Modeling method for catwalk side span anchoring end arrangement structure based on finite element simulation

Abstract

The application discloses a catwalk side span anchoring end arrangement structure modeling method based on finite element simulation, and comprises the following steps: step one, according to the drawing of the to-be-constructed catwalk of a suspension bridge, data materials for design checking and modeling are prepared, and a layout scheme of the side span anchoring end of the catwalk load-bearing cable in the catwalk is initially determined; step two, the whole catwalk of the suspension bridge is systematically modeled, the anchoring end of the catwalk load-bearing cable in the modeling model is replaced by the extension section of the catwalk load-bearing cable to replace the connection between the anchoring adjusting device and the anchorage, and the end point of the extension section of the catwalk load-bearing cable is directly anchored on the anchorage; step three, the mechanical parameters of the replacement steel wire rope are calculated according to the parameters of the anchoring adjusting device; step four, debugging operation and data analysis are carried out; step five, the related data and parameters are debugged, and step four is repeated until the model and data are correct. The catwalk load-bearing cable can be directly obtained without stress, and the length of the anchoring end of the catwalk load-bearing cable does not need to be corrected during construction, so that the construction quality is effectively improved, and the construction efficiency is accelerated.

Description

Technical Field

[0001] This invention relates to the field of bridge engineering construction technology, and in particular to a modeling method for the arrangement structure of the side span anchorage end of a catwalk based on finite element simulation. Background Technology

[0002] A catwalk is a temporary construction structure erected below the main cable and generally parallel to its alignment during the construction of a suspension bridge. It serves as a temporary, elevated operating platform for construction workers. A catwalk typically consists of the catwalk's load-bearing cables, surface layer, displacement frame, anchorage adjustment device, pull-down device, transverse passageway, and wind-resistant system. Catwalks are generally classified as either separated or continuous.

[0003] Currently, the commonly used continuous catwalk structure uses an anchorage adjustment device to fix the catwalk load-bearing cable to the anchorage. This device transfers the cable force to a small tie rod, which in turn transfers the force to an anchorage adjustment beam. The beam then transfers the force to a large tie rod, which, via pins, transmits the force to the pre-embedded anchoring steel fixed to the anchorage. However, current modeling methods for designing and verifying catwalks in suspension bridges extend the calculation starting point from the anchorage point between the catwalk load-bearing cable and the small tie rod to the top of the pre-embedded anchoring steel on the anchorage. This direct connection between the catwalk load-bearing cable and the anchorage for load analysis results in a model that does not match the actual engineering structure. The catwalk load-bearing cable and the anchorage are connected by an anchorage adjustment device, which transmits the load through this device. The anchoring point at the top of the pre-embedded anchoring steel on the anchorage has a calculation diagram in the load-bearing analysis that does not match the actual layout of the construction structure. It ignores the influence of the anchoring adjustment device on the load-bearing capacity in the direction of the catwalk load-bearing cable, which will reduce the accuracy of the calculation data during modeling and analysis and bring significant errors to the later construction. Furthermore, when calculating the unloaded length of the catwalk load-bearing cable, due to the error in the load-bearing analysis, it is necessary to perform cable end adjustment and correction calculations for each catwalk load-bearing cable, which is complicated, tedious, time-consuming and labor-intensive. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a modeling method for the arrangement structure of the catwalk side span anchorage end based on finite element simulation, which can effectively improve the calculation accuracy of the catwalk load-bearing cable anchorage end and simplify the verification work.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by this invention is: a modeling method for the catwalk side span anchorage end arrangement structure based on finite element simulation, including the following steps:

[0006] Step 1: Prepare data related to the design verification and modeling of the catwalk based on the drawings of the proposed suspension bridge catwalk, and formulate a preliminary layout scheme for the side span anchorage ends of the catwalk load-bearing cables in accordance with the specifications.

[0007] Step 2: Systematically model the entire catwalk of the suspension bridge. In the model, the anchorage end of the catwalk load-bearing cable is replaced by extending the extension section of the catwalk load-bearing cable to replace the connection between the anchorage adjustment device and the anchor. The end of the extension section of the catwalk load-bearing cable is directly anchored to the anchor.

[0008] Step 3: Calculate the mechanical parameters of the replacement steel wire rope based on the parameters of the anchoring adjustment device. The displacement of the endpoints of the replacement steel wire rope and the anchoring adjustment device after bearing the load are consistent. Then, replace the extension section of the catwalk load-bearing cable with the replacement steel wire rope in the model.

[0009] Step 4: Debug and run the program and perform data analysis;

[0010] Step 5: Debug the relevant data and parameters, and repeat step 4 until the model and data are correct.

[0011] Furthermore, the component model of the anchoring adjustment device includes a large tie rod, a small tie rod, and an adjustment beam. The diameter of the replacement steel wire rope is equal to the diameter of the catwalk load-bearing cable. The total weight of the replacement steel wire rope is equal to the sum of the weights of the large tie rod and the small tie rod in the anchoring adjustment device of the corresponding length replacement zone. The self-weight of the adjustment beam and the self-weight of other related components are loaded as a concentrated load at the intersection of the adjustment beam and the replacement steel wire rope.

[0012] Furthermore, in step three, under the same load conditions, the elongation of the replacement wire rope along the direction of tension is equal to the elongation of the anchoring adjustment device under actual load conditions.

[0013] Furthermore, in the modeling, the replacement steel wire rope is a segmented structure connected by a catwalk anchorage adjustment beam. The segmented structure of the replacement steel wire rope is fixedly connected to the catwalk load-bearing cable and the anchorage, respectively. The catwalk anchorage adjustment beam can move in a direction parallel to the replacement steel wire rope. By translating the catwalk anchorage adjustment beam along the replacement steel wire rope, the length of the segmented structure of the replacement steel wire rope can be adjusted.

[0014] Furthermore, in step three, the mechanical parameters of the replacement wire rope are calculated according to the following formula:

[0015] F z L0 / 4E b A b +F z L1 / 8E b A d =F z (L0+L1) / NE0A0、

[0016] E0 = 8Eb A b (L0+L1) / NA0(2L0+L1) and P0=P b (4A b L0+NA d L1) / A0(L0+L1);

[0017] Where E0 is the stiffness of the replacement wire rope, P0 is the density of the replacement wire rope, N is the number of catwalk load-bearing cables, L0 and L1 are the lengths of the segmented structure of the replacement wire rope, and A b P represents the area of ​​a single tie rod in the anchoring adjustment device. b For the density of the large tie rod in the anchoring adjustment device, E b A represents the elastic modulus of the large and small tie rods in the anchoring adjustment device. d A0 is the area of ​​a single tie rod in the anchoring adjustment device, and F is the area of ​​a single catwalk load-bearing cable. z This represents the total load.

[0018] The beneficial effects of this invention are as follows: This invention replaces the anchorage adjustment device connecting the catwalk load-bearing cable and the anchorage with a replacement steel wire rope in the modeling and analysis of the catwalk of a suspension bridge. The replacement steel wire rope is equivalent to the actual anchorage adjustment device in construction in terms of load-bearing effect, deformation degree, and tensile amount. This eliminates the error caused by neglecting the anchorage adjustment device in existing modeling methods that calculate based on the arrangement of the catwalk load-bearing cable directly connecting to the anchorage. By replacing and analyzing the part between the catwalk load-bearing cable and the anchorage with the replacement steel wire rope, the mechanical parameters required in actual construction can be accurately calculated. The stress-free length of the anchorage end of the catwalk load-bearing cable can be directly obtained, eliminating the need to correct the length of the anchorage end of a single catwalk load-bearing cable during construction. This significantly improves the calculation accuracy of relevant catwalk parameters, effectively improves construction quality, and accelerates construction efficiency. Attached Figure Description

[0019] Figure 1 An elevation view of the model for the anchorage end of the catenary support cable in the existing technology;

[0020] Figure 2 A plan view of the modeling of the anchorage end of the catenary support cable in the existing technology;

[0021] Figure 3 This is an elevation view of the modeling of the anchorage end of the catwalk load-bearing cable in this invention;

[0022] Figure 4 This is a plan view of the modeling of the anchorage end of the catwalk load-bearing cable in this invention;

[0023] Figure 5 This is a plan view used in the model of the present invention to calculate the mechanical parameters of the replacement steel wire rope.

[0024] The markings in the diagram are: 100-anchor, 200-anchoring steel, 300-catwalk load-bearing cable, 310-anchoring adjustment beam, 320-extension section, 400-replacement wire rope, 510-large tie rod, and 520-small tie rod. Detailed Implementation

[0025] To facilitate understanding of the present invention, the invention will be further described below with reference to the accompanying drawings.

[0026] In the description of this invention, it should be noted that the terms "front", "rear", "left", "right", "up", "down", "inner", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0027] The modeling method for the catwalk side span anchorage arrangement structure disclosed in this invention improves upon the existing modeling methods and models for catwalk anchorage ends in suspension bridges. Existing modeling structures, such as... Figure 1 and Figure 2 As shown, during modeling and analysis, the portion between the catwalk load-bearing cable 300 and the anchor 100 is directly considered as an extension 320 of the catwalk load-bearing cable 300 for calculation. However, in actual construction, an anchoring adjustment device is installed between the catwalk load-bearing cable 300 and the anchor 100, such as... Figure 5 As shown, the anchoring adjustment device includes a large tie rod 510 and a small tie rod 520. The catwalk load-bearing cable 300 is anchored to the anchoring steel 200 on the anchorage 100 through a connection structure composed of the large tie rod 510, the small tie rod 520, and the anchoring adjustment beam 310. However, the large tie rod 510 and the small tie rod 520 in the anchoring adjustment device have significant differences in their load-bearing capacity and mechanical properties relative to the catwalk load-bearing cable 300. The cable end of the catwalk load-bearing cable 300 first transmits force to the small tie rod 520 in the anchoring adjustment device. In the case where the small tie rod 520 transmits force to the anchoring adjustment beam 310, the anchoring adjustment beam 310 transmits force to the large tie rod 510, and the large tie rod 510 transmits force to the anchoring steel 200, there is a significant difference in load-bearing analysis compared to the case where the end of the catwalk load-bearing cable 300 directly transmits force to the anchoring steel 200. Furthermore, the existing model directly connects the anchoring end of the catwalk load-bearing cable 300 to the anchoring steel 200 of the anchorage 100 for load-bearing analysis and calculation, which undoubtedly results in errors and low accuracy.

[0028] The specific improvement of this invention is that when modeling and analyzing the catwalk of a suspension bridge, a replacement steel wire rope 400 is constructed at the anchorage end of the catwalk load-bearing cable 300. Based on the principle of equivalent replacement between the replacement steel wire rope 400 and the anchorage adjustment device, the modeling mechanical parameters of the replacement steel wire rope 400 are calculated. The replacement steel wire rope 400 replaces the extension section 320 of the catwalk load-bearing cable commonly used in current catwalk calculations, thus achieving the technical objective. Specifically, the modeling method for the catwalk side span anchorage end arrangement structure based on finite element simulation described in this invention is carried out according to the following steps:

[0029] Step 1: Prepare data related to the design verification and modeling of the catwalk based on the drawings of the proposed suspension bridge catwalk, and formulate a preliminary arrangement scheme for the side span anchorage ends of the catwalk load-bearing cables in accordance with the specifications.

[0030] Step 2: Systematically model the entire catwalk of the suspension bridge using the currently common modeling method. In the model, the anchorage end of the catwalk load-bearing cable 300 is replaced by the connection between the anchorage adjustment device and the anchor 100 by extending the extension section 320 of the catwalk load-bearing cable 300. The front end of the extension section 320 of the catwalk load-bearing cable 300 is directly anchored to the anchor 100.

[0031] Step 3: Calculate the mechanical parameters of the replacement wire rope based on the parameters of the pre-designed anchoring adjustment device. The mechanical parameters of the replacement wire rope must satisfy the condition that the displacement of the replacement wire rope along the catwalk cable direction is equal to that of the anchoring adjustment device after bearing load. In this step, it is necessary to first calculate the corresponding parameters of the replacement wire rope 400 using the actual structure and mechanical parameters of the pre-designed anchoring adjustment device, such as... Figure 5 As shown, in the actual structure of the anchorage adjustment device at the anchorage end of the catwalk load-bearing cable 300, the component model of the anchorage adjustment device includes a large tie rod 510, a small tie rod 520, and an anchorage adjustment beam 310. In this invention, an equivalent substitution method is adopted, such as... Figures 3 to 5As shown, in the modeling, the known parameters of the anchoring adjustment device are used to calculate the mechanical parameters of the replacement steel wire rope 400 according to the equivalence principle, thereby achieving an equivalent substitution of the anchoring adjustment device, and replacing the extension section 320 of the catwalk load-bearing cable 300 in the commonly used model during modeling; the replacement steel wire rope 400 is a segmented structure connected by the anchoring adjustment beam 310. The segmented structure of the replacement steel wire rope 400 is fixedly connected to the catwalk load-bearing cable 300 and the anchor 100 respectively. The anchoring adjustment beam 310 moves in a direction parallel to the replacement steel wire rope 400. By translating the anchoring adjustment beam 310 along the replacement steel wire rope 400, the length of the segmented structure of the replacement steel wire rope 400 can be adjusted; the total weight of the replacement steel wire rope 400 is equal to the total weight of the tie rod in the anchoring adjustment device of the corresponding length replacement area. In this invention, during the modeling process, a replacement steel wire rope 400 is used to replace the anchoring adjustment device to compensate for the distance between the catwalk load-bearing cable 300 and the anchor 100. Furthermore, a replacement steel wire rope 400, equivalent to the anchoring adjustment device, replaces the extension section 320 of the catwalk load-bearing cable 300 in commonly used models, making the model more consistent with actual load-bearing conditions. The stress-free length of the catwalk load-bearing cable 300 is calculated through stress analysis simulation of the model. In this invention, the finite element method of the modeling software is used to simulate the anchoring adjustment device based on the replacement steel wire rope 400. The replacement steel wire rope 400 at the anchoring end of the catwalk load-bearing cable 300 has the same load-bearing effect and deformation as the anchoring adjustment device. That is, under the same load magnitude in the extension direction of the catwalk load-bearing cable 300, the elongation of the replacement steel wire rope 400 along the tension direction of the catwalk load-bearing cable 300 is consistent with the elongation of the anchoring adjustment device. Therefore, the stiffness and density of the replacement steel wire rope 400 under this load condition can be calculated. Specifically, the calculation is simplified according to the following formula:

[0032] F z L0 / 4E b A b +F z L1 / 8E b A d =F z (L0+L1) / NE0A0、

[0033] E0 = 8E b A b (L0+L1) / NA0(2L0+L1) and P0=P b (4A b L0+NA d L1) / A0(L0+L1);

[0034] In this formula, E0 is the stiffness of the replacement steel wire rope 400, P0 is the density of the replacement steel wire rope 400, N is the number of catwalk load-bearing cables 300, L0 and L1 are the respective lengths of the segmented structure of the replacement steel wire rope 400, and A... bP represents the area of ​​a single tie rod in the anchoring adjustment device. b For the density of the large tie rod in the anchoring adjustment device, E b A represents the elastic modulus of the large and small tie rods in the anchoring adjustment device. d A0 is the area of ​​a single tie rod in the anchoring adjustment device, and F is the area of ​​a single 300mm catenary load-bearing cable. z This represents the total load.

[0035] This invention uses a replacement steel wire rope 400 to equivalently replace the anchorage adjustment device in the modeling and analysis. During modeling, the extension section 320 of the catwalk load-bearing cable 300 in commonly used models is actually replaced. After model debugging and analysis, the accuracy of the calculation data can be improved, and the stress-free length of each catwalk load-bearing cable 300 can be directly obtained without needing to correct the length of the anchorage end of the catwalk load-bearing cable 300.

[0036] Step 4: Debug, run, and perform data analysis.

[0037] Step 5: Debug the relevant data and parameters, and repeat step 4 until the model and data are correct.

[0038] This invention, through the aforementioned modeling method, can construct a model that more closely matches the load-bearing state of the catwalk support cable 300 in actual construction structures. The calculation and analysis method more accurately reflects the actual load-bearing state of the component, resulting in higher precision in the structural calculations. Furthermore, when calculating the stress-free total length of the catwalk support cable 300, it is unnecessary to correct the anchorage length, providing more accurate construction parameters for the prefabrication and installation of the catwalk support cable 300 during suspension bridge construction. The modeling method described in this invention provides a more systematic approach to the design verification of suspension bridge catwalks, and the constructed theoretical model better meets actual construction requirements. This ensures the assembly accuracy of all prefabricated components during suspension bridge catwalk construction, thereby accelerating the design and construction progress, improving construction quality, and reducing the overall design and construction costs.

Claims

1. A modeling method for the arrangement structure of the side span anchorage end of a catwalk based on finite element simulation, characterized in that: Includes the following steps: Step 1: Prepare data related to the design verification and modeling of the catwalk based on the drawings of the proposed suspension bridge catwalk, and formulate a preliminary layout scheme for the side span anchorage ends of the catwalk load-bearing cables in accordance with the specifications. Step 2: Systematically model the entire catwalk of the suspension bridge. In the model, the anchorage end of the catwalk load-bearing cable is replaced by extending the extension section of the catwalk load-bearing cable to replace the connection between the anchorage adjustment device and the anchor. The end of the extension section of the catwalk load-bearing cable is directly anchored to the anchor. Step 3: Calculate the mechanical parameters of the replacement wire rope based on the parameters of the anchoring adjustment device. The displacement of the endpoints of the replacement wire rope and the anchoring adjustment device after bearing the load is consistent. Then, replace the extension section of the catwalk load-bearing cable with the replacement wire rope in the model. In the model, the replacement wire rope is a segmented structure connected by the catwalk anchoring adjustment beam. The segmented structure of the replacement wire rope is fixedly connected to the catwalk load-bearing cable and the anchor. The catwalk anchoring adjustment beam can move in a direction parallel to the replacement wire rope. The length of the segmented structure of the replacement wire rope can be adjusted by translating the catwalk anchoring adjustment beam along the replacement wire rope. The mechanical parameters of the replacement wire rope are calculated according to the following formula: F z L0 / 4E b A b +F z L1 / 8E b A d =F z (L0+L1) / NE0A0、 E0=8E b A b (L0+L1) / NA0(2L0+L1) and P0=P b (4A b L0+NA d L1) / A0(L0+L1); Where E0 is the stiffness of the replacement wire rope, P0 is the density of the replacement wire rope, N is the number of catwalk load-bearing cables, L0 and L1 are the lengths of the segmented structure of the replacement wire rope, and A b P represents the area of ​​a single tie rod in the anchoring adjustment device. b For the density of the large tie rod in the anchoring adjustment device, E b A represents the elastic modulus of the large and small tie rods in the anchoring adjustment device. d A0 is the area of ​​a single tie rod in the anchoring adjustment device, and F is the area of ​​a single catwalk load-bearing cable. z Total load; Step 4: Debugging and running, and performing data analysis; Step 5: Adjust the relevant data and parameters, and repeat Step 4 until the model and data are correct, that is, under the condition that the load on the replacement steel wire rope is the same in the extension direction of the catwalk load-bearing cable, the elongation along the direction of the catwalk load-bearing cable tension is consistent with the elongation of the anchoring adjustment device.

2. The modeling method for the catwalk side span anchorage arrangement structure based on finite element simulation as described in claim 1, characterized in that: The component model of the anchoring adjustment device includes a large tie rod, a small tie rod, and an adjustment beam. The diameter of the replacement steel wire rope is equal to the diameter of the catwalk load-bearing cable. The total weight of the replacement steel wire rope is equal to the sum of the weights of the large tie rod and the small tie rod in the anchoring adjustment device of the corresponding length replacement zone. The self-weight of the adjustment beam and the self-weight of other components involved in the adjustment beam are loaded as a concentrated load at the intersection of the adjustment beam and the replacement steel wire rope.

3. The modeling method for the catwalk side span anchorage arrangement structure based on finite element simulation as described in claim 1, characterized in that: In step three, under the same load conditions, the elongation of the replacement wire rope along the direction of tension is equal to the elongation of the anchoring adjustment device under actual load conditions.

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