A method for quickly positioning and installing a cable tower steel beam section

Abstract

This invention discloses a method for rapid positioning and installation of steel crossbeam segments in cable-stayed bridges. The method includes: welding hanging plates with fixed sections and cantilever sections to the joint ends of the steel crossbeam segments; hoisting the segments to the installation position, using overlapping hanging plates and wedge blocks for rough positioning, while keeping the hoisting equipment hooked; fine-tuning the axis, elevation, and alignment based on measurement data, followed by welding multi-faceted temporary fixing plates to form rigid constraints; assembling and welding the mounting plates, then releasing the hooks; and cyclically constructing the installation according to a symmetrical principle, with the mounting plate construction and subsequent hoisting carried out in parallel. This invention achieves rapid, precise, and safe installation of large-segment steel crossbeams through rapid overlapping of hanging plates, wedge block posture constraints, and multi-directional rigid positioning, significantly shortening high-altitude work time, reducing construction risks, allowing for normal daytime construction without being limited by the early morning window, and significantly improving installation efficiency and alignment control accuracy. It is applicable to the construction of steel crossbeams for cable-stayed bridge towers using the scaffolding method.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering technology, specifically relating to a method for rapid positioning and installation of steel crossbeam segments in cable towers, which is particularly suitable for the rapid installation, alignment and fixing of large steel crossbeam segments in scaffolding construction. Background Technology

[0002] In modern cable-stayed and suspension bridge structures, the pylon crossbeam is a crucial load-bearing component connecting the two tower columns. It is a core part of the bridge superstructure, not merely a decorative element, and its load-bearing function is paramount. Common bridge tower types include H-shaped towers, A-shaped towers, diamond-shaped towers, and portal towers. H-shaped towers typically have multiple crossbeams at the top, middle, and bottom; A-shaped and diamond-shaped towers generally have one or two key load-bearing crossbeams; and portal towers have a single, large-tonnage integral crossbeam at the top. The main function of the pylon crossbeam is to connect the two independent tower columns into a unified portal frame structure, significantly improving the overall stiffness, wind resistance, seismic performance, and lateral force resistance of the bridge tower. During the construction and operation of cable-stayed and suspension bridges, the loads from the cables and main beams generate significant horizontal thrust on the tower columns. The crossbeam can transfer this horizontal thrust to the opposite tower column and cancel it out, effectively preventing the tower columns from tilting inward or outward, thus strictly controlling the tower column alignment and ensuring structural safety and construction stability.

[0003] Currently, the mainstream construction technology for steel crossbeams of cable towers is the scaffolding method, including ground-mounted steel pipe scaffolding, tower column pre-embedded bracket scaffolding, and bracket scaffolding. The core idea is to erect a stable temporary support system at high altitude, serving as a load-bearing and operating platform for steel crossbeam installation, segment splicing, elevation adjustment, and welding operations. During construction, tower cranes with a capacity of tens of thousands of tons or large crawler cranes are typically used to divide the factory-prefabricated steel crossbeams into 2 to 5 independent segments according to the design. These segments are then hoisted sequentially to their designed positions. Three-way jacks positioned at the top of the scaffolding are used to repeatedly adjust the axis, elevation, cross slope, and longitudinal alignment of the steel crossbeam segments. Once the positions meet the design requirements, welding connections between segments, plate fixing, and subsequent construction are carried out.

[0004] Besides the scaffolding method, the industry also employs a construction technique of displaced assembly + overall lifting. This involves welding individual segments together on a ground-based formwork, then installing a lifting frame and steel strand jacks at the top of the tower to simultaneously lift the entire crossbeam to the design elevation. For large bridges spanning rivers or seas, a large-segment floating crane technique can be used, directly lifting the entire or large segments of the crossbeam into place in one go using a large floating crane on the water. However, both of these techniques are highly dependent on site conditions, weather conditions, lifting equipment resources, and structural form, limiting their applicability and versatility. Therefore, the scaffolding method remains the most mainstream and commonly used installation technique for cable tower steel crossbeam construction in China.

[0005] However, existing traditional support methods have significant shortcomings in the positioning and installation of steel beam segments:

[0006] (1) Segmental spatial positioning mainly relies on repeated adjustments with three-way jacks. The adjustment process is cumbersome, time-consuming, and has low construction efficiency.

[0007] (2) The steel crossbeam segments are easily affected by environmental factors such as changes in on-site temperature, temperature difference of sunlight, and wind disturbance, and the alignment is prone to deviation. In order to ensure accuracy, traditional processes can only be used for positioning operations during the night and early morning when the temperature is uniform and the temperature difference is small. The construction window is short and the organization is difficult.

[0008] (3) The high-altitude adjustment time is long and there are many procedures. The risk of personnel working at height is high and the safety hazards are prominent.

[0009] (4) Multiple fine-tuning can easily cause problems such as segment collision, misaligned interface, and uneven line shape, which affect the installation quality and structural durability. Summary of the Invention

[0010] The purpose of this invention is to overcome the shortcomings of traditional scaffolding construction methods, such as cumbersome positioning procedures, long adjustment time, great susceptibility to environmental influences, high risk of high-altitude operations, and low construction efficiency. This invention provides a rapid positioning and installation method for steel crossbeam segments of cable towers. Through technologies such as rapid overlapping support with hanging plates, wedge block posture constraints, multi-faceted rigid positioning and fixing, and symmetrical assembly line operation, the invention achieves rapid positioning of steel crossbeam segments, one-time coarse positioning, high-precision fine adjustment, and short-time fixing. This significantly shortens the time spent in high-altitude operations, reduces construction risks, improves the accuracy of alignment control, and allows for normal daytime construction, no longer limited to the low-temperature operation window in the early morning.

[0011] To address the aforementioned technical problems, this invention provides a method for rapid positioning and installation of steel crossbeam segments in cable towers, applicable to the installation of large-segment steel crossbeams using the scaffolding method, comprising the following steps:

[0012] S1: A hanging plate for quick overlapping and positioning is pre-fixed to the butt joint end of the steel beam segment to be installed. The hanging plate is configured as a rigid positioning component with a fixed section and a cantilever section.

[0013] S2: The steel beam segments are hoisted to the installation position above the support using hoisting equipment. The cantilever section of the hanging plate is connected to the pre-embedded interface of the tower column or the adjacent steel beam segments that have been installed. At the same time, wedge blocks are matched and set at the support position for attitude constraint to complete the rough positioning of the steel beam segments. During the rough positioning process, the hoisting equipment is kept under force and the hook is not loosened.

[0014] S3: Based on real-time measurement data, the axis, elevation and alignment of the steel beam segment are finely adjusted. After the fine adjustment is in place, temporary fixing plates are welded on multiple facades of the steel beam segment to form rigid positioning constraints.

[0015] S4: After the steel beam segments have been positioned, they are assembled and welded to secure them. Once the operation is completed, the hoisting equipment is released and the next segment hoisting process begins.

[0016] S5: Repeat the above procedures according to the principle of symmetrical installation, and complete the installation of all steel beam segments in sequence. The construction of the stacking plate and the subsequent segment hoisting are carried out in parallel.

[0017] Furthermore, the hanging plate is arranged at the corresponding position of the longitudinal ribs along the steel beam segment, the fixed section of the hanging plate is welded and fixed to the entire cross section of the steel beam segment, and the cantilever section extends outward to form an overlapping positioning structure.

[0018] Furthermore, the hanging plates are arranged symmetrically in multiple sections, and the length of the cantilever section of the hanging plate is consistent with the length of the fixed section to ensure the balance of force during overlapping and positioning.

[0019] Furthermore, when the steel crossbeam segment is hoisted to a preset distance from the docking interface, it is aligned and calibrated using hoisting equipment and chain hoists. After calibration, it is lowered to the hanging plate for overlapping and positioning.

[0020] Furthermore, the temporary fixing plate includes a vertical side fixing plate and a bottom fixing plate. After fine adjustment, the plate is simultaneously welded on the top, side and bottom surfaces of the steel beam segment to form a multi-directional constraint positioning system.

[0021] Furthermore, the steel crossbeam segment is supported by a combined support system consisting of a ground-mounted steel pipe support and a tower column pre-embedded corbel. The top of the combined support system is equipped with a load-bearing beam, a distribution beam, and an adjustable wedge block.

[0022] Furthermore, during the fine-tuning process, the hoisting equipment remains suspended until the temporary fixing plate is welded and forms an effective rigid constraint before the hook can be released.

[0023] Furthermore, the steel beam segments are hoisted symmetrically and synchronously by double-sided tower cranes, with the segment installation sequence proceeding from both sides towards the middle, and the closing segment positioned in the middle of the installation sequence.

[0024] Furthermore, coarse positioning is achieved through the joint of hanging plate overlap and wedge block posture constraint, while fine adjustment is completed through the cooperation of the code plate and jack.

[0025] Furthermore, the method is applicable to the installation of large segments of the crossbeams under the pylons of suspension bridges, enabling rapid positioning during non-early morning hours and shortening the time spent on high-altitude operations.

[0026] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0027] 1. This invention pre-welds hanging plates with fixed and cantilever sections at the joint ends of steel beam segments. After hoisting, the hanging plates can be directly attached to the tower column or the installed segments to achieve rapid support, eliminating the cumbersome steps of repeated adjustment with three-way jacks in the traditional process, significantly shortening the segment placement time, and realizing rapid rough positioning of steel beam segments.

[0028] 2. This invention uses wedge blocks at the support position to work with hanging plates to complete coarse positioning, which can quickly constrain the elevation, inclination angle and lateral position of the segments, improve the interface matching accuracy and alignment control effect, reduce segment misalignment and offset problems, and improve installation quality.

[0029] 3. This invention keeps the hoisting equipment hooked throughout the entire process of coarse positioning and fine adjustment, and only releases the hook after the temporary fixing plate is welded to form a rigid constraint, thus avoiding the risk of segment falling, displacement or overturning, and greatly improving the safety of high-altitude installation operations.

[0030] 4. By welding multi-directional temporary fixing plates on the top, side and bottom surfaces, this invention can quickly achieve rigid fixing of segments after fine adjustment, reducing springback, deformation and displacement after positioning, and ensuring the stability of welding and stacking operations.

[0031] 5. This invention adopts a construction sequence of symmetrical installation from both sides towards the middle and centered closing section, and enables the installation of the mounting plates and the hoisting of subsequent segments to be carried out in parallel, realizing cross-flow operation, greatly shortening the overall construction period and improving construction efficiency.

[0032] 6. This invention significantly reduces the time spent on high-altitude adjustments and stays by using a fast positioning plate, wedge block constraint, and rigid fixing process, thereby reducing the risks of high-altitude operations. It also reduces the impact of sunlight and temperature differences on positioning accuracy, allowing installation to be completed during normal daytime hours, no longer limited to the low-temperature construction window in the early morning.

[0033] 7. The coarse positioning of this invention is achieved by using a hanging plate and a wedge block, while the fine adjustment is achieved by using a jack and a clamp plate. The positioning logic is clear and the process is simple. It does not require complex equipment or repeated fine adjustments, thus reducing construction difficulty and labor costs, and making it more applicable. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of the segmented arrangement of the cable tower crossbeam in a preferred embodiment of the present invention;

[0035] Figure 2 This is a preferred embodiment of the invention, showing the arrangement of the lower crossbeam support and tower crane.

[0036] Figures 3-5 This is a construction diagram of a preferred embodiment of the present invention. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0038] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0039] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0040] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, 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 the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0041] refer to Figures 1-5 This embodiment provides a rapid positioning and installation method for the steel crossbeam segments of a cable tower. Taking the lower crossbeam of a large suspension bridge tower as the construction object, the lower crossbeam is 40.4m long, 7.5m wide, 9m high at the ends, and 11.2m high in the middle section. The bottom of the beam has a gradually changing arc-shaped cross section, resulting in high overall rigidity and requiring high positioning accuracy. To ensure installation quality and construction efficiency, the entire lower crossbeam is prefabricated and processed in the factory into eight independent segments (XHL1, XHL2, XHL3, and XHL4). The weight of a single segment ranges from 40t to 140t, representing a large-tonnage, large-size steel component installation condition. The middle segment is the closure section, and the construction sequence adopts a symmetrical installation from both sides towards the middle.

[0042] On-site, a combined support system of ground-mounted steel pipe scaffolding and pre-embedded corbels in the tower columns serves as the main load-bearing and positioning platform. The ground-mounted scaffolding is positioned on the top surface of the foundation, with columns constructed from φ800×16mm straight-seam welded pipes. Horizontal bracing, transverse bracing, and diagonal bracing all utilize φ426×8mm steel pipes, forming a spatial truss structure to ensure overall stability and rigidity. Double-section HM588 steel sections are installed at the top of the scaffolding as the main load-bearing beam. I32a distribution beams are laid above the main beams, with wedge-shaped adjustment blocks pre-installed on the top surface of the distribution beams for elevation adjustment and attitude constraint of the steel crossbeam segments. Pre-embedded corbels on the inner side of the tower columns share the load with the ground-mounted scaffolding, forming a stable system with coordinated upper and lower sections and multi-point support. Two large tower cranes with a rated lifting capacity of 160t are used for hoisting, achieving symmetrical lifting, synchronous shifting, and smooth positioning of the segments.

[0043] During the ground pre-assembly stage, the joints of the steel beam segments XHL1, XHL2, XHL3, and XHL4 were first ground, cleaned, and checked for matching to confirm that the flatness, bevel angle, and matching accuracy of the joints met the design requirements. Then, hanging plates 1 were welded to the joint ends of each segment. Hanging plates 1 are made of high-strength rigid steel plates and are evenly distributed along the longitudinal ribs of the segment. Hanging plates 1 consist of a fixed section and a cantilever section. The fixed section is welded to the entire cross-section of the steel beam end face to ensure connection strength; the cantilever section extends outwards for rapid overlap, initial support, and positioning during high-altitude docking. The number, position, and extension length of hanging plates 1 are rationally set according to the segment weight, interface type, and stress requirements to ensure that the segments are evenly stressed in the overlap state and do not experience localized stress concentration or end-face deformation.

[0044] After the welding of the hanging plate 1 is completed and inspected, two tower cranes are used to bind and lift the XHL1 segment, smoothly raising it to the installation height above the support. When the segment descends to about 20cm from the docking interface, the descent is paused, and the port alignment is calibrated by using the tower crane's micro-motion in conjunction with the chain hoist, so that the center line, end face gap, and misalignment of the segment to be installed and the pre-embedded interface of the tower column meet the preliminary matching requirements.

[0045] After alignment, the XHL1 segment is slowly lowered to ensure that the cantilever section of the hanging plate 1 accurately overlaps with the pre-embedded interface of the tower column. Simultaneously, wedge blocks 2 are inserted at the bottom support position of the segment. These wedge blocks constrain the segment's elevation, inclination angle, and lateral position, quickly completing the coarse positioning. During coarse positioning, the tower crane maintains constant suspension force, without loosening the hook or unloading the load, keeping the segment in a stable and controllable state to avoid collisions, misalignments, or safety hazards caused by external forces, wind vibration, or attitude deviations.

[0046] After coarse positioning, the axial deviation, top elevation, longitudinal alignment, and end face gap of segment XHL1 are monitored in real time using a total station. Based on the measurement results, the segment's attitude is fine-tuned. Fine-tuning employs a combination of clamps and jacks for micro-adjustment, allowing for precise correction of the segment's front-to-back, left-to-right, and height variations until all indicators meet design and specification requirements. Once fine-tuned, temporary fixing plates 3 are immediately welded to the top, both vertical sides, and bottom of segment XHL1, rigidly connecting the segment to the tower column's embedded structure, forming a multi-directional constraint positioning system to ensure that the segment does not shift, rotate, or settle under subsequent welding, clamp installation, or external forces.

[0047] After the temporary fixing plate 3 is welded and forms an effective constraint, the assembly and welding of the mounting plates 4 for the XHL1 segment begins. The mounting plates 4 are evenly arranged along the butt joint face to ensure uniform stress and consistent shrinkage of the weld. Welding is performed in layers, symmetrically, and intermittently according to process requirements to control welding deformation and ensure the quality of the joint connection. Once the welding is completed, the weld has cooled, and a preliminary inspection has passed, the tower crane can be completely released and moved to a safe area to prepare for the hoisting of the XHL2 segment.

[0048] Following the sequence XHL1→XHL2→XHL3→XHL4, each segment is installed symmetrically from the two side tower columns towards the center, with the final segment being the central closure section. This ensures symmetrical structural stress and a smooth alignment. During construction, subsequent processes such as the installation, welding, and alignment of the mounting plates 4 for the already installed XHL1, XHL2, and other segments can be carried out in parallel with the hoisting, alignment, and rough positioning of the next segment. This allows for cross-flow operations between high-altitude work and ground preparation, as well as between hoisting and welding processes. This significantly shortens the time spent at height, improves construction efficiency, reduces safety risks, and minimizes the impact of environmental factors such as sunlight and temperature on positioning accuracy. Installation can be completed during regular daytime hours, no longer limited to the low-temperature window of early morning.

[0049] Through the above procedures, this embodiment achieves rapid positioning, precise docking, and efficient installation of XHL1, XHL2, XHL3, XHL4, and the closure section, significantly simplifying the traditional process of repeated adjustments with jacks, improving alignment control accuracy, shortening the construction period, and enhancing the safety and reliability of the entire construction process.

[0050] The above is only one specific embodiment of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be deemed as infringing the protection scope of the present invention.

Claims

1. A method for rapid positioning and installation of steel crossbeam segments in cable towers, applicable to the installation of large-segment steel crossbeams using the scaffolding method, characterized in that... Includes the following steps: S1: A hanging plate for quick overlapping and positioning is pre-fixed to the butt joint end of the steel beam segment to be installed. The hanging plate is configured as a rigid positioning component with a fixed section and a cantilever section. S2: The steel beam segments are hoisted to the installation position above the support using hoisting equipment. The cantilever section of the hanging plate is connected to the pre-embedded interface of the tower column or the adjacent steel beam segments that have been installed. At the same time, wedge blocks are matched and set at the support position for attitude constraint to complete the rough positioning of the steel beam segments. During the rough positioning process, the hoisting equipment is kept under force and the hook is not loosened. S3: Based on real-time measurement data, the axis, elevation and linear attitude of the steel beam segment are finely adjusted. After the fine adjustment is in place, temporary fixing plates are welded on multiple facades of the steel beam segment to form rigid positioning constraints. S4: After the steel beam segments have been positioned, they are assembled and welded to secure them. Once the operation is completed, the hoisting equipment is released and the next segment hoisting process begins. S5: Repeat the above procedures according to the principle of symmetrical installation, and complete the installation of all steel beam segments in sequence. The construction of the stacking plate and the subsequent segment hoisting are carried out in parallel.

2. The method for rapid positioning and installation of steel crossbeam segments for cable towers according to claim 1, characterized in that, The hanging plate is arranged at the corresponding position of the longitudinal ribs along the steel beam segment. The fixed section of the hanging plate is welded and fixed to the entire cross section of the steel beam segment, and the cantilever section extends outward to form an overlapping positioning structure.

3. The method for rapid positioning and installation of steel crossbeam segments for cable towers according to claim 1, characterized in that, The hanging plates are arranged symmetrically in multiple sections, and the length of the cantilever section of the hanging plate is consistent with the length of the fixed section to ensure the force balance of the overlapping positioning.

4. The method for rapid positioning and installation of steel crossbeam segments for cable towers according to claim 1, characterized in that, When the steel beam segment is hoisted to the preset distance from the docking interface, it is aligned and calibrated by hoisting equipment and chain hoist. After calibration, it is lowered to the hanging plate for overlapping and positioning.

5. The method for rapid positioning and installation of steel crossbeam segments of a cable tower according to claim 1, characterized in that, The temporary fixing plate includes a vertical side fixing plate and a bottom fixing plate. After fine adjustment, it is simultaneously welded on the top, side and bottom surfaces of the steel beam segment to form a multi-directional constraint positioning system.

6. The method for rapid positioning and installation of steel crossbeam segments of a cable tower according to claim 1, characterized in that, The steel crossbeam segment is supported by a combined support system consisting of a ground-mounted steel pipe support and a tower column pre-embedded corbel. The top of the combined support system is equipped with a load-bearing beam, a distribution beam, and an adjustable wedge block.

7. The method for rapid positioning and installation of steel crossbeam segments for cable towers according to claim 1, characterized in that, During the fine-tuning process, the hoisting equipment remains suspended until the temporary fixing plate is welded and forms an effective rigid constraint before the hook can be released.

8. The method for rapid positioning and installation of steel crossbeam segments of a cable tower according to claim 1, characterized in that, The steel crossbeam segments are hoisted symmetrically and synchronously by double-sided tower cranes. The installation sequence of the segments proceeds from both sides towards the middle, with the closing segment positioned in the middle of the installation sequence.

9. The method for rapid positioning and installation of steel crossbeam segments of a cable tower according to claim 1, characterized in that, Coarse positioning is achieved by the combination of hanging plate overlap and wedge block posture constraint, while fine adjustment is completed by the cooperation of the code plate and jack.

10. The method for rapid positioning and installation of steel crossbeam segments of a cable tower according to claim 1, characterized in that, The method is applicable to the installation of large sections of the crossbeam under the suspension bridge tower, and can achieve rapid positioning during non-early morning hours, shortening the time for high-altitude operations.

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