scholarly journals A New Approach for Cylindrical Steel Structure Deformation Monitoring by Dense Point Clouds

2021 ◽  
Vol 13 (12) ◽  
pp. 2263
Author(s):  
Dongfeng Jia ◽  
Weiping Zhang ◽  
Yuhao Wang ◽  
Yanping Liu
Keyword(s):  
Steel Structure ◽  
Steel Structures ◽  
Point Clouds ◽  
Deformation Monitoring ◽  
Deformation Analysis ◽  
Relative Deformation ◽  
Structure Deformation ◽  
Single Time ◽  
Cylindrical Steel ◽  
Cylinder Fitting

As fundamental load-bearing parts, the cylindrical steel structures of transmission towers relate to the stability of the main structures in terms of topological relation and performance. Therefore, the periodic monitoring of a cylindrical steel structure is necessary to maintain the safety and stability of existing structures in energy transmission. Most studies on deformation analysis are still focused on the process of identifying discrepancies in the state of a structure by observing it at different times, yet relative deformation analysis based on the data acquired in single time has not been investigated effectively. In this study, the piecewise cylinder fitting method is presented to fit the point clouds collected at a single time to compute the relative inclination of a cylindrical steel structure. The standard deviation is adopted as a measure to evaluate the degree of structure deformation. Meanwhile, the inclination rate of each section is compared with the conventional method on the basis of the piecewise cylinder fitting parameters. The validity and accuracy of the algorithm are verified by real transmission tower point cloud data. Experimental results show that the piecewise cylinder fitting algorithm proposed in this research can meet the accuracy requirements of cylindrical steel structure deformation analysis and has high application value in the field of structure deformation monitoring.

scholarly journals Monitoring Dynamic Deformation of Building Using Unmanned Aerial Vehicle

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yongquan Ge ◽  
Xianzhi Yu ◽  
Mingzhi Chen ◽  
Chengxin Yu ◽  
Yingchun Liu ◽  
...  
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Dynamic Deformation ◽  
Motion Parallax ◽  
Steel Structure ◽  
Steel Structures ◽  
Deformation Monitoring ◽  
Dynamic Monitoring ◽  
Structure Deformation ◽  
Aerial Vehicle ◽  
Mp Method

The height irregularity and complexity of steel structures bring difficulties to dynamic deformation monitoring. PDMS (photogrammetric dynamic monitoring system) can obtain the dynamic deformation of the steel structure, but the flexibility of monitoring is limited because the camera station can only be placed on the ground. In this study, UAV (unmanned aerial vehicle) -PDMS is innovatively proposed to be used in monitoring dynamic deformation of steel structures, and it is verified in the steel frame test and Jinan Olympic Sports Center Tennis Stadium test. To solve the problem that the attitude of UAV cannot be strictly maintained in the hovering process, the improved Z-MP (zero-centered motion parallax) method is used, and the monitoring results are compared with the original Z-MP method. The feasibility of UAV-PDMS applied to steel structure deformation monitoring and the feasibility of improving the Z-MP method to reduce UAV hovering error are verified. The monitoring results showed that the steel structures of the Jinan Olympic Sports Center Tennis Stadium were robust, and the deformations were elastic and within the permissible value.

Robust external calibration of terrestrial laser scanner and digital camera for structural monitoring

2019 ◽  
Vol 13 (2) ◽  
pp. 105-134 ◽  
Author(s):  
Mohammad Omidalizarandi ◽  
Boris Kargoll ◽  
Jens-André Paffenholz ◽  
Ingo Neumann
Keyword(s):  
Em Algorithm ◽  
Laser Scanner ◽  
Digital Camera ◽  
Point Clouds ◽  
Deformation Monitoring ◽  
Deformation Analysis ◽  
Terrestrial Laser Scanner ◽  
External Calibration ◽  
3D Point Clouds ◽  
Calibration Parameters

Abstract In the last two decades, the integration of a terrestrial laser scanner (TLS) and digital photogrammetry, besides other sensors integration, has received considerable attention for deformation monitoring of natural or man-made structures. Typically, a TLS is used for an area-based deformation analysis. A high-resolution digital camera may be attached on top of the TLS to increase the accuracy and completeness of deformation analysis by optimally combining points or line features extracted both from three-dimensional (3D) point clouds and captured images at different epochs of time. For this purpose, the external calibration parameters between the TLS and digital camera needs to be determined precisely. The camera calibration and internal TLS calibration are commonly carried out in advance in the laboratory environments. The focus of this research is to highly accurately and robustly estimate the external calibration parameters between the fused sensors using signalised target points. The observables are the image measurements, the 3D point clouds, and the horizontal angle reading of a TLS. In addition, laser tracker observations are used for the purpose of validation. The functional models are determined based on the space resection in photogrammetry using the collinearity condition equations, the 3D Helmert transformation and the constraint equation, which are solved in a rigorous bundle adjustment procedure. Three different adjustment procedures are developed and implemented: (1) an expectation maximization (EM) algorithm to solve a Gauss-Helmert model (GHM) with grouped t-distributed random deviations, (2) a novel EM algorithm to solve a corresponding quasi-Gauss-Markov model (qGMM) with t-distributed pseudo-misclosures, and (3) a classical least-squares procedure to solve the GHM with variance components and outlier removal. The comparison of the results demonstrates the precise, reliable, accurate and robust estimation of the parameters in particular by the second and third procedures in comparison to the first one. In addition, the results show that the second procedure is computationally more efficient than the other two.

scholarly journals Concept for completeness checking of joined structures exemplified on rail vehicle car body shells

2017 ◽  
Vol 6 (1) ◽  
pp. 53-63
Author(s):  
Uwe Jurdeczka
Keyword(s):  
Steel Structure ◽  
Steel Structures ◽  
Point Clouds ◽  
Constructional Steel ◽  
Car Body ◽  
Target State ◽  
Beam Geometry ◽  
The Difference ◽  
Actual Configuration ◽  
D Model

Abstract. Completeness checking of constructional steel structures with several hundred weld-on parts (mountings, such as car body shells/chassis for rail vehicles, for example) still represents a great challenge. It has been performed manually so far. By the use of 3-D scanners, it is possible to obtain sufficiently comprehensive information about the actual configuration (as-is state) of the constructional steel structure to be checked. For this purpose, the laser beam geometry must be contemplated. By using an adapted algorithm for post-processing of the resulting point clouds, difference figures are superimposed over the respective 3-D model as the target state. Therefore, an algorithm was adapted and applied here. The difference figures are useful for signalling the possible deviations and the missing parts, at least, however, suspect points. Thus, the disadvantages of the exclusively manual completeness checking practiced so far, i.e. tiredness and slowness of the inspector, can largely be avoided. The 3-D model-based inspection procedure allows one to handle the variation in the target state with just a few volumes of equal configuration (e.g. less than 10 trains with equal configuration). There is a general problem that the tolerance for the structure is in the same range as the size of the mountings. It is possible to solve this problem by dividing the test item as well as the point cloud into areas. Superposing the 3-D model by point clouds and calculating the difference figures will be performed area by area.

scholarly journals F2S3: Robustified determination of 3D displacement vector fields using deep learning

2020 ◽  
Vol 14 (2) ◽  
pp. 177-189
Author(s):  
Zan Gojcic ◽  
Caifa Zhou ◽  
Andreas Wieser
Keyword(s):  
Displacement Vector ◽  
Point Clouds ◽  
Deformation Monitoring ◽  
Swiss Alps ◽  
Local Context ◽  
Deformation Analysis ◽  
Natural Scenes ◽  
Interest Points ◽  
Data Set ◽  
Cloud Data

AbstractAreal deformation monitoring based on point clouds can be a very valuable alternative to the established point-based monitoring techniques, especially for deformation monitoring of natural scenes. However, established deformation analysis approaches for point clouds do not necessarily expose the true 3D changes, because the correspondence between points is typically established naïvely. Recently, approaches to establish the correspondences in the feature space by using local feature descriptors that analyze the geometric peculiarities in the neighborhood of the interest points were proposed. However, the resulting correspondences are noisy and contain a large number of outliers. This impairs the direct applicability of these approaches for deformation monitoring. In this work, we propose Feature to Feature Supervoxel-based Spatial Smoothing (F2S3), a new deformation analysis method for point cloud data. In F2S3 we extend the recently proposed feature-based algorithms with a neural network based outlier detection, capable of classifying the putative pointwise correspondences into inliers and outliers based on the local context extracted from the supervoxels. We demonstrate the proposed method on two data sets, including a real case data set of a landslide located in the Swiss Alps. We show that while the traditional approaches, in this case, greatly underestimate the magnitude of the displacements, our method can correctly estimate the true 3D displacement vectors.

scholarly journals TLS-Based Feature Extraction and 3D Modeling for Arch Structures

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Xiangyang Xu ◽  
Xin Zhao ◽  
Hao Yang ◽  
Ingo Neumann
Keyword(s):  
3D Modeling ◽  
Laser Scanning ◽  
High Efficiency ◽  
Data Extraction ◽  
Point Clouds ◽  
Deformation Monitoring ◽  
Deformation Analysis ◽  
Unknown Parameters ◽  
Automatic Data ◽  
B Spline

Terrestrial laser scanning (TLS) technology is one of the most efficient and accurate tools for 3D measurement which can reveal surface-based characteristics of objects with the aid of computer vision and programming. Thus, it plays an increasingly important role in deformation monitoring and analysis. Automatic data extraction and high efficiency and accuracy modeling from scattered point clouds are challenging issues during the TLS data processing. This paper presents a data extraction method considering the partial and statistical distribution of the point clouds scanned, called the window-neighborhood method. Based on the point clouds extracted, 3D modeling of the boundary of an arched structure was carried out. The ideal modeling strategy should be fast, accurate, and less complex regarding its application to large amounts of data. The paper discusses the accuracy of fittings in four cases between whole curve, segmentation, polynomial, and B-spline. A similar number of parameters was set for polynomial and B-spline because the number of unknown parameters is essential for the accuracy of the fittings. The uncertainties of the scanned raw point clouds and the modeling are discussed. This process is considered a prerequisite step for 3D deformation analysis with TLS.

The Deformation Analysis and Control of Large Steel Structures Based on Non-Slide Construction Site

2011 ◽  
Vol 255-260 ◽  
pp. 649-653
Author(s):  
Yan Guo ◽  
Qing Zhang ◽  
Xiang Qiang Bai ◽  
Shen Hong Pan
Keyword(s):  
Dimensional Accuracy ◽  
Steel Structure ◽  
Steel Structures ◽  
Deformation Analysis ◽  
Construction Technique ◽  
Deformation Control ◽  
Large Steel ◽  
Temporary Support ◽  
The Common ◽  
And Control

The layered construction technique is the common method of large steel structures in the non-slide construction. In process of the former three-tier construction, the structure is prone to forming large deformation because of great span, large weight of interlayer equipments and other various factors. In this article, to obtain high dimensional accuracy and good deformation control data, the positions of temporary support points of the 3M201 that is a module of large steel structure in a project are optimized successfully with the ANSYS optimization of finite element.

Laser Scanning Based Growth Analysis of Plants as a New Challenge for Deformation Monitoring

2016 ◽  
Vol 10 (1) ◽  
Author(s):  
Jan Dupuis ◽  
Christoph Holst ◽  
Heiner Kuhlmann
Keyword(s):  
Leaf Area ◽  
High Precision ◽  
Laser Scanning ◽  
Leaf Surface ◽  
Leaf Growth ◽  
Spline Approximation ◽  
Point Clouds ◽  
Deformation Monitoring ◽  
Deformation Analysis ◽  
Absolute Size

AbstractNowadays, the areal deformation analysis has become an important task in engineering geodesy. Thereby, not only manmade objects are of high interest, also natural objects, like plant organs, are focused more frequently. Thus, the analysis of leaf growth, i. e. the spatial development of the leaf surface, can be seen as a problem of deformation monitoring. In contrast to classical geodetic tasks, the absolute size of the deformation of the leaf surface is small, but usually great compared to the object size. Due to the optical characteristics of leaf surfaces, the point clouds, commonly acquired with high precision close-up laser scanners, provide a point-to-point distance that is small or equal compared to the measurement accuracy. Thus, the point clouds are usually processed and the leaf area is derived from a triangulation-based surface representation (mesh), resulting in a significant uncertainty of area calculation. In this paper, we illustrate the lacks of the mesh-based leaf area calculation. Using high precision gauge blocks as well as a number of tomato leaves, uncertainties of the area derivation are revealed and evaluated. The application of a B-spline approximation illustrates the advantages of an approximation-based approach and introduces the prospect for further research.

scholarly journals Monitoring of Excessive Deformation of Steel Structure Extra-High Voltage Pylons

2017 ◽  
Author(s):  
Lačezar Ličev ◽  
Jakub Hendrych ◽  
Jan Tomeček ◽  
Radim Čajka ◽  
Martin Krejsa
Keyword(s):  
High Voltage ◽  
Power Grid ◽  
Steel Structure ◽  
Steel Structures ◽  
Geodetic Survey ◽  
The State ◽  
Deformation Analysis ◽  
Original Design ◽  
Critical Position ◽  
Extra High Voltage

Reliability and security of a power transmission depends on the state of the power grid and mainly on the state of the Extra-High Voltage pylons. The paper deals with deformation analysis of existing steel structure of selected Extra-High Voltage pylons which showed excessive differences comparing to the original design. In the assessment of the situation, geodetic survey of selected pylons of power grid that showed the greatest deformation was performed. On taken images, deformation of steel structures by using the FOTOMNG system was also analyzed. The proposed method allows a modeling of the structure of the object based on precisely obtained photographic documentation of the current state. It also represents a very effective method which allows to quickly and efficiently analyze the deformation in the structure of Extra-High Voltage pylons in the critical position of the power grid. Other benefits include the possibility of repeatable and safe measurement.

Research on Earthquake Load Analysis of Large Structures in Non-Slide Construction

2012 ◽  
Vol 157-158 ◽  
pp. 1632-1635
Author(s):  
Gong Sheng Yang
Keyword(s):  
Finite Element ◽  
Large Scale ◽  
Level Structure ◽  
Steel Structure ◽  
Steel Structures ◽  
Deformation Analysis ◽  
Seismic Load ◽  
Large Steel ◽  
Large Bulk ◽  
Earthquake Load

Ocean large steel structures are usually constructed on the slide site, being prone to forming large deformation because of its features such as heavy weight, large bulk and great span. However, the 18 large-scale steel structures of a nickel ore project are need to building on the non-slide foundation, resulting in different settlements of foundation. Moreover, the earthquake load is one of main load of the high-level structure. And the earthquake often happens suddenly and is out of control, with devastating destructive power. To ensure the safety of construction, it’s necessary to analyze the influence of large steel structure responding to the seismic load. This paper expounds the analyzing method on the response of the large steel structure based on non-slide site to the earthquake load. This article has analyzed responses of three-dimensional finite element model to the earthquake load with ANSYS analysis of finite element, such as the stress, deformation analysis, modal analysis and transient dynamic analysis, and assessed the risk of earthquake. This paper provides a feasible and effective analyzed method for researching the response of structure built on non-slide site to the earthquake load, which has important significance for the seismic design of the structure.

Dynamic Characteristics of Base-Isolated Steel Frame under Seismic Ground Motion

2011 ◽  
Vol 255-260 ◽  
pp. 2341-2344
Author(s):  
Mohammad Saeed Masoomi ◽  
Siti Aminah Osman ◽  
Ali Jahanshahi
Keyword(s):  
Ground Motion ◽  
Base Isolation ◽  
Time History ◽  
Steel Structure ◽  
Steel Structures ◽  
Steel Frame ◽  
Nonlinear Time History Analysis ◽  
Seismic Load ◽  
Vector Method ◽  
Seismic Ground Motion

This paper presents the performance of base-isolated steel structures under the seismic load. The main goals of this study are to evaluate the effectiveness of base isolation systems for steel structures against earthquake loads; to verify the modal analysis of steel frame compared with the hand calculation results; and development of a simulating method for base-isolated structure’s responses. Two models were considered in this study, one a steel structure with base-isolated and the other without base-isolated system. The nonlinear time-history analysis of both structures under El Centro 1940 seismic ground motion was used based on finite element method through SAP2000. The mentioned frames were analyzed by Eigenvalue method for linear analysis and Ritz-vector method for nonlinear analysis. Simulation results were presented as time-acceleration graphs for each story, period and frequency of both structures for the first three modes.

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