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 bridges. Comprising the steps of collecting bridge construction process images and construction environment and material data, obtaining image data, environment data and material data, preprocessing the image data, the environment data and the material data, including filtering and removing errors, and evaluating the outside of a bridge by using the preprocessed image data. Judging whether the layout mode of the bridge parts has errors or not, evaluating the bridge parts and the construction parts by utilizing the preprocessed construction environment and material data, and judging whether the structural stress and the finished bridge line shape of the bridge parts exceed threshold values or not; and when it is detected that the layout mode has errors and / or the internal force of the internal structure of the bridge component and the line shape of the finished bridge exceed threshold values, an alarm is given, and alarm causes are sent to a control terminal. According to the method, construction can be adjusted in time, and universality is better achieved.

Description

Technical Field

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

[0002] During the construction of large-span bridges, for bridges with steel tube concrete structures assembled with beams first and arches later and with few brackets, strict requirements are imposed on the axis shape of the arch, the internal force of the box beam and the tension force of the suspender. The change of each node coordinate will affect the distribution of the internal force of the structure. Once the bridge line shape deviates from the design value, the internal force will inevitably deviate from the design value. In addition, the stiffness of the various components of the structure varies greatly, and the relationship between force and deformation is very complicated due to the interference of complex factors such as the suspender force, temperature change, wind and sunshine, and temporary construction load. In the construction calculation, although a variety of calculation methods can be used to calculate the suspender force and the corresponding beam and arch rib deformation at each construction stage, the actual deformation of the structure may not achieve the expected result when the construction is carried out according to the suspender force and line shape given by the theoretical calculation. This is mainly due to the fact that the calculation parameters used in the design, such as the elastic modulus of the material, the weight of the component, the temperature change during construction, and the temporary construction load conditions, are not completely consistent with those shown in the actual project. The deviation between theory and practice in the construction of complex bridges is cumulative. If it is not controlled and adjusted in a timely and effective manner, the structural line shape will eventually deviate significantly from the design target, affecting the internal force state of the bridge after completion.

[0003] Therefore, it is an urgent problem for technical personnel in this field to propose a large-span bridge construction monitoring design method to solve the problem of inaccurate detection and susceptibility to influence of existing technologies. Summary of the invention

[0004] In view of this, the present invention provides a large-span bridge construction monitoring design method, which can achieve the effect of accurate detection and prevent cumulative errors.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A long-span bridge construction monitoring design method comprises the following steps:

[0007] Data collection steps: collecting images of the bridge construction process and the construction environment and material data to obtain image data, environmental data and material data;

[0008] Data preprocessing step: preprocess image data, environmental data and material data, including filtering and error elimination;

[0009] Appearance judgment step: Use the pre-processed image data to evaluate the exterior of the bridge and determine whether there are errors in the layout of bridge components;

[0010] Material judgment step: Use the pre-processed construction environment and material data to evaluate the bridge components and construction components to determine whether the structural stress of the bridge components and the bridge alignment exceed the threshold;

[0011] Early warning step: When it is detected that there is an error in the layout mode and / or the internal structural forces of the bridge components and the bridge alignment exceed the threshold, an alarm is issued and the cause of the alarm is sent to the control terminal.

[0012] In the above method, optionally, in the data acquisition step, an infrared camera is used to obtain image data, a resistive strain sensor is used to obtain environmental data, and the "Railway Bridge and Culvert Design Specifications" is used to obtain material data.

[0013] In the above method, optionally, in the data preprocessing step, the image preprocessing includes: extracting an image from the image data at intervals of a certain number of frames to obtain an image set, denoising and enhancing the images in the image set to obtain a preprocessed image;

[0014] The preprocessing of environmental data and material data includes: using mean filtering to eliminate errors.

[0015] In the above method, optionally, in the appearance judgment step, features are extracted and classified for the preprocessed image to obtain construction nodes corresponding to the image, and the feature values ​​of the node modeling image and the corresponding node image are compared to determine whether there are errors in the bridge layout.

[0016] In the above method, optionally, in the material determination step, the bridge component structural stress is calculated using the stress equivalence principle.

[0017] The completed bridge alignment is calculated by calculating the initial stress-free lengths of the main cables and hangers of the suspension bridge, and the initial deformation of the stiffening beams of the suspension bridge, establishing a finite element model of the suspension bridge, simulating the completed bridge alignment, and judging whether the bridge alignment error exceeds the threshold.

[0018] In the above method, optionally, the early warning step includes a buzzer alarm and an alarm for stopping the bridge construction process.

[0019] It can be seen from the above technical solution that compared with the prior art, the present invention provides a large-span bridge construction monitoring and design method, which has the following beneficial effects: 1) The present invention collects construction process information and bridge component appearance information for comprehensive analysis to improve the accuracy of monitoring and facilitate the joint judgment between various data for monitoring and analysis; 2) The present invention can convert stress into internal force that is consistent with the requirements of the specification, thereby calculating the static load test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0021] Figure 1 The invention discloses a flow chart of a long-span bridge construction monitoring design method. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In this application, relational terms such as first and second, etc. are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of more restrictions, the elements defined by the sentence "comprise one..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0024] Reference Figure 1 As shown, the present invention discloses a long-span bridge construction monitoring design method, comprising the following steps:

[0025] Data collection steps: collecting images of the bridge construction process and the construction environment and material data to obtain image data, environmental data and material data;

[0026] Data preprocessing step: preprocess image data, environmental data and material data, including filtering and error elimination;

[0027] Appearance judgment step: Use the pre-processed image data to evaluate the exterior of the bridge and determine whether there are errors in the layout of bridge components;

[0028] Material judgment step: Use the pre-processed construction environment and material data to evaluate the bridge components and construction components to determine whether the structural stress of the bridge components and the bridge alignment exceed the threshold;

[0029] Early warning step: When it is detected that there is an error in the layout mode and / or the internal structural forces of the bridge components and the bridge alignment exceed the threshold, an alarm is issued and the cause of the alarm is sent to the control terminal.

[0030] Furthermore, in the data collection step, an infrared camera is used to obtain image data, a resistive strain sensor is used to obtain environmental data, and the "Railway Bridge and Culvert Design Specifications" are used to obtain material data.

[0031] Furthermore, in the data preprocessing step, image preprocessing includes: extracting an image from the image data at intervals of a certain number of frames to obtain an image set, denoising and enhancing the images in the image set to obtain a preprocessed image.

[0032] The preprocessing of environmental data and material data includes: using mean filtering to eliminate errors.

[0033] Specifically, the video frame extraction script is called to extract the frame number from the image data, the denoising method adopts mean filtering, the average value of the target pixel and the surrounding pixels is taken and then filled to the target pixel to obtain the denoised image, and the histogram equalization is performed on the denoised image to obtain the enhanced image.

[0034] Data preprocessing includes: giving a mean value as the filter window length, calculating the mean of the data in the window, taking the mean value of the data at the center of the window, and then sliding the window backwards by bytes to eliminate errors.

[0035] Furthermore, in the appearance judgment step, features are extracted and classified from the preprocessed image to obtain the construction nodes corresponding to the image, and the feature values ​​of the node modeling image and the corresponding node image are compared to determine whether there are errors in the bridge layout.

[0036] Specifically, the judgment methods include:

[0037] 1) Input the image into the model,

[0038] 2) Find candidate areas where objects may exist in the image;

[0039] 3) The candidate region is adjusted to fit the size of the input image of the AlexNet network, feature vectors are extracted from the candidate region through CNN, multiple CNN features are combined into the network AlexNet to finally output a multi-dimensional feature matrix;

[0040] 4) The multi-dimensional features are passed through the SVM classifier to obtain a refined category matrix;

[0041] 5) Non-maximum suppression is performed on the category matrix to eliminate overlapping suggestion boxes, obtain some suggestion boxes with the highest value to the target object, obtain image features, and judge the bridge layout nodes according to the image features.

[0042] Furthermore, in the material judgment step, the stress of the bridge components is calculated using the stress equivalence principle.

[0043] The completed bridge alignment is calculated by calculating the initial stress-free lengths of the main cables and hangers of the suspension bridge, and the initial deformation of the stiffening beams of the suspension bridge, establishing a finite element model of the suspension bridge, simulating the completed bridge alignment, and judging whether the bridge alignment error exceeds the threshold.

[0044] Specifically, stress equivalence means that the stress generated by the static load test of the precast beam is the same as the stress in a certain state during the construction process or after the bridge is completed. Suppose the stress of the control section in a certain stage state is σ 1 , which is completely consistent with the stress state after erection. The construction of wet joints and diaphragms is still carried out when the structure is in this stage, and it is easy to obtain the stress increment σ of the control section. 2 Then, the negative moment zone prestress is applied to the whole model (only the wet joints and diaphragms are constructed), and the stress change of the control section is Δσ 预 (For the bottom surface of the section with the maximum positive bending moment of the side span, Δσ is the pre-compressive stress), and the stress of the control section at this time is σ 1 +σ 2 +Δσ 预 , and then superimpose other stresses, that is, σ=σ 1 +σ 2 +Δσ 预 +σ 其他 ,

[0045] When the load distribution length is considered to be a, we have: Let qa = F, then M = F(L / 4-a / 8),

[0046] Among them, M is the internal force of the mid-span section test, F is the equivalent concentrated force, and L is the length of the beam. At this time, q is calculated, that is, the uniformly distributed load.

[0047] The compressive stress is combined with the uniformly distributed load using the Midas / civil finite element model to obtain the material stress and determine whether the stress exceeds the threshold.

[0048] Furthermore, the early warning step includes a buzzer alarm and an alarm for stopping the bridge construction process.

[0049] Specifically, when it is detected that the threshold is exceeded, an alarm signal is issued. When the control end detects the alarm signal, the construction of the bridge is stopped and the error part is determined and adjusted.

[0050] Each embodiment in this specification is described in a progressive manner, and the same or similar parts between the embodiments can refer to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system or system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules may be selected according to actual needs to achieve the purpose of the scheme of this embodiment. Ordinary technicians in this field can understand and implement it without creative work.

[0051] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A long-span bridge construction monitoring design method, characterized in that: The following steps are involved: Data collection steps: collecting images of the bridge construction process and the construction environment and material data to obtain image data, environmental data and material data; Data preprocessing step: preprocess image data, environmental data and material data, including filtering and error elimination; Appearance judgment step: Use the pre-processed image data to evaluate the exterior of the bridge and determine whether there are errors in the layout of bridge components; Material judgment step: Use the pre-processed construction environment and material data to evaluate the bridge components and construction components to determine whether the structural stress of the bridge components and the bridge alignment exceed the threshold; Early warning step: When it is detected that there is an error in the layout mode and / or the internal structural forces of the bridge components and the bridge alignment exceed the threshold, an alarm is issued and the cause of the alarm is sent to the control terminal.

2. A long-span bridge construction monitoring design method according to claim 1, characterized in that: In the data collection step, infrared cameras are used to obtain image data, resistive strain sensors are used to obtain environmental data, and the "Railway Bridge and Culvert Design Specifications" are used to obtain material data.

3. A long-span bridge construction monitoring design method according to claim 1, characterized in that: In the data preprocessing step, image preprocessing includes: extracting an image from the image data at intervals of a certain number of frames to obtain an image set, denoising and enhancing the images in the image set to obtain a preprocessed image; The preprocessing of environmental data and material data includes: using mean filtering to eliminate errors.

4. A long-span bridge construction monitoring design method according to claim 1, characterized in that: In the appearance judgment step, the preprocessed image is feature extracted and classified to obtain the construction nodes corresponding to the image. The feature values ​​of the node modeling image and the corresponding node image are compared to determine whether there are any errors in the bridge layout.

5. A long-span bridge construction monitoring design method according to claim 1, characterized in that: In the material judgment step, the stress of the bridge components is calculated using the stress equivalence principle. The completed bridge alignment is calculated by calculating the initial stress-free lengths of the main cables and hangers of the suspension bridge, and the initial deformation of the stiffening beams of the suspension bridge, establishing a finite element model of the suspension bridge, simulating the completed bridge alignment, and judging whether the bridge alignment error exceeds the threshold.

6. A long-span bridge construction monitoring design method according to claim 1, characterized in that: The early warning steps include buzzer alarm and alarm for stopping the bridge construction process.

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