Large-span bridge construction monitoring design method

Abstract

The invention discloses a large-span bridge construction monitoring design method, and relates to the technical field of large-span bridge construction. Comprising the following steps: S1, acquiring data: acquiring construction information of a to-be-monitored construction bridge; s2, a monitoring stage division step: based on the construction information of the construction bridge to be monitored obtained in the S1, setting a corresponding monitoring scheme for the stage of the construction bridge; s3, a monitoring target determination step: determining a corresponding construction monitoring target; s4, a monitoring arrangement step: determining a corresponding monitoring means, arranging monitoring points, and collecting monitoring data; and S5, a monitoring analysis step: establishing a monitoring evaluation model to monitor and evaluate the construction process of the to-be-constructed bridge. By means of the large-span bridge construction monitoring design method, it can be effectively guaranteed that bridge construction is conducted smoothly, and the project quality reaches the standard.

Description

Technical Field

[0001] This invention relates to the field of long-span bridge construction technology, and in particular to a construction monitoring and design method for long-span bridges. Background Technology

[0002] In the construction monitoring design of long-span bridges, a common method is to combine modern information technology and sensor technology, and use an intelligent monitoring system for comprehensive monitoring and real-time data collection.

[0003] Sensor technology: Sensor technology is one of the key technologies in the monitoring and design of long-span bridges. By deploying various sensor devices, such as displacement sensors, strain sensors, inclinometers, and temperature sensors, the deformation, stress, temperature and other parameters of the bridge structure can be monitored in real time, providing reliable data support for safety and quality during construction.

[0004] Data acquisition and transmission technology: The development of modern information technology has made data acquisition and transmission more efficient and convenient. Through wireless transmission technology and cloud computing technology, real-time acquisition, transmission and storage of monitoring data can be realized, providing reliable data support for monitoring systems.

[0005] Intelligent monitoring system: The intelligent monitoring system is the core of the construction monitoring design for long-span bridges. By integrating sensor technology, data acquisition and transmission technology, and data processing algorithms, it enables comprehensive monitoring and real-time analysis of the bridge structure and construction process, timely detection of problems and corresponding measures, and ensures the safety and quality of construction.

[0006] In actual construction, firstly, bridge cantilever construction will cause short-term elastic deflection and long-term creep deflection of statically determinate structures, resulting in a large difference in elevation between the two cantilevers when the bridge is closed in the same span. Secondly, due to the influence of temperature, there will be a problem that the actual closure temperature is inconsistent with the design reference temperature.

[0007] Therefore, proposing a construction monitoring design method for long-span bridges to address the difficulties in existing technologies is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0008] In view of this, the present invention provides a construction monitoring and design method for long-span bridges, which analyzes the difference between measured data and predicted values ​​in real time, and makes necessary corrections to the design parameters to ensure the safety and smooth closure of the bridge during construction, and to keep the internal forces of the structure in an optimal state and ensure that the alignment of the completed bridge meets the design and current specifications.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: a construction monitoring and design method for long-span bridges, comprising the following steps: S1. Data Acquisition Steps: Acquire construction information of the bridge to be monitored; S2, Monitoring phase division steps: Based on the construction information of the bridge to be monitored obtained in S1, set up corresponding monitoring schemes for the phases of the bridge construction. S3. Steps for determining monitoring targets: Based on the corresponding monitoring scheme obtained in S2, determine the corresponding construction monitoring targets; S4. Monitoring Deployment Steps: Based on the monitoring objectives determined in S3, determine the corresponding monitoring methods, deploy monitoring points, and collect monitoring data. S5. Monitoring and Analysis Steps: Based on the monitoring data obtained in S4, establish a monitoring and evaluation model to monitor and evaluate the construction process of the bridge under construction, and obtain a risk analysis of the construction process.

[0010] Optionally, the construction information of the bridge to be monitored in S1 includes: construction organization structure, construction plan, construction method, construction technology, and construction schedule.

[0011] The above method, optionally, includes the following specific content in S2: Based on the bridge construction information obtained in S1, the construction stages are divided, including: The main beam is divided into three stages: the cantilever casting stage, the main beam segment casting stage, and the main beam closure stage; and corresponding monitoring schemes are set up for each stage.

[0012] Optionally, the monitoring targets in S3 include the following: 1) Provide technical basis and measures for design and construction units based on construction quality and structural safety. Construction quality includes internal forces and alignment. 2) The internal forces of the structure during construction and after the main bridge is completed meet the design requirements; 3) The completed bridge's alignment closely approximates the design specifications; 4) The measures for precision control and error adjustment do not have a substantial adverse impact on the construction period.

[0013] The above method, optionally, includes the following details regarding the placement of monitoring points in S4: 1) Monitoring points for the main structure of the bridge: The main bridge structure monitoring points are located at the main parts of the bridge, including but not limited to: the main bridge beams, piers and abutments, to monitor the deformation, cracks and stress of the structure; the monitoring equipment at the main bridge structure monitoring points includes but is not limited to: inclinometers, crack gauges, strain gauges and displacement sensors, to monitor changes in the structure in real time; 2) Monitoring points during construction: The locations of construction process monitoring points on the construction site include, but are not limited to: construction platforms, lifting machinery, and pouring formwork, to monitor safety and quality during the construction process; among them, construction process monitoring points should include, but are not limited to: video surveillance cameras, sound monitors, vibration sensors, and temperature and humidity sensors, to monitor the conditions of the construction site in real time; 3) Environmental monitoring points: Environmental monitoring points are set up in the environment surrounding the bridge to monitor the impact of meteorological conditions, geological conditions and hydrological conditions on bridge construction; the environmental monitoring points should include monitoring equipment for meteorological stations, geological monitoring points and hydrological monitoring points to monitor changes in the environment in real time.

[0014] The above method can be optionally applied during the main beam segment cantilever construction stage: maintaining balance at both ends of the statically determinate cantilever construction, and pre-setting the curve and value of the upward camber based on the elastic deformation of the formwork.

[0015] The above method can be optionally applied during the main beam segment casting stage: selecting a period with a uniform temperature field to complete the casting positioning control of the current segment; identifying the impact of existing errors on parameters and optimizing and adjusting subsequent positioning coordinates and cable forces.

[0016] The above method can be optionally applied during the main beam closure stage: statistical analysis of the temperature influence pattern using data collected from monitoring points to predict the impact of temperature on closure; analysis and prediction of the impact of temperature on the closure stage, and adjustment by applying counterweight to the last segment.

[0017] The above method, optionally, includes the following specific content in S5: Based on the monitoring data collected in S4, the monitoring results are calculated and compared with the calculation results of the design unit. The main contents of the calculation include: (1) Structural internal forces and stresses at each construction stage; (2) Calculated deflection values ​​for each construction beam segment; (3) The elevation of the formwork for each construction beam segment.

[0018] As can be seen from the above technical solution, compared with the prior art, the present invention, a construction monitoring and design method for long-span bridges, has the following beneficial effects: 1) Safety: By using monitoring design methods, potential safety hazards during bridge construction can be detected in a timely manner, such as structural deformation and stress concentration, and timely measures can be taken to repair and reinforce them, ensuring the safety of the construction process.

[0019] 2) Stability: The monitoring design method can monitor the deformation, displacement, vibration and other parameters of the bridge in real time, detect the changing trend of the bridge in a timely manner, provide a basis for adjustment and optimization during the construction process, and ensure the stability of the bridge.

[0020] 3) Quality control: The monitoring design method can monitor and record various parameters in real time during the bridge construction process, providing data support for the control and evaluation of construction quality, and ensuring that the construction quality meets the design requirements.

[0021] 4) Real-time early warning: The monitoring design method can realize real-time monitoring and early warning of abnormal situations during bridge construction, take timely measures to deal with them, avoid unexpected events during construction, and ensure the smooth progress of the project.

[0022] 5) Data support: The monitoring design method can collect and record a large amount of data during the bridge construction process, providing a scientific basis for project management and decision-making, and improving construction efficiency and management level. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0024] Figure 1 This is a flowchart of a construction monitoring and design method for long-span bridges disclosed in this invention. Figure 2 This is a schematic diagram of the linear shape of the main beam segment during the cantilever casting stage disclosed in this invention. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0027] Reference Figure 1 As shown, this invention discloses a construction monitoring and design method for long-span bridges, comprising the following steps: S1. Data Acquisition Steps: Acquire construction information of the bridge to be monitored; S2, Monitoring phase division steps: Based on the construction information of the bridge to be monitored obtained in S1, set up corresponding monitoring schemes for the phases of the bridge construction. S3. Steps for determining monitoring targets: Based on the corresponding monitoring scheme obtained in S2, determine the corresponding construction monitoring targets; S4. Monitoring Deployment Steps: Based on the monitoring objectives determined in S3, determine the corresponding monitoring methods, deploy monitoring points, and collect monitoring data. S5. Monitoring and Analysis Steps: Based on the monitoring data obtained in S4, establish a monitoring and evaluation model to monitor and evaluate the construction process of the bridge under construction, and obtain a risk analysis of the construction process.

[0028] Furthermore, the construction information of the bridge to be monitored in S1 includes: construction organization structure, construction plan, construction method, construction technology, and construction schedule.

[0029] Furthermore, the specific content of S2 includes: Based on the bridge construction information obtained in S1, the construction stages are divided, including: The main beam is divided into three stages: the cantilever casting stage, the main beam segment casting stage, and the main beam closure stage; and corresponding monitoring schemes are set up for each stage.

[0030] Furthermore, the monitoring targets in S3 include: 1) Provide technical basis and measures for design and construction units based on construction quality and structural safety. Construction quality includes internal forces and alignment. 2) The internal forces of the structure during construction and after the main bridge is completed meet the design requirements; 3) The completed bridge's alignment closely approximates the design specifications; 4) The measures for precision control and error adjustment do not have a substantial adverse impact on the construction period.

[0031] Furthermore, the specific details of setting up monitoring points in S4 are as follows: 1) Monitoring points for the main structure of the bridge: The main bridge structure monitoring points are located at the main parts of the bridge, including but not limited to: the main bridge beams, piers and abutments, to monitor the deformation, cracks and stress of the structure; the monitoring equipment at the main bridge structure monitoring points includes but is not limited to: inclinometers, crack gauges, strain gauges and displacement sensors, to monitor changes in the structure in real time; 2) Monitoring points during construction: The locations of construction process monitoring points on the construction site include, but are not limited to: construction platforms, lifting machinery, and pouring formwork, to monitor safety and quality during the construction process; among them, construction process monitoring points should include, but are not limited to: video surveillance cameras, sound monitors, vibration sensors, and temperature and humidity sensors, to monitor the conditions of the construction site in real time; 3) Environmental monitoring points: Environmental monitoring points are set up in the environment surrounding the bridge to monitor the impact of meteorological conditions, geological conditions and hydrological conditions on bridge construction; the environmental monitoring points should include monitoring equipment for meteorological stations, geological monitoring points and hydrological monitoring points to monitor changes in the environment in real time.

[0032] Furthermore, in the main beam segment cantilever construction stage: the two ends of the statically determinate cantilever construction are kept in balance, and the curve and value of the camber are preset based on the elastic deformation of the hanging basket.

[0033] Specifically, in order to overcome the short-term elastic deflection and long-term creep deflection of statically determinate structures caused by bridge cantilever construction, and to ensure that the elevation difference between the two cantilevers is not significant when the bridge is closed in the same span, the two ends of the statically determinate cantilever construction should be kept in balance and the camber should be preset.

[0034] Generally, the curve and values ​​for setting the pre-camber are set by reversing the elastic and creep total deflection curves and values ​​at each node from the start of construction to about five years after completion. This is the theoretical camber curve for the main bridge. Considering the different temperature and humidity environments at various bridge construction sites, as well as the different bridge construction methods and schedules, the values ​​of each coefficient are different and are adjusted and controlled as appropriate based on the actual construction situation.

[0035] like Figure 2 As shown, after the cantilever beam is closed and transformed into a continuous system, there are still secondary dead loads, secondary internal forces (secondary prestressing, creep, shrinkage and temperature effects), and the influence of 1 / 2 of the vehicle's static live load. For the sake of construction simplification, the sum of these influence values ​​can usually be taken as the maximum value of the mid-span precamber, as shown in formula (1): (1) Taking the two bridge piers as the zero point, the remaining points can be approximately distributed according to a quadratic parabola.

[0036] During cantilever construction using a formwork system, the elastic deformation of the formwork is a crucial factor to consider when setting the pre-camber. Its specific magnitude is mainly related to factors such as the weight of the poured beam segment and the tightness of the formwork's slings. Before the initial concrete pouring of the beam segment, a pre-loading test is generally required to eliminate inelastic deformation of the formwork and to obtain a more ideal linear relationship between the formwork's elastic deformation and the beam segment's weight. The pre-loading test can employ a staged loading method. The number of loading stages and the amount of load should be as close as possible to the actual weight of the beam segment. Each load stage should last for at least 30 minutes.

[0037] However, during the cantilever casting of each beam segment, unforeseen factors such as varying tension in the formwork's slings can cause discrepancies between the actual elastic deformation of the formwork and the preloading results. Therefore, it is necessary to monitor the actual elastic deformation of the formwork during casting and compare it with the preloading results to accurately predict the elastic deformation of the next beam segment.

[0038] During the construction of this bridge, the following formula was used to calculate the actual deformation value of the formwork: (2) In the formula: —The elastic deformation value of the formwork when casting the nth block; , , —After pouring the nth concrete block n , n -1、 n Displacement at the front end of beam segment -2; , ——No. n , n -Length of beam segment No. 1.

[0039] It is important to note that: This refers to the displacement of the front end of the concrete formwork, which is the difference between the positioning elevation of the formwork in this segment and the elevation after the concrete is poured. It includes both the rigid body displacement caused by the positioning of the constructed segment and the elastic deformation of the formwork. = When, it is obtained from formula (2).

[0040] (3)

[0041] Therefore, the deformation of the formwork in the constructed segment can be obtained from the above formula. By referring to the load test results after the formwork is assembled, the deformation law of the formwork can be deduced, and the elastic deformation of the formwork in the next segment can be predicted more accurately.

[0042] Furthermore, during the main beam segment casting stage: select a period with a uniform temperature field to complete the casting positioning control of the current segment; identify the parameter impact of existing errors and optimize and adjust the subsequent positioning coordinates and cable force.

[0043] Specifically, during the casting of main girder segments, the focus of controlling the main girder alignment is on the positioning control after the current segment is cast. When positioning the current segment, a period with a uniform temperature field should be selected to avoid the influence of temperature. For errors that have occurred, parameter influence identification and subsequent optimization and adjustment of positioning coordinates and cable tension should be carried out to ensure the realization of the target state of the completed bridge.

[0044] Furthermore, during the main beam closure stage: statistical analysis of the temperature influence pattern is performed using data collected from monitoring points to predict the impact of temperature on closure; the impact of temperature on the closure stage is analyzed and predicted, and counterweights are applied to the last segment for adjustment.

[0045] Specifically, a reasonable main girder closure scheme should be selected. When the closure temperature is inconsistent with the design reference temperature, the temperature influence law needs to be explored clearly using measured data within a certain period of time. Temperature monitoring should be used to understand the temperature field distribution law, and theoretical analysis should be used to predict the impact of temperature on closure. The impact of temperature on the closure stage should be analyzed and predicted to ensure the closure of the main girder of the bridge deck system. The bridge's completed state should be kept consistent with the design by applying counterweights to the last segment.

[0046] Furthermore, the specific content of S5 includes: Based on the monitoring data collected in S4, the monitoring results are calculated and compared with the calculation results of the design unit. The main contents of the calculation include: (1) Structural internal forces and stresses at each construction stage; (2) Calculated deflection values ​​for each construction beam segment; (3) The elevation of the formwork for each construction beam segment.

[0047] Specifically, by monitoring temperature and understanding the distribution patterns of the temperature field, and by using theoretical analysis to predict the impact of temperature on the deformation of the main beam during construction, the stress and deformation during construction can be evaluated in a timely and intuitive manner; the impact of temperature on the main bridge construction stage can be analyzed and predicted to ensure that the bridge can be constructed across seasons and in all weather conditions; and the extreme temperature loads that may occur during construction can be predicted.

[0048] The results of the monitoring calculations should be verified against those of the design unit to ensure construction safety. The main contents of the calculations are the internal forces and stresses of the structure at each construction stage, and the formwork elevation of the cantilevered beam segment is also provided.

[0049] (1) Structural internal forces and stresses at each construction stage

[0050] (2) Calculated deflection values ​​of each construction beam segment

[0051] The calculation of deflection during construction is not only related to the selection of mechanical calculation mode, but more importantly, it is related to many factors that affect deflection, making it difficult to accurately calculate deflection deformation. In order to guide the construction with theory, the deflection must be calculated and controlled according to the predetermined construction degree in terms of both elastic and creep components.

[0052] 1) The deflection value at the front end of the cantilever caused by its own weight, prestress, and concrete shrinkage and creep; 2) Elastic deformation of the hanging basket; 3) Live load deflection value.

[0053] (3) Elevation of formwork for each construction beam segment

[0054] In the cantilever construction of long-span continuous beam bridges, deflection control is crucial for construction control. The purpose of deflection control is to adjust the pre-camber value of the beam segment (reflected in the formwork elevation calculation) based on calculation results and measured data at each stage, comparing them with the design calculation results. This ensures the completed bridge alignment meets design requirements and guarantees closure accuracy. The absolute elevation form of the formwork elevation for the cantilevered box girder casting segment is as follows:

[0055] In the formula: —Bridge completion elevation; —Bridge design elevation; —The deformation of a bridge under half a static live load is positively considered downwards; —Deformation caused by the later creep of concrete after the bridge is completed is considered positive when it is downward; —After the formwork is erected, the subsequent construction operations cause deformation at a certain point in the structure, and this deformation continues until the bridge is completed. — The deflection of the hanging basket itself caused by the weight of beam segment i (positive downwards).

[0056] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple, and relevant parts can be referred to the descriptions in the method embodiments. The systems and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0057] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A construction monitoring design method for long-span bridges, characterized in that, Includes the following steps: S1. Data Acquisition Steps: Acquire construction information of the bridge to be monitored; S2, Monitoring phase division steps: Based on the construction information of the bridge to be monitored obtained in S1, set up corresponding monitoring schemes for the phases of the bridge construction. S3. Steps for determining monitoring targets: Based on the corresponding monitoring scheme obtained in S2, determine the corresponding construction monitoring targets; S4. Monitoring Deployment Steps: Based on the monitoring objectives determined in S3, determine the corresponding monitoring methods, deploy monitoring points, and collect monitoring data. S5. Monitoring and Analysis Steps: Based on the monitoring data obtained in S4, establish a monitoring and evaluation model to monitor and evaluate the construction process of the bridge under construction, and obtain a risk analysis of the construction process.

2. The construction monitoring and design method for long-span bridges according to claim 1, characterized in that, The construction information of the bridges to be monitored in S1 includes: construction organization structure, construction plan, construction method, construction technology, and construction schedule.

3. The construction monitoring and design method for long-span bridges according to claim 1, characterized in that, The specific content of S2 includes: Based on the bridge construction information obtained in S1, the construction stages are divided, including: The main beam is divided into three stages: the cantilever casting stage, the main beam segment casting stage, and the main beam closure stage; and corresponding monitoring schemes are set up for each stage.

4. The construction monitoring and design method for long-span bridges according to claim 1, characterized in that, The targets monitored in S3 include: 1) Provide technical basis and measures for design and construction units based on construction quality and structural safety. Construction quality includes internal forces and alignment. 2) The internal forces of the structure during construction and after the main bridge is completed meet the design requirements; 3) The completed bridge's alignment closely approximates the design specifications; 4) The measures for precision control and error adjustment do not have a substantial adverse impact on the construction period.

5. The construction monitoring and design method for long-span bridges according to claim 3, characterized in that, The specific details of setting up monitoring points in S4 are as follows: 1) Monitoring points for the main structure of the bridge: The main bridge structure monitoring points are located at the main bridge structure, including but not limited to: the main bridge beams, piers, and abutments, to monitor the deformation, cracks, and stress of the structure; the monitoring equipment at the main bridge structure monitoring points includes but is not limited to: inclinometers, crack gauges, strain gauges, and displacement sensors, to monitor changes in the structure in real time; 2) Monitoring points during construction: The locations of construction process monitoring points on the construction site include, but are not limited to: construction platforms, lifting machinery, and pouring formwork, to monitor safety and quality during the construction process; among them, construction process monitoring points should include, but are not limited to: video surveillance cameras, sound monitors, vibration sensors, and temperature and humidity sensors, to monitor the conditions of the construction site in real time; 3) Environmental monitoring points: Environmental monitoring points are set up in the environment surrounding the bridge to monitor the impact of meteorological conditions, geological conditions and hydrological conditions on bridge construction; the environmental monitoring points should include monitoring equipment for meteorological stations, geological monitoring points and hydrological monitoring points to monitor changes in the environment in real time.

6. The construction monitoring and design method for long-span bridges according to claim 5, characterized in that, Main beam segment cantilever construction stage: keep both ends of the statically determinate cantilever construction in balance, and pre-set the curve and value of the camber based on the elastic deformation of the hanging basket.

7. The construction monitoring and design method for long-span bridges according to claim 5, characterized in that, Main beam segment casting stage: Select a period with uniform temperature field to complete the casting positioning control of the current segment; identify the parameter impact of existing errors and optimize and adjust the subsequent positioning coordinates and cable force.

8. The construction monitoring and design method for long-span bridges according to claim 5, characterized in that, Main beam closure stage: Statistical analysis of temperature influence patterns is performed using data collected from monitoring points to predict the impact of temperature on closure; the impact of temperature on the closure stage is analyzed and predicted, and counterweights are applied to the last segment for adjustment.

9. The construction monitoring and design method for long-span bridges according to claim 8, characterized in that, The specific content of S5 includes: Based on the monitoring data collected in S4, the monitoring results are calculated and compared with the calculation results of the design unit. The main contents of the calculation include: (1) Structural internal forces and stresses at each construction stage; (2) Calculated deflection values ​​for each construction beam segment; (3) The elevation of the formwork for each construction beam segment.

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