An optimization method and installation method for stress-free installation of an arch bridge cable-stayed buckle

Abstract

This invention relates to the field of bridge technology, specifically to an optimized method and installation method for stress-free installation of cable-stayed arch bridges. The optimization method establishes a finite element model of the entire arch rib process, including geometric parameters, material parameters, and active correction parameters for the closing posture, and calculates the influence matrix of control point displacements based on this model. Subsequently, using the influence matrix as a mapping relationship, a mathematical optimization model is constructed, including cable force and displacement variables, initial tension values, and multiple displacement and rotation constraints, and iteratively solved to accurately determine the initial tension load of each cable segment and the installation coordinates of the arch rib. During the installation stage, lateral deviation is eliminated by adjusting the lateral guy cable force, and a temporary closing device is used to actively correct the relative displacement and rotation of the closing joint, ensuring that all parameters are controlled within allowable ranges. This invention brings the arch rib's arched state close to the stress-free state of a single-stage frame formation, significantly improving construction efficiency while ensuring closing accuracy.

Description

Technical Field

[0001] This invention relates to the field of arch rib construction technology, and in particular to an optimized method and installation method for stress-free installation of cable-stayed arch bridges. Background Technology

[0002] The core idea of ​​the stress-free state method is that as long as the stress-free configuration of the structure (usually referring to the stress-free length and stress-free curvature) remains unchanged, the final state of the structure is independent of its forming process. For arch bridges, as long as the stress-free configuration of the arch rib segments remains unchanged during installation, the arched state can reach the optimal state of a single-stage arch formation. Currently, most long-span arch bridges are constructed using cable-stayed cable-stayed installation, and the method for installing and closing the arch ribs mainly uses the closure and cable loosening method. This method often involves length cutting based on site requirements when installing the cross braces between the ribs, leading to changes in the stress-free length of the cross braces. After the arch ribs are installed to their maximum cantilever state, they also need to be cut and processed according to the actual required length of the closure section before hoisting and closing. However, since the length of the closure section cut on site usually deviates from the designed closure section length, the stress-free length of the arch rib changes. These two situations alter the stress-free configuration of the arch ribs, and the arched state often deviates significantly from the optimal arched state achieved in a single-stage arch formation. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of existing technologies, such as the need for on-site length matching during the installation of cross braces between ribs and the splicing of arch ribs, which leads to changes in the stress-free length and a large deviation between the arched state and the optimal arched state. This invention provides an optimized and stress-free installation method for the cable-stayed tie rods of arch bridges.

[0004] In a first aspect, the present invention provides an optimized method for stress-free installation of cable-stayed arch bridges, the method comprising:

[0005] A finite element model of the arch rib is established based on the geometric parameters, material parameters, boundary conditions, load conditions, and active correction parameters of the closing posture of the arch bridge to be constructed. The influence matrix is ​​obtained based on the finite element model; A mathematical optimization model is established based on the influence matrix. The mathematical optimization model includes cable force variables, displacement variables, initial tension values, constraints, and objective function. An optimization algorithm is used to iterate and optimize the mathematical optimization model to obtain the initial tensile load of each segment of the cable and the installation coordinates of each segment of the arch rib.

[0006] This invention provides an optimized method for stress-free installation of cable-stayed arch bridges. By establishing a finite element model of the arch rib and obtaining the influence matrix, and combining parameters such as cable force variables, displacement variables, initial tension values, constraints, and objective functions, an optimization model is constructed. This allows for the determination of the initial tension load of each cable segment and the installation coordinates of each arch rib segment before construction, achieving stress-free installation during construction. The optimized calculation results provide clear initial tension and installation coordinates, allowing construction personnel to directly tension the cables and install the arch ribs based on the calculated values, eliminating the need for frequent on-site testing or adjustments. This reduces construction time and manpower consumption, improving construction efficiency. Furthermore, the optimized results provide the installation coordinates of each arch rib segment, ensuring that the arch rib reaches a near-design stress-free state after installation. After construction, the internal force distribution of the arch rib is close to the design value, residual stress is significantly reduced, and structural deformation is controllable. This invention, based on a finite element model and optimized calculation method, achieves accurate determination of initial tension and installation coordinates before construction, improving construction efficiency and reducing labor consumption while ensuring structural mechanical performance and stress-free installation.

[0007] Preferably, the boundary conditions include: The lateral displacement of the arch ribs is constrained during the arch rib installation stage. During the temporary closure stage of the arch ribs, the relative axial displacement of the arch ribs on both sides of the closure opening is constrained. The active correction parameters for the closing posture include: Before the arch ribs are closed, the relative displacement and rotation of the closure joint are adjusted by adjusting the tension of the fastening cables or by applying a forced force near the closure joint.

[0008] Preferably, the cable force variable includes: ; In the formula: This represents the initial tension load of the sling and side cable wind cables.

[0009] Preferably, the displacement variable includes: ; In the formula: The displacement of the control points during the installation of the current arch rib segment and the tensioning of the tie cables and side cables; Displacement of control points during installation of arch rib cross braces; To control the displacement of the control point after the slack cable is closed; to counteract the displacement caused by the cross brace, appropriate pre-offset is made before installing the cross brace; for and The average value; The displacement matrix of the control points after the removal of the cable clamps; The displacement vector of the control point caused by the dead load after the removal of the slings and side cables.

[0010] Preferably, the initial tensile force value includes: ; In the formula: and This is the displacement matrix of the control points when tensioning the arch rib cable and side cable wind cables of the current segment; The target displacement of the control point after the slack cable is closed; This is the displacement vector of the control point caused by the dead load during the installation of the current arch rib segment; This is the displacement vector of the control point caused by the dead load during the installation of the cross brace.

[0011] Preferably, the constraints include: ; In the formula: and These are the longitudinal, lateral, and vertical displacement values ​​on both sides during temporary closure; and These are the corner values ​​on both sides before the formal closure; and The allowable values ​​for the maximum relative displacement and the maximum relative rotation angle are 1 mm and 0.0001 rad, respectively.

[0012] Preferably, the objective function includes: ; In the formula: for and The average value; The vertical and lateral target displacements of the control points after the slack cable is closed.

[0013] This invention provides an optimized method for stress-free installation of cable-stayed arch bridges. By establishing a finite element model of the arch rib and obtaining the influence matrix, and combining parameters such as cable force variables, displacement variables, initial tension values, constraints, and objective functions, an optimization model is constructed. This allows for the acquisition of the initial tension load of each cable segment and the installation coordinates of each arch rib segment before construction, achieving stress-free installation during construction. The optimized calculation results provide clear initial tension and installation coordinates, allowing construction personnel to directly tension the cables and install the arch ribs based on the calculated values, eliminating the need for frequent on-site testing or adjustments. This reduces construction time and manpower consumption, improving construction efficiency. Furthermore, the optimized results provide the installation coordinates of each arch rib segment, ensuring that the arch rib reaches a near-design stress-free state after installation. After construction, the internal force distribution of the arch rib is close to the design value, residual stress is significantly reduced, and structural deformation is controllable. This invention, based on a finite element model and optimization calculation method, achieves accurate determination of initial tension and installation coordinates before construction, improving construction efficiency and reducing labor consumption while ensuring structural mechanical performance and stress-free installation.

[0014] In a second aspect, the present invention provides a stress-free installation method for cable-stayed arch bridges, employing the aforementioned optimized method for stress-free installation of cable-stayed arch bridges. The method includes several segments of first and second arch ribs, with each first and second arch rib symmetrically arranged, and further includes the following steps: S1: Install the first and second arch ribs; S2: Adjust the relative lateral offset between the first arch rib and the second arch rib to zero; S3: Interrib cross bracing is provided between the first arch rib and the second arch rib; S4: Repeat steps S1-S3 until the arch rib is in the maximum cantilever state; S5: Temporarily close the first and second arch ribs; S6: Adjust the relative displacement and rotation of the first and second arch ribs at the closure by adjusting the fastening force or applying a forced force near the closure until the relative displacement and rotation are less than the allowable value. S7: Close the connection.

[0015] Preferably, in step S2, the relative lateral offset between the first arch rib and the second arch rib is adjusted to zero by adjusting the lateral guy cable force of the arch rib or by mutual traction of the hand-operated hoist, thereby achieving the adjustment of the relative lateral offset between the first arch rib and the second arch rib.

[0016] By laterally aligning the first and second arch ribs, the arch rib segments are kept on the same plane during installation, eliminating lateral misalignment and improving installation accuracy.

[0017] Preferably, step S5 involves temporarily closing the first arch rib and the second arch rib by setting a temporary closing device at the closing point of the first arch rib and the second arch rib to achieve temporary closing.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention provides an optimized method for stress-free installation of cable-stayed arch bridges. By establishing a finite element model of the arch rib and obtaining the influence matrix, and combining parameters such as cable force variables, displacement variables, initial tension values, constraints, and objective functions, an optimization model is constructed. This allows for obtaining the initial tension load of each cable segment and the installation coordinates of each arch rib segment before construction, achieving stress-free installation during construction. The optimized calculation results provide clear initial tension and installation coordinates, allowing construction personnel to directly tension the cables and install the arch ribs based on the calculated values, eliminating the need for frequent on-site testing or adjustments. This reduces construction time and manpower consumption, improving construction efficiency. Furthermore, the optimized results provide the installation coordinates of each arch rib segment, ensuring that the arch rib reaches a near-design stress-free state after installation. After construction, the internal force distribution of the arch rib is close to the design value, residual stress is significantly reduced, and structural deformation is controllable. This invention, based on a finite element model and optimized calculation method, achieves accurate determination of initial tension and installation coordinates before construction, improving construction efficiency and reducing manpower consumption while ensuring structural mechanical performance and stress-free installation. Attached Figure Description

[0019] Figure 1 This is a finite element model diagram of the arch bridge in this invention; Figure 2 This is a schematic diagram illustrating the adjustment of the relative offset of the arch ribs on both sides of the interrib cross brace in this invention. Figure 3 This is a schematic diagram of step S4 in Embodiment 2 of the present invention; Figure 4 This is a schematic diagram illustrating the adjustment of the relative displacement and rotation angle of the arch ribs on both sides of the closing section in this invention. Figure 5 This is a schematic diagram of the arch ribs closing and cable gathering in this invention; Figure 6 This is a schematic diagram of the stress-free installation control process of the arch rib in this invention; Figure 7 This is a comparison diagram of the arch shape formed by slack cable laying and the arch shape formed by one-time frame lowering in this invention; Figure 8 This is a flowchart of Embodiment 1 of the present invention; Figure 9 This is a flowchart of Embodiment 2 of the present invention; Figure 10 This is a structural diagram of the temporary closing device in this invention; Figure 11 This is a schematic diagram showing the connection between the temporary closing device and the first and second arch ribs in this invention.

[0020] Reference numerals: 1-First arch rib; 2-Second arch rib; 3-Temporary closing device; 31-First connecting part; 311-First vertical plate; 312-First horizontal plate; 32-Second connecting part; 321-Second vertical plate; 322-Second horizontal plate; 33-Connecting plate. Detailed Implementation

[0021] The present invention will now be described in further detail with reference to specific embodiments. However, this should not be construed as limiting the scope of the present invention to the following embodiments; all technologies implemented based on the content of the present invention fall within the scope of the present invention.

[0022] Unless otherwise specified, the terms "upper," "lower," "left," "right," "center," "inner," and "outer," etc., used in the description of specific embodiments of the present invention to indicate orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, or the orientation or positional relationship in which the product / equipment / device is usually placed during use. These terms are merely for the purpose of facilitating the description of the present invention or simplifying the description in specific embodiments, and for enabling those skilled in the art to quickly understand the solution, and do not indicate or imply that a particular device / component / element must have a specific orientation, or be constructed and operated in a specific positional relationship. Therefore, they should not be construed as limitations on the present invention.

[0023] Furthermore, the use of terms such as "horizontal," "vertical," "suspended," "parallel," and "coaxial" does not imply that the corresponding device / component / element must be absolutely horizontal, vertical, suspended, parallel, or coaxial. Slight tilt or deviation is permissible, as long as it does not affect the normal function of the relevant component. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," not that the structure must be perfectly horizontal; a slight tilt is acceptable. "Coaxial" means that two components are arranged as coaxially as possible, allowing them to move coaxially or approximately coaxially when their relative positions change. Alternatively, it can be simplified to mean that the corresponding device / component / element, when arranged in "horizontal," "vertical," "suspended," "parallel," or "coaxial" directions, can have an error / deviation of ±10% relative to the corresponding direction, more preferably within ±8%, more preferably within ±6%, more preferably within ±5%, and more preferably within ±4%. For example, the deviation in the "coaxial" direction is controlled within 0.2-1mm, preferably within 0.2-0.5mm. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its function in the solution of the present invention.

[0024] Furthermore, the use of terms such as "first," "second," and "third" in terminology is merely for distinguishing descriptions of identical or similar components and should not be interpreted as emphasizing or implying the relative importance of a particular component.

[0025] Furthermore, in the description of the embodiments of the present invention, "several", "more than", and "a number of" represent at least two. The number can be any number, such as two, three, four, five, six, seven, eight, or nine, and can even exceed nine.

[0026] Furthermore, in the description of the technical solution of this invention, unless otherwise explicitly specified / limited / restricted, the terms "set up," "install," "connect," "link," "provided with," "laid out," and "arranged" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to connection methods commonly used in the art, such as welding, riveting, bolting, and threaded connections. Such connections can be mechanical, electrical, or communication connections; they can be direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components.

[0027] Example 1 This embodiment takes a certain bridge as an example. The bridge is a double-span, mid-span steel-concrete composite arch bridge with a main span of 310m and a rise-to-span ratio of 1 / 4.48. The arch axis is a catenary (arch axis coefficient m=1.5), and the transverse center-to-center distance between the two arch ribs is 16.2m. The arch rib adopts a steel-concrete composite truss structure. Each arch rib has a variable-height four-tube truss section (5m radial height at the arch crown, 8m radial height at the arch foot, and 2.8m rib width). The upper and lower chords are both two φ1000mm steel-concrete composite chord tubes (20mm and 24mm wall thicknesses, respectively). C55 self-compacting shrinkage-compensating concrete is poured inside the tubes, and the chord tubes are made of Q355C steel. The entire bridge consists of 48 installation segments (12 segments per arch rib). The maximum weight of a segment is 87.7t. The construction adopts a cable-stayed, inclined-hanging method, with symmetrical alternating installation on both banks and simultaneous installation of cross bracing to ensure stability. The main beam of the bridge deck is a lattice-type steel-concrete composite beam, and the arch abutments on both banks adopt gravity-type thrust-resistant structural foundations.

[0028] like Figure 1 , Figure 2 , Figure 4 , Figure 5 , Figure 6 , Figure 7 and Figure 8 The embodiment shown provides an optimized method for stress-free installation of cable-stayed arch bridges, including: A finite element model of the entire arch rib construction process was constructed based on the arch bridge to be constructed on site. The entire arch rib construction process includes constraining the lateral displacement of the arch rib during the arch rib installation segment, constraining the relative axial displacement of the arch ribs on both sides of the arch rib closure opening during the temporary closure stage, and adjusting the relative displacement and rotation angle of the closure opening before the arch rib is officially closed. The finite element model of the entire arch rib construction process was constructed based on the above stages. The influence matrix of factors such as cable force and dead load during the entire construction process of the arch rib was obtained based on the finite element model. An optimization calculation model is constructed, which includes a cable force variable model, a displacement variable model, an initial tension value model, a constraint condition model, and an objective function model. Substitute the influence matrix into the optimization calculation model to obtain the optimization solution; The initial tension load of the cable in each segment and the installation coordinates of the arch rib in each segment were obtained based on the optimization scheme. On-site installation is carried out based on the initial tension load of each cable segment and the installation coordinates of each arch rib segment. Specifically, using the influence matrix as a mapping relationship, the optimization model is iteratively solved using a gradient search-based sequential quadratic programming (SQP) algorithm. By solving the quadratic programming subproblem in each iteration, the cable force variables are continuously corrected until the objective function reaches the convergence deviation threshold while satisfying displacement and rotation constraints, thereby obtaining the initial tension load of each cable segment and the installation coordinates of each arch rib segment. On-site installation is then carried out based on the initial tension load of each cable segment and the installation coordinates of each arch rib segment.

[0029] In one or more embodiments, the cable force variable model includes: ; In the formula: This represents the initial tension load of the sling and side cable wind cables.

[0030] In one or more embodiments, the displacement variable includes: ; In the formula: The displacement of the control points during the installation of the current arch rib segment and the tensioning of the tie cables and side cables; Displacement of control points during installation of arch rib cross braces; To control the displacement of the control point after the slack cable is closed; to counteract the displacement caused by the cross brace, appropriate pre-offset is made before installing the cross brace; for and The average value; The displacement matrix of the control points after the removal of the cable clamps; The displacement vector of the control point caused by the dead load after the removal of the slings and side cables.

[0031] In one or more embodiments, the initial tensile force value includes: ; In the formula: and This is the displacement matrix of the control points when tensioning the arch rib cable and side cable wind cables of the current segment; The target displacement of the control point after the slack cable is closed; This is the displacement vector of the control point caused by the dead load during the installation of the current arch rib segment; This is the displacement vector of the control point caused by the dead load during the installation of the cross brace.

[0032] In one or more embodiments, the constraints include: ; In the formula: and These are the longitudinal, lateral, and vertical displacement values ​​on both sides during temporary closure; and These are the corner values ​​on both sides before the formal closure; and The allowable values ​​for the maximum relative displacement and the maximum relative rotation angle are 1 mm and 0.0001 rad, respectively.

[0033] In one or more embodiments, the objective function includes: ; In the formula: for and The average value; The vertical and lateral target displacements of the control points after the slack cable is closed.

[0034] Example 2 like Figure 3 and Figure 9 The illustrated embodiment 2 provides a stress-free installation method for cable-stayed arch bridges, employing an optimized method from embodiment 1. The method includes several segments of first and second arch ribs 1, symmetrically arranged, and further includes the following steps: S1: Install the first arch rib 1 and the second arch rib 2; S2: Adjust the relative lateral offset between the first arch rib 1 and the second arch rib 2 to zero; S3: Interrib cross bracing is provided between the first arch rib 1 and the second arch rib 2; S4: Repeat steps S1-S3 until the arch rib is in the maximum cantilever state; S5: Temporarily close the first arch rib 1 and the second arch rib 2; S6: Adjust the relative displacement and rotation of the first arch rib 1 and the second arch rib 2 at the closing joint until the relative displacement and rotation are less than the allowable values, wherein the allowable value of the maximum relative displacement is 1 mm and the allowable value of the maximum relative rotation is 0.0001 rad. S7: Close the connection.

[0035] In one or more embodiments, in step S2, the relative lateral offset between the first arch rib 1 and the second arch rib 2 is adjusted to zero by adjusting the lateral guy cable force of the arch ribs or by mutual traction of the pull hoists. This adjustment of the relative lateral offset between the first arch rib 1 and the second arch rib 2 is achieved by laterally aligning the first arch rib 1 and the second arch rib 2, so that each segment of the arch rib remains on the same plane during installation, eliminating lateral offset and improving installation accuracy.

[0036] In one or more embodiments, S5 involves temporarily closing the first arch rib 1 and the second arch rib 2 by setting a temporary closing device 3 at the closing point of the first arch rib 1 and the second arch rib 2 to achieve temporary closing.

[0037] Example 3 This Example 3 is a practical application of Example 1.

[0038] The bridge is a double-span, mid-span steel-concrete composite arch bridge with a main span of 310m and a rise-to-span ratio of 1 / 4.48. The arch axis is a catenary (arch axis coefficient m=1.5), and the transverse center-to-center distance between the two arch ribs is 16.2m. The arch ribs adopt a steel-concrete composite truss structure, with each arch rib having a variable-height four-tube truss section (5m radial height at the arch crown, 8m radial height at the arch foot, and 2.8m rib width). Both the upper and lower chords consist of two φ1000mm steel-concrete composite chord tubes (20mm and 24mm wall thicknesses), filled with C55 self-compacting shrinkage-compensating concrete. The chord tubes are made of Q355C steel. The entire bridge consists of 48 installation segments (12 segments per arch rib), with the largest segment weighing 87.7t. The construction employed a cable-stayed, inclined-stayed method, with symmetrical alternating installation on both banks and simultaneous installation of cross bracing to ensure stability. The main beam of the bridge deck is a lattice-type steel-concrete composite beam, and the arch abutments on both banks adopt gravity-type thrust-resistant structural foundations.

[0039] Optimization analysis process: S1: Based on the geometric parameters, material parameters, boundary conditions, load conditions, and active correction parameters of the closing posture of the arch bridge, an OpenSeeSpy finite element model of the arch bridge is established, including: structural group, boundary value group, and load group, which forms the various construction stages of the structure. Then, the influence matrices ut, M1, M2, Mn, C1, C2, Cn and T0 are calculated based on the OpenSeeSpy finite element model. Because the influence matrix is ​​a long topic and the solution of the influence matrix is ​​a current technology, it will not be described in detail here.

[0040] S2: The constraint model is as follows: and These are the longitudinal, lateral, and vertical displacement values ​​on both sides during temporary closure; and These are the corner values ​​on both sides before the formal closure; and The allowable values ​​for the maximum relative displacement and the maximum relative rotation angle are 1 mm and 0.0001 rad, respectively.

[0041] S3: Construct a mathematical optimization model based on S1 and S2. This includes: Cable force variables: ; In the formula: This represents the initial tension load of the sling and side cable wind cables.

[0042] Displacement variables: ; In the formula: The displacement of the control points during the installation of the current arch rib segment and the tensioning of the tie cables and side cables; Displacement of control points during installation of arch rib cross braces; To control the displacement of the control point after the slack cable is closed; to counteract the displacement caused by the cross brace, appropriate pre-offset is made before installing the cross brace; for and The average value; The displacement matrix of the control points after the removal of the cable clamps; The displacement vector of the control point caused by the dead load after the removal of the slings and side cables.

[0043] Initial tension value: ; In the formula: and This is the displacement matrix of the control points when tensioning the arch rib cable and side cable wind cables of the current segment; The target displacement of the control point after the slack cable is closed; This is the displacement vector of the control point caused by the dead load during the installation of the current arch rib segment; This is the displacement vector of the control point caused by the dead load during the installation of the cross brace.

[0044] Constraints: ; In the formula: and These are the longitudinal, lateral, and vertical displacement values ​​on both sides during temporary closure. Objective function: .

[0045] The sequential quadratic programming (SQP) algorithm based on gradient search iteratively solves the optimization model S3, obtaining the initial tension T of each cable as follows: Figure 6 As shown, the control elevation of the construction process can be obtained by substituting the initial tension T back into the finite element model. Since the method is conventional, it will not be elaborated here.

[0046] Based on the calculated cable tension and pre-lifting value, install the arch ribs of each segment, specifically including the following steps: a) Install the first arch rib on both banks, upstream and downstream. b) Apply coercive measures to ensure that the relative lateral deviation of the upper second arch rib is zero. c) Install the first section of the cross brace d) Repeat steps a) through c) until the maximum cantilever state is reached. e) Install a temporary closing device on the upper or lower chord of the arch rib to temporarily close the upper or lower chord of the arch rib. f) Apply coercive measures. Adjust the tension of the No. 3 sling to 0%, so that the permissible values ​​for the maximum relative displacement and the maximum relative rotation angle are less than 1 mm and 0.0001 rad, respectively.

[0047] g) Arch ribs closing Remove all the bridge's cable ties.

[0048] It should be noted that in this embodiment, the results of ut, M1, M2, Mn, C1, C2, Cn and T0 are obtained by combining the calculations of finite element software, such as structural analysis software like Midas, Ansys, and Opensees, and then assembling the matrix. The optimization solution process can be performed iteratively using general mathematical optimization methods, such as first-order optimal algorithms and gradient search-based sequential quadratic programming methods.

[0049] Example 4 like Figure 10 and Figure 11The temporary closing device 3 shown in this scheme includes a first connecting part 31 and a second connecting part 32. The first connecting part 31 and the second connecting part 32 are connected by a connecting plate 33. The end of the first connecting part 31 that is not connected to the connecting plate 33 is connected to the upper chord and / or lower chord of the first arch rib 1, and the end of the second connecting part 32 that is not connected to the connecting plate 33 is connected to the upper chord and / or lower chord of the second arch rib 2 (if the first connecting part 31 is connected to the upper chord of the first arch rib 1, then the second connecting part 32 is connected to the upper chord and / or lower chord of the second arch rib 2). The upper chord is connected; the first connecting part 31 is connected to the lower chord of the first arch rib 1, and the second connecting part 32 is connected to the lower chord of the second arch rib 2. The first connecting part 31 includes a first vertical plate 311 and a first horizontal plate 312, and the first vertical plate 311 and the first horizontal plate 312 form a cross-shaped structure. The two ends of the first vertical plate 311 abut against the inner wall of the upper chord of the first arch rib 1 or the inner wall of the lower chord of the first arch rib 1, and the two ends of the first horizontal plate 312 abut against the inner wall of the upper chord of the first arch rib 1 or the inner wall of the lower chord of the first arch rib 1. The second connecting part 32 includes a second vertical plate 321 and a second horizontal plate 322, which form a cross-shaped structure. The two ends of the second vertical plate 321 abut against the inner wall of the upper chord or the inner wall of the lower chord of the second arch rib 2. The first horizontal plate 312 and the first vertical plate 311 are connected to the upper or lower chord of the first arch rib 1 by welding. The second horizontal plate 322 and the second vertical plate 321 are connected to the upper or lower chord of the second arch rib 2 by welding. The first connecting part 31 is connected to the connecting plate 33 by welding. The second connecting part 32 is connected to the connecting plate 33 by welding or bolting. Optionally, when both the first connecting part 31 and the second connecting part 32 are bolted to the connecting plate 33, the connecting plate 33 can be a pair of clamping plates. The clamping plates clamp the first vertical plate 311 of the first connecting part 31 and the second vertical plate 321 of the second connecting part 32 respectively, and bolt holes are opened at corresponding positions of the clamping plates, the first vertical plate 311 and the second vertical plate 321 for bolt connection.

[0050] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An optimized method for stress-free installation of cable-stayed arch bridges, characterized in that the method... include: A finite element model of the arch rib is established based on the geometric parameters, material parameters, boundary conditions, load conditions, and active correction parameters of the closing posture of the arch bridge to be constructed. The influence matrix is ​​obtained based on the finite element model; A mathematical optimization model is established based on the influence matrix. The mathematical optimization model includes cable force variables, displacement variables, initial tension values, constraints, and objective function. An optimization algorithm is used to iterate and optimize the mathematical optimization model to obtain the initial tensile load of each segment of the cable and the installation coordinates of each segment of the arch rib.

2. The optimized method for stress-free installation of cable-stayed arch bridges according to claim 1, characterized in that, The boundary conditions include: The lateral displacement of the arch ribs is constrained during the arch rib installation stage. During the temporary closure stage of the arch ribs, the relative axial displacement of the arch ribs on both sides of the closure opening is constrained. The active correction parameters for the closing posture include: Before the arch ribs are closed, the relative displacement and rotation of the closure joint are adjusted by adjusting the tension of the fastening cables or by applying a forced force near the closure joint.

3. The optimized method for stress-free installation of cable-stayed arch bridges according to claim 1, characterized in that, The cable force variables include: ； In the formula: This represents the initial tension load of the sling and side cable wind cables.

4. The optimized method for stress-free installation of cable-stayed arch bridges according to claim 1, characterized in that, The displacement variables include: ； In the formula: The displacement of the control points during the installation of the current arch rib segment and the tensioning of the tie cables and side cables; Displacement of control points during installation of arch rib cross braces; This refers to the displacement of the control point after the slack cable is closed; for and The average value; The displacement matrix of the control points after the removal of the cable clamps; The displacement vector of the control point caused by the dead load after the removal of the slings and side cables.

5. An optimized method for stress-free installation of cable-stayed arch bridges according to claim 1, characterized in that, The initial tensile force value includes: ； In the formula: and This is the displacement matrix of the control points when tensioning the arch rib cable and side cable wind cables of the current segment; The target displacement of the control point after the slack cable is closed; This is the displacement vector of the control point caused by the dead load during the installation of the current arch rib segment; This is the displacement vector of the control point caused by the dead load during the installation of the cross brace.

6. An optimized method for stress-free installation of cable-stayed arch bridges according to claim 1, characterized in that, The constraints include: ； In the formula: and These are the longitudinal, lateral, and vertical displacement values ​​on both sides during temporary closure; and These are the corner values ​​on both sides before the formal closure; and The allowable values ​​for the maximum relative displacement and the maximum relative rotation angle are 1 mm and 0.0001 rad, respectively.

7. An optimized method for stress-free installation of cable-stayed arch bridges according to claim 1, characterized in that, The objective function includes: 。 In the formula: for and The average value; The vertical and lateral target displacements of the control points after the slack cable is closed.

8. A stress-free installation method for cable-stayed arch bridges, characterized in that, The installation is carried out using the optimized method for stress-free installation of the cable-stayed arch bridge as described in any one of claims 1-7, including a plurality of first arch ribs (1) and a plurality of second arch ribs (2) arranged opposite to each other, and further including the following steps: S1: Install the first arch rib (1) and the second arch rib (2); S2: Adjust the relative lateral offset between the first arch rib (1) and the second arch rib (2) to zero; S3: An inter-rib cross brace is provided between the first arch rib (1) and the second arch rib (2); S4: Repeat steps S1-S3 until the arch rib is in the maximum cantilever state; S5: Temporarily close the first arch rib (1) and the second arch rib (2); S6: Adjust the relative displacement and rotation angle of the first arch rib (1) and the second arch rib (2) at the closure by adjusting the fastening force or applying a forced force near the closure; S7: Close the connection.

9. A stress-free installation method for cable-stayed arch bridges according to claim 8, characterized in that, The adjustment of the relative lateral offset between the first arch rib (1) and the second arch rib (2) in S2 to zero includes: adjusting the lateral cable force of the arch ribs or using a hand-operated hoist to pull each other to adjust the first arch rib (1) and the second arch rib (2).

10. A stress-free installation method for cable-stayed arch bridges according to claim 8, characterized in that, S5 involves temporarily closing the first arch rib (1) and the second arch rib (2) by setting a temporary closing device (3) at the closing point of the first arch rib (1) and the second arch rib (2).

Images