause it to touch the railway overhead contact line, resulting in power outages and train accidents. Furthermore, the formwork poses a risk of accidental falling, which seriously threatens the railway facilities below and train safety. This invention solves the problems of encroachment and falling during formwork removal.

[0006] The technical solution of the present invention is as follows: On the one hand, the present invention provides a construction process for wet joints within overpass railway bridges, including: Two long ropes that can be operated independently are tied to the upper edges of both ends of the wet joint template to be removed. Establish a real-time voice communication link between the bridge deck operation position, the under-bridge observation position, and the ground receiving position; During railway operation breaks, the spatial posture and falling trajectory of the formwork after it detaches from the concrete are actively controlled by adjusting the lengths of the two long ropes in a differentiated manner. The observers under the bridge can use the communication link to provide real-time feedback on the distance between the template and the railway contact network. The bridge operators can then make dynamic adjustments based on this information to lower the template to avoid obstacles. Personnel under the bridge receive and transfer the lowered templates, and after completing the work, clear the site and destroy the record.

[0007] In existing formwork removal processes, the formwork's posture becomes uncontrollable after detaching from the concrete, easily swaying and rotating, posing a significant risk of contact with the railway overhead contact line, causing power outages and train accidents. There is also a risk of accidental fall, seriously threatening railway facilities and train safety below. This solution addresses this by pre-tying double ropes and establishing a real-time communication link, enabling active remote control of the formwork's posture and trajectory the moment it detaches from the concrete. Observers below the bridge provide real-time distance feedback, creating a closed loop of observation, feedback, and adjustment throughout the lowering process, ensuring the formwork remains under control. This effectively avoids the risks of swaying, rotating, and colliding with the contact line due to uncontrollable formwork posture, as well as accidental falls caused by loss of control, reducing construction safety risks and resolving the issues of encroachment and falls during formwork removal.

[0008] Furthermore, to further avoid the template colliding with the contact network, one feasible solution is to pause the vertical descent when the template is lowered to a preset distance from the obstacle below during the obstacle avoidance process. After adjusting the template to deviate from the obstacle, the controlled descent can then continue. By adjusting the template to deviate from directly above the contact network before continuing to descend to the ground, this solution can further prevent the template from colliding with the contact network.

[0009] Furthermore, to reduce the risk of scratches and collisions, one feasible solution is: the preset distance is 1-2 meters, and the adjustment template deviates from the obstacle, including: Adjust the length difference between the two ropes to increase the angle between the template surface direction and the railway contact wire direction; The template is deflected from the area directly above the obstacle by lateral traction.

[0010] When this scheme is adopted, the angle between the two ropes is changed by adjusting the length difference of the two ropes, and the template is pulled laterally to facilitate the turning and displacement of the template in the air. It is a simple and effective spatial obstacle avoidance method, which enables the template to bypass linear or columnar obstacles such as catenary in an optimized posture and path, reducing the risk of scratches and collisions.

[0011] Furthermore, to reduce the overall operation time, one feasible solution is: the obstacle avoidance lowering of the template includes: Assign a unique identifier to all templates; Based on the identifier, multiple work groups are directed to perform demolding and lowering operations alternately at multiple wet joint locations in a preset parallel flow sequence. When adopting this scheme, by assigning a unique identifier to each template and organizing parallel flow operations accordingly, the fine scheduling and management of multiple work surfaces and multiple templates are realized, avoiding mutual interference and waiting between work surfaces, compressing the overall operation time, and improving the utilization efficiency of railway operation intervals.

[0012] Furthermore, to ensure the success rate and smoothness of formal operations, one feasible solution is to include a full-element practical rehearsal before establishing a real-time voice communication link: during non-operational periods, all real equipment and personnel are used to fully simulate the entire process from demolding to site clearing, in order to optimize the coordination sequence and operational rhythm. When adopting this solution, the connection between procedures is optimized through simulation exercises, enabling each operator to become familiar with the process and emergency response, so that they can quickly, accurately, and tacitly complete various operations during the short railway operation intervals, ensuring the success rate and smoothness of formal operations.

[0013] Furthermore, this solution does not exclusively limit the specific steps of clearing and closing out points. One feasible solution is: the clearing and closing out of points includes: The bridge deck inspectors lined up in a row along the width of the bridge deck, while the inspectors under the bridge lined up in a row along the railway line. Two lines of inspectors each start from the beginning of their respective inspection area and move synchronously towards the end to cover the entire inspection area.

[0014] When this solution is adopted, a systematic inspection method is used to effectively prevent small tools, fasteners and other items from being left on the bridge or within the railway clearance.

[0015] On the other hand, the present invention also provides a construction system for wet joints within overpass railway bridge points, used to perform the above-mentioned construction process for wet joints within overpass railway bridge points, comprising: The dual-rope active control module is used to remotely adjust the template's attitude and trajectory via two independent long ropes. The real-time closed-loop communication module is used to establish a closed-loop link for observation, feedback and command transmission between the bridge deck, the area under the bridge and the ground. The assembly line operation organization module is used to schedule multiple work groups to perform parallel assembly line operations based on a unified template number.

[0016] By controlling two long ropes to adjust the posture of the template, a stable and clear voice command and information feedback link is established between the bridge deck, the area under the bridge and the ground by a real-time closed-loop communication module, ensuring the synchronization of observation information, adjustment commands and execution actions. The assembly line operation organization module controls the demolding and lowering process of multiple work groups and multiple wet joint sites.

[0017] Furthermore, to facilitate the connection between the long rope and the template, one feasible solution is as follows: the template is equipped with a connector for threading and tying two independent long ropes, and a guide hole is formed on the template. When this solution is adopted, by setting the connector and guide hole on the template, the long rope is passed through the guide hole and one end of the long rope is fixed to the template, ensuring the stability of the force point and making the lowering control of the template smoother and more precise.

[0018] Furthermore, to facilitate the release of the long rope, one feasible solution is to provide a back support steel bar on the back of the template, and to tie the long rope to the back support steel bar with a slip knot. When this solution is adopted, the slip knot design allows the rope to be quickly untied after the template is landed, which improves the work efficiency during the transfer phase.

[0019] Furthermore, the length of the long rope exceeds the vertical distance from the bridge deck to the preset ground receiving area by at least 2 meters. When this scheme is adopted, the template is pulled laterally above the preset ground receiving area, leaving enough length to allow the template to continue to be lowered to the ground receiving area.

[0020] Compared with existing technologies, the advantages of this invention are: 1. By pre-tying double ropes and establishing a real-time communication link, the posture and trajectory of the formwork can be actively and remotely controlled the instant it detaches from the concrete. Observers below the bridge provide real-time distance feedback, creating a closed loop of observation-feedback-adjustment throughout the lowering process, ensuring the formwork remains under control. This effectively avoids the risks of swaying, rotation, and collision with the contact wire caused by uncontrollable formwork posture, as well as accidental falls due to loss of control, reducing construction safety risks and solving the problems of encroachment and falls during formwork removal. Second, when the template is lowered to a preset distance from the obstacle below, the vertical descent is paused, the template is adjusted to deviate from the obstacle, and then the controlled descent continues. By adjusting the template so that it is deviated from directly above the contact wire, the template can continue to descend to the ground, which can further prevent the template from colliding with the contact wire. Third, by adjusting the difference in length between the two ropes to change the angle between the panels and by laterally pulling the template, the template can be turned and displaced in the air. This is a simple and effective method for spatial obstacle avoidance, which allows the template to bypass linear or columnar obstacles such as overhead contact lines with an optimized posture and path, reducing the risk of collision. Attached Figure Description

[0021] Figure 1 A flowchart illustrating the construction process of wet joints within an overpass railway bridge, as provided in Embodiment 1 of the present invention; Figure 2 A flowchart of a safe formwork removal construction method provided in Embodiment 1 of the present invention; Figure 3 A flowchart illustrating the spatial attitude and falling trajectory of the active control template provided in Embodiment 1 of the present invention; Figure 4 This is a flowchart of the template obstacle avoidance deployment process provided in Embodiment 1 of the present invention; Figure 5 A wet joint construction system for an overpass railway bridge is provided as an embodiment 2 of the present invention. Figure 6This is a schematic diagram and a partial enlarged view of the wet joint construction structure provided in Embodiment 2 of the present invention.

[0022] Figure label: 100. Dual-rope active control module; 200. Real-time closed-loop communication module; 300. Assembly line operation organization module; 110. Long rope; 120. Template; 130. Connector; 140. Ground receiving area. Detailed Implementation

[0023] It should be noted that relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the term "comprising" or any other variations thereof is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0024] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0025] Example 1: Please refer to Figure 1 and Figure 2 A construction process for wet joints within a railway overpass, comprising: S100. Two long ropes that can be operated independently are tied to the upper edges of both ends of the wet joint template to be removed. S200: Establish a real-time voice communication link between the bridge deck operation position, the under-bridge observation position, and the ground receiving position; S300: During railway operation breaks, the spatial posture and falling trajectory of the formwork after it detaches from the concrete are actively controlled by adjusting the lengths of the two long ropes in a differentiated manner. S400, under-bridge observers use communication links to provide real-time feedback on the distance between the template and the railway contact network, allowing bridge deck operators to make dynamic adjustments and lower the template to avoid obstacles. S500: Personnel under the bridge receive and transfer the lowered templates, and after completing the work, clear the site and deregister the site.

[0026] In existing formwork removal processes, the formwork's posture becomes uncontrollable after detaching from the concrete, easily swaying and rotating, posing a significant risk of contact with the railway overhead contact line, causing power outages and train accidents. There is also a risk of accidental fall, seriously threatening railway facilities and train safety below. This solution addresses this by pre-tying double ropes and establishing a real-time communication link, enabling active remote control of the formwork's posture and trajectory the moment it detaches from the concrete. Observers below the bridge provide real-time distance feedback, creating a closed loop of observation, feedback, and adjustment throughout the lowering process, ensuring the formwork remains under control. This effectively avoids the risks of swaying, rotating, and colliding with the contact line due to uncontrollable formwork posture, as well as accidental falls caused by loss of control, reducing construction safety risks and resolving the issues of encroachment and falls during formwork removal.

[0027] Reference Figure 3 To further avoid the template colliding with the contact network, one feasible solution is as follows: During the template obstacle avoidance descent process, when the template is lowered to a preset distance from the obstacle below, execute S310 to pause the vertical descent, adjust the template to deviate from the obstacle, and then continue the controlled descent. When using this solution, by adjusting the template to deviate from directly above the contact network before continuing to descend to the ground, the template collision with the contact network can be further avoided.

[0028] To reduce the risk of scratches and collisions, one feasible solution is to preset the distance to 1-2 meters and adjust the template to deviate from the obstacle, including: S320. Adjust the length difference of the two ropes to increase the angle between the template surface direction and the railway contact wire direction; S330, the template is deflected from the area directly above the obstacle by lateral traction.

[0029] When this scheme is adopted, the angle between the two ropes is changed by adjusting the length difference of the two ropes, and the template is pulled laterally to facilitate the turning and displacement of the template in the air. It is a simple and effective spatial obstacle avoidance method, which enables the template to bypass linear or columnar obstacles such as catenary in an optimized posture and path, reducing the risk of scratches and collisions.

[0030] Reference Figure 4 To reduce overall operation time, one feasible solution is to implement obstacle avoidance measures on the template, including: S410. Assign a unique identifier to all templates; S420: Based on the identifier, direct multiple work groups to alternately perform demolding and lowering operations at multiple wet joint locations in a preset parallel flow sequence.

[0031] When this scheme is adopted, by assigning a unique identifier to all templates and organizing parallel flow operations accordingly, it is possible to achieve refined scheduling and management of multiple work surfaces and multiple templates, avoid mutual interference and waiting between work surfaces, reduce the overall operation time, and improve the utilization efficiency of railway operation intervals.

[0032] To ensure the success rate and smoothness of formal operations, one feasible solution is to conduct a full-element practical rehearsal before establishing a real-time voice communication link. During non-operational periods, all real equipment and personnel are used to simulate the entire process from demolding to site clearing, optimizing the coordination sequence and operational rhythm. When this solution is adopted, the connection between procedures is optimized through simulation exercises, enabling each operator to become familiar with the process and emergency response. This allows them to complete various operations quickly, accurately, and seamlessly during short railway operation breaks, ensuring the success rate and smoothness of formal operations.

[0033] This plan does not exclusively limit the specific steps for clearing and closing out outlets; one feasible approach is to clear out and close out outlets, including: S510. The bridge deck inspectors line up in a row along the width of the bridge deck, and the under-bridge inspectors line up in a row along the railway line. S520: Two lines of inspectors start from the beginning of their respective inspection areas and move synchronously towards the end to cover the entire inspection area.

[0034] When this solution is adopted, a systematic inspection method is used to effectively prevent small tools, fasteners and other items from being left on the bridge or within the railway clearance.

[0035] Optionally, in this embodiment, each wet joint is treated as a work unit. Four operators (including rope controllers and assistants) are stationed on the bridge, and three receiving and transferring personnel are stationed under the bridge, along with a unified command personnel. When the template is lowered to 1-2 meters above the railway contact wire, the vertical lowering is paused. The observers under the bridge provide feedback via walkie-talkie, directing the rope controllers on the bridge to adjust the difference in length between the two ropes to change the template from a horizontal to a vertical position, thereby reducing the windward side. Simultaneously, the personnel under the bridge use a 7-meter-long self-made hook to apply lateral traction to the template, causing it to smoothly deviate from the area directly above the contact wire and be transferred to a position approximately 1 meter above the track surface. Then, the snap hook is released, and the template is unloaded onto the track surface.

[0036] Optionally, in this embodiment, after all the templates have been transferred, five inspectors are organized on the bridge and under the bridge respectively. Starting from 10 meters outside the construction area, they hold hands and advance synchronously along the width of the bridge and the direction of the railway line to conduct a thorough inspection, count all tools and materials, confirm that no items are left within the railway clearance, and apply for cancellation.

[0037] Example 2: Reference Figure 5 and Figure 6 A construction system for wet joints within overpass railway bridge points, used to perform the aforementioned construction process for wet joints within overpass railway bridge points, comprising: The dual-rope active control module 100 is used to remotely adjust the attitude and trajectory of the template 120 via two independent long ropes 110. The real-time closed-loop communication module 200 is used to establish a closed-loop link for observation, feedback and command transmission between the bridge deck, the area under the bridge and the ground. The assembly line operation organization module 300 is used to schedule multiple work groups to perform parallel assembly line operations based on a unified template number.

[0038] By controlling two long ropes 110 respectively to adjust the posture of the template 120, a stable and clear voice command and information feedback link is established between the bridge deck, under the bridge and the ground by the real-time closed-loop communication module, ensuring the synchronization of observation information, adjustment commands and execution actions. The assembly line operation organization module controls the demolding and lowering process of multiple work groups and multiple wet joint sites.

[0039] To facilitate the connection between the long rope 110 and the template 120, one feasible solution is to provide a connector 130 on the template 120 for threading and tying two independent long ropes 110, and to form a guide hole on the template 120. When this solution is adopted, by providing the connector 130 and the guide hole on the template 120, the long rope 110 is passed through the guide hole and one end of the long rope 110 is fixed to the template 120, which ensures the stability of the stress point and makes the lowering control of the template 120 smoother and more precise.

[0040] To facilitate the release of the long rope 110, one feasible solution is to install a back frame steel bar on the back of the template 120, and tie the long rope 110 to the back frame steel bar with a slip knot. When this solution is adopted, the slip knot design allows the rope to be quickly untied after the template 120 lands, which improves the work efficiency during the transfer phase.

[0041] Optionally, the back of the formwork 120 is equipped with two Φ16 back-frame steel reinforcement groups to enhance the overall integrity of the formwork 120 and provide a stable stress point for the hanging long rope 110. The formwork 120 has 5cm diameter channels with PVC pipes installed inside to effectively reduce rope wear and ensure smooth rope threading. The hanging long rope is a 16mm diameter high-strength nylon rope, the length of which is determined based on the measured elevation from the bridge deck to the rail surface, ensuring it exceeds the vertical distance by at least 2 meters to provide sufficient operating space for lateral traction and attitude adjustment of the formwork. The nylon rope is secured to the back-frame steel reinforcement with a slipknot for quick release after the formwork 120 is placed on the ground.

[0042] The length of the long rope 110 exceeds the vertical distance from the bridge deck to the preset ground receiving area 140 by at least 2 meters. When this method is adopted, the template 120 is pulled laterally above the preset ground receiving area 140, leaving enough length to allow the template 120 to continue to be lowered to the ground receiving area 140.

[0043] How this solution works: Two independently operable long ropes are pre-attached to the upper edges of both ends of each wet joint template. During construction, a real-time voice communication link is established between the bridge deck operation position, the under-bridge observation position, and the ground receiving position. During railway operation breaks, the bridge deck operators actively control the pitch, tilt, and descent trajectory of the template after demolding by adjusting the length of the two long ropes. At the same time, the under-bridge observation personnel continuously monitor the distance between the template and obstacles such as the railway contact network and provide real-time feedback to the bridge deck through the communication link. The command personnel then dynamically adjust the ropes accordingly to achieve precise obstacle avoidance during the template's descent. After the template is lowered to the designated area under the bridge, it is quickly received and transferred by ground personnel. Finally, a systematic site clearance inspection ensures that no items are left behind, completing the clearance process.

[0044] To address the issues of encroachment and falls during formwork removal, this solution employs a pre-attached double rope system and a real-time communication link. The formwork's attitude and trajectory are actively and remotely controlled the instant it detaches from the concrete. Observers below the bridge provide real-time distance feedback, creating a closed-loop observation-feedback-adjustment process that ensures the formwork remains under control. This effectively avoids the risks of swaying, rotation, and collisions with the contact wire caused by uncontrollable formwork attitude, as well as accidental falls due to loss of control, thus reducing construction safety risks and resolving the encroachment and fall issues during formwork removal.

[0045] To further prevent the template from colliding with the contact network, this solution involves pausing the vertical descent when the template is lowered to a preset distance from the obstacle below, adjusting the template to deviate from the obstacle, and then continuing the controlled descent. By adjusting the template to deviate from directly above the contact network, the template can continue to descend to the ground, thus further preventing the template from colliding with the contact network.

[0046] To reduce the risk of collisions, this solution adjusts the angle between the two ropes and laterally pulls the template to facilitate its turning and displacement in the air. This is a simple and effective spatial obstacle avoidance method that allows the template to bypass linear or columnar obstacles such as overhead contact lines with an optimized posture and path, thus reducing the risk of collisions.

[0047] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A construction process for wet joints within a railway overpass, characterized in that, include: Two long ropes that can be operated independently are tied to the upper edges of both ends of the wet joint template to be removed. Establish a real-time voice communication link between the bridge deck operation position, the under-bridge observation position, and the ground receiving position; During railway operation breaks, the spatial posture and falling trajectory of the formwork after it detaches from the concrete are actively controlled by adjusting the lengths of the two long ropes in a differentiated manner. The observers under the bridge can use the communication link to provide real-time feedback on the distance between the template and the railway contact network. The bridge operators can then make dynamic adjustments based on this information to lower the template to avoid obstacles. Personnel under the bridge receive and transfer the lowered templates, and after completing the work, clear the site and destroy the record.

2. The construction process for wet joints within an overpass railway bridge according to claim 1, characterized in that, During the template obstacle avoidance descent process, when the template is lowered to a preset distance from the obstacle below, the vertical descent is paused, the template is adjusted to deviate from the obstacle, and then the controlled descent continues.

3. The construction process for wet joints within an overpass railway bridge according to claim 2, characterized in that, The preset distance is 1-2 meters, and the adjustment template deviates from the obstacle, including: Adjust the length difference between the two ropes to increase the angle between the template surface direction and the railway contact wire direction; The template is deflected from the area directly above the obstacle by lateral traction.

4. The construction process for wet joints within an overpass railway bridge according to claim 1, characterized in that, The process of placing the template with obstacle avoidance includes: Assign a unique identifier to all templates; Based on the identifier, multiple work groups are directed to perform demolding and lowering operations alternately at multiple wet joint locations in a preset parallel flow sequence.

5. The construction process for wet joints within a railway overpass as described in claim 1, characterized in that, Before establishing a real-time voice communication link, a full-element practical rehearsal step is also included: during non-operational hours, all real equipment and personnel are used on-site to fully simulate the entire process from demolding to clearing, in order to optimize the timing of collaboration and the rhythm of operation.

6. The construction process for wet joints within a railway overpass as described in claim 1, characterized in that, The clearing and disposal points include: The bridge deck inspectors lined up in a row along the width of the bridge deck, while the inspectors under the bridge lined up in a row along the railway line. Two lines of inspectors each start from the beginning of their respective inspection area and move synchronously towards the end to cover the entire inspection area.

7. A construction system for wet joints at the point of connection of an overpass railway bridge, used to perform the construction process for wet joints at the point of connection of an overpass railway bridge as described in any one of claims 1-6, characterized in that, include: The dual-rope active control module is used to remotely adjust the template's attitude and trajectory via two independent long ropes. The real-time closed-loop communication module is used to establish a closed-loop link for observation, feedback and command transmission between the bridge deck, the area under the bridge and the ground. The assembly line operation organization module is used to schedule multiple work groups to perform parallel assembly line operations based on a unified template number.

8. A construction system for wet joints within a railway overpass as described in claim 7, characterized in that, The template is equipped with connectors for threading and tying two independent long ropes, and guide holes are formed on the template.

9. A construction system for wet joints within a railway overpass as described in claim 7, characterized in that, The template has a back support steel bar, and the long rope is tied to the back support steel bar with a slip knot.

10. A construction system for wet joints within an overpass railway bridge according to claim 7, characterized in that, The length of the long rope exceeds the vertical distance from the bridge deck to the preset ground receiving area by at least 2 meters.

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