Calculation method for lifting-changing loosening length of catwalk bearing cable

Abstract

The invention relates to the technical field of engineering, and provides a method for calculating the lifting-changing loosening length of a catwalk load-bearing cable in order to conveniently obtain the lifting-changing loosening length of the catwalk load-bearing cable, before the lifting-changing of the catwalk and the erection of a steel box girder, the no-load state of a main cable is basically parallel to the catwalk, and the line shape is kept consistent; when entering the catwalk rehanging and steel box girder erection stage, the catwalk needs to be hung on a main cable, the line shape of the catwalk is basically parallel to the main cable, and the line shape of the catwalk is consistent with that of the main cable, so that the loosening length of the catwalk needs to be consistent with the deformation length of the main cable; on the basis, the main cable variable quantity is firstly calculated, then the catwalk loosening quantity is calculated according to the main cable variable quantity, the calculation mode is simple and high in accuracy, the construction efficiency is greatly improved, and the construction cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of engineering, and in particular to a method for calculating the length of a catwalk load-bearing cable after it is suspended. Background Art

[0002] Before the steel box girder of the suspension bridge catwalk system is erected, the catwalk needs to be suspended on the main cable, and then the steel box girder is erected. During the process of lifting and erecting the steel box girder, the length of the anchor rods at both ends of the catwalk needs to be continuously adjusted to relax the catwalk load-bearing cables. Accurately adjusting the length of the rods (relaxed length of the load-bearing cables) plays a vital role in the quality and safety control of the catwalk construction. The relaxed length of the catwalk load-bearing cables is generally estimated based on experience, which is highly subjective and relies on the experience of technicians. It is impossible to accurately calculate the relaxed length of the catwalk, which has a high safety risk, low construction efficiency, and increased construction costs. Summary of the invention

[0003] In order to facilitate the acquisition of the relaxed length of a catwalk load-bearing cable, the present application provides a method for calculating the relaxed length of a catwalk load-bearing cable.

[0004] The technical solution adopted by the present invention to solve the above problems is:

[0005] The calculation method of the relaxed length of the catwalk load-bearing cable includes:

[0006] Step 1: Establish a no-load model of the main cable of the suspension bridge, obtain the no-load line shape of the main cable, and mark the length of the main cable as L0;

[0007] Step 2: Establish a catwalk model based on the no-load model of the main cable, keep the catwalk parallel to the main cable, and obtain the catwalk bridge line shape;

[0008] Step 3: Load the concentrated load on the main cable after the catwalk is lifted to the main cable as a uniformly distributed load;

[0009] Step 4: Establish a steel box girder installation model, and load the steel box girder installation load on the main cable as a concentrated load;

[0010] Step 5: Simulate the installation construction phase and obtain the main cable length L during the construction phase d ;

[0011] Step 6: Calculate the relaxed length of the catwalk load-bearing cable: ΔS = k × (L d -L0).

[0012] Furthermore, k is calculated as: f is the main cable sagitta corresponding to the construction stage, d is the distance between the mid-span of the main cable bridge line and the mid-span of the catwalk bridge line, and L is the bridge span.

[0013] Further, d is 1.5-1.7 m.

[0014] Furthermore, the final construction stage is the stage when the steel box girder is hoisted and installed.

[0015] Compared with the prior art, the present invention has the following beneficial effects: before the catwalk is re-hoisted and the steel box girder is erected, the main cable is basically parallel to the catwalk in an unloaded state, and the line shape remains consistent; when the catwalk is re-hoisted and the steel box girder is erected, the catwalk needs to be suspended above the main cable, and its line shape also remains basically parallel to the main cable. To make the line shape of the catwalk consistent with the line shape of the main cable, the relaxed length of the catwalk needs to be consistent with the deformed length of the main cable; based on this, the change of the main cable is first calculated, and then the relaxation of the catwalk is calculated according to the change of the main cable. The calculation method is simple and accurate, which greatly improves the construction efficiency and reduces the construction cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Flow chart of the calculation method for the relaxed length of the catwalk load-bearing cable;

[0017] Figure 2 Schematic diagram of the location of the main cable and catwalk in the final construction stage. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] like Figure 1 As shown in the figure, the calculation method of the relaxed length of the catwalk load-bearing cable includes:

[0020] Step 1: Establish a no-load model of the main cable of the suspension bridge, obtain the no-load line shape of the main cable, and mark the length of the main cable as L0;

[0021] Step 2: Establish a catwalk model based on the no-load model of the main cable, keep the catwalk parallel to the main cable, and obtain the catwalk bridge line shape;

[0022] Step 3: Load the concentrated load on the main cable after the catwalk is lifted to the main cable as a uniformly distributed load;

[0023] Step 4: Establish a steel box girder installation model, and load the steel box girder installation load on the main cable as a concentrated load;

[0024] Step 5: Simulate the installation construction phase and obtain the main cable length L during the construction phase d ;

[0025] Step 6: Calculate the relaxed length of the catwalk load-bearing cable: ΔS = k × (L d-L0). k can be determined based on engineering experience. In this embodiment, k is calculated using a calculation formula, and the calculation method of k is: f is the main cable sagitta corresponding to the construction stage, d is the distance between the mid-span of the main cable bridge line and the mid-span of the catwalk bridge line, generally 1.5-1.7m; L is the bridge span.

[0026] like Figure 2 As shown in the figure, after the final construction stage is completed, that is, when the steel box girder is hoisted, the main cable length is L n At this time, the main cable main cable height is f n , then the relaxed length of the catwalk load-bearing cable under this condition is: ΔS n =k n ×(L n -L0),

[0027] If it is necessary to calculate the relaxation of the catwalk load-bearing cable during the installation of the steel box girder, the main cable length L under this condition can be obtained through numerical simulation. i , and obtain the main cable height f under this condition i , then the relaxed length of the catwalk load-bearing cable under this condition is: ΔS i =k i ×(L i -L0),

[0028] The relaxed length of the catwalk load-bearing cable is calculated based on the change in the main cable, and the calculation method is simple and has higher accuracy.

Claims

1. The method for calculating the length of the catwalk load-bearing cable after it is suspended is characterized in that: include: Step 1: Establish a no-load model of the main cable of the suspension bridge, obtain the no-load line shape of the main cable, and mark the length of the main cable as L0; Step 2: Establish a catwalk model based on the no-load model of the main cable, keep the catwalk parallel to the main cable, and obtain the catwalk bridge line shape; Step 3: Load the concentrated load on the main cable after the catwalk is lifted onto the main cable as a uniformly distributed load; Step 4: Establish a steel box girder installation model, and load the steel box girder installation load on the main cable as a concentrated load; Step 5: Simulate the installation construction phase and obtain the main cable length L during the construction phase d ; Step 6: Calculate the relaxed length of the catwalk load-bearing cable: ΔS = k × (L d -L0).

2. The method for calculating the length of the catwalk load-bearing cable after re-hanging according to claim 1 is characterized in that: k is calculated as: f is the main cable sagitta corresponding to the construction stage, d is the distance between the mid-span of the main cable bridge line and the mid-span of the catwalk bridge line, and L is the bridge span.

3. The method for calculating the length of the catwalk load-bearing cable after re-hanging according to claim 2 is characterized in that: d is 1.5-1.7m.

4. The method for calculating the length of the catwalk load-bearing cable after re-hanging according to any one of claims 1 to 3, characterized in that: The final construction stage is when the steel box girder hoisting is completed.

Images