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Optical Principles of LiDAR: a) 3D LiDAR and Idealized Field of View (FOV); b) Basic Range Detection from Laser Wave Signals.
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... 2 shows an example of a schematic moving-iron type galvanometer. Figure 3 shows a scanning LiDAR and basics of the detection of returning signals. There are two approaches to the detection of the position data: 1) time of flight differences between emitted pulse and returned signals and 2) phase differences between the two signals (Jelalian, 1992). ...
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... It decreases the need for human resources and makes inspection easier without interfering with the facility's operations. Nowadays, terrestrial laser scanner has many application in civil engineering community such as structural health monitoring, detect pavements distresses, monitoring the facades of ancient architectural and historical monuments, trilateration networks for accurate Georeferencing of spaces, etc. [7,9,[11][12][13]. Structural deformation monitoring is the primary use of scanners for evaluating an object's state [1]. ...
... Several researches had studied using geodetic techniques and instruments such as robotic reflecorless total station and TLS in structural health monitoring for different and special structures [6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Beshr et al. [14] used TLS in determining the deformation of R.C beams through laboratory tests. ...
The appearance and development of new construction materials, technology and accurate geodetic instruments have led to the necessity of their inevitable use in the health monitoring, maintenance, and restoration of civil structures and special structures such as high-rise cooling towers. This paper presents an accurate practical and analytical method for determining the structural deformation and axis inclination of high rise cooling towers using terrestrial laser scanner (TLS) observations through the projection of tower surface points coordinates on a vertical plane. Four cooling towers in El-Mahla El-Kubra city, Egypt are observed and studied. Two of them with height 56 m, and the others were 36 m height. The studied four towers have different cross-section diameters along the tower height. Each tower has a cone shape with a curved wall. The equation of the tower wall is determined using TLS observations and least squares adjustment techniques. The equations of cone projection with a curved wall are derived and presented in this paper. From TLS observations, the radii and accuracy of each 2 m tower height are determined with center coordinates , and then the inclination of the tower axis is calculated and drawn. From the results of TLS observations, data processing, and analysis using the suggested techniques, it is deduced that there is a deformation in tower walls with small values. The specified technique for observations collection and TLS data analysis through projection on a vertical plane is significant and valuable for determining the structural deformation of circular high rise buildings and towers. From the results, there are obvious deformation values in some cooling towers, so maintenance work must be included. The towers also must be checked and monitored several times at brief intervals.
... The selected fragments containing changes have been transferred to CloudCompare such that the changes can be demonstrated and dimensioned. To present the defect map, a reference plane was fitted into the point cloud based on the mean sum error method [42]. Next, the distances, z i , of all points from the reference plane were calculated. ...
The popularity of smartphones along with advances in sensor technologies has opened new possibilities for scientific application and low-cost observation. Particularly useful is the LiDAR sensor, which can be used to measure building elements.
The aim of study is to propose a new methodology of using the smartphone with LiDAR Apple iPhone XR, in examining wall cracks and resulting displacement. Due to the fact, that the measured walls were quasi-flat and homogeneous, dedicated spatial measurement targets (SMTs) were used for measurement. These SMTs are designed to change the geometry of the tested object. The methodology proposed in the study includes measurements using a smartphone with LiDAR in variants with and without SMTs, and its analysis.
The test results are compared with the measurements using a terrestrial laser scanner (TLS). Analysis showed that for detecting small cracks such as 0.5–1.0 mm, smartphone measurement with LiDAR and SMT is better than TLS.
... LiDAR-laser imaging detection and ranging (LiDAR) or Terrestrial (ground-based) laser scanning systems have found significant applications in monitoring of structures [32]. The movable mirror system can either use an hexagonal mirror or a multiple-axis rotating flat mirror. ...
The paper focuses on a review of augmented reality/mixed reality (AR/MR) technologies in the perspective of the application to structural health monitoring (SHM) for submerged floating tunnels (SFT). In particular, Microsoft HoloLens Devices (MHD) are precious tools for survey purposes, since they allow the superimposition of information about the surrounding environment, leading to its complete control with a reduction of errors. Preliminary, the most common SHM techniques in traditional waterway crossings are examined, for identifying those best fitting with SFTs. The infrared (IR) thermography for damage detection is deepen. The possibility of connecting IR Camera and MHD, with the aim at facilitating the acquisition of thermal data and enabling stereoscopic thermal overlays in the worker’s augmented view, is examined through three different experiments, namely steel fatigue crack detection on a steel plate, CFRP delamination detection and coating thickness detection on a steel members. To this purpose, a simulation of the combination of thermal image with HoloLens is performed showing the potentiality of how the view of the thermal camera in front of the user can enhance the perception of possible problems on the target structure earlier with respect to analyzing the data afterwards.
... Over time, applying this technique can provide a clear picture of damage progression [117,118]. Due to these capabilities, laser scanning has become increasingly popular for NDT and SHM applications [119,120]. ...
This paper provides a state-of-the-art review of the effects of Environmental and Operational Conditions (EOCs) on Structural Health Monitoring (SHM) and Non-Destructive Testing (NDT) systems. It presents recent developments in advanced sensing technology, signal processing, and analysis techniques that aim to eliminate the masking effect of EOC variations and increase the damage sensitivity and performance of SHM and NDT systems. The paper concludes with current research challenges, trends, and recommendations for future research directions.
... Many thousands of these points, each one corresponding to a different location on the physical object, can be amassed to form a file named point cloud. This file may subsequently be utilized for a variety of applications, after post-processing and optimization, including bridge inspection and assessment (Fuchs et al., 2004;Tang et al., 2007;Chen, 2012;Mizoguchi et al., 2013;Teza et al., 2009;Kim et al., 2015;Conde-Carnero et al., 2016), and Bridge Information Model (BrIM) development (Barazzetti, 2016;Xiong et al., 2013;Mohammadi et al., 2022). ...
In the current modern era of information and technology, the concept of Building Information Modeling (BIM), has made revolutionary changes in different aspects of engineering design, construction, monitoring, and management of infrastructure assets, especially bridges. In the field of bridge engineering, Bridge Information Modeling (BrIM), as a specific form of BIM, includes digital twinning of bridge assets associated with geometrical information and non-geometrical inspection data. BrIM has demonstrated tremendous potential in substituting traditional paper-based documentation and handwritten reports with digital bridge documentation/trans-formation, allowing professionals and managers to execute bridge management more efficiently and effectively. However, concerns remain about the quality of the acquired data in BrIM development, as well as lack of research on utilizing these information for remedial actions/decisions in a reliable Bridge Management System (BMS), which are mainly reliant on the knowledge and experience of the involved inspectors, or asset managers, and are susceptible to a certain degree of subjectivity. To address these concerns, this research paper presents a comprehensive methodology as an advanced asset management system that employs BrIM data to improve and facilitate the BMS. This innovative BMS is comprised of a precise Terrestrial Laser Scan (TLS)-derived BrIM as a qualitative digital replica of the existing bridge, incorporating geometrical and non-geometrical information of the bridge elements, and equipped with a requirement-driven framework in a redeveloped condition assessment model for priority ranking of bridge elements based on their health condition. In another step ahead, the proposed BMS integrates a Decision Support System (DSS) to score the feasible remedial strategies and provide more objective decisions for optimal budget allocation and remedial planning. This methodology was further implemented via a developed BrIM-oriented BMS plugin and validated through a real case study on the Werrington Bridge, a cable-stayed bridge in New South Wales, Australia. The finding of this research confirms the reliability of BrIM-oriented BMS implementation and the integration of proposed DSS for priority ranking of bridge elements that require more attention based on their structural importance and material vulnerability, as well as optimizing remedial actions in a practical way while preserving the bridge in a safe and healthy condition.
... For the maintenance of infrastructure such as bridges (Chen, 2012;Kalasapudi, 2017;Truong-Hong andLaefer, 2019), tunnels (Van Goor, 2011;Delaloye et al., 2012), structures (Mukupa, 2017;Lindenbergh et al., 2019), and dams (Herring, 2019), point clouds have been used to create 3D representations of objects for quality evaluation. To perform automated spatial change analysis of mechanical, electrical, and plumbing (MEP) components, a relational-graph-based framework was developed. ...
Over recent decades, 3D point clouds have been a popular data source applied in automatic change detection in a wide variety of applications. Compared with 2D images, using 3D point clouds for change detection can provide an alternative solution offering different modalities and enabling a highly detailed 3D geometric and attribute analysis. This article provides a comprehensive review of point-cloud-based 3D change detection for urban objects. Specifically, in this study, we had two primary aims: (i) to ascertain the critical techniques in change detection, as well as their strengths and weaknesses, including data registration, variance estimation, and change analysis; (ii) to contextualize the up-to-date uses of point clouds in change detection and to explore representative applications of land cover and land use monitoring, vegetation surveys, construction automation, building and indoor investigations, and traffic and transportation monitoring. A workflow following the PRISMA 2020 rules was applied for the search and selection of reviewed articles, with a brief statistical analysis of the selected articles. Additionally, we examined the limitations of current change detection technology and discussed current research gaps between state-of-the-art techniques and engineering demands. Several remaining issues, such as the reliability of datasets, uncertainty in results, and contribution of semantics in change detection, have been identified and discussed. Ultimately, this review sheds light on prospective research directions to meet the urgent needs of anticipated applications.
... This is a common approach to deviation analysis [46]. The reference plane is determined from the points belonging to the wall using the mean sum error (MSE) method presented by Chen [47]. The deformation maps of the wall are then created. ...
Remote measurement of historic buildings and structures using the technology of terrestrial laser scanning (TLS) is becoming a more and more popular approach for conducting inventory activities, documentation and conservation works. In this paper, TLS was harnessed for analysis of historic brickwork structures from the 19th century. During the research programme, chosen brickwork heritage buildings were scanned. Based on the collected geometric data of the point cloud, it was possible to create an exact model of the scanned objects. The obtained radiometric information of the point cloud allowed us to identify changes in the surface of walls, such as cavities, cracks and previous repairs. Moisture was also identified in some cases. The conducted tests enabled the identification of brickwork in need of urgent repair. It was possible to assess the general technical state of the tested structures. The possibilities and limitations of the TLS diagnostic methodology of analysing the quality of historic brickwork and its future possible applications were indicated.
... The effect of individual LSS specimens on the precision of TLS measurements conducted at various distances was investigated. The mean sum error (MSE) method presented by Chen [51] was used to determine the precision of the distance measurement for LSS targets. The LSS targets were assumed to be flat and homogeneous surfaces. ...
In the near future, permanent human settlements on the Moon will become increasingly realistic. It is very likely that the Moon will serve as a transit point for deep space exploration (e.g., to Mars). The key to human presence on the Moon is the ability to erect the necessary structures and habitats using locally available materials, such as lunar soil. This study explores the feasibility of using terrestrial laser scanning technology as a measurement method for civil engineering applications on the Moon. Three lunar soil simulants representing highland regions (LHS-1, AGK-2010, CHENOBI) and three lunar soil simulants representing mare regions (LMS-1, JSC-1A, OPRL2N) were used in this study. Measurements were performed using three terrestrial laser scanners (Z+F IMAGER 5016, FARO Focus3D, and Leica ScanStation C10). The research programme focused on the radiometric analysis of datasets from the measurement of lunar soil simulants. The advantages and limitations of terrestrial laser scanning technology for possible lunar applications are discussed. Modifications of terrestrial laser scanners that are necessary to enable their use on the Moon are suggested.
... Laser scanning technology, also known as range-finding laser or LiDAR (Light Detection and Ranging) is based on the transmission and receiving of pulsed light (Chen, 2012). LiDAR systems can detect position data points (point cloud) in two possible ways: (1) by measuring the traveling time of emitted light pulses between the scanner and the object, and (2) by detecting the phase shift between the two signals. ...
... LiDAR system can be effective to assess deformations, deflections, vibration levels, and cracking of concrete structures (ACI Committee 444, 444 2021). Examples of the use of LiDAR systems in load tests on reinforced concrete bridges can be found in the literature since it is useful to extract general geometrical information as in Schmidt et al. (2018), and Trias, Yu, Gong, and Moon (2021) or to assess deformations as in Chen (2012). In Lõhmus, Ellmann, M€ ardla, and Idnurm (2018), LiDAR was used to capture vertical deformations during load tests. ...
... LiDAR was able to measure the bridge response in terms of deflections and rotation, and it was useful to capture the unexpected response due to asymmetric geometry. The measurement resolution is in millimeters (Chen, 2012). ...
Nowadays, with the aging of the bridges and the advancements in technology, load testing has emerged as an effective method to assess existing concrete bridges with missing information, or where analytical methods do not provide an accurate assessment. Two types of load tests are identified: diagnostic load tests and proof load tests. Both rely on field measurements of parameters or structural responses of the bridge during the test. A diagnostic load test measures the response of the bridge so that analytical models can be calibrated and evaluated. In a proof load test, the bridge directly demonstrates that it can carry a certain load. Since large loads are applied, the bridge needs to be carefully monitored. In this case, monitoring the measurements provide a warning to avoid damage. This paper reviews the literature on reported load tests and the measurement techniques used during these tests. It also includes a review of traditional and recently developed sensing technologies. Finally, the measurement requirements for diagnostic and proof load tests are given as well as a flow chart to guide engineers in the selection process of appropriate monitoring and measurement techniques during load tests. This paper can serve engineers during the preparation of a load test. ARTICLE HISTORY
... In this study, the advantages of using TLS in collecting accurate data were compared to traditional methods of manual data collection. Another research study conducted by Chen [33] described how TLS can be used to ascertain minimum clearance measurements, detect damage, confirm, and compare post-event geometry with pre-event geometry. Moreover, they provided an example where TLS has served as an alternative means of evaluating static load deflections of a bridge which could not have reasonably had strain gauges attached to its underside without shutting down a major thoroughfare. ...
Over the past years, bridge inspection practices and condition assessments were predicated upon long-established manual and paper-based data collection methods which were generally unsafe, time-consuming, imprecise, and labor-intensive, influenced by the experience of the trained inspectors involved. In recent years, the ability to turn an actual civil infrastructure asset into a detailed and precise digital model using state-of-the-art emerging technologies such as laser scanners has become in demand among structural engineers and managers, especially bridge asset managers. Although advanced remote technologies such as Terrestrial Laser Scanning (TLS) are recently established to overcome these challenges, the research on this subject is still lacking a comprehensive methodology for a reliable TLS-based bridge inspection and a well-detailed Bridge Information Model (BrIM) development. In this regard, the application of BrIM as a shared platform including a geometrical 3D CAD model connected to non-geometrical data can benefit asset managers, and significantly improve bridge management systems. Therefore, this research aims not only to provide a practical methodology for TLS-derived BrIM but also to serve a novel sliced-based approach for bridge geometric Computer-Aided Design (CAD) model extraction. This methodology was further verified and demonstrated via a case study on a cable-stayed bridge called Werrington Bridge, located in New South Wales (NSW), Australia. In this case, the process of extracting a precise 3D CAD model from TLS data using the sliced-based method and a workflow to connect non-geometrical information and develop a BrIM are elaborated. The findings of this research confirm the reliability of using TLS and the sliced-based method, as approaches with millimeter-level geometric accuracy, for bridge inspection subjected to precise 3D model extraction, as well as bridge asset management and BrIM development.
