Extra-large span catwalk structure and construction method of main cable for suspension bridge based on the catwalk

Abstract

This invention discloses an ultra-large span catwalk structure and a method for constructing the main cable of a suspension bridge based on this catwalk, belonging to the field of suspension bridge construction technology. The catwalk structure includes load-bearing cables and a catwalk surface layer, a support frame, a self-balancing counterweight structure, and a surface layer counterweight structure. The support frame is fixed to the catwalk surface layer and is used for fixed connection with the cooperating load-bearing strands of the main cable, realizing the coordinated load-bearing of the temporary catwalk and the permanent main cable. The self-balancing counterweight structure includes a longitudinally movable counterweight balancing cable and a driving device, which can move synchronously with the concentrated load of the cable strands to achieve dynamic balance. During construction, the load-bearing cables and surface layer are erected first, then the support frame, counterweight cables, and surface layer counterweight are installed. Next, the cooperating load-bearing strands are erected while the counterweight balancing cable moves synchronously, and finally the remaining cable strands are erected. This invention effectively solves the problems of low stiffness, poor wind resistance, and unbalanced construction loads in ultra-large span catwalks, significantly improving the accuracy and safety of the main cable erection.

Description

Technical Field

[0001] This invention relates to the field of catwalk technology for suspension bridges, specifically to an ultra-large span catwalk structure and a method for constructing the main cable of a suspension bridge based on the catwalk. Background Technology

[0002] Suspension bridges, due to their strong spanning capacity and economical and rational structure, have become one of the preferred bridge types for ultra-long-span bridge projects such as those spanning rivers, seas, and canyons. During the construction of the superstructure of a suspension bridge, the catwalk serves as a core temporary construction platform for main cable erection, cable strand traction, alignment adjustment, and subsequent cable tightening and wire wrapping operations. Its structural safety and stability are directly related to the quality of main cable construction and the overall safety of bridge construction.

[0003] Currently, catwalk structures commonly use steel wire ropes as load-bearing cables, transferring construction loads to the bridge towers and anchorages through an independent load-bearing cable system. However, with the continuous increase in the span of suspension bridges, the traditional all-steel wire rope catwalk system has gradually revealed problems such as heavy structural weight, a significant increase in concentrated loads on the cable saddles at the top of the main tower, and an excessively high proportion of dead loads during the construction phase, adversely affecting the safety of the tower-beam structure. To solve these problems, in recent years, technical solutions have emerged that use lightweight, high-strength fiber materials to replace traditional steel wire ropes as catwalk load-bearing cables. For example, an existing technology called a lightweight catwalk system for suspension bridges uses high-strength fiber ropes as load-bearing cables, utilizing their advantages of light weight, high strength, and corrosion resistance to reduce the self-weight and traction of the catwalk and simplify installation and dismantling. This solution also includes a tensioning adjustment system and a pull-down adjustment system to adjust the alignment of the fiber ropes and their distance from the main cable, and protective sleeves and spaced dampers are installed on the outside of the fiber ropes to reduce wind-induced swaying.

[0004] Although the aforementioned lightweight catwalk system alleviates the problems of heavy weight and traction difficulties associated with traditional wire rope catwalks to some extent, it still has the following shortcomings when applied to the construction of suspension bridges with ultra-long spans (such as main spans of 2000 meters or more): First, the overall stiffness of the lightweight fiber rope catwalk is too low and its flexibility is too high. Although the modulus of fiber rope is higher than that of steel wire, its structural weight is significantly reduced, resulting in a decrease in the overall stiffness of the catwalk system. Under construction live loads and strong winds, it is prone to excessive deflection, linear fluctuations, or even lateral overturning, making it difficult to meet the requirements of high-precision main cable erection for the linear stability of the catwalk.

[0005] Second, there is a lack of dynamic stress balancing mechanisms during the construction phase. In existing lightweight catwalk systems, the alignment adjustment of the load-bearing cables mainly relies on the tension adjustment system in the anchor chamber and the tower end pull-down adjustment system, which are static adjustment methods. This cannot adjust the stress state of the catwalk in real time during the dynamic process of pulling the main cable strands one by one and the location of the concentrated construction load constantly changing. This results in obvious local eccentric load effects and uneven cable force distribution, affecting the accuracy of main cable erection and structural safety.

[0006] Third, lightweight catwalks lack sufficient wind resistance stability. Although existing technologies improve stiffness by adding dampers and increasing the density of transverse bridges, they have not effectively solved the risks of overall buoyancy, vibration, and overturning of lightweight catwalks under strong winds, especially under ultra-large span conditions, where the wind resistance stability problem is even more prominent.

[0007] Fourth, the counterweight method is singular and uneven. Traditional counterweights often use concentrated sandbags or steel blocks, which easily leads to localized stress concentration and makes it difficult to form continuous and uniform downward pressure, which is not conducive to the overall alignment control and stability improvement of lightweight catwalks.

[0008] Therefore, how to effectively improve the overall stiffness, dynamic balance capability and wind resistance of ultra-long span catwalk structures while maintaining the advantages of lightweight catwalks has become a technical problem that urgently needs to be solved in the field of suspension bridge construction technology. Summary of the Invention

[0009] The purpose of this invention is to overcome the shortcomings of the above-mentioned background technology and provide an ultra-large span catwalk structure and a method for constructing the main cable of a suspension bridge based on the catwalk.

[0010] The technical solution of this invention is: an ultra-large catwalk structure, comprising: The load-bearing structure includes several load-bearing cables erected longitudinally and a catwalk surface layer fixed to the load-bearing cables. The co-load-bearing structure includes a support frame fixed on the catwalk surface; the support frame is used to be fixedly connected in the vertical direction to the co-load-bearing strands pre-erected in the main cable strands, so that the load-bearing cable and the co-load-bearing strands share the load together. The self-balancing counterweight structure includes a counterweight balancing cable that can move longitudinally along the catwalk, and a drive device for pulling the counterweight balancing cable to move synchronously with the main cable strand erection load concentration area. The surface counterweight structure includes a continuous distributed counterweight laid on the catwalk surface layer to provide continuous and uniform downward pressure on the catwalk structure.

[0011] According to the present invention, an ultra-large catwalk structure is provided, wherein the support frame is provided with an upper roller assembly, a lower roller assembly and a buffer structure; the cooperative force-bearing strand is introduced into the support frame and forms rolling contact with the upper and lower roller assemblies.

[0012] According to the present invention, the length of the counterweight balancing cable is 1 / 3 to 2 / 3 of the main span, preferably 1 / 2; its weight per unit length is matched with the weight per unit length of the cooperating force-bearing cable strand, so that the total weight of the counterweight balancing cable is 1 / 3 to 2 / 3 of the weight of the cooperating force-bearing cable strand, preferably 1 / 2, so as to cover the main stress and load variation concentration area in the middle of the main span.

[0013] According to the present invention, an ultra-large span catwalk structure is provided, wherein the self-balancing counterweight structure further includes multiple track frames arranged at intervals along the longitudinal direction of the catwalk at the center line of the catwalk; the counterweight balancing cable is arranged on the track frames.

[0014] According to the present invention, an ultra-large catwalk structure is provided, wherein the surface counterweight structure includes multiple water pipe units evenly distributed along the longitudinal direction of the catwalk surface, and adjacent water pipe units are quickly connected by flexible hose joints; the water pipe units form a continuous linear counterweight after water is supplied.

[0015] According to the present invention, a super-large catwalk structure is provided, wherein the load-bearing cable is made of a mixture of aramid fiber rope and steel wire strands.

[0016] This invention also relates to a method for constructing the main cable of a suspension bridge based on the aforementioned ultra-large span catwalk structure, comprising: Erect load-bearing cables and install the catwalk surface layer based on the load-bearing cables; Install a support frame, a drive unit, and a counterweight balancing cable on the catwalk surface. After the load-bearing cables are erected and before or simultaneously with the installation of the coordinating force-bearing cables, a continuous distributed counterweight is laid on the catwalk surface. Select a cooperating tension cable from the main cable strands, erect the cooperating tension cable, and during the erection process, use a drive device to pull the counterweight balance cable so that the counterweight balance cable moves synchronously with the erection of the cooperating tension cable. After the co-supporting cable strands are erected and form a co-supporting system with the load-bearing cable, the other cable strands of the main cable are erected until all cable strands are erected.

[0017] According to the suspension bridge main cable construction method provided by the present invention, the method of selecting cooperative stress strands from the main cable strands includes: selecting two strands located at the top positions on both sides of the main cable cross section as cooperative stress strands.

[0018] According to the suspension bridge main cable construction method provided by the present invention, the method of using a driving device to pull the counterweight balance cable so that the counterweight balance cable moves synchronously with the erection and advancement of the cooperating force-bearing cable strand includes: during the erection of the cooperating force-bearing cable strand, when the front end of the cooperating force-bearing cable strand moves to the vicinity of the end of the counterweight balance cable, the driving device is activated to drive the counterweight balance cable to move synchronously with the cooperating force-bearing cable strand in the longitudinal direction, so that the counterweight balance cable always corresponds to the concentrated load area of ​​the cooperating force-bearing cable strand in the longitudinal direction.

[0019] According to the suspension bridge main cable construction method provided by the present invention, the moving speed of the counterweight balance cable is consistent with the moving speed of the front end of the cooperating force strand during synchronous movement.

[0020] The advantages of this invention are: 1. The permanent structure of the main cable and the catwalk work together to bear the load, reducing the size of the temporary structure and improving the overall stiffness. The catwalk structure of this invention uses a support frame to vertically connect the catwalk to pre-erected co-supporting cable strands (permanent main cable strands), allowing the main cable structure to participate in the stress during the construction phase in advance, breaking away from the traditional catwalk's stress system that relies entirely on independent load-bearing cables. This co-supporting mechanism can significantly reduce the amount and specifications of load-bearing cables, reducing the scale of temporary structures; at the same time, the high stiffness of the permanent cable strands directly improves the overall spatial stiffness and construction stability of the catwalk system.

[0021] 2. The counterweight moves synchronously with the main cable strands during installation, achieving dynamic self-balancing of the load and improving construction accuracy. The catwalk structure of this invention features a counterweight balancing cable that can move longitudinally along the catwalk. This cable is driven by a drive device and moves synchronously with the main cable strand erection position, ensuring that the counterweight always acts on the area of ​​concentrated construction load. This dynamic self-balancing mechanism effectively counteracts the eccentric loading effect caused by load movement during cable strand erection, reduces catwalk deflection changes and load-bearing cable force fluctuations, avoids localized stress concentration, and thus significantly improves the alignment control accuracy of the main cable erection.

[0022] 3. The guide buffer and rolling contact design reduces vibration and local deformation, improving construction stability. The catwalk structure of this invention integrates upper and lower roller assemblies and a buffer structure within its supporting frame, allowing the load-bearing cable strands to roll in contact with the rollers within the frame. This structure not only provides vertical support and lateral restraint for the cable strands but also absorbs impact energy caused by traction, wind loads, etc., during erection through low-friction rolling pairs and buffer elements, effectively suppressing structural vibration and local deformation, improving the dynamic response characteristics of the catwalk, and enhancing overall stability during the construction phase.

[0023] 4. The lightweight, high-strength load-bearing cable and multiple counterweight mechanisms work together to achieve a balance between lightweight and high rigidity. The load-bearing cables of the catwalk structure of this invention are made of a mixture of aramid fiber rope and steel wire strands, which significantly reduces the structure's self-weight while ensuring load-bearing capacity. Simultaneously, a combined counterweight system is introduced, consisting of a continuous distributed surface layer counterweight and a movable counterweight balancing cable. The surface layer counterweight provides continuous and uniform downward pressure, while the self-balancing counterweight dynamically follows load changes. Together, they compensate for the increased flexibility caused by lightweight materials, enabling the catwalk system to maintain the advantages of lightweight construction while possessing good overall rigidity and resistance to deformation.

[0024] 5. Continuous distributed surface layer counterweights provide uniform ballast, enhancing wind resistance and construction safety. The surface counterweight structure preferably consists of multiple water pipe units evenly distributed along the longitudinal direction of the catwalk, forming a continuous linear counterweight after water is supplied. This distribution method provides uniform mass damping, effectively improving the catwalk's resistance to wind vibration and aerodynamic stability. The water pipe units can be quickly connected via flexible hoses, and the counterweight size can be flexibly adjusted for both flow and drainage, adapting to different construction conditions and further ensuring operational safety and efficiency during the main cable erection process. Attached Figure Description

[0025] Figure 1 : Schematic diagram of the cat passage structure of the present invention; Figure 2 : A schematic diagram of the main cable cross-section of the present invention; Figure 3 : A schematic diagram of the traction of the cooperative force-bearing cable strand to point D (point D indicates that the front end of the cooperative force-bearing cable strand is located at the top of the starting tower). Figure 4 : A schematic diagram of the traction of the co-force-bearing cable strand to point C in this invention (point C indicates that the front end of the co-force-bearing cable strand is located at 1 / 4 of the main span); Figure 5 : A schematic diagram of the traction of the cooperative force-bearing cable strand to point E in this invention (point E indicates that the front end of the cooperative force-bearing cable strand is located at the mid-span of the main span, and point A indicates that the end of the counterweight balance cable is located at the mid-span). Figure 6 : A schematic diagram of the cooperative force-bearing cable strand being pulled to point A (point A indicates that the front end of the cooperative force-bearing cable strand has reached the top of the tower on the opposite bank); Figure 7 : A schematic diagram illustrating the collaborative force-bearing cable strand traction process of the present invention; Wherein: 1-load-bearing cable; 2-catwalk surface layer; 3-support frame; 31-upper roller assembly; 32-lower roller assembly; 33-buffer structure; 4-Counterweight balancing cable; 5-Track frame; 6-Water pipe unit; 10-Main cable; 11-Cooperative force-bearing cable strand. Detailed Implementation

[0026] Embodiments of the present invention are described in detail below, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0028] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to specific embodiments. It should be understood that the description herein is for illustrative purposes only and is not intended to limit the scope of protection of this invention.

[0031] Example 1: A super-large catwalk structure in this example, such as Figure 1 As shown, it mainly includes four major systems: load-bearing structure, cooperative force-bearing structure, self-balancing counterweight structure, and surface counterweight structure.

[0032] The load-bearing structure is the basic load-bearing part of the catwalk, consisting of components along the longitudinal direction of the bridge (i.e., along the bridge direction, such as...). Figure 1 The system consists of several load-bearing cables 1 (in the direction perpendicular to the paper shown) and a catwalk surface layer 2 fixedly laid above the load-bearing cables 1. The two ends of the load-bearing cables 1 are anchored to the anchorages on both banks or to the cable saddles on the top of the tower, forming a suspended aerial passage. The catwalk surface layer 2 provides a working platform for construction personnel and equipment.

[0033] The co-load-bearing structure is used to couple the construction process of the catwalk and the main cable 10, and includes a support frame 3 fixedly installed on the upper surface of the catwalk surface layer 2. This support frame 3 is vertically fixedly connected to a pre-selected co-load-bearing strand 11 in the main cable strands at the designed location. This connection method allows the co-load-bearing strand 11 to share the load with the load-bearing cable 1. Construction loads generated during the erection of other strands of the main cable are no longer solely borne by the load-bearing cable 1, but are transferred to the co-load-bearing strand 11 through the support frame 3, achieving co-load-bearing between the load-bearing cable 1 and the co-load-bearing strand 11, greatly enhancing the overall rigidity of the system.

[0034] The self-balancing counterweight structure is a dynamic balancing system consisting of a counterweight balancing cable 4 and a drive unit. The counterweight balancing cable 4 is designed to move longitudinally along the catwalk and is typically laid flat on the catwalk surface layer 2 or within a dedicated track. The drive unit, such as a frequency-controlled winch or a hydraulic traction device, is used to pull the counterweight balancing cable 4, enabling it to move synchronously with the area where construction loads are concentrated during the erection of the main cable strands (i.e., the front tension area of ​​the cable strands).

[0035] The surface counterweight structure is a static counterweight system, consisting of continuous distributed counterweights laid on the catwalk surface layer 2. These counterweights are arranged almost uninterruptedly along the longitudinal direction of the catwalk, and their function is to provide a continuous and uniform downward load for the entire catwalk structure, thereby increasing the gravity stiffness of the catwalk, resisting upward or lateral displacement caused by wind loads, and enhancing structural stability.

[0036] The specific steps of the suspension bridge main cable construction method based on the structure described in this embodiment are as follows: Step 1: Install load-bearing cable 1, and install catwalk surface layer 2 based on the already installed load-bearing cable 1 to form a basic aerial work passage.

[0037] Step two: On the laid catwalk surface layer 2, precisely install the support frame 3 at the designed location. At the same time, install the drive device and arrange the counterweight balancing cable 4 on the predetermined track or path on the catwalk surface layer 2.

[0038] Step 3: Lay a continuous distributed counterweight on the catwalk surface layer 2, such as water-filled pipes, sandbag chains, or precast concrete counterweight blocks, to provide uniform ballast for the catwalk foundation.

[0039] Step four: Begin erecting the main cable strands. First, select several strands from all the cable strands as co-supporting strands 11. Erect these co-supporting strands 11, thread them into the support frame 3, and fix them thereto. During the erection process, keep the drive device running throughout, precisely pulling the counterweight balance cable 4, so that the counterweight balance cable 4 moves synchronously with the front traction head of the co-supporting strands 11.

[0040] Step 5: After all the co-supporting strands 11 have been erected and have formed a co-supporting overall system with the load-bearing cable 1 through the support frame 3, the remaining ordinary strands of the main cable 10 will be erected until all strands are erected.

[0041] This embodiment constructs a catwalk mechanics system integrating load-bearing, coordination, balance, and counterweight. Traditional catwalks passively bear loads, while this invention uses a support frame 3 to forcibly connect a portion of the main cable strands (coordinating load-bearing strands 11) to the catwalk load-bearing cable 1, transferring the construction load from the catwalk load-bearing cable to the coordinating load-bearing strands, transforming passive loads into active loads. Simultaneously, the self-balancing counterweight structure specifically addresses the problem of excessive local deformation of the catwalk caused by moving concentrated loads during cable strand erection. By moving the counterweight wherever the load goes, it dynamically offsets unbalanced forces.

[0042] This embodiment significantly improves the overall stiffness and wind resistance stability of catwalks with ultra-long spans, transforming the main cable erection load, which was originally detrimental to the stability of the catwalk, into a favorable factor for enhancing the system's stiffness. The construction method has a clear logic: first, a stable and collaboratively stressed foundation framework is formed, and then large-scale cable strand erection is carried out, ensuring the safety and efficiency of the entire construction process. It is especially suitable for the construction of suspension bridges exceeding 1,000 meters in length across straits, canyons, and other high-wind environments.

[0043] Example 2: This example refines the support frame 3 in the cooperative stress structure.

[0044] Based on Embodiment 1, this embodiment incorporates a guiding and buffering system within the support frame 3. The internal space of the support frame 3 houses an upper roller assembly 31 and a lower roller assembly 32. These two sets of rollers are arranged opposite each other, forming a channel through which the cooperating force-bearing strand 11 can pass. After the cooperating force-bearing strand 11 is introduced into the support frame 3, its upper and lower surfaces respectively form rolling contact with the upper and lower roller assemblies. More importantly, a buffering structure 33 is integrated into the support structure of these roller assemblies, such as a buffer pad composed of high-damping rubber, polyurethane elastomer, or a spring-damper combination.

[0045] In this embodiment, multiple sets of longitudinally spaced support frames 3 are provided on the catwalk surface layer 2. Each set includes multiple transversely spaced support frames 3, and connecting beams are provided between adjacent support frames 3 in the same set. Figure 1 As shown, each set of support frames 3 in this embodiment has two members, arranged symmetrically around the centerline of the catwalk surface layer 2. A low-friction structure can be installed on the connecting beam. During the traction process of the main cable strands, the main cable strands contact the low-friction structure, avoiding collisions between the main cable strands and other structures that could cause damage.

[0046] When the coordinated load-bearing cable strand 11 sways, vibrates, or tends to slip axially due to temperature changes during the erection process, the upper and lower roller assemblies confine it within the channel and convert sliding friction into rolling friction, greatly reducing frictional resistance. The buffer structure 33 absorbs energy through elastic deformation when the cable strand impacts the rollers, buffering the impact load, protecting the galvanized layer on the cable strand surface from wear, and smoothly transferring the impact force to the support frame 3 and the catwalk.

[0047] This embodiment of the structure not only ensures a reliable connection and coordinated force sharing between the cable strands and the catwalk in the vertical direction, but more importantly, it eliminates the risk of wear and stress concentration caused by rigid contact. It allows for slight longitudinal displacement and dynamic adjustment of the cable strands during erection and use, achieving a connection that combines rigidity and flexibility, and significantly improving the durability and safety redundancy of the connection nodes.

[0048] Example 3: This example limits the parameters and collaborative control method of the self-balancing counterweight structure.

[0049] Based on Example 1, the parameters of the counterweight balancing cable 4 were optimized. The length of the counterweight balancing cable 4 was determined to be approximately half the main span diameter, and its weight per unit length or total weight was designed to match half the self-weight of the selected cooperating load-bearing strand 11. This design allows the counterweight balancing cable 4 to perfectly cover the mid-span area of ​​the main span, which is precisely the area where structural stress deformation and load changes are most concentrated and intense during the erection of the main cable 10.

[0050] This embodiment further refines the synchronous movement control method described in step four. During the erection of the cooperative force-bearing cable strand 11, the spatial position of the front end of the cooperative force-bearing cable strand 11 needs to be monitored in real time. When it is detected that the front end has moved to the vicinity of the end of the counterweight balance cable 4 (for example, at a predetermined safety distance), the control system immediately activates the drive device, driving it to precisely pull the counterweight balance cable 4 along the longitudinal direction of the catwalk, keeping it in the same direction and synchronous with the cooperative force-bearing cable strand 11. Through this triggering and following control logic, it is ensured that at any given moment, the longitudinal spatial position of the counterweight balance cable 4 always corresponds to the moving concentrated load area formed by the cooperative force-bearing cable strand 11, forming a dynamic balancing torque.

[0051] In this embodiment, the half-span length of the counterweight balancing cable 4 ensures that it covers the most unfavorable deformation area at the mid-span. From a mechanical balance perspective, the half-weight provides the optimal load to counteract the unbalanced force generated during the erection of the cooperating force-bearing cable strands 11, avoiding over- or under-weighting. The trigger-and-follow control method is an efficient and stable closed-loop control strategy, ensuring the real-time performance and accuracy of dynamic balance.

[0052] Through precise parameter design and intelligent control methods, this embodiment enables the self-balancing counterweight system to operate in the most efficient manner, saving the amount of counterweight material and achieving the best dynamic balance effect. It significantly suppresses the dynamic fluctuations of the catwalk during the main cable erection process, creating stable working conditions for high-precision and high-speed cable strand erection.

[0053] Example 4: This example specifies the guiding and supporting method of the counterweight balancing cable 4 in the self-balancing counterweight structure.

[0054] Based on Embodiment 1, the self-balancing counterweight structure of this embodiment further includes multiple track frames 5. These track frames 5 are made of shaped steel or square steel and are installed along the longitudinal direction of the catwalk at preset fixed intervals (e.g., one every 6 meters or 9 meters) at the centerline position of the catwalk. The upper part of the track frame 5 is provided with channels or rollers through which the counterweight balancing cable 4 can pass or sit, forming a continuous, low-friction guide path. The counterweight balancing cable 4 is arranged on these track frames 5, allowing the counterweight balancing cable 4 to move stably on a defined path that coincides with the centerline of the catwalk.

[0055] The track frame 5 provides physical constraints and support for the counterweight balancing cable 4. When the counterweight balancing cable 4 is pulled by the drive device, it will not swing arbitrarily, jump off, or interfere with other components of the catwalk surface layer 2, but will run smoothly along the predetermined track. Its placement at the centerline of the catwalk is to ensure, to the greatest extent possible, that the additional force generated by the movement of the counterweight balancing cable 4 is symmetrical with respect to the catwalk cross-section, and will not introduce torsional moments.

[0056] This design structure greatly improves the reliability, stability, and safety of the movement of the counterweight balancing cable 4. In complex environments such as strong winds or swaying catwalks, the track frame 5 can effectively restrain the counterweight balancing cable 4, preventing safety accidents or functional failures caused by large-scale swinging. It is a key structural guarantee to ensure that the dynamic counterweight system can accurately perform its functions.

[0057] Example 5: This example describes in detail the specific implementation of the counterweight structure for the surface layer.

[0058] Based on Embodiment 1, the surface counterweight structure of this embodiment is implemented using a convenient water-loaded system. Specifically, it includes multiple water pipe units 6 laid evenly and side-by-side along the longitudinal direction of the catwalk surface layer 2. These water pipe units 6 can be made of aluminum alloy. Adjacent water pipe units 6 are provided with flexible hose connectors for quick connection, such as quick connectors with fire-fighting interfaces or socket connectors with sealing rings. During construction, empty water pipe units 6 can be laid and connected first, and after the entire pipeline system is formed, water is pumped in uniformly. After the water pipe units 6 are filled with water, their own weight forms a continuous and linear uniform counterweight load extending longitudinally along the catwalk.

[0059] The surface counterweight structure utilizes water as the counterweight medium, which boasts advantages such as easy availability, uniform density, and extremely low cost. The flexibility of water pipe unit 6 allows it to perfectly adapt to the curved shape of the catwalk surface layer 2. The quick-connect design minimizes on-site high-altitude work; workers only need to lay and connect the pipes, significantly reducing manpower consumption and high-altitude risks. The construction process of laying pipes first and then connecting water avoids the difficulty of directly hoisting heavy counterweights.

[0060] This embodiment achieves lightweight transportation, convenient installation, and efficient loading of the surface layer counterweight structure. It avoids the high-intensity manual labor of using a large number of scattered counterweight blocks, has a fast construction speed, uniform and stable counterweight quality, and can be easily removed after drainage. It has extremely high economic efficiency, adaptability, and environmental friendliness, making it an ideal solution for counterweighting of the surface layer of ultra-large span catwalks.

[0061] Example 6: In this example, the material of the load-bearing cable 1 has been optimized.

[0062] Based on Example 1, the load-bearing cable 1 in this example is not made of a traditional single steel wire strand, but is made of a mixture of high-performance aramid fiber rope and traditional high-strength steel wire strand. For example, in a strand cross-section, the central part is steel wire, and the outer layer is covered with stranded aramid fiber; or the steel wire strand is used as the core, and the aramid fiber rope is used as the outer layer for winding; or several aramid fiber ropes and several steel wire strands can be twisted in parallel to form a large-specification load-bearing cable 1.

[0063] Aramid fibers possess characteristics such as high strength, low density (only about 1 / 5 that of steel), corrosion resistance, and excellent fatigue resistance. When mixed with steel wire strands, they create a complementary mechanical advantage. Aramid fibers provide higher specific strength, significantly reducing the self-weight of the load-bearing cable 1, thereby reducing the sag effect caused by its own weight and increasing the crossing capacity of the catwalk; while steel wire strands provide good ductility and mature anchoring technology.

[0064] By adopting this hybrid load-bearing cable 1, the self-weight of the catwalk load-bearing cable 1 itself can be significantly reduced, fundamentally reducing the self-locking effect in the design of ultra-large span catwalk structures (i.e., the increased span leads to the need for thicker cables, which in turn leads to greater self-weight, creating a vicious cycle). At the same time, the weight reduction also reduces the load requirements on anchorages and towers, improves the ease of construction, and, thanks to the weather resistance and fatigue resistance of aramid fibers, it is expected to extend the service life of temporary structures like catwalks or provide the possibility of converting them into permanent maintenance access routes.

[0065] Example 7: This example refines the selection strategy for the cooperative force-bearing strand 11.

[0066] In step four of Embodiment 1, the method for selecting the co-strength-bearing strands 11 from the main cable strands has a specific optimization strategy. That is, among all the prefabricated strands, two strands located at the top positions on both sides of the main cable cross-section are intentionally selected as the co-strength-bearing strands 11, such as... Figure 2 As shown. For example, in a hexagonal cross-section cabled using the prefabricated parallel wire strand (PPWS) method, two strands are specifically selected that are located to the upper left and upper right of the horizontal centerline of the cross-section, close to the outermost edge.

[0067] The selection of the cable strands located at the top of both sides is based on multiple considerations of mechanics and construction convenience. First, the connection path between these two cable strands and the support frame 3 on the lower catwalk surface layer 2 is the shortest and most direct, facilitating a stable vertical connection. Second, the symmetrical distribution of these two cable strands on both sides of the cross-section allows them to form a stable couple when providing synergistic forces to the catwalk, which is extremely beneficial for suppressing lateral instability and torsion of the catwalk, providing the best lateral stability effect. Finally, the top cable strands are erected or positioned first, which is conducive to forming a synergistic force system as early as possible, guiding and controlling the erection alignment of the subsequent middle and bottom cable strands.

[0068] The selection method in this embodiment is a simple yet efficient design principle. Without complex analysis and calculation, it can select the two cable strands that maximize the effectiveness of the synergistic load-bearing structure, are easiest to connect during construction, and contribute the most to the overall stability. This ensures that the synergistic load-bearing system is in optimal working condition from the beginning, laying a solid foundation for the high-quality erection of large-scale cable strands in the future.

[0069] Example 8: This example provides a more precise definition of the synchronous movement control method for the counterweight balancing cable 4.

[0070] Based on the synchronous movement control method described in Embodiment 3, this embodiment further clarifies that during the dynamic process of erecting the cooperative force-bearing cable strand 11, the moving speed of the counterweight balance cable 4 during its synchronous movement phase is precisely controlled to maintain real-time consistency with the moving speed of the front end of the cooperative force-bearing cable strand 11. This can be achieved through a closed-loop control system. The system reads the speed signal of the winch traction cooperative force-bearing cable strand 11 in real time, or directly measures the moving speed of the front end of the cable strand through a laser rangefinder / visual recognition sensor, and uses this speed signal as a target value to feed back and control the drive device of the counterweight balance cable 4, so that its output speed matches the target speed.

[0071] The synchronous movement in this embodiment ensures the correspondence between the counterweight and the load in spatial location, while maintaining consistent speed in this embodiment deepens and precisely defines synchronization in the time dimension. Only by achieving speed matching can we ensure that the concentrated load area and the counterweight balance cable 4 neither lag behind nor lead, forming a truly stable subsystem that remains balanced at all times. Any speed difference will accumulate over time and transform into a spatial position difference, leading to the failure of dynamic balance.

[0072] For details, please refer to the appendix. Figure 3 To be continued Figure 7 As shown. Figure 3 As shown, in the initial state, the counterweight balancing cable 4 is located at the mid-span of the main span, and the end of the counterweight balancing cable 4 is located at the 1 / 4 span position (see attached diagram). Figures 3-7 Point C in the middle), the front end is at the 3 / 4 span position (attached) Figures 3-7 Point B in the diagram), at this time the front end of the coordinating force-bearing cable strand 11 is located on one side of the main tower (attached). Figures 3-7 Point D in the middle); such as Figure 4 As shown, the front end of the synergistic force-bearing strand 11 is pulled to the 1 / 4 span position (see attached diagram). Figures 3-7 (Point C in the diagram), reaching near the end of counterweight balance cable 4, and then synchronously pulling counterweight balance cable 4 begins; as... Figure 5 As shown, the front end of the cooperating force-bearing cable strand 11 is pulled to the mid-span position (see attached diagram). Figures 3-7 Point E in the diagram), the front end of counterweight cable 4 is pulled to the other side of the main tower (see attached diagram). Figures 3-7 Point A in the middle); such as Figure 6 As shown, traction continues, and the counterweight balance cable 4 is pulled to the side span position, while the front end of the cooperating force-bearing cable strand 11 is pulled to the position of the main tower on the other side (see attached diagram). Figures 3-7 (Point A in the diagram) Once the counterweight balance cable 4 has been completely pulled out of the main span area, the pulling can be stopped, and the counterweight balance cable 4 will remain at the side span position; as shown... Figure 7 As shown, the synergistic force-bearing cable 11 continues to pull until it is fully pulled into place.

[0073] This precise speed matching control in this embodiment eliminates dynamic imbalance forces caused by speed inconsistencies to a minimum. This keeps the catenary's alignment and internal force fluctuations within a very small range throughout the entire dynamic process of cable strand tensioning, achieving a near-static equivalent dynamic equilibrium effect. This provides unprecedented construction precision and safety assurance for the erection of main cable strands in ultra-large span, wind-sensitive areas.

[0074] The present invention discloses an ultra-large span catwalk structure, wherein the load-bearing cable 1 of the load-bearing structure is made of a mixture of aramid fiber rope and steel wire strands to reduce its weight and increase the span. The catwalk surface layer 2 is laid on this load-bearing cable 1.

[0075] Above the catwalk surface layer 2, three major functional structures are integrated: Firstly, the co-force-bearing structure includes multiple support frames 3 arranged longitudinally and at intervals along the catwalk. Each support frame 3 is equipped with upper and lower roller assemblies and a buffer structure 33, which are used to connect and buffer the impact from the main cable strands.

[0076] Secondly, the self-balancing counterweight structure includes a counterweight balancing cable 4 with a length of 1 / 2 of the main span and a weight of 1 / 2 of the self-weight of the cooperating force-bearing cable strand 11. The counterweight balancing cable 4 is arranged on multiple track frames 5 arranged longitudinally along the center line of the catwalk and is pulled by a drive device.

[0077] Third, the surface counterweight structure includes multiple water pipe units 6 evenly distributed along the longitudinal direction of the catwalk surface layer 2. Adjacent water pipe units 6 are quickly connected by flexible hose joints, forming a continuous linear counterweight after water is supplied.

[0078] In actual construction, the main cable strand of this invention can be installed according to the following steps: The first step is to install the hybrid material load-bearing cable 1 and the catwalk surface layer 2.

[0079] The second step is to install the support frame 3 with integrated buffer roller assembly on the catwalk surface layer 2, install the drive device, and lay the counterweight balance cable 4 on the center line track frame 5.

[0080] The third step is to quickly lay and connect water pipe units 6 on the surface layer, and then pump water uniformly to form a uniform surface layer weight.

[0081] The fourth step is to install the main cable strands. First, from the main cable strands, accurately select two strands located at the top positions on both sides of the main cable cross-section as the cooperating force-bearing strands 11. Introduce them into the support frame 3, making them roll into contact with and fix them to the upper and lower roller assemblies.

[0082] The fifth step is to begin erecting the coordinating force-bearing cable strand 11. During the advancement process, when the front end of the cable strand moves to the vicinity of the end of the counterweight balance cable 4, the drive device is activated to pull the counterweight balance cable 4 along the track frame 5, ensuring that its moving speed is precisely consistent with the moving speed of the front end of the coordinating force-bearing cable strand 11, achieving synchronous following in both time and space dimensions.

[0083] The sixth step is to continue erecting all the remaining strands of the main cable after the two synergistic force-bearing cable strands 11 have been erected and formed a strong and stable synergistic force-bearing system with the load-bearing cable 1.

[0084] The catwalk structure of this invention reduces weight from the material source (hybrid fiber load-bearing cable 1), establishes a high-rigidity foundation system through static ballast (water-filled pipes) and structural connections (buffered support frame 3), and then completely solves the fundamental problems of low stiffness, large deformation, and poor wind resistance stability in the construction of ultra-large span catwalks through a refined dynamic balance strategy of spatial positioning (top and side cable strands), parameter matching (half-span, half-weight), physical constraints (central track frame 5), and precise control (constant speed following). The entire solution creatively transforms the negative effects of construction loads into positive factors that enhance system stability, exhibiting extremely high construction safety, economy, and technological foresight.

[0085] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A super-large catwalk structure, characterized in that, include: The load-bearing structure includes several load-bearing cables erected longitudinally and a catwalk surface layer fixed to the load-bearing cables. The co-load-bearing structure includes a support frame fixed on the catwalk surface; the support frame is used to be fixedly connected in the vertical direction to the co-load-bearing strands pre-erected in the main cable strands, so that the load-bearing cable and the co-load-bearing strands share the load together. The self-balancing counterweight structure includes a counterweight balancing cable that can move longitudinally along the catwalk, and a drive device for pulling the counterweight balancing cable to move synchronously with the main cable strand erection load concentration area. The surface counterweight structure includes a continuous distributed counterweight body laid on the catwalk surface layer to provide continuous and uniform downward pressure on the catwalk structure.

2. The ultra-large catwalk structure according to claim 1, characterized in that, The support frame is provided with an upper roller assembly, a lower roller assembly, and a buffer structure; the cooperative force-bearing strand is introduced into the support frame and forms rolling contact with the upper and lower roller assemblies.

3. The ultra-large catwalk structure according to claim 1, characterized in that, The length of the counterweight balancing cable is 1 / 2 of the main span, and its weight per unit length matches the weight per unit length of the cooperating force-bearing cable strand, so that the total weight of the counterweight balancing cable is equal to the self-weight of the cooperating force-bearing cable strand, so that it covers the main stress and load variation concentrated area in the middle of the main span.

4. The ultra-large catwalk structure according to claim 1, characterized in that, The self-balancing counterweight structure also includes multiple track frames arranged longitudinally at intervals along the centerline of the catwalk; the counterweight balancing cable is arranged on the track frames.

5. The ultra-large catwalk structure according to claim 1, characterized in that, The surface counterweight structure includes multiple water pipe units evenly distributed along the longitudinal direction of the catwalk surface, with adjacent water pipe units quickly connected by flexible hose joints; the water pipe units form a continuous linear counterweight after water is supplied.

6. The ultra-large catwalk structure according to claim 1, characterized in that, The load-bearing cable is made of a mixture of aramid fiber rope and steel wire strands.

7. A method for constructing the main cable of a suspension bridge based on the ultra-large span catwalk structure described in any one of claims 1 to 6, characterized in that, include: Erect load-bearing cables and install the catwalk surface layer based on the load-bearing cables; Install a support frame, a drive unit, and a counterweight balancing cable on the catwalk surface. After the load-bearing cables are erected and before or simultaneously with the installation of the coordinating force-bearing cables, a continuous distributed counterweight is laid on the catwalk surface. Select a cooperating tension cable from the main cable strands, erect the cooperating tension cable, and during the erection process, use a drive device to pull the counterweight balance cable so that the counterweight balance cable moves synchronously with the erection of the cooperating tension cable. After the co-supporting cable strands are erected and form a co-supporting system with the load-bearing cable, the other cable strands of the main cable are erected until all cable strands are erected.

8. The method for constructing the main cable of a suspension bridge according to claim 7, characterized in that, The method for selecting cooperative stress-bearing strands from the main cable strands includes: selecting two strands located at the top positions on both sides of the main cable cross-section as cooperative stress-bearing strands.

9. The method for constructing the main cable of a suspension bridge according to claim 7, characterized in that, The method of using a drive device to pull the counterweight balance cable so that the counterweight balance cable moves synchronously with the erection and advancement of the cooperating force-bearing cable strand includes: during the erection of the cooperating force-bearing cable strand, when the front end of the cooperating force-bearing cable strand moves to the vicinity of the end of the counterweight balance cable, the drive device is activated to drive the counterweight balance cable to move synchronously with the cooperating force-bearing cable strand in the longitudinal direction, so that the counterweight balance cable always corresponds to the concentrated load area of ​​the cooperating force-bearing cable strand in the longitudinal direction.

10. The method for constructing the main cable of a suspension bridge according to claim 9, characterized in that, During synchronous movement, the speed of the counterweight balancing cable is consistent with the speed of the front end of the cooperating force-bearing cable strand.

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