Method for installing circular arc cross beam in circular tower steel structure

Abstract

This invention relates to the field of steel structure building construction technology, and in particular to a method for installing a circular arc beam in a circular tower steel structure. The method includes: creating a matching arc-shaped template based on the measured arc contour of the steel column on site; machining the ends of the beam to form a uniformly fitting arc surface; installing the steel column in sections; installing an adjustable ear plate assembly using the pre-reserved connection holes in the steel column and adjusting it to the installation height; hoisting the beam onto the assembly; finely adjusting its three-dimensional posture to ensure precise alignment of the fitting surfaces before locking it in place; welding the beam to the steel column; and finally removing the adjustable ear plate assembly. The purpose of this invention is to solve the problems of low beam fitting accuracy, difficulty in hoisting and positioning adjustment, damage to the steel column base material, and poor welding quality caused by deviations between the actual contour of the steel column and the design.

Description

Technical Field

[0001] This invention relates to the field of steel structure building construction technology, and in particular to a method for installing a circular arc beam in a circular tower steel structure. Background Technology

[0002] Circular tower steel structures are widely used in construction projects such as towers, observation towers, and industrial silos due to their uniform stress distribution and high space utilization. The arc-shaped crossbeam, as the core connecting component of this type of steel structure, directly determines the overall structure's load-bearing capacity and service life through its connection accuracy and installation stability with the steel columns. The arc-shaped crossbeam is connected to the circular tower steel column via a curved surface. Compared to the planar connection between a straight beam and the steel column, this places higher technical demands on the machining accuracy of the crossbeam ends and the on-site installation positioning accuracy. Its installation requires balancing the arc matching during machining with the posture adjustability during on-site assembly, making it a critical process in the construction of circular tower steel structures.

[0003] In the actual production and installation of circular tower steel structure arc beams, there are many technical problems that seriously affect the construction quality and efficiency: First, the steel columns are prone to slight deformation during production, on-site transportation and segmented installation, which leads to deviations between the actual arc profile of the steel column on site and the theoretical design parameters. If the arc beam is only processed at the end according to the theoretical drawings, problems such as insufficient processing accuracy of the end contact surface of the beam and the arc side of the steel column, large and uneven contact gaps, and misalignment of the connection surface will occur, thereby reducing the effective contact area of ​​the welding surface and causing welding defects. Secondly, it is difficult to achieve precise positioning after the arc-shaped crossbeam is hoisted. Traditional positioning methods lack flexible attitude adjustment mechanisms, making it impossible to make three-dimensional fine adjustments to the crossbeam and ensuring precise fitting of the arc-shaped contact surface. Thirdly, in traditional construction, crossbeam positioning is often achieved by additionally drilling holes in the steel column and welding temporary plates. This method will damage the steel column base material structure and anti-corrosion layer, affecting the mechanical properties of the steel column itself. Moreover, the removal process of temporary plates is cumbersome, further reducing construction efficiency. At the same time, the obstruction of the positioning structure can easily lead to welding dead angles, making it difficult to guarantee the welding quality around the entire circumference.

[0004] After searching relevant materials, patent publication number CN119244015A was found, which discloses a construction method for connecting arc-shaped components of steel structures. This patent forms a load-bearing whole by spot-welding plates, tie rods, and bottom support rods to support the installation of the upper arc-shaped steel beam. After the upper steel beam is welded, the lower steel beam is welded. This effectively solves the problem of construction space conflict caused by scaffolding support and improves the installation efficiency of vertically spaced arc-shaped components. The advantage of this technology lies in fully utilizing the components themselves to form a load-bearing support system, eliminating the need for external scaffolding and saving time and costs associated with tooling erection and dismantling. It is suitable for the batch installation of multiple vertically distributed arc steel beams. However, its disadvantages are also significant. This solution only addresses the space and support issues for the vertical installation of arc components, without providing solutions to core problems such as insufficient fitting accuracy of the arc surface, inconvenient on-site positioning and adjustment, and positioning damage to the base material. Furthermore, its temporary positioning method using spot welding plates still causes welding damage to the steel structure base material. It also lacks precision control methods for the processing of the arc component ends, making it unsuitable for the high-precision fitting of the arc beams and arc surfaces of the steel columns in circular tower-type steel structures. It also struggles to solve the connection matching problems caused by the actual contour deviation of the steel columns. In addition, existing technologies still rely on conventional methods such as using general-purpose contour molds to process curved components and using fixed ear plates for on-site positioning. However, these general-purpose contour molds are not tailored to the actual contours of the steel columns on-site, failing to eliminate matching deviations caused by steel column deformation. Furthermore, the fixed ear plates lack posture adjustment capabilities and have low positioning accuracy, thus failing to fundamentally solve the multiple technical challenges of installing curved beams in circular tower steel structures. Therefore, it is necessary to develop an installation method that combines high-precision machining of the curved beam ends, non-destructive on-site positioning, and flexible posture adjustment to meet the construction requirements of circular tower steel structures and improve the connection quality and installation efficiency between the curved beams and steel columns. Summary of the Invention

[0005] This invention provides a method for installing arc-shaped crossbeams in circular tower steel structures, which solves the technical problems of insufficient processing accuracy of the end contact surface of the crossbeam, large contact gap, and misalignment caused by the deviation between the actual arc contour of the steel column on site and the theoretical design during the installation of arc-shaped crossbeams in existing circular tower steel structures. In addition, the crossbeams are difficult to position after hoisting, and the posture adjustment is inconvenient. Furthermore, traditional positioning methods are prone to damaging the steel column base material, resulting in low installation efficiency and difficulty in ensuring welding quality.

[0006] To solve the above problems, the technical solution adopted by the invention is as follows: A method for installing a circular arc-shaped crossbeam in a circular tower steel structure includes the following steps: (1) Factory prefabricated arc beam: Based on the actual measured arc profile of the circular tower steel column, an arc-shaped template that perfectly matches the arc side of the steel column is made. Using the arc-shaped template as a reference, the two ends of the arc beam are cut and processed so that the two ends of the beam form an arc-shaped contact surface that fully fits the arc side of the steel column with uniform gap. (2) Install steel columns in sections and pre-install adjustable positioning devices: hoist and fix multiple steel columns in sections, use the pre-reserved connection holes of the steel columns to detachably install the adjustable ear plate assembly on the top of the steel columns, and pre-adjust the adjustable ear plate assembly to the installation height of the arc crossbeam; (3) Precise positioning of the arc beam: The prefabricated arc beam is hoisted onto the adjustable ear plate assembly. The arc beam is then finely adjusted in three dimensions through the adjustable ear plate assembly so that the arc-shaped contact surface at the end of the beam is precisely fitted with the arc-shaped side of the steel column. After the fit is in place, the adjustment mechanism is locked to achieve temporary fixation. (4) Welding and fixing: Weld the fitted arc beam to the steel column; (5) Device removal: After welding is completed, the adjustable ear plate assembly is removed from the steel column connection hole as a whole, and the arc beam is installed.

[0007] The principle and advantages of this scheme are as follows: The principle of this solution is to first obtain the actual arc contour of the steel column through on-site measurement, and then create a perfectly matching arc-shaped template. Using this template as the sole benchmark, the ends of the arc-shaped beam are cut and processed to eliminate the deviation between the theoretical design of the steel column and the actual on-site contour from the processing source. This ensures that the ends of the beam form an arc-shaped fitting surface that fully fits the arc-shaped side of the steel column with uniform gaps. Then, the adjustable ear plate assembly can be detachably installed using the pre-reserved connection holes on the steel column itself. No additional drilling or welding is required on the steel column. After the arc-shaped beam is hoisted to the desired installation height using the adjustable ear plate assembly, the three-dimensional posture of the beam is finely adjusted to ensure that the arc-shaped fitting surface precisely fits the arc-shaped side of the steel column. After the adjustment mechanism is locked to complete the temporary fixation, welding is performed. After welding, the adjustable ear plate assembly is removed to complete the entire installation process. This achieves dual control over processing accuracy and installation accuracy, while ensuring the integrity of the steel column's base structure.

[0008] Compared to existing technologies, which process curved components according to theoretical drawings and use general-purpose contour molds, this solution uses a specially designed contour template based on the actual measured contour of the steel column on-site. This fundamentally eliminates contour deviations caused by deformation during steel column production, transportation, and installation, enabling precise surface-to-surface contact between the curved fitting surface of the beam and the steel column. This solves the problems of large fitting gaps and misalignment, significantly increasing the effective contact area of ​​the welding surface and avoiding welding defects such as slag inclusions and incomplete penetration caused by uneven gaps. In existing technologies, the gap between the curved fitting surfaces often exceeds 3mm and is unevenly distributed, while this solution achieves uniform fitting gaps and significantly reduces them, resulting in a significant improvement in welding quality and structural connection strength. Compared to existing technologies that lack flexible adjustment mechanisms and can only achieve simple fixed positioning, this solution uses an adjustable ear plate assembly to achieve three-dimensional micro-adjustment of the curved beam's posture. It allows for precise adjustment of the beam's height, horizontal position, and fitting angle, solving the problems of difficult positioning and posture adjustment after the curved beam is hoisted. This solution addresses the inconvenience of fixed adjustment, enabling precise alignment of the curved mating surfaces. The improved installation positioning accuracy compared to existing technologies significantly reduces rework rates caused by positioning deviations. Compared to existing technologies that require additional holes in the steel column and welding of temporary support plates, this solution utilizes the pre-drilled connection holes on the steel column itself to install the adjustable ear plate assembly. This process avoids damage to the steel column base material and anti-corrosion layer, ensuring the mechanical properties and durability of the steel column. Furthermore, the adjustable ear plate assembly is a detachable structure, allowing for complete removal and reuse after welding. This solves the problems of damage to the base material and unusable tooling associated with traditional positioning methods. It also avoids the obstruction of the welding surface by temporary support plates, eliminating welding dead angles and ensuring overall welding quality. This solution combines high-precision prefabrication in the factory with non-destructive rapid on-site positioning, simplifying on-site processing and adjustment procedures. Existing technologies require multiple adjustments and welding repairs for single-column installation of curved crossbeams, resulting in significant time consumption. This solution, due to its high prefabrication accuracy and convenient positioning adjustment, greatly shortens on-site installation time and improves construction efficiency.

[0009] Furthermore, in step (1), the arc-shaped contour template is made based on the on-site three-dimensional laser scanning data of the steel column. The arc contour of the template is concentric and has the same curvature as the actual arc-shaped side of the steel column, so that the arc-shaped fitting surface at the end of the arc beam forms a surface-contact adaptive fit with the steel column. By making the arc-shaped contour template based on the on-site three-dimensional laser scanning data of the steel column, the actual arc contour parameters of the steel column can be accurately captured, allowing the arc contour of the template to achieve a precise match with the actual arc-shaped side of the steel column in terms of concentricity and curvature. The arc-shaped fitting surface at the end of the arc beam processed based on this reference can... It forms a tight, self-adaptive surface contact with the curved side of the steel column, completely eliminating deformation deviations caused by production, transportation, hoisting, and segmented installation of the steel column from the processing source, as well as fitting problems caused by deviations between theoretical design parameters and actual on-site contours. It effectively ensures the fitting accuracy and uniformity of the curved fitting surface, avoiding situations such as excessive local gaps and misalignment, providing a good connection foundation for subsequent on-site welding, significantly increasing the effective contact area of ​​the welding surface, reducing the generation of welding defects, and ensuring the structural strength and stability of the connection between the arc beam and the steel column.

[0010] Furthermore, the end of the arc-shaped crossbeam is machined using a contour template as the sole reference, employing a combination of plasma roughing and abrasive wheel grinding. After machining, a trial assembly is performed. The gap between the arc-shaped mating surface and the side of the steel column is no more than 1mm and is evenly distributed throughout the circumference. Using the contour template as the sole reference for machining the end of the arc-shaped crossbeam fundamentally ensures the uniformity of the machining reference, avoiding machining deviations caused by switching between multiple references. The combination of plasma roughing and abrasive wheel grinding achieves efficient material cutting through plasma roughing and refines the mating surface through abrasive wheel grinding, significantly improving the flatness and smoothness of the arc-shaped mating surface. The inspection and adjustment during the trial assembly phase ultimately achieve the high-precision requirement that the gap between the arc-shaped mating surface and the side of the steel column is no more than 1mm and is evenly distributed throughout the circumference. This processing method allows the beam and the steel column to form a tight surface contact, significantly increasing the effective contact area for welding. It effectively avoids welding defects such as incomplete penetration and slag inclusion caused by uneven gaps or excessively large local gaps. At the same time, the uniform small gap also allows for more uniform weld penetration, improving the weld formation quality and welding strength. This processing phase lays a solid foundation for subsequent precise on-site installation and high-quality welding, reducing the need for adjustments and re-welding procedures on-site due to insufficient mating precision, and improving overall construction efficiency.

[0011] Furthermore, in step 3, the adjustable ear plate assembly includes a connecting base, a drive mechanism, multiple tension rods, an ear plate body, and a sliding adjustable support plate. The connecting base is detachably connected to the connecting hole at the top of the steel column via bolts. The drive mechanism is connected to the ear plate body via tension rods. The ear plate body is adjustable along the height direction of the steel column. The sliding adjustable support plate is slidably engaged with the ear plate body. The adjustable ear plate assembly is configured as a combination structure of the connecting base, drive mechanism, multiple tension rods, ear plate body, and sliding adjustable support plate. The connecting base is detachably connected to the original connecting hole at the top of the steel column via bolts, eliminating the need for additional drilling and welding on the steel column. This effectively protects the steel column base structure and anti-corrosion layer from damage and ensures the mechanical properties of the steel column itself. Meanwhile, the drive mechanism uses a tension rod to move the ear plate body to flexibly adjust the height of the steel column, which can accurately adapt to the installation elevation of the arc beam. Combined with the sliding fit structure of the ear plate body and the sliding adjustable support plate, it can adjust the horizontal position of the beam end. The combination of the two can realize multi-dimensional position adjustment after the arc beam is hoisted, providing a flexible adjustment basis for the subsequent precise docking of the arc-shaped contact surface between the beam and the steel column. Moreover, the overall prefabricated structural design makes the installation and disassembly of the adjustable ear plate assembly convenient. It can be quickly removed after welding and can be reused for the construction of the same type of steel structure, improving the utilization rate of the tooling and reducing construction costs.

[0012] Furthermore, the tension rod consists of three synchronous spiral adjusting rods, evenly arranged around the circumference of the steel column. This arrangement ensures that the ear plate receives a uniform circumferential driving force during lifting and lowering, effectively preventing ear plate misalignment and jamming caused by uneven force distribution from a single or two adjusting rods. This guarantees that the ear plate remains coaxial with the steel column, ensuring the stability and precision of its lifting and lowering adjustment, allowing the ear plate to precisely stop at the desired installation height on the arc-shaped crossbeam. Simultaneously, the three synchronous spiral adjusting rods significantly enhance the overall load-bearing capacity of the tension rod, stably supporting the weight of the arc-shaped crossbeam. This provides a stable support foundation for subsequent fine-tuning and temporary fixing of the crossbeam, preventing ear plate sinking or displacement during adjustment or welding. This structural support ensures the accuracy of the arc-shaped crossbeam's positioning and welding.

[0013] Furthermore, the ear plate body and the sliding adjustable support plate are connected by a slide rail. This sliding rail connection allows for smoother and more stable adjustment of the sliding adjustable support plate, preventing jamming or offset, and ensuring the accuracy of horizontal adjustment. It also allows for fine-tuning of the position of the arc-shaped crossbeam end, ensuring precise alignment between the arc-shaped contact surface of the crossbeam and the arc-shaped side of the steel column. Simultaneously, the slide rail structure ensures the stability of the connection between the sliding adjustable support plate and the ear plate body. During the lifting of the arc-shaped crossbeam and welding processes, there will be no loosening or displacement of the support plate, providing stable support and positioning for the crossbeam. The small clearance of the slide rail structure further improves the adjustment and positioning accuracy. In addition, the slide rail structure is not easily worn, ensuring the reusability of the adjustable ear plate assembly and extending the service life of the tooling.

[0014] Furthermore, the welding in step (4) adopts a step-by-step welding process: first, the upper end and left and right sides of the arc-shaped contact surface between the arc beam and the steel column are welded. After welding, the sliding adjustable support plate is unlocked and retracted. Then, the lower end weld of the contact surface between the beam and the steel column is welded. The step-by-step process of welding the upper end and left and right sides first, retracting the support plate, and then welding the lower end is adopted. This can quickly fix the arc beam and the steel column into a whole by using the three welds welded in the early stage, avoid the beam from shifting or deforming due to external force or welding stress during the subsequent welding process, and ensure the overall welding accuracy. It can also completely avoid the tooling obstruction of the lower welding surface by retracting the sliding adjustable support plate, eliminate welding dead corners, and achieve full circumference welding of the arc-shaped contact surface between the arc beam and the steel column. This effectively avoids defects such as incomplete penetration and insufficient weld leg caused by obstruction of the lower weld in the traditional positioning method. Meanwhile, the welds welded in the early stage can disperse the stress generated by the subsequent welding at the lower end, reduce overall welding deformation, improve the weld formation quality and structural strength of the connection, and the pallet retraction operation is simple, without the need to remove the entire ear plate assembly. While ensuring the integrity of the weld, the operation process is simplified and the efficiency of on-site welding construction is improved.

[0015] Furthermore, the specific steps for using the adjustable ear plate assembly are as follows: (1) Fix the connecting base to the top of the steel column and complete the assembly using the original connecting holes of the steel column; (2) Adjust the tension rod through the drive mechanism to lower the ear plate body to the installation height of the crossbeam, and at the same time extend the sliding adjustable support plate and lock it; (3) Hoist the arc crossbeam to the sliding adjustable support plate, and finely adjust the posture to make the arc-shaped contact surface completely fit; (4) After welding in steps, unlock the sliding adjustable support plate and retract it, drive the mechanism to lift the ear plate body, and finally remove the connecting base. The steps for using the adjustable ear plate assembly are standardized and streamlined. The assembly and fixing are completed entirely by relying on the original connecting holes of the steel column. No additional holes or welding are required. The operation steps are simple and fit the actual construction on site. Construction personnel can carry out the work in an orderly manner according to the steps, which greatly reduces the difficulty of on-site operation and improves the efficiency of positioning and installation. First, assemble the base, then adjust the ear plate body to the designated elevation and lock the support plate. This provides a stable and precise support foundation for the beam hoisting. After hoisting, fine adjustments can be made directly to achieve precise alignment of the curved mating surfaces, reducing the need for repeated adjustments. After step-by-step welding, retract the support plate, lift the ear plate body, and then remove the base. This avoids welding obstruction and prevents collisions and damage to the welded seams during disassembly, ensuring welding quality and structural stability. The entire disassembly and assembly process is convenient and efficient. After completion, the ear plate assembly can be quickly removed and transferred to the next construction site for reuse, improving tooling utilization and accelerating the overall construction progress. This method is suitable for the installation and construction needs of multi-position curved beams in circular tower steel structures.

[0016] Furthermore, the arc-shaped template is made of the same steel as the arc-shaped beam. The template has stable overall rigidity and can be repeatedly used for end-cutting processing of arc-shaped beams of the same batch and specifications. The use of the same steel as the arc-shaped beam ensures that the template and the beam have consistent thermal expansion and contraction characteristics during processing and changes in ambient temperature. This avoids processing benchmark deviations caused by differences in material thermal deformation, ensuring the processing accuracy of the arc-shaped fitting surface at the beam end from a material perspective. At the same time, the template has stable overall rigidity and is not prone to deformation or warping during repeated cutting processes. It can always maintain a precise arc contour benchmark and can be reliably and repeatedly used for end-cutting processing of arc-shaped beams of the same batch and specifications. There is no need to make a separate template for each beam, which greatly reduces the production cost and time of the template, improves the processing efficiency of factory prefabrication, and ensures that the processing accuracy of beams of the same batch is consistent. This lays the foundation for precise docking in subsequent batch installation on site and reduces the adjustment process caused by single-piece processing deviations on site. Attached Figure Description

[0017] Figure 1 This is a flowchart of the steps of the present invention.

[0018] Figure 2 This is a schematic diagram of the installation structure of the present invention.

[0019] The reference numerals in the accompanying drawings include: steel column 1, connecting base 2, telescopic rod 3, drive mechanism 4, adjustable ear plate assembly 5, ear plate body 6, adjustable support plate 7, arc crossbeam 8, anti-slip and wear-resistant pad 9. Detailed Implementation

[0020] Example 1 As attached Figure 1-2 As shown, a method for installing a circular arc-shaped crossbeam in a circular tower steel structure includes the following steps: (1) Factory prefabricated arc beam: Based on the actual measured arc profile of the circular tower steel column, an arc-shaped template that perfectly matches the arc side of the steel column is made. Using the arc-shaped template as a reference, the two ends of the arc beam are cut and processed so that the two ends of the beam form an arc-shaped contact surface that fully fits the arc side of the steel column with uniform gap. (2) Install steel columns in sections and pre-install adjustable positioning devices: hoist and fix multiple steel columns in sections, use the pre-reserved connection holes of the steel columns to detachably install the adjustable ear plate assembly on the top of the steel columns, and pre-adjust the adjustable ear plate assembly to the installation height of the arc crossbeam; (3) Precise positioning of the arc beam: The prefabricated arc beam is hoisted onto the adjustable ear plate assembly. The arc beam is then finely adjusted in three dimensions through the adjustable ear plate assembly so that the arc-shaped contact surface at the end of the beam is precisely fitted with the arc-shaped side of the steel column. After the fit is in place, the adjustment mechanism is locked to achieve temporary fixation. (4) Welding and fixing: Weld the fitted arc beam to the steel column; (5) Device removal: After welding is completed, the adjustable ear plate assembly is removed from the steel column connection hole as a whole, and the arc beam is installed.

[0021] The principle and advantages of this scheme are as follows: The principle of this solution is to first obtain the actual arc contour of the steel column through on-site measurement, and then create a perfectly matching arc-shaped template. Using this template as the sole benchmark, the ends of the arc-shaped beam are cut and processed to eliminate the deviation between the theoretical design of the steel column and the actual on-site contour from the processing source. This ensures that the ends of the beam form an arc-shaped fitting surface that fully fits the arc-shaped side of the steel column with uniform gaps. Then, the adjustable ear plate assembly can be detachably installed using the pre-reserved connection holes on the steel column itself. No additional drilling or welding is required on the steel column. After the arc-shaped beam is hoisted to the desired installation height using the adjustable ear plate assembly, the three-dimensional posture of the beam is finely adjusted to ensure that the arc-shaped fitting surface precisely fits the arc-shaped side of the steel column. After the adjustment mechanism is locked to complete the temporary fixation, welding is performed. After welding, the adjustable ear plate assembly is removed to complete the entire installation process. This achieves dual control over processing accuracy and installation accuracy, while ensuring the integrity of the steel column's base structure.

[0022] Compared to existing technologies, which process curved components according to theoretical drawings and use general-purpose contour molds, this solution uses a specially designed contour template based on the actual measured contour of the steel column on-site. This fundamentally eliminates contour deviations caused by deformation during steel column production, transportation, and installation, enabling precise surface-to-surface contact between the curved fitting surface of the beam and the steel column. This solves the problems of large fitting gaps and misalignment, significantly increasing the effective contact area of ​​the welding surface and avoiding welding defects such as slag inclusions and incomplete penetration caused by uneven gaps. In existing technologies, the gap between the curved fitting surfaces often exceeds 3mm and is unevenly distributed, while this solution achieves uniform fitting gaps and significantly reduces them, resulting in a significant improvement in welding quality and structural connection strength. Compared to existing technologies that lack flexible adjustment mechanisms and can only achieve simple fixed positioning, this solution uses an adjustable ear plate assembly to achieve three-dimensional micro-adjustment of the curved beam's posture. It allows for precise adjustment of the beam's height, horizontal position, and fitting angle, solving the problems of difficult positioning and posture adjustment after the curved beam is hoisted. This solution addresses the inconvenience of fixed adjustment, enabling precise alignment of the curved mating surfaces. The improved installation positioning accuracy compared to existing technologies significantly reduces rework rates caused by positioning deviations. Compared to existing technologies that require additional holes in the steel column and welding of temporary support plates, this solution utilizes the pre-drilled connection holes on the steel column itself to install the adjustable ear plate assembly. This process avoids damage to the steel column base material and anti-corrosion layer, ensuring the mechanical properties and durability of the steel column. Furthermore, the adjustable ear plate assembly is a detachable structure, allowing for complete removal and reuse after welding. This solves the problems of damage to the base material and unusable tooling associated with traditional positioning methods. It also avoids the obstruction of the welding surface by temporary support plates, eliminating welding dead angles and ensuring overall welding quality. This solution combines high-precision prefabrication in the factory with non-destructive rapid on-site positioning, simplifying on-site processing and adjustment procedures. Existing technologies require multiple adjustments and welding repairs for single-column installation of curved crossbeams, resulting in significant time consumption. This solution, due to its high prefabrication accuracy and convenient positioning adjustment, greatly shortens on-site installation time and improves construction efficiency.

[0023] In step (1), the arc-shaped contour template is made based on the on-site three-dimensional laser scanning data of the steel column. The arc contour of the template is concentric and has the same curvature as the actual arc-shaped side of the steel column, so that the arc-shaped contact surface at the end of the arc beam forms a surface-contact adaptive fit with the steel column. The arc-shaped contour template is made based on the on-site three-dimensional laser scanning data of the steel column, which can accurately capture the actual arc contour parameters of the steel column on-site, so that the arc contour of the template and the actual arc-shaped side of the steel column achieve a precise match of concentricity and curvature. The arc-shaped contact surface at the end of the arc beam processed based on this can fit with the steel column. The curved side of the column forms a tight, self-adaptive surface contact, completely eliminating deformation deviations caused by production, transportation, hoisting, and segmented installation of the steel column from the processing source, as well as fitting problems caused by deviations between theoretical design parameters and actual on-site contours. This effectively ensures the fitting accuracy and uniformity of the curved surface, avoiding excessive local gaps and misalignments, providing a good connection foundation for subsequent on-site welding, significantly increasing the effective contact area of ​​the welding surface, reducing welding defects, and ensuring the structural strength and stability of the connection between the curved beam and the steel column.

[0024] The end of the arc-shaped crossbeam is machined using a contour template as the sole reference, employing a combination of plasma roughing and abrasive wheel grinding. After machining, a trial assembly is performed. The gap between the arc-shaped mating surface and the side of the steel column is no more than 1mm and is evenly distributed throughout the circumference. Using the contour template as the sole reference for machining the end of the arc-shaped crossbeam fundamentally ensures the uniformity of the machining reference, avoiding machining deviations caused by switching between multiple references. The combination of plasma roughing and abrasive wheel grinding not only achieves efficient material cutting through plasma roughing but also refines the mating surface through abrasive wheel grinding, significantly improving the flatness and smoothness of the arc-shaped mating surface. After trial assembly... The inspection and adjustment of the fitting process ultimately achieves the high-precision requirement that the gap between the arc-shaped fitting surface and the side of the steel column is no more than 1mm and is evenly distributed throughout the circumference. This processing method allows the beam and the steel column to form a tight surface contact, greatly increasing the effective contact area for welding. It effectively avoids welding defects such as incomplete penetration and slag inclusion caused by uneven gaps or excessive local gaps. At the same time, the uniform small gap also allows for more uniform weld penetration, improving the weld formation quality and welding strength. This processing process lays a solid foundation for subsequent precise on-site installation and high-quality welding, reducing the need for adjustments and repair welding on-site due to insufficient fitting precision, and improving overall construction efficiency.

[0025] In step 3, the adjustable ear plate assembly includes a connecting base, a drive mechanism, multiple tension rods, an ear plate body, and a sliding adjustable support plate. The connecting base is detachably connected to the connecting hole at the top of the steel column by bolts. The drive mechanism is connected to the ear plate body by tension rods. The ear plate body is adjustable along the height direction of the steel column. The sliding adjustable support plate is slidably engaged with the ear plate body. The adjustable ear plate assembly is configured as a combination structure of the connecting base, drive mechanism, multiple tension rods, ear plate body, and sliding adjustable support plate. The connecting base is detachably connected to the original connecting hole at the top of the steel column by bolts, eliminating the need for additional drilling and welding on the steel column. This effectively protects the steel column base structure and anti-corrosion layer from damage and ensures the mechanical properties of the steel column itself. Meanwhile, the drive mechanism uses a tension rod to move the ear plate body to flexibly adjust the height of the steel column, which can accurately adapt to the installation elevation of the arc beam. Combined with the sliding fit structure of the ear plate body and the sliding adjustable support plate, it can adjust the horizontal position of the beam end. The combination of the two can realize multi-dimensional position adjustment after the arc beam is hoisted, providing a flexible adjustment basis for the subsequent precise docking of the arc-shaped contact surface between the beam and the steel column. Moreover, the overall prefabricated structural design makes the installation and disassembly of the adjustable ear plate assembly convenient. It can be quickly removed after welding and can be reused for the construction of the same type of steel structure, improving the utilization rate of the tooling and reducing construction costs.

[0026] The tension rod consists of three synchronous spiral adjusting rods, evenly arranged around the circumference of the steel column. This arrangement ensures the ear plate receives a uniform circumferential driving force during lifting and lowering, effectively preventing ear plate misalignment and jamming caused by uneven force distribution from a single or two adjusting rods. This guarantees the ear plate remains coaxial with the steel column, ensuring smooth and precise lifting and lowering, allowing the ear plate to accurately stop at the desired installation height on the arc-shaped crossbeam. Furthermore, the three synchronous spiral adjusting rods significantly enhance the overall load-bearing capacity of the tension rod, stably supporting the weight of the arc-shaped crossbeam. This provides a stable foundation for subsequent fine-tuning and temporary fixing of the crossbeam, preventing ear plate sinking or displacement during adjustment or welding. This structural support ensures the accuracy of the arc-shaped crossbeam's positioning and welding.

[0027] The ear plate body and the sliding adjustable support plate are connected by a slide rail, which allows for smoother and more stable adjustment and movement of the sliding adjustable support plate, avoiding jamming or offset, and ensuring the accuracy of horizontal adjustment. It also allows for fine-tuning of the position of the arc-shaped crossbeam end, ensuring precise alignment of the crossbeam's curved contact surface with the curved side of the steel column. Simultaneously, the slide rail structure ensures the stability of the connection between the sliding adjustable support plate and the ear plate body, preventing the support plate from loosening or shifting during the lifting of the arc-shaped crossbeam and welding processes. This provides stable support and positioning for the crossbeam. Furthermore, the small clearance of the slide rail structure further improves the adjustment and positioning accuracy. In addition, the slide rail structure is not easily worn, ensuring the reusability of the adjustable ear plate assembly and extending the service life of the tooling.

[0028] The welding in step (4) adopts a step-by-step welding process: first, weld the upper end and left and right sides of the arc-shaped contact surface between the arc beam and the steel column, then unlock and retract the sliding adjustable support plate after welding, and then weld the lower end weld of the contact surface between the beam and the steel column. The step-by-step process of welding the upper end and left and right sides first, retracting the support plate and then welding the lower end is adopted. This can quickly fix the arc beam and the steel column into a whole by using the three welds welded in the early stage, avoid the beam from shifting or deforming due to external force or welding stress during the subsequent welding process, and ensure the overall welding accuracy. It can also completely avoid the tooling obstruction of the lower welding surface by retracting the sliding adjustable support plate, eliminate welding dead corners, and achieve full circumference welding of the arc-shaped contact surface between the arc beam and the steel column. This effectively avoids defects such as incomplete penetration and insufficient weld leg caused by obstruction of the lower weld in the traditional positioning method. Meanwhile, the welds welded in the early stage can disperse the stress generated by the subsequent welding at the lower end, reduce overall welding deformation, improve the weld formation quality and structural strength of the connection, and the pallet retraction operation is simple, without the need to remove the entire ear plate assembly. While ensuring the integrity of the weld, the operation process is simplified and the efficiency of on-site welding construction is improved.

[0029] The specific steps for using the adjustable ear plate assembly are as follows: (1) Fix the connecting base to the top of the steel column and complete the assembly using the original connecting holes of the steel column; (2) Adjust the tension rod through the drive mechanism to lower the ear plate body to the installation height of the crossbeam, and extend and lock the sliding adjustable support plate at the same time; (3) Hoist the arc crossbeam to the sliding adjustable support plate, and finely adjust the posture to make the arc-shaped contact surface completely fit; (4) After welding in steps, unlock the sliding adjustable support plate and retract it, drive the mechanism to lift the ear plate body, and finally remove the connecting base. The steps for using the adjustable ear plate assembly are standardized and streamlined. The assembly and fixing are completed entirely by relying on the original connecting holes of the steel column. No additional holes or welding are required. The operation steps are simple and fit the actual construction on site. Construction personnel can carry out the work in an orderly manner according to the steps, which greatly reduces the difficulty of on-site operation and improves the efficiency of positioning and installation. First, assemble the base, then adjust the ear plate body to the designated elevation and lock the support plate. This provides a stable and precise support foundation for the beam hoisting. After hoisting, fine adjustments can be made directly to achieve precise alignment of the curved mating surfaces, reducing the need for repeated adjustments. After step-by-step welding, retract the support plate, lift the ear plate body, and then remove the base. This avoids welding obstruction and prevents collisions and damage to the welded seams during disassembly, ensuring welding quality and structural stability. The entire disassembly and assembly process is convenient and efficient. After completion, the ear plate assembly can be quickly removed and transferred to the next construction site for reuse, improving tooling utilization and accelerating the overall construction progress. This method is suitable for the installation and construction needs of multi-position curved beams in circular tower steel structures.

[0030] The arc-shaped template is made of the same steel as the arc-shaped beam. The template has stable overall rigidity and can be repeatedly used for end-cutting of arc-shaped beams of the same batch and specifications. The use of the same steel as the arc-shaped beam ensures that the template and beam have consistent thermal expansion and contraction characteristics during processing and environmental temperature changes, avoiding processing benchmark deviations caused by differences in material thermal deformation. This guarantees the processing accuracy of the arc-shaped fitting surface at the beam end from a material perspective. Simultaneously, the template's overall rigidity is stable, making it less prone to deformation and warping during repeated cutting processes, maintaining a precise arc contour benchmark. It can be reliably and repeatedly used for end-cutting of arc-shaped beams of the same batch and specifications, eliminating the need to make a separate template for each beam. This significantly reduces template manufacturing costs and time, improves factory prefabrication efficiency, and ensures consistent processing accuracy for beams in the same batch. This lays the foundation for precise docking during subsequent batch installation on-site, reducing adjustment procedures caused by individual piece processing deviations.

[0031] In actual use.

[0032] A method for installing arc-shaped crossbeams in circular tower steel structures is disclosed. This method is suitable for the installation of arc-shaped crossbeams in circular tower steel structures such as tower cylinders, observation towers, and industrial silos. The arc-shaped crossbeam 8 is made of Q355B steel, with a single crossbeam weighing 1.2t. The steel column 1 is a circular cross-section steel column with a diameter of 1.5m. The on-site construction environment is open-air, and the construction elevation ranges from 0 to 30m. The specific construction steps are as follows: First, a 3D laser scanner was used to perform a full contour scan of the steel column 1, which had already been positioned on site, to obtain 3D point cloud data of the actual arc-shaped contour of the steel column 1. The point cloud data was imported into modeling software for processing to generate an arc contour model that is concentric with and has the same curvature as the arc side of the steel column 1. Based on this model, an arc-shaped contour template was made. The arc-shaped contour template was made of the same Q355B steel as the arc-shaped crossbeam 8, using an integral welding process. After aging treatment to eliminate welding stress, the template's rigidity and stability were ensured. The arc surface of the template was precision milled to a surface roughness Ra≤1.6μm. Using the completed arc-shaped contour template as the sole processing reference, the two ends of the arc-shaped crossbeam 8 were fitted and processed. First, a plasma cutter was used for rough cutting with a rough cutting allowance of 0.5mm, and then a grinding wheel was used for fine grinding until the arc-shaped fitting surface of the crossbeam end was completely fitted with the arc surface of the contour template. After processing, the arc-shaped crossbeam 8 and the steel column 1 are trial-assembled to check the fitting gap of the arc-shaped mating surface. The gap is guaranteed to be no more than 1mm and evenly distributed around the circumference. After the trial assembly is qualified, the ends of the crossbeam are subjected to anti-corrosion pretreatment to complete the factory prefabrication of the arc-shaped crossbeam 8.

[0033] The steel column 1 was lifted in sections using a truck crane. Each section of the steel column 1 was 6m long. During the lifting process, a total station was used to check the verticality, and the verticality deviation was controlled within 1 / 1000. After the check was completed, the sections of the steel column 1 were connected and fixed using flanges to complete the overall installation of the steel column 1. Utilizing the pre-drilled connection holes at the top of the steel column 1, an adjustable lug assembly 5 was installed. This assembly includes a connecting base 2, a drive mechanism 4, three tension rods 3, a lug body 6, and a sliding adjustable support plate 7. The connecting base 2 is a flange structure and can be detachably fixed to the connection holes at the top of the steel column 1 using bolts. The drive mechanism 4 is a worm gear type lifting drive mechanism. The three tension rods 3 are synchronous spiral adjustment rods, evenly arranged around the circumference of the steel column 1 at 120°. One end of the tension rod 3 is connected to the output end of the drive mechanism 4, and the other end is hinged to the lug body 6. The lug body 6 and the sliding adjustable support plate 7 are connected by a sliding rail with a dovetail-type rail and a clearance ≤0.1mm. Start the drive mechanism 4, adjust the three synchronous screw adjustment rods to raise and lower synchronously, and precisely adjust the ear plate body 6 to the installation height of the arc crossbeam 8. The installation elevation deviation is controlled within ±2mm. Then, extend the sliding adjustable support plate 7 outward along the slide rail to the preset position, and temporarily lock the sliding adjustable support plate 7 with the locking bolt to complete the pre-installation positioning of the adjustable ear plate assembly 5.

[0034] A truck crane is used to hoist the prefabricated arc-shaped crossbeam 8 onto the adjustable ear plate assembly 5 between the steel columns 1, so that both ends of the arc-shaped crossbeam 8 are supported on the bearing surface of the sliding adjustable support plate 7. During the hoisting process, a hand-operated hoist is used to adjust the posture of the crossbeam to prevent the crossbeam from colliding with the steel columns 1 and the adjustable ear plate assembly 5. The height of the crossbeam is adjusted by finely adjusting the lifting amount of the tension rod 3 through the drive mechanism 4. During the fine-tuning process, a feeler gauge is used to detect the contact gap between the arc-shaped contact surface at the end of the crossbeam and the arc-shaped side of the steel column 1 in real time until the contact gap is uniform and ≤1mm throughout the entire circumference of the contact surface. After precise contact, the locking bolts of the sliding adjustable support plate 7 and the self-locking mechanism of the drive mechanism 4 are locked in sequence to lock the entire adjustment mechanism, thereby temporarily fixing the arc-shaped crossbeam 8. After positioning, the axial deviation of the crossbeam is controlled within ±3mm.

[0035] The circular arc beam 8 and the steel column 1 are welded together using a step-by-step welding process. The welding method is gas shielded welding, the welding wire is ER50-6, the welding current is 220-250A, and the voltage is 28-32V. The first step involves welding the upper end and both sides of the arc-shaped mating surface between the arc-shaped crossbeam 8 and the steel column 1. All three welds utilize a segmented skip welding process, with each segment measuring 100-150mm in length and 8mm in weld leg height to prevent stress concentration and beam deformation. After the first weld is completed and cooled to room temperature, the weld formation quality is inspected. Once defects such as slag inclusions, incomplete penetration, and porosity are ruled out, the locking bolts of the sliding adjustable support plate 7 are unlocked, and the plate is retracted inwards along the slide rail to completely avoid the lower welding area of ​​the mating surface between the crossbeam and the steel column 1, eliminating welding dead angles. The second step involves welding the lower weld of the mating surface between the crossbeam and the steel column 1, also using a segmented skip welding process. The weld leg height is consistent with the upper end and both sides. After completing the lower weld, a full-circumference filler weld is performed on the arc-shaped mating surface to ensure weld continuity and good formation. After welding, the weld undergoes non-destructive testing (UT) at level II to ensure welding quality.

[0036] After the weld has completely cooled and passed non-destructive testing, the adjustable ear plate assembly 5 is dismantled: First, the drive mechanism 4 is activated to control the three tension rods 3 to lift synchronously, raising the ear plate body 6 by 50mm, so that the ear plate body 6 is completely separated from the arc beam 8; then, the connection structure between the sliding adjustable support plate 7 and the ear plate body 6 is removed, and the support plate is removed separately; finally, the high-strength bolts connecting the base 2 and the steel column 1 are unscrewed, and the connecting base 2, drive mechanism 4, tension rods 3, and ear plate body 6 are dismantled as a whole. During the dismantling process, rope traction is used to prevent the parts from falling. After the adjustable ear plate assembly 5 is dismantled, it is cleaned and maintained, and can be transferred to the next construction site for reuse. The connection hole at the top of the steel column 1 is sealed with a special plug, completing the entire installation process of the single arc beam 8.

[0037] Example 2 The core difference between this embodiment and Embodiment 1 lies in the specifications of the arc-shaped crossbeam 8 and the driving form of the adjustable ear plate assembly 5. The remaining construction steps and process parameters are the same as in Embodiment 1. The specific applicable scenarios and adjustments are as follows: This embodiment is suitable for large-span circular tower steel structures. The arc-shaped crossbeam 8 is made of Q420 steel, with a single crossbeam weighing 3.5t. The steel column 1 has a cross-sectional diameter of 2.2m. To improve the load-bearing capacity and adjustment accuracy of the adjustable ear plate assembly 5, the driving mechanism 4 is replaced with an electric hydraulic lifting driving mechanism. The tension rod 3 is a hydraulic telescopic synchronous adjusting rod. The three hydraulic telescopic adjusting rods are supplied with oil by the same hydraulic pump station to achieve synchronous lifting and lowering, improving the adjustment accuracy to ±0.5mm. The support surface of the sliding adjustable support plate 7 is equipped with an anti-slip and wear-resistant pad 9 to prevent the crossbeam from slipping during hoisting and welding. The anti-slip and wear-resistant pad 9 is made of polyurethane material with a thickness of 20mm. During construction, the circular arc beam 8 was hoisted using a crawler crane. During three-dimensional posture fine-tuning, the extension and retraction of the adjusting rod was controlled by the precision pressure regulating valve of the hydraulic pump station to achieve more precise posture adjustment. During welding, the weld leg height was adjusted to 12mm, and the non-destructive testing level of the weld was upgraded to Level I. The remaining processing, installation, and welding processes all followed the requirements of Example 1, ultimately achieving a high-precision fit between the large-span circular arc beam 8 and the steel column 1. The installation quality met the requirements of the "Standard for Acceptance of Construction Quality of Steel Structures" (GB50205-2020).

[0038] Example 3 This embodiment is an on-site emergency construction adaptation solution, applicable to scenarios where steel column 1 has slight local deformation on-site and it is impossible to achieve precise fitting of the arc-shaped mating surface in one go. Based on embodiment 1, the factory prefabrication and on-site fine-tuning steps are partially optimized, while the remaining steps remain unchanged. The specific optimizations are as follows: During the factory prefabrication stage, when making the arc-shaped template, a machining allowance of 0.3-0.5mm is reserved. After the end of the crossbeam is rough-cut, it is not directly fine-ground. Instead, the crossbeam is transported to the site and adapted to the steel column 1 on site. Based on the actual situation of the local deformation of the steel column 1, a handheld grinder is used for on-site fine grinding to achieve adaptive fitting of the arc-shaped mating surface and avoid fitting deviation caused by the deformation of the steel column during factory processing.

[0039] During the on-site fine-tuning stage, fine-tuning screws are added to the sliding adjustable support plate 7 of the adjustable ear plate assembly 5. The screws are arranged along the circumference of the crossbeam, with 3 screws arranged on each side support plate. When there is a local gap at the end of the crossbeam, the end of the crossbeam is locally pushed by turning the fine-tuning screws to achieve precise elimination of the gap and ensure that the gap of the mating surface is ≤1mm throughout the circumference.

[0040] This embodiment combines factory prefabrication with on-site precision grinding to adapt to the complex working conditions of on-site deformation of the steel column 1. At the same time, it uses fine-tuning screws to achieve precise adjustment of local gaps, further improving the adaptability of the installation process and ensuring the installation accuracy of the arc beam 8.

Claims

1. A method for installing a circular arc-shaped crossbeam in a circular tower steel structure, characterized in that, Includes the following steps: (1) Factory prefabricated arc beam: Based on the actual measured arc profile of the circular tower steel column, an arc-shaped template that perfectly matches the arc side of the steel column is made. Using the arc-shaped template as a reference, the two ends of the arc beam are cut and processed so that the two ends of the beam form an arc-shaped contact surface that fully fits the arc side of the steel column with uniform gap. (2) Install steel columns in sections and pre-install adjustable positioning devices: hoist and fix multiple steel columns in sections, use the pre-reserved connection holes of the steel columns to detachably install the adjustable ear plate assembly on the top of the steel columns, and pre-adjust the adjustable ear plate assembly to the installation height of the arc crossbeam; (3) Precise positioning of the arc beam: The prefabricated arc beam is hoisted onto the adjustable ear plate assembly. The arc beam is then finely adjusted in three dimensions through the adjustable ear plate assembly so that the arc-shaped contact surface at the end of the beam is precisely fitted with the arc-shaped side of the steel column. After the fit is in place, the adjustment mechanism is locked to achieve temporary fixation. (4) Welding and fixing: Weld the fitted arc beam to the steel column; (5) Device removal: After welding is completed, the adjustable ear plate assembly is removed from the steel column connection hole as a whole, and the arc beam is installed.

2. The method for installing the arc-shaped crossbeam in a circular tower steel structure according to claim 1, characterized in that, In step (1), the arc-shaped template is made based on the on-site three-dimensional laser scanning data of the steel column. The arc contour of the template is concentric and has the same curvature as the actual arc side of the steel column, so that the arc-shaped fitting surface at the end of the arc beam forms a surface contact adaptive fitting with the steel column.

3. The method for installing the arc-shaped crossbeam in a circular tower steel structure according to claim 2, characterized in that, The end of the arc-shaped crossbeam is processed using a combination of plasma rough cutting and grinding wheel fine grinding, with the conforming template as the sole reference. After processing, a trial assembly is performed, and the gap between the arc-shaped mating surface and the side of the steel column is no more than 1mm and is evenly distributed around the circumference.

4. The method for installing the arc-shaped crossbeam in a circular tower steel structure according to claim 1, characterized in that, In step 3, the adjustable ear plate assembly includes a connecting base, a driving mechanism, multiple tension rods, an ear plate body, and a sliding adjustable support plate. The connecting base is detachably connected to the connecting hole at the top of the steel column by bolts. The driving mechanism is connected to the ear plate body by tension rods. The ear plate body is adjustable along the height direction of the steel column. The sliding adjustable support plate is slidably engaged with the ear plate body.

5. The method for installing the arc-shaped crossbeam in a circular tower steel structure according to claim 4, characterized in that, The tension rod consists of three synchronous spiral adjusting rods, which are evenly arranged around the circumference of the steel column.

6. The method for installing the arc-shaped crossbeam in a circular tower steel structure according to claim 4, characterized in that, The ear plate body and the sliding adjustable support plate are connected by a slide rail.

7. The method for installing the arc-shaped crossbeam in a circular tower steel structure according to claim 1, characterized in that, The welding in step (4) adopts a step-by-step welding process: first, weld the upper end and left and right sides of the arc-shaped contact surface between the arc beam and the steel column, then unlock and retract the sliding adjustable support plate after welding, and then weld the lower end weld of the contact surface between the beam and the steel column to achieve full circumference welding without interfering with the positioning device.

8. The method for installing the arc-shaped crossbeam in a circular tower steel structure according to claim 4, characterized in that, The specific steps for using the adjustable ear plate assembly are as follows: (1) Fix the connecting base to the top of the steel column and complete the assembly using the original connecting holes of the steel column; (2) Adjust the tension rod through the drive mechanism to lower the ear plate body to the installation height of the crossbeam, and at the same time extend the sliding adjustable support plate and lock it; (3) Hoist the arc crossbeam to the sliding adjustable support plate, and finely adjust the posture to make the arc-shaped contact surface completely fit; (4) After welding in steps, unlock the sliding adjustable support plate and retract it, drive the mechanism to lift the ear plate body, and finally remove the connecting base.

9. The construction method according to claim 1, characterized in that, The arc-shaped template is made of the same steel as the arc-shaped beam. The template has stable overall rigidity and can be repeatedly used for end-cutting processing of arc-shaped beams of the same batch and specifications.

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