Intelligent control system and method for closure of long-span steel truss girder cable-stayed bridge

Abstract

The present application relates to a kind of large-span steel truss beam cable-stayed bridge closure intelligent control system and method, adopt beidou positioning instrument, wireless tiltmeter and IMU sensor etc. and form closure intelligent control system, reduce the difficulty of construction survey, improve the measurement efficiency.The data obtained by the automatic monitoring system are analyzed to analyze the closure mouth state and control the force analysis of construction adjustment, the closure mouth state is adjusted using full-automatic hydraulic jack, and the large-span steel truss beam cable-stayed bridge is closed in the middle of the span by combining fine adjustment measures.The method helps to reduce the waiting operation time of large cantilever construction, solves the problems of low construction efficiency, different synchronization of closure adjustment measures, and realizes the accurate closure of large-span steel truss beam cable-stayed bridge.

Description

Technical Field

[0001] This invention belongs to the field of bridge engineering technology, and in particular to an intelligent control system and method for the closure of a long-span steel truss cable-stayed bridge. Background Technology

[0002] Steel structure bridges are widely used in highway and railway bridges due to their advantages such as high material strength, light weight, and faster and more convenient erection compared to concrete bridges. With the rapid development of the national economy, the volume of highway and railway transportation in my country has been increasing year by year, posing a huge challenge to the traffic capacity of bridges. To meet the traffic demand, dual-purpose road-rail bridges are receiving increasing attention, and steel truss cable-stayed bridges are also being used more and more.

[0003] Long-span cable-stayed bridges consist of three basic components: towers, beams, and cables. They are highly statically indeterminate flexible structural systems, and their geometric nonlinearity leads to numerous sensitive factors at the bridge closure joint, making closure construction control extremely difficult. The closure methods for steel truss cable-stayed bridges mainly include natural closure and forced closure. Natural closure relies on continuous observation of the closure joint's position and temperature to determine control parameters such as the cutting length of the closure segment, placement temperature, and closure temperature. The temperature difference method is used to complete the beam feeding and closure processes separately. Forced closure, based on sensitivity analysis of various parameters at the closure joint, determines adjustment measures to actively eliminate positioning deviations at the closure joint, achieving stress-free closure of the steel beams. The closure joint of an "N"-shaped steel truss girder involves numerous closure members. These members are affected by closure adjustment measures and ambient temperature, increasing the difficulty of measuring deformation and controlling alignment, resulting in long closure periods and low construction efficiency. How to reduce the construction time of long-span steel truss cable-stayed bridges in a large cantilever state and how to achieve rapid and accurate mid-span closure have become common concerns for builders. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and propose an intelligent control system and method for the closure of a long-span steel truss cable-stayed bridge. This system can solve problems such as the large number of control measurement points during closure construction, low construction efficiency, and asynchronous closure adjustment measures. It helps to reduce the waiting time for large cantilever construction and achieve precise closure of the steel truss cable-stayed bridge.

[0005] The technical problem solved by this invention is achieved through the following technical solution:

[0006] A smart control system for the closure of a long-span steel truss cable-stayed bridge includes a Beidou positioning device, a wireless inclinometer, an IMU inertial sensor, a cloud platform, and hydraulic jacks. The Beidou positioning device, the wireless inclinometer, and the IMU inertial sensor are connected to the cloud platform via wireless transmission. The cloud platform is connected to the hydraulic jacks at the tower-beam support, the cable tension adjustment point, and the closure joint via wireless transmission.

[0007] Furthermore, the Beidou positioning device is installed at the cantilever end and closure section of the steel truss beam to locate the positions on both sides of the closure opening. The wireless inclinometer is installed at the cantilever end and closure section of the steel truss beam to measure the rotation angle on both sides of the closure opening. The IMU inertial sensor is installed at the member nodes on both sides of the closure opening to measure the acceleration of each member at the closure opening. Hydraulic jacks are respectively installed at the tower-beam support, cable tension adjustment point, and closure opening. The lifting hydraulic jacks arranged at the tower-beam support are used to eliminate the height difference and rotation displacement at the closure opening. The fine-tuning hydraulic jack device set at the closure opening is used for fine-tuning the spacing of the closure opening. The hydraulic jacks set at the cable tension adjustment point are used to adjust the vertical displacement of the closure opening. The cloud platform is used to receive the detection data from the Beidou positioning device, wireless inclinometer, and IMU inertial sensor and perform calculations, converting the calculation results into control signals and inputting them to the hydraulic jacks at the tower-beam support, cable tension adjustment point, and closure opening.

[0008] A control method for an intelligent control system for the closure of a long-span steel truss cable-stayed bridge includes the following steps:

[0009] Step 1: The Beidou positioning device locates the positions on both sides of the closure joint, and the wireless inclinometer measures the turning angles on both sides of the closure joint, and transmits the position information and turning angle information to the cloud platform;

[0010] Step 2: The IMU inertial sensor measures the triaxial acceleration of each member at the closure joint and outputs the acceleration data to the cloud platform. The cloud platform converts the acceleration data into triaxial displacement information of each member at the closure joint through double integration.

[0011] Step 3: The cloud platform integrates the three-dimensional displacement information and rotation data of the closure joint, determines the attitude of each member of the closure joint based on the positioning information, and analyzes and calculates the control force required for the three-dimensional displacement and rotation adjustment of the closure joint.

[0012] Step 4: Transmit the control force as a command to the hydraulic jacks at the tower beam support, cable tension adjustment point, and closure point to adjust the closure status;

[0013] Step 5: Repeat steps 1 to 4, fine-tuning the deviation at the closure joint until the positional deviation between the members on both sides of the closure joint is within the error range, and then perform the closure of the members one by one.

[0014] Furthermore, the specific implementation method of step 3 is as follows: the cloud platform integrates three-dimensional displacement and rotation information, calculates the posture of each member at the closure joint using displacement and position information, determines the positional deviation on both sides of the closure joint, and uses spatial finite element software to analyze and calculate the closure control force. A spatial three-dimensional finite element model of the steel truss cable-stayed bridge at the closure stage is established. The bottom of the tower piers adopts general elastic support, the bridge bearings, main towers and main beams adopt elastic connection, and the bridge deck system and main truss adopt rigid connection. The steel truss members and bridge towers are simulated using beam elements, the stay cables are simulated using truss elements, and the bridge deck is simulated using plate elements. Sensitivity analysis is performed on the closure joint, which includes vertical displacement, longitudinal displacement, and lateral deviation. The deformation of the closure joint is calculated by applying pier top thrust, stay cable force, closure joint counterweight, and tension. Based on the model calculation results, the deformation curve of the closure joint under different adjustment measures is plotted, and the closure control force under the actual closure joint state is determined by linear interpolation.

[0015] Moreover, the specific method for fine-tuning the deviation at the closure joint in step 5 is as follows: arranging counter-pull, diagonal cross counter-pull, and diagonal bar counter-pull chain hoists on both sides of the closure joint to adjust the bolt hole deviation, so that the bolt hole deviation is controlled within 1mm.

[0016] Furthermore, in step 5, the closure sequence of the members is determined by establishing a three-dimensional finite element model in space, comparing different closure sequences of the members, and determining the closure sequence of each member as the main truss lower chord, diagonal members, main truss upper chord, and secondary truss.

[0017] The advantages and positive effects of this invention are:

[0018] 1. This invention employs a Beidou positioning system, a wireless inclinometer, and an IMU sensor to form an intelligent closure control system, reducing the difficulty of construction surveying and improving surveying efficiency. This invention analyzes the closure joint status based on data obtained from an automated monitoring system and performs construction adjustment control force analysis. It uses fully automatic hydraulic jacks to adjust the closure joint status, combined with fine-tuning measures, to achieve mid-span closure of a large-span steel truss cable-stayed bridge. This method helps reduce waiting time during large cantilever construction, solves problems such as low construction efficiency and asynchronous closure adjustment measures, and achieves precise closure of the steel truss cable-stayed bridge.

[0019] 2. In this invention, a Beidou positioning device and a wireless inclinometer are installed at the cantilever end and the closure section of the steel truss beam to locate the three-dimensional coordinate position on both sides of the closure opening and to measure the rotation angle on both sides of the closure opening.

[0020] 3. This invention transmits the detected data to a cloud platform, analyzes the position information during the closure process, uses finite element software to simulate the closure process, determines the closure adjustment force, and transmits the adjustment force as a command to the fully automatic hydraulic jack via wireless transmission, providing technical support for actual construction and improving the efficiency of closure construction.

[0021] 4. This invention helps to reduce the waiting time for large cantilever construction, improve the efficiency of closure construction, and achieve precise closure of steel truss cable-stayed bridges. Attached Figure Description

[0022] Figure 1 A flowchart of the intelligent control system for mid-span closure provided in this application embodiment;

[0023] Figure 2 A schematic diagram showing the arrangement of the BeiDou positioning device, wireless inclinometer, and IMU inertial sensor in the mid-span closure section provided in this application embodiment;

[0024] Figure 3 A schematic diagram showing the arrangement of the Beidou positioning device, wireless inclinometer, and IMU inertial sensor at the cantilever end of the device, as provided in an embodiment of this application.

[0025] Figure 4 A schematic diagram of the longitudinal fine-tuning device for the closure joint provided in the embodiments of this application;

[0026] Figure 5 A schematic diagram of the finite element model for calculating the closure control force provided in this application embodiment;

[0027] Label Explanation:

[0028] 1-Beidou positioning device, 2-Wireless inclinometer, 3-IMU inertial sensor, 4-One side of steel truss, 5-The other side of steel truss, 6-Connecting plate, 7-First top tie seat, 8-Hydraulic jack, 9-Support seat, 10-Second top tie seat. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings.

[0030] A smart control system for the closure of a long-span steel truss cable-stayed bridge, such as Figure 2 , Figure 3 and Figure 4 As shown, the system includes a Beidou positioning device 1, a wireless inclinometer 2, an IMU inertial sensor 3, a cloud platform, and hydraulic jacks 8. The Beidou positioning device, the wireless inclinometer, and the IMU inertial sensor are connected to the cloud platform via wireless transmission. The cloud platform is connected to the hydraulic jacks at the tower beam support, the cable tension adjustment point, and the closure point via wireless transmission.

[0031] The Beidou positioning device, wireless inclinometer, and IMU sensor are all fixed to the upper chord of the steel truss beam using screws. The support base is connected to one side of the steel truss beam member via a base plate and high-strength bolts. The jacking seat surrounds the support base at both ends through elongated holes. The other side of the steel truss beam member is connected to the connecting plate via high-strength bolts. Jacks are positioned between the first steel truss beam member and the support base, or between the second steel truss beam and the support base, to perform jacking or pulling-back operations.

[0032] Beidou positioning devices are installed at the cantilever ends and closure sections of the steel truss beam to locate the three-dimensional coordinates of both sides of the closure joint. Wireless inclinometers are installed at the closure section and cantilever ends to measure the rotation angles on both sides of the closure joint. Inertial measurement units (IMUs) are installed at the member nodes on both sides of the closure joint to measure the acceleration of each member. Specifically, the IMUs inertial sensors in the closure section are arranged at the positions of the upper chord, lower chord, secondary truss, and diagonal members. Due to symmetry, they only need to be arranged on one side of the steel truss beam cross-section. The IMUs at the cantilever ends are arranged at the positions of the upper chord, lower chord, and secondary truss, also only on one side of the steel truss beam cross-section.

[0033] An Inertial Measurement Unit (IMU) is a device that measures the three-axis angular velocity and acceleration of an object. An IMU contains gyroscopes and accelerometers mounted on three orthogonal axes, providing six degrees of freedom, to measure the object's angular velocity and acceleration in three-dimensional space. The IMU data is transmitted wirelessly to a cloud platform in real time. The acceleration signals recorded on the cloud platform are integrated twice to convert the IMU acceleration data into displacement data, thus obtaining the displacement state of each member during the closure process.

[0034] Hydraulic jacks are installed at the tower-beam supports, cable tension adjustment points, and the closure joint. The lifting hydraulic jacks at the tower-beam supports are used to eliminate the height difference and angular displacement at the closure joint. The fine-tuning hydraulic jacks at the closure joint are used to fine-tune the spacing of the closure joint. The hydraulic jacks at the cable tension adjustment points are used to adjust the vertical displacement of the closure joint.

[0035] Among them, the jack device at the longitudinal fine adjustment point of the closure joint should be arranged in one set at the upper and lower chords. This arrangement can not only reduce the amount of jacks used, but also adjust the longitudinal displacement of the upper and lower chords simultaneously, reducing the impact of longitudinal adjustment on lateral displacement.

[0036] The cloud platform is used to receive and calculate the detection data from the Beidou positioning instrument, wireless inclinometer, and IMU inertial sensor, and then convert the calculation results into control signals to be input to the hydraulic jacks at the tower beam support, cable tension adjustment point, and closure point.

[0037] The Beidou positioning device has an accuracy of centimeters, and the wireless tilt meter has an accuracy of 0.001 degrees.

[0038] A control method for an intelligent control system for the closure of a long-span steel truss cable-stayed bridge, such as... Figure 1 As shown, it includes the following steps:

[0039] Step 1: The Beidou positioning device locates the positions on both sides of the closure joint, and the wireless inclinometer measures the turning angles on both sides of the closure joint, and transmits the position information and turning angle information to the cloud platform.

[0040] Step 2: The IMU inertial sensor measures the triaxial acceleration of each member at the closure joint and outputs the acceleration data to the cloud platform. The cloud platform converts the acceleration data into triaxial displacement information of each member at the closure joint through a second integration. The displacement data can be obtained from the acceleration data using the following equations (1) and (2):

[0041] (1)

[0042] (2)

[0043] Step 3: The cloud platform integrates the three-dimensional displacement (the displacement data in Step 2) and rotation data of the closure joint, determines the attitude of each member of the closure joint based on the positioning information, and analyzes and calculates the control force required for adjusting the three-dimensional displacement and rotation of the closure joint.

[0044] The specific implementation method of this step is as follows: The cloud platform integrates three-dimensional displacement and rotation information, and calculates the attitude of each member at the closure joint using displacement and position information, determines the positional deviation on both sides of the closure joint, and adopts methods such as... Figure 5 The spatial finite element method software is used to analyze and calculate the closure control force.

[0045] A three-dimensional finite element model of the closure stage of the steel truss cable-stayed bridge was established. General elastic supports were used at the base of the towers and piers, and the bridge bearings, main towers, and main girders were elastically connected, while the bridge deck system and main truss were rigidly connected. Steel truss members and bridge towers were simulated using beam elements, stay cables using truss elements, and the bridge deck using plate elements. Sensitivity analysis was performed on the closure joint, including vertical displacement, longitudinal displacement, and lateral deviation. Deformation of the closure joint was calculated by applying pier top thrust, stay cable force, closure joint counterweight, and tension. Deformation curves of the closure joint under different adjustment measures were plotted based on the model calculation results. The closure control force under the actual closure joint state was determined by linear interpolation.

[0046] Step 4: Transmit the control force as a command to the hydraulic jacks at the tower beam support, cable tension adjustment point, and closure point to adjust the closure status.

[0047] Step 5: Repeat steps 1 to 4, fine-tuning the deviation at the closure joint until the positional deviation between the members on both sides of the closure joint is within the error range, and then perform the closure of the members one by one.

[0048] The specific method for fine-tuning the deviation at the closure joint is as follows: arrange counter-pull, diagonal cross counter-pull, and diagonal bar counter-pull chain hoists on both sides of the closure joint to adjust the bolt hole deviation, so that the bolt hole deviation is controlled within 1mm.

[0049] The closure sequence was determined by establishing a three-dimensional finite element model and comparing different closure sequences for different members. The following four working conditions were selected for simulation: ① Main truss lower chord → Main truss upper chord → Secondary truss → Diagonal member; ② Main truss lower chord → Secondary truss → Main truss upper chord → Diagonal member; ③ Main truss lower chord → Diagonal member → Main truss upper chord → Secondary truss; ④ Main truss lower chord → Diagonal member → Secondary truss → Main truss upper chord. The closure sequence of each member was determined to be the main truss lower chord, diagonal member, main truss upper chord, and secondary truss.

[0050] It should be emphasized that the embodiments described in this invention are illustrative rather than limiting. Therefore, this invention includes, but is not limited to, the embodiments described in the specific implementation. Any other implementations derived by those skilled in the art based on the technical solutions of this invention are also within the scope of protection of this invention.

Claims

1. A control method for an intelligent control system for the closure of a long-span steel truss cable-stayed bridge, characterized in that: It includes a Beidou positioning device, a wireless inclinometer, an IMU inertial sensor, a cloud platform, and hydraulic jacks. The Beidou positioning device, the wireless inclinometer, and the IMU inertial sensor are connected to the cloud platform via wireless transmission. The cloud platform is connected to the hydraulic jacks at the tower beam support, cable tension adjustment point, and closure point via wireless transmission. The Beidou positioning device is installed at the cantilever end and closure section of the steel truss beam to locate the positions on both sides of the closure opening. The wireless inclinometer is installed at the cantilever end and closure section of the steel truss beam to measure the rotation angle on both sides of the closure opening. The IMU inertial sensor is installed at the member nodes on both sides of the closure opening to measure the acceleration of each member at the closure opening. Hydraulic jacks are respectively installed at the tower-beam support, cable tension adjustment point, and closure opening. The lifting hydraulic jacks arranged at the tower-beam support are used to eliminate the height difference and rotation displacement at the closure opening. The fine-tuning hydraulic jack device set at the closure opening is used for fine-tuning the spacing of the closure opening. The hydraulic jacks set at the cable tension adjustment point are used to adjust the vertical displacement of the closure opening. The cloud platform is used to receive the detection data from the Beidou positioning device, wireless inclinometer, and IMU inertial sensor and perform calculations, converting the calculation results into control signals and inputting them to the hydraulic jacks at the tower-beam support, cable tension adjustment point, and closure opening. The control method includes the following steps: Step 1: The Beidou positioning device locates the positions on both sides of the closure joint, and the wireless inclinometer measures the turning angles on both sides of the closure joint, and transmits the position information and turning angle information to the cloud platform; Step 2: The IMU inertial sensor measures the triaxial acceleration of each member at the closure joint and outputs the acceleration data to the cloud platform. The cloud platform converts the acceleration data into triaxial displacement information of each member at the closure joint through double integration. Step 3: The cloud platform integrates the three-dimensional displacement information and rotation data of the closure joint, determines the attitude of each member of the closure joint based on the positioning information, and analyzes and calculates the control force required for the three-dimensional displacement and rotation adjustment of the closure joint. The cloud platform integrates three-dimensional displacement and rotation information, and calculates the attitude of each member at the closure joint using displacement and position information to determine the positional deviations on both sides of the closure joint. Spatial finite element software is used to analyze and calculate the closure control force. A three-dimensional spatial finite element model of the steel truss cable-stayed bridge at the closure stage is established. The bottom of the tower piers adopts general elastic support, the bridge bearings, main towers and main beams adopt elastic connection, and the bridge deck system adopts rigid connection with the main truss. The steel truss members and bridge towers are simulated using beam elements, the stay cables are simulated using truss elements, and the bridge deck is simulated using plate elements. Sensitivity analysis is performed on the closure joint, which includes vertical displacement, longitudinal displacement, and lateral deviation. The deformation of the closure joint is calculated by applying the pier top thrust, stay cable force, closure joint counterweight, and tension. Based on the model calculation results, the deformation curves of the closure joint under different adjustment measures are plotted, and the closure control force under the actual closure joint state is determined by linear interpolation. Step 4: Transmit the control force as a command to the hydraulic jacks at the tower beam support, cable tension adjustment point, and closure point to adjust the closure status; Step 5: Repeat steps 1 to 4, fine-tuning the deviation at the closure joint until the positional deviation between the members on both sides of the closure joint is within the error range, and then perform the closure of the members one by one.

2. The control method of the intelligent control system for the closure of a long-span steel truss cable-stayed bridge according to claim 1, characterized in that: The specific method for fine-tuning the deviation at the closure joint in step 5 is as follows: arranging counter-pull, diagonal cross counter-pull, and diagonal bar counter-pull chain hoists on both sides of the closure joint to adjust the bolt hole deviation, so that the bolt hole deviation is controlled within 1mm.

3. The control method of the intelligent control system for the closure of a long-span steel truss cable-stayed bridge according to claim 1, characterized in that: In step 5, the closure sequence of the members is determined by establishing a three-dimensional finite element model in space, comparing different closure sequences of the members, and determining the closure sequence of each member as follows: lower chord of the main truss, diagonal member, upper chord of the main truss, and secondary truss.

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