High-precision bolted steel tower end face size control method

Abstract

The present application relates to a kind of high-precision bolted steel tower end face size control method, which can be used for the end face size control of bolted steel tower, effectively improve assembly precision and assembly efficiency, ensure that the deviation value of steel tower box mouth mismatching platform meets ≤1mm, and the axial perpendicularity is 1 / 10000, and save construction period cost and repair cost, the assembly precision of tower section is controlled in the process of steel tower manufacturing, by installing fixed size constraint tooling when tower column block assembly and section assembly, relative fixation is carried out to tower column circumference wallboard and intermediate web to form monomer internal constraint control, by monomer internal constraint control constraint, welding deformation is reduced, so as to realize the size precision control of control box mouth.

Description

Technical Field

[0001] This invention relates to a high-precision bolted steel tower end face dimension control method that can be used for end face dimension control of bolted steel towers, effectively improve assembly accuracy and efficiency, ensure that the misalignment of the steel tower box opening meets the deviation requirement of ≤1mm and the verticality of the axis is 1 / 10000, and save on construction period and rework costs. Background Technology

[0002] The existing steel tower is a bolted steel tower with 1m radius arcs at the four corners and a closed annular structure across the entire cross-section. The misalignment of the tower's full-section wall panels must be ≤1mm, and the verticality of the axis must be within 1 / 10000, requiring extremely high precision. During segment assembly and welding, due to the closed-loop design of the tower's end faces, the use of ultra-thick plates, welding shrinkage, and the tower's structural form, the internal residual stress is greater than that of traditional steel tower lap welds. This makes controlling welding deformation difficult, resulting in misalignment of the segment cross-sectional dimensions and between segments due to welding deformation. Summary of the Invention

[0003] Design objective: To overcome the shortcomings of the prior art, this paper proposes a high-precision method for controlling the end face dimensions of bolted steel towers. This method can be used to control the end face dimensions of bolted steel towers, effectively improve assembly accuracy and efficiency, ensure that the misalignment of the steel tower box opening meets the deviation requirement of ≤1mm and the verticality of the axis is 1 / 10000, and save on construction time and rework costs.

[0004] Design Scheme: To address the assembly accuracy issue of closed-loop ultra-thick plate steel towers, this invention proposes a "control method combining internal constraints within individual units and matching constraints between adjacent units," which has been successfully applied in existing steel tower projects. Practice has proven that this method has good control effects on the assembly of high-precision components. Currently, the dimensions of the bolted tower column openings can all meet the allowable deviation of ≤2mm. The misalignment of the openings, the tower column axis, and the pre-assembly effect have all been well verified. This control method has high application and promotion value and can be widely used in similar structural products.

[0005] The steel tower product upon which this invention is based is a four-corner rounded closed-end ultra-thick plate bolted steel tower segment. The structural form of this steel tower segment is described below. Figure 4 , Figure 5 , Figure 6 and Figure 7 The diagram shows: 1. Wall panel; 2. Corner wall panel; 3. Side wall panel; 4. Bulkhead; 5. Web panel; 6. Intermediate bulkhead; 7. Side bulkhead; 8. Vertical stiffener; 9. Corner wall panel joint; 10. Anchor box.

[0006] The difficulties in processing the steel tower structure described in this invention are as follows: (1) This structure is a bolted steel tower with a four-corner rounded arc cross section of an ultra-thick plate, which is the first time it has been used in this field. The bolted steel tower transmits force between the upper and lower tower columns by metal contact. The end face machining requires the flatness of the entire cross section to be within 0.25mm, the misalignment of the entire cross section wall panel to be ≤2mm, and the verticality of the axis to be within 1 / 10000. The precision requirements are extremely high. (2) Compared with the previous steel tower, the outer wall panel is a four-corner rounded arc cross section. The rounded wall panel and the straight section wall panel are welded into an integral closed frame structure by a full penetration butt weld and the maximum plate thickness is 78mm. The forming control of the rounded wall panel unit and the segment welding are difficult. After the segment welding, due to the welding shrinkage and its own structural form, the internal residual stress is greater than the stress of the lap weld of the traditional steel tower. The welding deformation control is difficult, which makes the cross-sectional dimensions of the segment and the segment misalignment due to the welding deformation. (3) In particular, the residual internal stress of bending at the four corner arcs overlaps with the stress after welding the butt weld, making it extremely difficult to control the cross-sectional dimensions and the misalignment between segments.

[0007] To address the aforementioned difficulties in fabricating steel tower structures, the key innovative method of this invention is as follows: the steel tower is manufactured using a process of plate unit → block → segment. Due to the high precision requirements for misalignment and axial perpendicularity, the fabrication precision requirements for tower segment blocks and individual segments are also extremely high, with allowable deviations as follows: Figure 5-6 As shown, the cross-sectional dimensions of the block after welding are ±1.0mm and the diagonal deviation is ≤3.0mm; the cross-sectional dimensions of the segment after welding are ±2.0mm and the diagonal deviation is ≤3.0mm.

[0008] To overcome the challenges of factory manufacturing of this type of steel tower and ensure manufacturing precision and processing quality, this invention systematically developed a control method that combines internal constraints within a single unit with matching constraints between adjacent units, thereby achieving high-precision manufacturing and precision control of bolted steel tower segments.

[0009] Compared with the prior art, this invention has two main advantages: First, it is the first to propose a "control method combining intra-unit constraints and matching constraints between adjacent individuals," which has been successfully applied in steel tower projects (the cross-sectional dimensions of the steel tower are approximately 6.5m*7m, and the height is 3-7.6m). Practice has proven that this method has a good control effect on the assembly of high-precision components. Currently, the dimensions of the bolted tower column box openings of the steel tower can meet the allowable deviation of ≤2mm. The misalignment of the box openings, the tower column axis, and the pre-assembly effect have all been well verified. Second, this control method has high application and promotion value and can be widely used in similar structural products. Attached Figure Description

[0010] Figure 1 This is an elevation view of a steel tower segment.

[0011] Figure 2 This is a schematic diagram of the cross-section of a steel tower segment. Figure 1 .

[0012] Figure 3 This is a schematic diagram of the cross-section of a steel tower segment. Figure 2 .

[0013] Figure 4 This is a three-dimensional schematic diagram of a steel tower segment.

[0014] Figure 5 This is a diagram showing the allowable deviations after welding of the blocks.

[0015] Figure 6 This is a diagram showing the allowable deviations after segmental welding.

[0016] Figure 7 This is a schematic diagram of a fixed constraint support device.

[0017] Figure 8 This is a schematic diagram of self-constrained installation within a block.

[0018] Figure 9 This is a schematic diagram of self-constraining installation within a segment.

[0019] Figure 10 This is a schematic diagram of the fabrication of continuous matching constraint control for multiple blocks.

[0020] Figure 11 This is a schematic diagram of the process splicing panel installation. Implementation

[0021] Example 1: Refer to Appendix Figure 1-11 (1) Internal constraint of a single unit: Internal constraint control of a single unit is to control the assembly accuracy of the tower section during the steel tower manufacturing process. By installing fixed size constraint fixtures during the assembly of tower block and segment, the surrounding wall plate and the middle web plate of the tower column are relatively fixed. Through constraint, welding deformation is reduced, thereby achieving control of the box opening size accuracy.

[0022] ① Fixed Constraint Structure: The fixed constraint is designed as a movable support structure, consisting of upper and lower parts for easy assembly and disassembly during use. The fixed constraint is designed to standard dimensions, consistent with the dimensions of the constrained space, and is connected with high-strength bolts and secured with punch pins to achieve dimensional control of the fixed constraint tooling. The fixed constraint support structure is as follows: Figure 5 As shown.

[0023] ② Implementation of Internal Constraint Control for Individual Units: a. Block Assembly Constraints: The blocks are assembled and positioned according to the assembly process, including corner wall panel units, web plate units, and partition plate units. After the dimensions of the box openings at both ends are inspected and found to be qualified, the longitudinal and transverse constraint fixtures are installed near the box openings to ensure that the connecting flanges do not affect the subsequent machining of the steel tower. After the constraints are fixed, the dimensions of the steel tower block box openings are re-measured, including longitudinal and transverse dimensions and diagonal dimensions. Welding is performed after the dimensions are qualified. After the assembly welding is completed, the constraints are released once to release the internal stress. After adjusting the misalignment between the blocks, the blocks are bolted a second time to ensure the overall rigidity of the segment assembly dimensions and subsequent machining. b. Segment Assembly Constraints: During segment assembly, the lower block, the intermediate anchor box structure, and the upper block are positioned in sequence, and then the side wall panels are installed to complete the segment assembly. The structural dimensions of the upper and lower blocks have been well controlled during block assembly. Therefore, the key control during segment assembly is the spacing of the web plates between the upper and lower blocks and the lateral relative position of the upper and lower blocks. During segment assembly, the lower block is positioned first, and then the anchor box is positioned. The weight of the upper block is mainly borne by the anchor box. After the upper and lower blocks and anchor boxes are accurately positioned, the web plates of the upper and lower blocks are bolted together using fixed constraint fixtures, forming a common steel structure. This increases the overall rigidity and provides fixed constraints on the relatively weak plates at the box opening. After welding each segment's welds, the dimensions are adjusted to the correct position, the constraints are released to relieve welding stress, and the constraints are reset, fixing the box opening dimensions in a frame-like manner. Because the total height of the fixed supports is consistent, they serve as an inner core for block and segment assembly, providing a basis for component fabrication and offering double assurance in dimensional inspection and control compared to tool measurement. Fixed supports of the same dimensions are reused during block and segment fabrication, effectively ensuring the box opening dimensions of each block and segment, improving assembly accuracy and efficiency. See the schematic diagram of the fixed support installation. Figure 8-9 As shown.

[0024] The self-constraint method for the fabrication of blocks and segments described above clarifies that the welding of the main weld seams inside the blocks (segments) is completed under a self-constraint state. However, it is not only a self-constraint state, but also has matching constraints from adjacent individuals that cooperate with it. The welding of the main weld seams of the blocks and segments is completed under the combined implementation of both.

[0025] (2) Control method for mutual verification of matching constraints between adjacent individuals: In order to ensure the assembly accuracy of bolted steel tower segments and ensure that the misalignment between the plates of the box opening and the tower column axis meet the design requirements during the installation of adjacent segments, in addition to the single-unit constraint control method, a mutual constraint method for simultaneous matching and fabrication of multiple adjacent blocks and segments is also formulated during the assembly of blocks and segments. During the process, while ensuring the tower column axis, the use of matching parts ensures that the longitudinal and transverse alignment of the box openings of blocks and segments is guaranteed, reducing misalignment, thereby effectively ensuring the matching accuracy of the box openings between adjacent segments.

[0026] Implementation of the Adjacent Individual Matching Constraint Method: a. The multi-block, multi-segment matching constraint method involves simultaneously fabricating at least three adjacent blocks or adjacent tower segments on the same side. It also requires that the already fabricated block (segment) adjacent to the first block (segment) be used as the parent block in the fabrication process. Each step of the fabrication process can refer to the dimensions of the parent block's opening, with adjacent blocks (segments) mutually verifying each other, completing mutual verification and correction throughout the assembly process. b. Multi-block (segment) matching constraints are achieved through auxiliary connections between individuals using matching components. On one hand, the sufficiently small spacing between the two sets of holes in the matching components (approximately 40mm) serves as an auxiliary connection while also controlling plate thickness misalignment; on the other hand, the connection of the matching components achieves rigid constraints between adjacent tower segments, thus playing a mutually restrictive role. c. The main internal welds of the blocks (segments) are completed under the combined effect of self-constraint within the individual unit and adjacent matching constraints.

[0027] In summary, the single-unit constraint control method and the adjacent-unit matching constraint control are simultaneous, complementary, and synergistic control methods used in the assembly of blocks and segments. Single-unit constraints are applied within each unit, while matching constraints are applied between units. Under the simultaneous action of these two constraint methods, the welding of the main welds within each unit is completed, minimizing welding thermal deformation and achieving effective control of the box opening dimensions.

[0028] It should be understood that although the above embodiments provide a relatively detailed textual description of the design concept of the present invention, these textual descriptions are merely simple textual descriptions of the design concept of the present invention, and not limitations on the design concept of the present invention. Any combination, addition, or modification that does not exceed the design concept of the present invention falls within the protection scope of the present invention.

Claims

1. A method for controlling the end face dimensions of a high-precision bolted steel tower, characterized by: To control the assembly precision of tower sections during the steel tower manufacturing process, fixed-dimensional constraint fixtures are installed during the assembly of tower blocks and segments. These fixtures relatively fix the tower column's perimeter wall panels and intermediate web plates, forming an internal constraint control within the tower unit. This internal constraint control reduces welding deformation, thereby achieving precise control of the box opening dimensions. The implementation of internal constraint control within the tower unit is as follows: (1) Block assembly constraints: The block is assembled and positioned according to the assembly process, including the corner wall panel unit, web plate unit and partition plate unit. After the dimensions of the box openings at both ends are qualified, the longitudinal and transverse constraint fixtures are installed near the box openings to ensure that the connecting flanges do not affect the subsequent machining of the steel tower. After the constraints are fixed, the dimensions of the box openings of the steel tower block are re-measured, including the longitudinal and transverse dimensions and the diagonal dimensions. After the dimensions are qualified, welding is performed. After the assembly welding is completed, the constraints are released once to release the internal stress once. After adjusting the misalignment between the blocks, the blocks are bolted a second time to ensure the overall rigidity of the segment assembly dimensions and subsequent machining. (2) Segment assembly constraints: During segment assembly, the lower block, the middle anchor box structure and the upper block are positioned in sequence and then the side wall plates are installed to complete the segment assembly. During segment assembly, the lower block is positioned first, and then the anchor box is positioned. The upper block bears the weight by the anchor box. After the upper and lower blocks and the anchor box are accurately positioned, the web plates of the upper and lower blocks are bolted and fixed by the fixed constraint tooling, so that the upper and lower blocks form a common steel structure, which increases the overall rigidity and provides a fixed constraint on the relatively weak plates at the box opening. After the welds of each segment are completed and the dimensions are adjusted to the correct position, the constraint is released to release the welding stress, and the constraint is reset so that the box opening size is fixed in a frame manner.

2. The high-precision bolted steel tower end face dimension control method according to claim 1, characterized in that: When the internal constraint control of the single unit is a fixed constraint control, the fixed constraint is designed as a movable support structure, consisting of upper and lower parts, which facilitates assembly and disassembly during use. The fixed constraint is designed to be of standard size, consistent with the size of the constrained space, and is connected by high bolts and fixed with punch pins to achieve size control of the fixed constraint tooling.

3. The high-precision bolted steel tower end face dimension control method according to claim 1, characterized in that: Implementation of the adjacent individual matching constraint method: (1) The multi-block, multi-segment matching constraint method involves simultaneously manufacturing at least three adjacent blocks or adjacent tower segments on the same side. It also requires that the completed block segments adjacent to the first block segment be used as the parent segment in the manufacturing process. Each step of the manufacturing process can refer to the size of the parent box opening, and adjacent block segments can be mutually verified. Mutual verification and correction are completed throughout the assembly process. (2) The multi-block segment matching constraint is achieved by using matching parts to make auxiliary connections between individuals. On the one hand, the spacing between the two sets of holes of the matching parts is small enough to play an auxiliary connection while controlling the plate thickness misalignment; on the other hand, the connection of the matching parts realizes the rigid constraint between adjacent tower columns, thus playing a mutual restraint role. (3) The block segments complete the welding of the main internal welds under the combined effect of intra-unit constraints and adjacent matching constraints.

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