Method for applying pre-stress to steel strand of guyed wind measurement tower under icing condition

Abstract

The application belongs to the technical field of ocean engineering, and is a method for applying pre-stress of steel strand of pull line type wind measurement tower under icing condition, comprising the following steps: (1) applying pre-stress of steel strand under design working condition, (2) recording data and calculating overall limit icing thickness, (3) calculating ratio coefficient according to displacement, (4) specifying pre-stress application scheme according to the ratio coefficient, and (5) calculating limit icing thickness to determine the optimal pre-stress application scheme. Compared with the prior art, the application finds the pre-stress application method of steel strand under the combined action of ice and wind load by using the method of multiple comparisons, enhances the overall stability of the wind measurement tower by simply adjusting the pre-stress of the steel strand, and avoids the damage of icing collapse of the wind measurement tower.

Description

Technical Field

[0001] This invention relates to a method for applying prestress to the steel strands of a wire-type anemometer tower under icing conditions, belonging to the field of marine engineering technology. Background Technology

[0002] Onshore wind measurement towers are fragile structures, primarily affected by environmental loads, with wind load being the most significant. However, the impact of ice load must also be taken into account, especially in high-altitude regions.

[0003] To reduce construction costs, most current wind measurement towers are guyed towers. These towers generally have low icing capacity, often only able to withstand icing of 25mm or less. When the tower is covered in ice, it increases the weight of the tower itself. If the wind speed is too high, the guy wires will not be able to support the weight of the tower, causing it to collapse and resulting in huge losses. It also affects the normal operation of the wind power prediction system and data uploading. Summary of the Invention

[0004] To overcome the shortcomings of existing technologies, the present invention aims to provide a method for applying prestress to the steel strands of a wire-operated anemometer tower under icing conditions. This invention finds the optimal prestressing application scheme, thereby improving the overall structural stability of the anemometer tower and avoiding the problem of tower instability due to the combined effects of wind and ice.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is: a method for applying prestress to the steel strands of a wire-type anemometer tower under icing conditions, comprising the following steps:

[0006] Step 1: Apply prestress to the steel strands under design conditions. Apply the wind load of the foundation wind pressure under design conditions to the entire guyed wind tower. Apply a prestress of not less than 200 MPa, which is one-tenth of the ultimate stress of the steel strands, to each layer of steel strands.

[0007] Step 2: Record data and calculate the overall ultimate icing thickness. Record the maximum displacement and maximum stress of the main tower under the working condition in Step 1, and record the location where the maximum displacement and maximum stress of the main tower occur. At the same time, record the icing of each layer of steel strands, the lateral displacement value of the main tower at the connection position between the steel strands and the main tower, and perform ultimate icing analysis on the working condition in Step 1, calculate the overall ultimate icing thickness and record it.

[0008] Step 3: Calculate the ratio coefficient based on the displacement. Based on the data recorded in Step 2, find the minimum lateral displacement of the main tower at the connection point of each layer of steel strands with the main tower. Ratio the lateral displacement of the main tower at the connection point of other guy wires with the main tower to this minimum value. According to the prestress setting requirements of the specification, set a reference prestress of not less than 100 MPa on the steel strand at the minimum lateral displacement of the main tower at the connection point of the steel strands with the main tower. Based on the calculated ratio, set a prestress of reference prestress multiplied by the ratio coefficient for each layer of steel strands.

[0009] Step 4: Specify the prestressing application scheme according to the ratio coefficient. Set up multiple prestressing application schemes according to Step 3, record the maximum displacement and maximum stress of the main tower under each working condition, and record the location where the maximum displacement and maximum stress of the main tower are generated. Compare them with the data recorded in Step 2 to find the prestressing application scheme with the smallest maximum lateral displacement and the smallest maximum stress of the main tower.

[0010] Step 5: Calculate the ultimate icing thickness to determine the optimal prestressing application scheme. Based on the prestressing application scheme determined in Step 4, perform an ultimate icing analysis and calculate its ultimate icing thickness. Compare the obtained data with the data calculated in Step 2 and observe the changes in the ultimate icing thickness. If the ultimate icing thickness increases or the change is not significant, select this scheme. If the ultimate icing thickness decreases significantly, repeat Step 4 and select other schemes to finally determine the optimal prestressing application scheme.

[0011] The beneficial effects of this invention are as follows: A method for applying prestress to the steel strands of a wire-type anemometer tower under icing conditions includes the following steps: (1) applying prestress to the steel strands under design conditions; (2) recording data and calculating the overall ultimate icing thickness; (3) calculating the ratio coefficient based on displacement; (4) specifying the prestress application scheme based on the ratio coefficient; and (5) calculating the ultimate icing thickness to determine the optimal prestress application scheme. Compared with existing technologies, this invention uses a multi-comparison method to find a method for applying prestress to the steel strands under the combined action of ice and wind loads. By simply adjusting the prestress of the steel strands, the overall stability of the anemometer tower is enhanced, avoiding the danger of the anemometer tower collapsing due to icing. Attached Figure Description

[0012] Figure 1 This is a flowchart of the method steps of the present invention. Detailed Implementation

[0013] The invention will now be further described with reference to the accompanying drawings.

[0014] like Figure 1 As shown, a method for applying prestress to the steel strands of a guyed anemometer tower under icing conditions includes the following steps:

[0015] Step 1: Apply prestress to the steel strands under design conditions. Apply the wind load of the foundation wind pressure under design conditions to the entire guyed wind tower. Apply a prestress of not less than 200 MPa, which is one-tenth of the ultimate stress of the steel strands, to each layer of steel strands.

[0016] Step 2: Record data and calculate the overall ultimate icing thickness. Record the maximum displacement and maximum stress of the main tower under the working condition in Step 1, and record the location where the maximum displacement and maximum stress of the main tower occur. At the same time, record the icing of each layer of steel strands, the lateral displacement value of the main tower at the connection position between the steel strands and the main tower, and perform ultimate icing analysis on the working condition in Step 1, calculate the overall ultimate icing thickness and record it.

[0017] Step 3: Calculate the ratio coefficient based on the displacement. Based on the data recorded in Step 2, find the minimum lateral displacement of the main tower at the connection point of each layer of steel strands with the main tower. Ratio the lateral displacement of the main tower at the connection point of other guy wires with the main tower to this minimum value. According to the prestress setting requirements of the specification, set a reference prestress of not less than 100 MPa on the steel strand at the minimum lateral displacement of the main tower at the connection point of the steel strands with the main tower. Based on the calculated ratio, set a prestress of reference prestress multiplied by the ratio coefficient for each layer of steel strands.

[0018] Step 4: Specify the prestressing application scheme according to the ratio coefficient. Set up multiple prestressing application schemes according to Step 3, record the maximum displacement and maximum stress of the main tower under each working condition, and record the location where the maximum displacement and maximum stress of the main tower are generated. Compare them with the data recorded in Step 2 to find the prestressing application scheme with the smallest maximum lateral displacement and the smallest maximum stress of the main tower.

[0019] Step 5: Calculate the ultimate icing thickness to determine the optimal prestressing application scheme. Based on the prestressing application scheme determined in Step 4, perform an ultimate icing analysis and calculate its ultimate icing thickness. Compare the obtained data with the data calculated in Step 2 and observe the changes in the ultimate icing thickness. If the ultimate icing thickness increases or the change is not significant, select this scheme. If the ultimate icing thickness decreases significantly, repeat Step 4 and select other schemes to finally determine the optimal prestressing application scheme.

Claims

1. A method for applying prestress to the steel strands of a guyed anemometer tower under icing conditions, characterized in that, Includes the following steps: Step 1: Apply prestress to the steel strands under design conditions. Apply the wind load of the foundation wind pressure under design conditions to the entire guyed wind tower. Apply a prestress of one-tenth of the ultimate stress of the steel strands to each layer of steel strands, with a minimum of 200 MPa. Step 2: Record data and calculate the overall ultimate icing thickness. Record the maximum displacement and maximum stress of the main tower under the working condition in Step 1, and record the location where the maximum displacement and maximum stress of the main tower occur. At the same time, record the icing thickness of each layer of steel strands, the lateral displacement value of the main tower at the connection position between the steel strands and the main tower, and perform ultimate icing analysis on the working condition in Step 1, calculate the overall ultimate icing thickness and record it. Step 3: Calculate the ratio coefficient based on the displacement. Based on the data recorded in Step 2, find the minimum lateral displacement of the main tower at the connection point of each layer of steel strands with the main tower. Ratio the lateral displacement of the main tower at the connection point of other guy wires with the main tower to this minimum value. According to the prestress setting requirements of the specification, set a reference prestress of not less than 100 MPa on the steel strand at the minimum lateral displacement of the main tower at the connection point of the steel strands with the main tower. Based on the calculated ratio, set a prestress of reference prestress multiplied by the ratio coefficient for each layer of steel strands. Step 4: Specify the prestressing application scheme according to the ratio coefficient. Set up multiple prestressing application schemes according to Step 3, record the maximum displacement and maximum stress of the main tower under each working condition, and record the location where the maximum displacement and maximum stress of the main tower are generated. Compare them with the data recorded in Step 2 to find the prestressing application scheme with the smallest maximum lateral displacement and the smallest maximum stress of the main tower. Step 5: Calculate the ultimate icing thickness to determine the optimal prestressing application scheme. Based on the prestressing application scheme determined in Step 4, perform an ultimate icing analysis and calculate its ultimate icing thickness. Compare the obtained data with the data calculated in Step 2 and observe the changes in the ultimate icing thickness. If the ultimate icing thickness increases or does not change significantly, select this scheme. If the ultimate icing thickness decreases significantly, repeat Step 4 and select other schemes to finally determine the optimal prestressing application scheme.

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