Steel truss arch ring internal force and linear double-control arching method based on cable-stayed buckling method

Abstract

The invention relates to the technical field of bridge engineering, in particular to a steel truss arch ring internal force and linear double-control arching method based on a cable-stayed buckling method, which comprises the following steps of: comparing, selecting and determining a linear target and an internal force target of an arch ring structure by adjusting an unstressed linear shape of a closure section based on a full-bridge finite element model of an arch ring primary falling frame; a cable-stayed buckling system arrangement scheme is determined, and cable-stayed buckling cable construction cable force needed for achieving an arching target is solved based on the comprehensive forward-installed finite element model conforming to the actual construction stage; setting a construction error threshold value through calculation based on a calculation model by taking the stress state of the key part of the structure as a judgment condition; the tension cable force is controlled based on a linear target, an internal force target, a construction cable force and an error threshold value proposed by the design, the internal force distribution of an arch ring chord member is actively adjusted, and a closure section rod piece is lengthened.

Description

Technical Field

[0001] The invention relates to the technical field of bridge engineering, in particular to an arch forming method for double-controlling the internal force and linear shape of a steel truss arch ring based on an inclined-stayed buckle-hanging method. Background Art

[0002] As an arch bridge construction technology, the inclined-stayed and buckled hanging method can complete the erection of the arch ring without setting up a scaffold, which significantly improves the construction efficiency and has been widely used in many arch bridge construction projects in China.

[0003] When the arch ring is erected, the cable tension of the inclined cable 2 has a significant impact on the internal force and deformation of the structure. However, in actual operation, the ideal bare arch line shape is often taken as the main control target and the internal force control is ignored, which will lead to the problem of fuzzy or uneven distribution of the permanent internal force state of the arch ring structure 5, thereby affecting the safety and durability of the structure.

[0004] In recent years, with the continuous progress of engineering technology, the maximum span of arch bridges has achieved a significant increase. Especially in the construction of large-span steel truss arch bridges, the traditional arch forming method has gradually exposed its limitations. If the inclined cable force is not actively used to effectively control the internal force of the arch ring, it will inevitably lead to a large difference in the internal force between the upper chord 6 and the lower chord 7, which will cause the maximum plate thickness of the rod to be thick, making it difficult to process and manufacture, and the material consumption will further increase.

[0005] Especially for parallel steel truss arch bridges with a span of 600 meters, the width-to-span ratio decreases rapidly, and the lateral force problem becomes prominent, which makes the lateral wind effect one of the control factors of structural design. Under the action of extreme crosswind, the chord at the arch foot will be subjected to a large tensile force, which not only increases the difficulty of anchoring the arch foot, but also poses a threat to the safety of the overall structure. Therefore, it is particularly important to actively control the internal force of the arch ring through the inclined cable force.

[0006] Therefore, in order to solve a series of problems in the application of traditional arch forming methods in large-span steel truss arch bridges, there is an urgent need for an arch forming method that dual-controls the internal force and linear shape of the steel truss arch ring based on the inclined-stayed buckle hanging method. Summary of the invention

[0007] The purpose of the present invention is to provide a steel truss arch ring internal force and linear dual control arch forming method based on the oblique-stayed and buckled hanging method for the existing large-span steel truss arch bridge. The traditional arch forming method has the problems of uneven distribution of structural internal forces and insufficient axial pressure reserve at the anchor end of the upper chord arch foot when the oblique-stayed and buckled hanging method is used for construction.

[0008] In order to achieve the above object, the technical solution adopted by the present invention is:

[0009] In a first aspect, the present invention provides a method for forming an arch by controlling both the internal force and the linear shape of a steel truss arch ring based on an inclined buckle hanging method, comprising the following steps:

[0010] Based on the finite element model of the whole bridge with the arch ring dropped at one time, the arch ring structure linear target and internal force target are compared and determined by adjusting the stress-free linear shape of the joint section;

[0011] Determine the layout of the cable-stayed cable system, and solve the cable force required to achieve the arching goal based on a comprehensive upright finite element model that conforms to the actual construction stage;

[0012] Taking the stress state of key parts of the structure as the judgment condition, the construction error threshold is established through calculation based on the calculation model;

[0013] Based on the linear target, internal force target, construction cable force and error threshold proposed in the design, the tension cable force is controlled, the internal force distribution of the arch ring chord is actively adjusted, and the length of the joint section member is set.

[0014] As a preferred technical solution of the present invention, a construction plan and a monitoring plan are formulated based on the linear target, internal force target, construction cable force and error threshold proposed in the design.

[0015] As a further preferred technical solution of the present invention, the manufacturer processes and manufactures the arch ring members in batches according to the erection sequence, and the arch ring cantilever segment members do not need to be pre-lifted.

[0016] As a further preferred technical solution of the present invention, the anchor cable is tensioned in a whole bundle.

[0017] As a further preferred technical solution of the present invention, before closure, the linear shape and internal force of the arch ring are comprehensively measured and verified to control the cable force in the maximum cantilever state and the stress-free linear shape of the closure section.

[0018] As a further preferred technical solution of the present invention, force, geometry, environment and structural parameters are monitored during the construction process.

[0019] As a further preferred technical solution of the present invention, the cable force of the inclined buckle anchor cable is monitored, and at least one of the buckle cable and anchor cable in the same group is monitored.

[0020] As a further preferred technical solution of the present invention, the deviation of the tower is monitored during the erection process.

[0021] In a second aspect, the present invention further provides a steel truss arch ring, which is constructed by using the steel truss arch ring internal force and linear double-control arch forming method based on the inclined buckle hanging method as described in any of the above items.

[0022] In a third aspect, the present invention further provides a steel truss arch bridge, comprising the steel truss arch ring as described above.

[0023] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0024] The present invention discloses a method for forming an arch by dual control of the internal force and linear shape of a steel truss arch ring based on the oblique-stayed buckle hanging method. The method can effectively adjust the internal force distribution of the arch ring, and its effect is similar to that of applying prestress in the steel truss arch ring. Through this method, the axial pressure reserve at the anchoring end of the arch foot of the upper chord can be significantly improved, thereby greatly reducing the difficulty of anchoring the arch foot and improving the safety performance of the overall structure. At the same time, the method can also optimize the axial force distribution of the upper and lower chords of the arch ring, making it more uniform, significantly reducing the axial force peak value, reducing the maximum thickness of the chord plate, thereby reducing the difficulty of welding and achieving the goal of further reducing the amount of steel used in the arch ring. The method can effectively lock the positive effect of active tensioning of the cable force on the deformation of the upper arch of the arch ring. In the bare arch state, the arch ring as a whole presents an upwardly lifted deformation state, thereby playing a role. The method does not seek to adjust the line shape of the arch ring by changing the cable tension. The internal force and line shape control of the arch ring structure are relatively independent. This independence makes the internal force state of the structure after the bridge is completed clear, which is conducive to ensuring the safety and durability of the structure during construction and operation. In the construction process of this method, the operation is based on the existing cable-stayed buckle system, without the need for additional large construction or material costs. For large-span steel truss arch bridges, especially parallel steel truss arch bridges with a span of 600 meters, actively using cable-stayed buckle technology to adjust the internal force of the arch ring is a key measure to ensure the economy, safety and rationality of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a flow chart of the arch forming method of double-controlling the internal force and linear shape of the steel truss arch ring;

[0026] Figure 2 It is a schematic elevation diagram of the arch ring and the inclined buckle hanging system;

[0027] Figure 3 It is a plan view of the arch ring and the inclined buckle hanging system;

[0028] Figure 4 It is a structural schematic diagram of the embedded parts of the arch foot;

[0029] Figure 5 It is a schematic diagram of the internal force of the main chord under the action of a constant load in the bridge completion state using the arch forming method of the present application;

[0030] Figure 6 Schematic diagram of the internal force of the main chord under constant load in the completed bridge state using the traditional arch forming method.

[0031] Markings in the figure: 1-cathedral, 2-cathedral, 3-anchor cable, 4-lateral oblique clinching cable, 5-arch ring structure, 6-upper chord, 7-lower chord, 8-arch foot anchoring end. DETAILED DESCRIPTION

[0032] The present invention is further described in detail below in conjunction with test examples and specific implementation methods. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0033] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all expressions based on the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.

[0034] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.

[0035] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.

[0036] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.

[0037] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.

[0038] In the related art, when a 600-meter-class large-span steel truss arch bridge is constructed using the inclined-stayed buckle-hanging method, the traditional arch-forming method has the problems of uneven distribution of structural internal forces and insufficient axial pressure reserve at the anchor end of the arch foot of the upper chord. Figures 1 to 6 To elaborate.

[0039] Example 1

[0040] like Figures 1 to 6 As shown, the present invention discloses a method for forming an arch by controlling both the internal force and the linear shape of a steel truss arch ring based on an inclined buckle hanging method, comprising the following steps:

[0041] Step 1: Design as an arch target

[0042] The internal force and linear dual control arching method is an innovative technology with internal force control as the core, which aims to actively adjust the internal force distribution of the arch ring chord by accurately controlling the tension cable force. In the process of erecting an arch bridge, this method combines the matching and growth setting of the joint section rods to achieve effective regulation of the internal force and deformation of the arch ring structure 5, thereby producing a beneficial effect.

[0043] 1. Determine the arch target

[0044] The first step in implementing this method is to define the arching targets, which include linear targets and internal force targets. The linear target covers the manufacturing linear shape (i.e. stress-free linear shape), installation linear shape and final arching linear shape of the arch ring structure 5. The internal force target focuses on the axial pressure reserve of the chord arch foot anchorage end 8 and the overall internal force distribution of the arch ring chord.

[0045] The principle of the method is that when the joint section is extended, it will push the arch ring cantilever segments on both sides, causing the arch ring structure 5 to deform in the opposite direction to the direction under the action of the dead load. This process not only helps to adjust the internal force distribution of the structure, but also ensures that the arch ring reaches the optimal state of upward arching in terms of deformation. Therefore, when manufacturing the arch ring cantilever segments, it is not necessary to set a pre-lift amount.

[0046] Based on the above principle, a finite element model of the whole bridge with the arch ring dropped at one time is first established. In this model, the linear shape of the arch ring cantilever segment remains unchanged, and the internal force distribution of the arch ring structure 5 is optimized only by adjusting the stress-free linear shape (including length and curvature) of the joint segment. After analyzing and comparing the internal force results, we select and determine the arch formation target, which includes the linear shape target and internal force target of the arch ring structure 5 mentioned above.

[0047] 2. Determine the cable tension

[0048] The key to achieving the arching goal is to set a reasonable cable force. First, the layout of the cable-stayed cable system needs to be determined based on the topography and geology of the bridge site. For large-span steel truss arch bridges, the lateral force and stability of the structure are particularly prominent in the cantilever state. In order to ensure that the cantilever structure has sufficient lateral force and stability, lateral inclined cables can be added if necessary4.

[0049] After the layout of the cable-stayed buckle system is determined, a comprehensive finite element model of the entire bridge is established. This model not only includes the cable-stayed buckle system, but also must conform to the actual construction steps. Based on this model, we can use methods such as influence matrix to solve the cable force of the cable-stayed buckle 2 required to achieve the arching target.

[0050] 3. Set up error thresholds

[0051] In the systematic project of bridge construction, ensuring that the bridge reaches the designed state is the ultimate goal of construction. However, during the construction process, the bridge structure will inevitably be affected by various uncertain factors (i.e. errors). In order to improve the real-time and efficiency of construction, an acceptable error threshold range needs to be set. When the error is within this threshold range, the state result after the bridge is completed is considered acceptable and no error adjustment is required; when the error exceeds this threshold, adjustment and correction are required.

[0052] Specifically, the stress state of the key parts that control the safety of the structure is selected as the judgment condition. For example, for a 600-meter-span parallel steel truss arch bridge project, the 8-axis pressure reserve level at the anchor end of the chord arch foot after the completion of the bridge can be selected as the judgment condition. According to the calculation results, we set the construction error threshold as follows: the error of a single cable force does not exceed 5% of the design value, and the sum of the absolute values ​​of all cable force errors does not exceed 2% of the sum of the cable force design values. At the same time, the angle deviation of the rod axis should be less than 1.5'. In this way, we can minimize the number and cost of error adjustments while ensuring the safety of the structure.

[0053] Step 2: Steel structure manufacturing and construction

[0054] The manufacture and construction of steel structures are key steps to achieve the goal of arching. In order to achieve this goal, the arch ring segment steel rods are manufactured in batches, and the arch ring on-site erection is carried out using the inclined buckle hanging method. In this process, it is crucial to control the accuracy of manufacturing and construction.

[0055] 1. Steel structure manufacturing

[0056] Steel structure manufacturing is carried out in the factory. With this method, no additional pre-lifting is required for the arch ring cantilever segment rods, which simplifies the drawing deepening process. Rod manufacturing is carried out in multiple batches according to the erection order. Errors will be monitored and adjusted in time during the implementation of the bridge. Linear adjustments can be made according to monitoring instructions in the subsequent batches of arch segment manufacturing for geometric correction. The joint segment rods need to be extended, and their linear compensation values ​​need to be proposed based on monitoring data and combined with theoretical calculation and analysis.

[0057] In order to ensure the processing quality of steel structures, the temperature effect needs to be corrected during the processing, and automated processing and manufacturing technology can be used to improve the cutting accuracy, and pre-assembly and advanced measurement technology can be used for re-testing. These measures will help to ensure the manufacturing quality and accuracy of steel structures.

[0058] 2. Arch ring installation

[0059] The erection process of the arch ring is divided into three main stages: pre-embedding of the arch feet, cantilever assembly and closure.

[0060] During the arch foot embedding stage, a qualified and reliable support system needs to be set up to ensure that the embedded parts are installed in place with reliable accuracy. At the same time, during the concrete pouring process, displacement and deformation must be prevented.

[0061] During the cantilever assembly and erection stage of the arch ring, the angle and force of the anchor cable are mainly controlled, and the requirements of the installation line are taken into account. The anchor cable can be tensioned as a whole bundle, and the tensioning jack is digital. The jack and oil gauge should be strictly calibrated before use. In order to reduce the linear error caused by on-site welding deformation, the arch ring should be connected on site by full bolting.

[0062] The stress-free linear shape of the joint section rod is the decisive factor to ensure the smooth locking of the cable force and the beneficial effect of active tensioning on the internal force and deformation of the arch ring structure 5. Before the joint is closed, the linear shape and internal force of the arch ring are fully measured and verified to control the cable force of the maximum cantilever state and the stress-free linear shape of the joint section. According to the actual situation such as the joint mouth deviation and temperature field distribution, appropriate error adjustment measures are selected. According to the monitoring instructions, the joint section rods are cut and installed on site. After the joint is closed, the external cable force is gradually and symmetrically released, and finally the beneficial effect of active tensioning of the cable force on the internal force of the arch ring structure 5 and the deformation of the upper arch is achieved.

[0063] Step 3: Construction monitoring and control

[0064] During the construction process, it is necessary to be guided by comprehensive construction stage calculations and control the entire construction process in combination with monitoring data. The purpose is to ensure that the stress and deformation errors of key parts of the structure at each construction stage are within the allowable range, and ultimately the bridge meets the design requirements.

[0065] 1. Monitoring content

[0066] Different from the traditional method, this method not only focuses on the ideal bare arch line shape, but more importantly, it controls the internal forces of the structure. Therefore, it is necessary to accurately identify the cause of the error during the construction process and propose targeted control measures.

[0067] To this end, the monitoring content and quantity need to have sufficient redundancy, mainly covering the following three aspects:

[0068] (1) Force monitoring

[0069] For monitoring of the cable force of the inclined cable anchor, at least one of the cable anchors 2 and 3 in the same group should be monitored, and a pressure ring with an accuracy of 0.5% can be used for monitoring.

[0070] For monitoring the stress of the arch foot anchoring device, if steel tie rods are used for anchoring, the axial force of the steel tie rods at least at the four corner points of each chord should be continuously monitored. Automatic monitoring can be carried out using a pressure ring with an accuracy of 0.5% and an automatic data collection device.

[0071] To monitor the stress of the arch ring structure 5, stress tests should be carried out on at least the arch foot and the eighth point section.

[0072] (2) Geometry Monitoring

[0073] Monitoring of the manufacturing alignment and the on-site reassembly alignment of the arch ribs before erection.

[0074] Monitoring of arch rib deformation during erection.

[0075] During the erection process, it is very important to monitor the deviation of the buckle tower 1, because any deviation will change the angle of the buckle anchor cable, thereby affecting the internal force distribution of the arch ring structure 5.

[0076] (3) Monitoring of environmental and structural parameters

[0077] Environmental parameters such as temperature and wind speed, as well as key parameters such as weight, elastic modulus, and cross-sectional dimensions of permanent and temporary structures must be accurately tested. The test results are used to calibrate and optimize the structural calculation and analysis model to ensure the accuracy and reliability of the design.

[0078] 2. Analysis and Regulation

[0079] Due to construction errors, such as inaccurate positioning and cable tension deviation, the actual structural state may differ from the ideal state of the design. Once these deviations are found, the measurement data should be used immediately to quickly identify the root cause of the problem. The following are some common situations:

[0080] (1) If the cable forces and internal forces meet the design requirements, but the linear shape of the arch ring does not, this is usually because there is an error in the linear shape of the steel structure during manufacturing or installation.

[0081] (2) When the cable tension and arch ring line shape meet the design calculation requirements, but the internal forces of the structure do not, this may be due to errors caused by inaccurate instrument measurement or changes in environmental and structural parameters.

[0082] (3) If the internal forces and arch line shape of the structure meet the design requirements, but the cable tension does not, it may also be due to errors caused by inaccurate instrument measurement or changes in environmental and structural parameters.

[0083] (4) When the cable forces, structural internal forces and arch ring line shape do not meet the design requirements, the first thing to consider is whether there are errors in the cable angle setting and the cable tensioning process.

[0084] Through these analyses, problems can be identified more accurately and appropriate measures can be taken to make adjustments and corrections.

[0085] After the construction of each control condition is completed, a detailed calculation and analysis must be performed based on the current structural state and identified parameters obtained through on-site monitoring. The purpose is to predict the target state in the subsequent construction process and the final state of the bridge. If the actual deviation is less than the predetermined error threshold, it can be considered that the internal forces and deformations of the structure will meet the requirements and achieve the ideal state of the design during the subsequent construction process. In this case, no adjustment is required at the current stage.

[0086] On the contrary, if the actual deviation exceeds the error threshold, it is necessary to formulate corresponding correction measures based on the current measurement data and analysis results, and issue correction instructions. For the arch ring linear error caused by non-cable force, it can be corrected by adjusting the manufacturing and installation linearity of the steel structure. For the error of the arch ring internal force, it is necessary to correct it by adjusting the cable force. This method avoids mutual interference between the two.

[0087] The present embodiment describes a method for forming an arch by dual control of the internal force and linear shape of a steel truss arch ring based on the oblique-stayed buckle hanging method. This method can effectively adjust the internal force distribution of the arch ring, and its effect is similar to applying prestress in the steel truss arch ring. Through this method, the axial pressure reserve of the arch foot anchoring end 8 of the upper chord 6 can be significantly improved, thereby greatly reducing the difficulty of anchoring the arch foot and improving the safety performance of the overall structure. At the same time, this method can also optimize the axial force distribution of the upper and lower chords 7 of the arch ring, making it more uniform, significantly reducing the axial force peak value, reducing the maximum thickness of the chord plate, thereby reducing the difficulty of welding, and achieving the goal of further reducing the amount of steel used in the arch ring; this method can effectively lock the positive effect of active tensioning of the cable force on the deformation of the upper arch of the arch ring. In the bare arch state, the arch ring as a whole presents an upwardly lifted deformation state, thereby playing a role The pre-arching effect is achieved, so the arch ring cantilever segment does not need to be additionally set with a pre-lift, which greatly reduces the work steps of most of the rod manufacturing linear deepening design, thereby improving the manufacturing efficiency; the method does not seek to adjust the linear shape of the arch ring by changing the cable force, and the internal force and linear control of the arch ring structure 5 are relatively independent. This independence makes the internal force state of the structure after the bridge is completed clear, which is conducive to ensuring the safety and durability of the structure during construction and operation; during the construction process of the method, the operation is based on the existing cable-stayed buckle hanging system, and there is no need to invest a large amount of additional construction or material costs; for large-span steel truss arch bridges, especially parallel steel truss arch bridges with a span of 600 meters, actively using the cable-stayed buckle cable force technology to adjust the internal force of the arch ring is a key measure to ensure the economy, safety and rationality of the structure.

[0088] Example 2

[0089] A steel truss arch ring internal force and linear double-control arching method based on the inclined buckle hanging method described in Example 1 is used to construct a top-supported steel truss arch bridge with a span of 600 meters. The bridge is located on a highway with a design speed of 100 kilometers per hour. The bridge deck is about 310 meters away from the river valley, and the wind field distribution is complex. The arch ring rise is 116m, and the rise span ratio is 1 / 5; the center line of the arch rib is a catenary, and the arch axis coefficient is 2.0. The main arch arch rib adopts a double-piece variable height steel truss structure, and the upstream and downstream main trusses are arranged in parallel, with a horizontal center spacing of 20.2m. The center height of the arch top truss is 13.5m, the center height of the arch foot truss is 16m, and the upper chord 6 and the lower chord 7 adopt a box section. This bridge has the characteristics of large span, light structure and high design wind speed. Conventional arch bridges are usually designed by vertical load control, while this bridge is designed by both vertical load and lateral wind load. This is a qualitative change that occurs when the span of a top-supported steel truss arch bridge reaches a certain level.

[0090] If the traditional arch forming method is used, then under the action of the constant load in the completed bridge state, the axial pressure reserve of the upper chord 6 arch foot anchor end 8 is only 31600kN. During operation, due to the combined action of live loads such as lateral wind, a large axial tension will appear at the upper chord 6 arch foot anchor end 8, which cannot meet the strength requirements. To solve this problem, the axial pressure reserve of the chord arch foot anchor end 8 can be increased by increasing the number of prestressed steel tie rods on the basis of the traditional arch forming method. According to calculations, 10 prestressed steel tie rods with a diameter of 120mm are required for a single upper chord 6 arch foot. At the same time, it is also necessary to further increase the cross-sectional profile size of the arch foot chord to provide sufficient space to set these steel tie rods. However, doing so will make the arch foot structure more complicated. In addition, under the basic combined action in the operation stage, the peak axial force of the chord reached about 207000kN. This situation occurred in the area of ​​the lower chord 7 close to the arch foot, such as Figure 6 As shown. At this time, the stress of the rod cannot meet the strength requirements of the specification. If the method of increasing the thickness of the rod is used to reduce the stress level, after measurement, the maximum plate thickness of the rod needs to be increased by 8 mm, and the amount of steel used will increase by about 200 tons. Therefore, the traditional arching method will not only increase the difficulty of rod welding, but also increase the material cost.

[0091] By applying the double-control arch forming method of the present invention, it can be achieved that under the action of the constant load in the bridge forming state, the arch foot reaction forces of the upper chord rod 6 and the lower chord rod 7 are equal, and the axial force levels of the corresponding parts of the upper chord rod 6 and the lower chord rod 7 are basically consistent. Figure 5 As shown. After calculation and research, it is only necessary to increase the cable force of each pair of cables 2 by about 20% on average and set the length of the dragon section by about 390mm to achieve the control target. In the actual construction process, the existing inclined-stayed buckle system is mainly used, supplemented by the addition of a small amount of internal force monitoring equipment. After adopting this method, the axial pressure reserve of the arch foot anchorage end 8 of the upper chord 6 can be enhanced to 59800kN, which greatly reduces the difficulty of arch foot anchorage; and under the basic load combination in the operation stage, the axial force peak of the chord is reduced to about 181000kN, achieving a reduction of about 12.6%, which significantly improves the stress condition of the structure. In the bare arch state, the entire arch ring shows an upward lifting deformation mode, in which the upper arch deformation at the arch top is about 200mm, and this deformation plays the role of preset arch degree.

[0092] 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 in the protection scope of the present invention.

Claims

1. A method for forming an arch by controlling the internal force and linear shape of a steel truss arch ring based on the inclined buckle hanging method, characterized in that: The following steps are involved: Based on the finite element model of the whole bridge with the arch ring dropped at one time, the arch ring structure linear target and internal force target are compared and determined by adjusting the stress-free linear shape of the joint section; Determine the layout of the cable-stayed cable system, and solve the cable force required to achieve the arching goal based on a comprehensive upright finite element model that conforms to the actual construction stage; Taking the stress state of key parts of the structure as the judgment condition, the construction error threshold is established through calculation based on the calculation model; Based on the linear target, internal force target, construction cable force and error threshold proposed in the design, the tension cable force is controlled, the internal force distribution of the arch ring chord is actively adjusted, and the length of the joint section member is set.

2. The method for forming an arch by controlling the internal force and linear shape of a steel truss arch ring based on the inclined buckle hanging method according to claim 1 is characterized in that: The construction plan and monitoring plan are formulated based on the linear targets, internal force targets, construction cable tension and error thresholds proposed in the design.

3. The method for forming an arch by controlling the internal force and linear shape of a steel truss arch ring based on the inclined buckle hanging method according to claim 2 is characterized in that: The manufacturer processes and manufactures the arch ring members in batches according to the erection sequence, and no additional pre-lifting amount is required for the arch ring cantilever segment members.

4. The method for forming an arch by controlling the internal force and linear shape of a steel truss arch ring based on the inclined buckle hanging method according to claim 2 is characterized in that: The anchor cable is tensioned as a whole bundle.

5. The method for forming an arch by controlling the internal force and linear shape of a steel truss arch ring based on the inclined buckle hanging method according to claim 2 is characterized in that: Before closure, the arch ring's linear shape and internal forces are comprehensively measured and reviewed to control the cable tension in the maximum cantilever state and the stress-free linear shape of the closure section.

6. The method for forming an arch by controlling the internal force and linear shape of a steel truss arch ring based on the inclined buckle hanging method according to any one of claims 2 to 5, characterized in that: During the construction process, force, geometry, environment and structural parameters are monitored.

7. The method for forming an arch by controlling the internal force and linear shape of a steel truss arch ring based on the inclined buckle hanging method according to claim 6 is characterized in that: Monitor the cable tension of the inclined buckle anchor cable, and monitor at least one of the buckle cable and anchor cable in the same group.

8. The method for forming an arch by controlling the internal force and linear shape of a steel truss arch ring based on the inclined buckle hanging method according to claim 6 is characterized in that: During the erection process, the deviation of the tower is monitored.

9. A steel truss arch ring, characterized in that: The arch is constructed by using the steel truss arch ring internal force and linear double-control arch forming method based on the inclined buckle hanging method as described in any one of claims 1 to 8.

10. A steel truss arch bridge, characterized in that: It comprises the steel truss arch ring as claimed in claim 9.

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