A method for steel structure damage detection based on three-dimensional laser scanning

Abstract

This application relates to a method for steel structure damage detection based on three-dimensional laser scanning, comprising: acquiring point cloud data of the steel structure to be inspected to establish a three-dimensional point cloud model of the steel structure; comparing the three-dimensional point cloud model with a BIM model of the steel structure to obtain a point cloud deviation map for preliminary judgment of the damaged area of ​​the steel structure; establishing a finite element model of the steel structure, and correcting the finite element model through the point cloud deviation map to obtain a stress map for accurate judgment of the damaged area of ​​the steel structure. This application establishes an accurate three-dimensional point cloud model of the damaged steel structure by acquiring high-precision point cloud data of the steel structure; then compares the three-dimensional point cloud model with a BIM model established based on design drawings, and the obtained point cloud deviation map can preliminarily judge the damaged area of ​​the steel structure; then, the finite element model is corrected based on the point cloud deviation map, more accurately simulating the impact and deformation process of the steel structure, and comprehensively assessing the damage status of the steel structure.

Description

TECHNICAL FIELD

[0001] The application relates to the field of global scanning, in particular to a steel structure damage detection method based on three-dimensional laser scanning. BACKGROUND

[0002] In the construction process of bridge engineering and building structures, steel structures are widely used due to their lightweight and high-strength characteristics. During the erection and assembly of steel structures, various damage conditions such as impact and deformation may occur. These damages may pose potential threats to the safety and integrity of the steel structure. Therefore, it is crucial to detect and evaluate these damages in a timely manner.

[0003] Traditional steel structure damage detection methods usually rely on total stations and levels, but have certain limitations. First, these two instruments are difficult to accurately capture minor but important damages, and their accuracy is even lower for complex structures. Second, due to the complex and variable environmental conditions during the erection process, the feasibility and accuracy of traditional methods are often limited. Finally, total station and level measurement requires a large amount of time and human resources, and multiple means are required during the detection process. The detection data is cumbersome and not intuitive to archive, and the detection accuracy of some indicators is greatly affected by human factors. Therefore, traditional steel structure damage detection methods have poor accuracy, a cumbersome detection process, and long detection time. SUMMARY

[0004] The application provides a steel structure damage detection method based on three-dimensional laser scanning, which can solve the technical problem of poor detection accuracy, cumbersome detection process, and long detection time caused by the dependence of steel structure damage detection methods on total stations and levels in related technologies.

[0005] The application provides a steel structure damage detection method based on three-dimensional laser scanning, which includes the following steps:

[0006] Obtain point cloud data of the steel structure to be detected to establish a three-dimensional point cloud model of the steel structure;

[0007] Compare the three-dimensional point cloud model with the BIM model of the steel structure to obtain a point cloud deviation cloud map for preliminary judgment of the damage area of the steel structure;

[0008] Establish a finite element model of the steel structure, and modify the finite element model through the point cloud deviation cloud map to obtain a stress map for accurate judgment of the damage area of the steel structure.

[0009] In one embodiment, the establishment of the finite element model of the steel structure and the modification of the finite element model through the point cloud deviation cloud map to obtain a stress map for accurate judgment of the damage area of the steel structure includes:

[0010] establishing a finite element model of the steel structure, simulating damage conditions of the steel structure;

[0011] comparing with the point cloud deviation chart, adjusting parameters of the finite element model so that the simulation result of the finite element model is consistent with the point cloud deviation chart Figure One , and obtaining a revised finite element model;

[0012] calculating a structure stress value based on the revised finite element model, and obtaining the stress chart.

[0013] In an embodiment, the steel structure damage detection method based on three-dimensional laser scanning further comprises:

[0014] performing section analysis on the bridge deck deformation area of the steel structure in the point cloud deviation chart to obtain a steel structure deformation chart for assisting in judging the damage area of the steel structure.

[0015] In an embodiment, the section analysis on the bridge deck deformation area of the steel structure in the point cloud deviation chart to obtain a steel structure deformation chart for assisting in judging the damage area of the steel structure comprises:

[0016] setting a threshold value for the bridge deck deformation area of the steel structure in the point cloud deviation chart;

[0017] dividing the section chart according to the transverse bridge direction and the longitudinal bridge direction for the bridge deck deformation area exceeding the threshold value;

[0018] measuring the length exceeding the threshold value in the section chart, and connecting the head and tail of each section area in the transverse bridge direction and the longitudinal bridge direction to obtain the steel structure deformation chart.

[0019] In an embodiment, when dividing the section chart, different intervals are uniformly set according to the size of the steel structure.

[0020] In an embodiment, the steel structure damage detection method based on three-dimensional laser scanning further comprises:

[0021] performing deflection analysis on the rod member of the steel structure to obtain a rod member damage result for judging the damage area of the rod member.

[0022] In an embodiment, the deflection analysis on the rod member of the steel structure to obtain a rod member damage result for judging the damage area of the rod member comprises:

[0023] obtaining the flatness of the rod member of the steel structure and the perpendicularity between the rod members to determine the deformation area of the rod member;

[0024] obtaining the deviation of the included angle between adjacent rod members, the included angle between the rod member and the bridge deck, and the design value to determine the deflection area of the rod member.

[0025] In an embodiment, the method comprises:

[0026] performing three-dimensional laser scanning on the steel structure to be detected by a three-dimensional laser scanner to obtain the point cloud data;

[0027] processing the point cloud data to export in a three-dimensional coordinate format to establish a three-dimensional point cloud model of the steel structure.

[0028] In an embodiment, a plurality of three-dimensional laser scanners are arranged around the steel structure, and scanning surfaces of the three-dimensional laser scanners cover the entire steel structure.

[0029] In an embodiment, the method comprises:

[0030] selecting a plurality of feature points of the steel structure in the three-dimensional point cloud model as reference points and aligning the reference points with corresponding points in the BIM model of the steel structure;

[0031] performing difference analysis on the three-dimensional point cloud model and the BIM model to form an optimal match;

[0032] obtaining deviation results of the three-dimensional point cloud model and the BIM model at corresponding positions, and drawing a color spectrum cloud map as the point cloud deviation cloud map.

[0033] The technical scheme provided by the embodiments of the present application has the following beneficial effects:

[0034] The steel structure damage detection method based on three-dimensional laser scanning provided by the present application obtains high-precision point cloud data of a steel structure based on three-dimensional laser scanning technology, and establishes an accurate three-dimensional point cloud model of a damaged steel structure. Then, the three-dimensional point cloud model is compared with a BIM model established based on design drawings, and a point cloud deviation cloud map obtained can preliminarily judge a steel structure damage area, such as a specific damage position and a deformation degree. Then, a finite element model is corrected according to the point cloud deviation cloud map, and a collision and a deformation process of the steel structure are simulated more accurately. Based on the corrected finite element model, stress conditions of each part of the steel structure are calculated, deformation conditions of any position of the steel structure are quickly and accurately obtained, and damaged areas in the steel structure, areas where damage does not exceed a plastic deformation threshold of the steel structure, and undamaged areas are accurately determined. Without relying on a total station and a level, three-dimensional laser scanning is used to quickly capture geometric data of the steel structure with very high precision, small-size or micro-deformation can be more accurately detected, detection efficiency is greatly improved, and the damaged condition of the steel structure is efficiently, accurately and comprehensively evaluated. BRIEF DESCRIPTION OF DRAWINGS

[0035] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 This is a flowchart illustrating a steel structure damage detection method based on three-dimensional laser scanning in one embodiment of the present invention.

[0037] Figure 2 This is a schematic diagram showing the position of the three-dimensional laser scanner in one embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the point cloud deviation cloud map of a steel structure in one embodiment of the present invention.

[0039] Figure 4 This is a schematic diagram of the cross-sectional division of a steel structure in one embodiment of the present invention.

[0040] Figure 5 This is a schematic diagram of the deformation of a steel structure in one embodiment of the present invention.

[0041] In the image: 1. Steel structure; 2. 3D laser scanner. Detailed Implementation

[0042] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0043] This application provides a method for detecting steel structure damage based on three-dimensional laser scanning, which can solve the technical problems in related technologies where steel structure damage detection methods rely on total stations and levels, resulting in poor detection accuracy, cumbersome detection process, and long time consumption.

[0044] Reference Figure 1 , Figure 1 This is a flowchart illustrating a steel structure damage detection method based on three-dimensional laser scanning in one embodiment of the present invention.

[0045] A method for detecting damage to steel structures based on three-dimensional laser scanning includes the following steps:

[0046] Step S1: Obtain point cloud data of the steel structure to be inspected in order to establish a three-dimensional point cloud model of the steel structure;

[0047] Step S2: Compare the 3D point cloud model with the BIM model of the steel structure to obtain a point cloud deviation map for preliminary judgment of the damaged area of ​​the steel structure.

[0048] Step S3: Establish a finite element model of the steel structure, and correct the finite element model by using point cloud deviation cloud map to obtain a stress map for accurately judging the damage area of ​​the steel structure.

[0049] In this embodiment, high-precision point cloud data of the steel structure is acquired based on 3D laser scanning technology to establish an accurate 3D point cloud model of the damaged steel structure. The 3D point cloud model is then compared with a BIM model built based on design drawings. The resulting point cloud deviation map can preliminarily determine the damaged areas of the steel structure, such as the specific location of the damage and the degree of deformation. The finite element model is then corrected based on the point cloud deviation map to more accurately simulate the impact and deformation process of the steel structure. Based on the corrected finite element model, the stress at various points in the steel structure is calculated, quickly and accurately determining the deformation at any location. This allows for precise identification of damaged areas, areas where the damage does not exceed the plastic deformation threshold, and undamaged areas within the steel structure. Without relying on total stations or levels, 3D laser scanning captures the geometric data of the steel structure with very high precision, enabling more accurate detection of small or minute deformations and significantly improving detection efficiency. This provides a highly efficient, accurate, and comprehensive assessment of the damage to the steel structure.

[0050] The following provides a detailed explanation of each step.

[0051] In one embodiment, step S1, acquiring point cloud data of the steel structure to be inspected to establish a three-dimensional point cloud model of the steel structure, includes:

[0052] Step S11: The 3D laser scanner performs a 3D laser scan on the steel structure to be inspected to obtain point cloud data;

[0053] Step S12: Process the point cloud data, export it in three-dimensional coordinate format, and establish a three-dimensional point cloud model of the steel structure.

[0054] The above scheme utilizes a 3D laser scanner to scan the surface of a damaged steel structure using a laser beam. The scanned data is then visualized through 3D reverse modeling, generating high-resolution, high-precision point cloud data. This data is used to create a precise 3D point cloud model of the damaged steel structure. Using 3D laser scanning technology to scan damaged steel structures achieves non-contact, high-precision, and high-efficiency measurements. No physical contact is required, preventing further damage or risk to the steel structure itself. Engineers or inspectors are not required to perform inspections in hazardous locations, thus improving the safety of the inspection process. The scanned data can establish a historical record of steel structure damage. Periodic scanning allows for tracking the development of damage, helping to predict potential maintenance needs and providing a high-precision method for periodic damage detection.

[0055] like Figure 2 As shown, Figure 2 This is a schematic diagram showing the position of a three-dimensional laser scanner in one embodiment of the present invention.

[0056] In one embodiment, in step S11, there are multiple 3D laser scanners 2 arranged around the steel structure 1, and the scanning surface of the 3D laser scanners 2 covers the entire steel structure 1.

[0057] The 3D laser scanner is multi-station; for large steel structures, a 25-station 3D laser scanner is used, and for medium-sized steel structures, a 15-station 3D laser scanner is used. Each station scans 2-3 target sphere features, with the horizontal angle set to 90° (corners) and 210° (front elevation) depending on the location. Stations are positioned around the steel structure 1, both on its surface and bottom, ensuring the integrity of the point cloud model and thus reflecting the overall outline of the steel structure 1. The 3D laser scanner offers high precision and speed, with high accuracy in detecting small dimensions or minute deformations, significantly improving detection efficiency.

[0058] Furthermore, in step S12, the point cloud data is processed, such as filtering, denoising, registering, and cropping the point cloud data before and after loading, and then exporting the point cloud data of the steel structure to be inspected after cropping in the format of three-dimensional coordinates.

[0059] Furthermore, the point cloud data retained after rotation and shearing is used to remove impurities and to make the axis of the steel structure to be inspected in the 3D point cloud model coincide with the principal axis of the coordinate system in the BIM model, so as to facilitate subsequent comparison between the two.

[0060] like Figure 3 As shown, Figure 3 This is a schematic diagram of the point cloud deviation cloud map of a steel structure in one embodiment of the present invention.

[0061] In one embodiment, step S2, comparing the 3D point cloud model with the BIM model of the steel structure to obtain a point cloud deviation map for preliminary judgment of the damaged area of ​​the steel structure, includes:

[0062] Step S21: Select multiple feature points of the steel structure in the 3D point cloud model as reference points and align them with the corresponding points in the BIM model of the steel structure.

[0063] Specifically, multiple feature points on the non-impact side of the steel structure in the 3D point cloud model are selected as reference points and coarsely matched with corresponding points in the BIM model built based on the design drawings. Based on the center point of the steel structure, cross-sectional views of the model in the transverse and longitudinal directions are compared. The cross-sectional views are used to determine whether the 3D point cloud model and the BIM model are aligned. If they are not aligned, the 3D point cloud model is translated and rotated until the 3D point cloud model and the BIM model are aligned.

[0064] Step S22: Perform overlap analysis on the 3D point cloud model and the BIM model to form the optimal match.

[0065] Step S23: Obtain the deviation results between the 3D point cloud model and the BIM model at corresponding positions, and draw a color cloud map as the point cloud deviation cloud map.

[0066] Using the above scheme and the point alignment-overlap analysis method, the deviation between the 3D point cloud model and the BIM model at corresponding positions, as well as the distance from the deviation point to the BIM model, are obtained. Based on the overall analysis results, a point cloud deviation cloud map is drawn, which intuitively reflects the distribution of the damaged area in the steel structure on the entire steel structure, and from this, the specific damage location and deformation degree can be preliminarily determined.

[0067] In one embodiment, step S3, establishing a finite element model of the steel structure, and correcting the finite element model using a point cloud deviation map to obtain a stress map for accurately determining the damage area of ​​the steel structure, includes:

[0068] Step S31: Establish a finite element model of the steel structure to simulate the damage to the steel structure.

[0069] Specifically, a finite element model is established to simulate the impact and deformation process of the steel structure. Boundary conditions and other parameters are set according to the site conditions, and the deformation of the steel structure is preliminarily calculated. Finite element analysis software is used.

[0070] Step S32: Compare the point cloud deviation map with the actual point cloud. Adjust the parameters of the finite element model to make the simulation results of the finite element model match the point cloud deviation map. Figure One Thus, the corrected finite element model was obtained.

[0071] Specifically, the deformation amount initially calculated by the finite element model is compared with the deformation amount in the point cloud deviation map obtained by three-dimensional laser scanning. By continuously adjusting the boundary conditions and other parameters of the finite element model, such as initial velocity, contact surface, friction coefficient and contact type, until the deformation result simulated by the finite element model is consistent with the result of the point cloud deviation map obtained by three-dimensional laser scanning, the finite element model can be corrected, and the damage of the steel structure can be simulated more accurately.

[0072] Step S33: Calculate the structural stress values ​​based on the modified finite element model to obtain the stress diagram.

[0073] The above scheme calculates the stress at various points in the steel structure based on the modified finite element model and outputs stress diagrams. It can quickly and accurately calculate the deformation at any location in the steel structure, and then accurately determine the damaged area, the area where the damage does not exceed the plastic deformation threshold of the steel structure, and the undamaged area, which facilitates the damage assessment of the structure.

[0074] In one embodiment, the steel structure damage detection method based on three-dimensional laser scanning further includes:

[0075] Step S4: Perform cross-sectional analysis on the deformation area of ​​the bridge deck of the steel structure in the point cloud deviation map to obtain a steel structure deformation map to help determine the damage area of ​​the steel structure.

[0076] like Figure 4 and Figure 5 As shown, where, Figure 4 This is a schematic diagram of the cross-sectional division of a steel structure in one embodiment of the present invention. Figure 5 This is a schematic diagram of the deformation of a steel structure in one embodiment of the present invention.

[0077] In one embodiment, step S4, performing cross-sectional analysis on the bridge deck deformation area of ​​the steel structure in the point cloud deviation map to obtain a steel structure deformation map for assisting in judging the damage area of ​​the steel structure, includes:

[0078] Step S41: Set a threshold for the deformation area of ​​the bridge deck of the steel structure in the point cloud deviation map;

[0079] Step S42: Divide the bridge deck deformation area that exceeds the threshold into cross-sectional views according to the transverse and longitudinal directions;

[0080] Step S43: Measure the length exceeding the threshold in the cross-sectional diagram, connect the ends of each cross-sectional area in the transverse and longitudinal directions to obtain the deformation diagram of the steel structure.

[0081] Using the above method, point cloud deviation cloud Figure OneOn the one hand, it is used to correct the finite element model to generate stress diagrams; on the other hand, it is used to refine the cross-sectional analysis to generate deformation diagrams of the steel structure. Before the stress diagram is generated, the deformation diagram of the steel structure is generated quickly to determine the specific size and area of ​​the damaged area, etc., so as to help judge the damaged area of ​​the bridge deck in the steel structure and guide the construction.

[0082] In one embodiment, when dividing the cross-sectional views, different intervals are uniformly set according to the size of the steel structure. For example, for large components, cross-sections are made at 1m intervals, and for medium and small components, cross-sections are made at 0.5m intervals, thereby improving inspection efficiency.

[0083] In one embodiment, the steel structure damage detection method based on three-dimensional laser scanning further includes:

[0084] Step S5: Perform deflection analysis on the steel structure members to obtain member damage results for determining the damaged area of ​​the members.

[0085] In one embodiment, step S5, performing deflection analysis on the steel structure members to obtain member damage results for determining the member damage area, includes:

[0086] Step S51: Obtain the flatness of the steel structure members and the perpendicularity between the members to determine the deformation area of ​​the members.

[0087] Specifically, when obtaining the flatness of the steel structure members, an algorithm is used to fit each plane, and the four planes are named Plane 1, Plane 2, Plane 3, and Plane 4. Using Plane 1 and Plane 2 of each member as cross-sections, cross-sectional diagrams of Plane 2 and Plane 4, and Plane 1 and Plane 3 are drawn respectively. Three cross-sectional lines are drawn for each plane, located at 1 / 4, 1 / 2, and 3 / 4 of the plane. The algorithm is then used to fit the straight line equation of the cross-sectional line and the Pearson correlation coefficient of each point on the cross-sectional line. If the correlation coefficient is close to 1 or -1, the straightness of the cross-sectional line is good. If the Pearson correlation coefficients of the three cross-sectional lines of a single plane are all close to 1 or -1, the flatness of that plane is good; otherwise, the flatness is poor.

[0088] By using the plane equations of each surface of the member obtained through the above fitting, the included angles between each plane are obtained, and the error with the design value is calculated. This error reflects the perpendicularity between the members.

[0089] Measuring the flatness of the rods and the perpendicularity between the rods reflects the local deformation of a single rod.

[0090] Step S52: Obtain the included angle between adjacent members and the deviation of the included angle between the member and the bridge deck from the design value through point cloud data, so as to determine the deflection area of ​​the member.

[0091] The angles between adjacent members and the angles between the members and the bridge deck obtained by 3D laser scanning are calculated based on the point cloud data of the truss, reflecting the deflection of the members.

[0092] The above scheme provides stress diagrams, steel structure deformation diagrams, and member damage results, reflecting the deformation of the entire steel structure from multiple perspectives, not just the damaged parts. This helps to comprehensively assess the overall condition of the bridge, including early detection of potential problems, and facilitates subsequent damage assessment and maintenance.

[0093] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0094] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0095] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0096] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0097] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk, etc.) and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0098] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for detecting damage of a steel structure based on three-dimensional laser scanning, characterized by, The method comprises the following steps: acquiring point cloud data of a steel structure to be detected to establish a three-dimensional point cloud model of the steel structure; comparing the three-dimensional point cloud model with a BIM model of the steel structure established based on design drawings to obtain a point cloud deviation cloud map for preliminary judgment of a damage area of the steel structure; establishing a finite element model of the steel structure and correcting the finite element model through the point cloud deviation cloud map to obtain a stress map for accurate judgment of the damage area of the steel structure; wherein the step of establishing the finite element model of the steel structure and correcting the finite element model through the point cloud deviation cloud map to obtain the stress map for accurate judgment of the damage area of the steel structure comprises: establishing the finite element model of the steel structure to simulate the damage condition of the steel structure; comparing the point cloud deviation cloud map to obtain a corrected finite element model by adjusting parameters of the finite element model so that the simulation result of the finite element model is consistent with the point cloud deviation cloud map; calculating a structural stress value based on the corrected finite element model to obtain the stress map.

2. The method for detecting damage of a steel structure based on three-dimensional laser scanning according to claim 1, wherein, The steel structure damage detection method based on three-dimensional laser scanning further comprises: performing section analysis on a bridge deck deformation area of the steel structure in the point cloud deviation cloud map to obtain a steel structure deformation map for auxiliary judgment of the damage area of the steel structure.

3. The method for detecting damage of a steel structure based on three-dimensional laser scanning according to claim 2, wherein, The step of performing section analysis on the bridge deck deformation area of the steel structure in the point cloud deviation cloud map to obtain the steel structure deformation map for auxiliary judgment of the damage area of the steel structure comprises: setting a threshold value for the bridge deck deformation area of the steel structure in the point cloud deviation cloud map; dividing a section map according to a transverse bridge direction and a longitudinal bridge direction for the bridge deck deformation area exceeding the threshold value; connecting the section areas in the transverse bridge direction and the longitudinal bridge direction to obtain the steel structure deformation map by measuring the length exceeding the threshold value in the section map.

4. The method for detecting damage of a steel structure based on three-dimensional laser scanning according to claim 3, wherein, When dividing the section map, different intervals are uniformly set according to the size of the steel structure.

5. The method for damage detection of a steel structure based on three-dimensional laser scanning according to claim 1, wherein, The steel structure damage detection method based on three-dimensional laser scanning further comprises: performing deflection analysis on a member of the steel structure to obtain a member damage result for judgment of a damage area of the member.

6. The method for detecting damage of a steel structure based on three-dimensional laser scanning according to claim 5, wherein, The step of performing deflection analysis on the member of the steel structure to obtain the member damage result for judgment of the damage area of the member comprises: acquiring flatness of the member of the steel structure and perpendicularity between the members to determine a deformation area of the member; acquiring deviations of an included angle of adjacent members, an included angle of the member and the bridge deck from design values through the point cloud data to determine a deflection area of the member.

7. The three-dimensional laser scanning-based steel structure damage detection method of claim 1, wherein, The step of acquiring point cloud data of a steel structure to be detected to establish a three-dimensional point cloud model of the steel structure comprises: performing three-dimensional laser scanning on the steel structure to be detected by a three-dimensional laser scanner to acquire the point cloud data; processing the point cloud data to be exported in a three-dimensional coordinate format to establish the three-dimensional point cloud model of the steel structure.

8. The three-dimensional laser scanning-based steel structure damage detection method of claim 7, wherein, The three-dimensional laser scanners are multiple and are arranged around the steel structure, and scanning surfaces of the three-dimensional laser scanners cover the entire steel structure.

9. The method of claim 1 to 8, wherein, The comparing the three-dimensional point cloud model with the BIM model of the steel structure to obtain a point cloud deviation cloud map for preliminarily judging the damage area of the steel structure comprises the following steps: A plurality of feature points on the non-impact side of the steel structure in the three-dimensional point cloud model are selected as reference points, and the corresponding points in the BIM model of the steel structure are aligned; The three-dimensional point cloud model and the BIM model are subjected to difference analysis to form an optimal match; The deviation results of the three-dimensional point cloud model and the BIM model at the corresponding positions are obtained, and a color spectrum cloud map is drawn as the point cloud deviation cloud map.

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