Monitoring of Progressive Damage in Buildings Using Laser Scan Data (original) (raw)
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Terrestrial Laser Scanner for Controlling the Deformations and Damage of Buildings
SUMMARY The paper presents the use of the terrestrial laser scanner for the study and and the assessment of damaged buildings. The terrestrial laser scanner provides the ability to detect the geometric 3D model of a building without any physical contact with the structure. Knowledge of the 3D model will give the opportunity to study the deformation and quantify the damages. Three case studies are presented relating to damaged and/or unsafe buildings: Sivillier Castle (Villasor-Sardinia-Italy), the bell tower of Mores (Sardinia-Italy) and industrial building (Cagliari-Italy). The first two cases concern buildings of historical and architectural importance that present a state of compromised conservation; the last, an industrial building compromised by fire. In all cases, a laser scanner survey was carried out that not only provided valuable information but also highlighted structural metric deformation and degradation.
Proceedings of the 10th International Conference on Photonics, Optics and Laser Technology, 2022
The main objective of the paper was to evaluate two approaches aimed at tracking small displacements. The first approach is based on the usage of laser targets commonly used for stitching point clouds together. The second approach is based on the estimation of a corner of a prismatic shape and utilizes thin horizontal slices of the shape's point cloud. The corner's location is estimated as an intersection of two straight lines best fitted to the point clouds before and after the corner. It was shown that for both approaches a sub-millimetre accuracy can be achieved. The first approach requires the installation of two laser targets in order to measure the change of the distance between them. The second approach offers more flexibility because it does not require the installation of a laser target. Hence it can be used in the quantitative assessment of structural damage in the aftermath of natural disasters such as earthquakes, fires, tsunamis, landslides and hurricanes, to name a few.
TERRESTRIAL LASER SCANNER FOR MONITORING THE DEFORMATIONS AND THE DAMAGES OF BUILDINGS
The paper presents the use of the terrestrial laser scanner for the study and the assessment of damaged buildings. The terrestrial laser scanner provides the ability to detect the geometric 3D model of a building without any physical contact with the structure. Knowledge of the 3D model will give the opportunity to study the deformation and quantify the damages. Three case studies are presented relating to damaged and/or unsafe buildings: Sivillier Castle (Villasor-Sardinia-Italy), the Bell Tower of Mores (Sardinia-Italy) and industrial building (Cagliari-Italy). The first two cases concern buildings of historical and architectural importance that present a state of compromised conservation; the last, an industrial building compromised by fire. In all cases, a laser scanner survey was carried out that not only provided valuable information but also highlighted structural metric deformation and degradation.
Monitoring Deformations of a Wooden Church Tower by Laser Scanning
12th International Conference on Structural Analysis of Historical Constructions, 2021
Churches are part of heritage structures that take an important role in Europe´s cultural identity. As such, these structures must be protected to prevent catastrophic collapse and any damage must be reported timely to establish planning to maintenance and restoration. This can be achievable when the churches are monitored periodically with regular intervals. However, this monitoring strategy has not been available in most of the Europe's churches for a number of reasons, complexity of the structures and limited budget are just two of them. Laser scanning has been widely used in capturing rich three-dimensional (3D) topographic data of visible surfaces of a structure with high accuracy. This paper presents a methodology to determine the shape and possible deviation from verticality of the church's tower for monitoring deformation using a terrestrial laser scanner. The 500-year old wooden tower of St. Bavo Church in Haarlem, Netherlands is selected as a case study. First, point clouds of the tower captured from different views are registered into the same coordinate system. Second, a RANSAC method is employed to extract point clouds of a whole façades of the tower. Next, a point and surface-based method is proposed to compute the deformation of the surface from its data points. The results indicate that there is slightly different deformation between the tower facades in the same story and in neighbour stories. Moreover, the maximum total relative deformation at Story 7 of the tower by 0.63m.
Monitoring and Assessing Structural Damage in Historic Buildings
The Photogrammetric Record, 2008
In the cultural heritage field, the monitoring of the integrity of structures can greatly benefit from 3D digitising techniques. The aim of deformation analysis and structural surveillance is the early detection of damage in order to be able to react appropriately and in good time. The devices that have been traditionally used in the measurement of fissures, cracks and fractures are contact tools whose application depends on accessibility; moreover, they only provide discrete point measurements rather than giving a continuous record of the damage dimension in the whole affected area, as modern 3D modelling techniques can do. Among these techniques, close range photogrammetry is still the most complete, economical, portable, flexible and widely used approach in architectural applications. This paper is focused on the application of close range photogrammetry in the detection and monitoring of structural damage. The following procedure is proposed: the gathering at different epochs of 3D point clouds in the neighbourhood of cracks; the comparison among the successive point clouds by means of shape parameters; and the application of a bootstrap test for the detection of the significant statistical results. This procedure is applied to the analysis of structural damage detected in a masonry structure of cultural heritage interest: Basílica da Ascensión, located in the north-west of Spain.
Deformation monitoring of structural elements using terrestrial laser scanner
2019
Civil infrastructure systems is important in terms of both safety and serviceability. So, large structure have been monitored using surveying techniques, while fine-scale monitoring of structural components has been done with geotechnical instrumentation. The advantages and disadvantages of using remote sensing methods, such as terrestrial laser scanning and digital close range photogrammetry, for the purposes of precise 3D reconstruction and the estimation of deflections in structural elements. This paper investigate that terrestrial laser scanner can be used for the monitoring of concrete beams subjected to different loading conditions. The system used does not require any physical targets. The setup was tested, and the beam deflections resulted from the 3D model from terrestrial laser scanner system were compared to the ones from ANSYS program. The experiments proved that it was possible to detect sub-millimeter level deformations given the used equipment and the geometry of the setup. Calculations and analysis of results are presented.
Key Engineering Materials, 2014
The surveys following severe earthquakes show that existing unreinforced masonry buildings are highly vulnerable to local collapse mechanisms. However, their assessment is strongly sensitive to the choice of the mechanism, whose boundary conditions are largely unknown. In the past the mechanism has been selected based on the crack survey alone, because the survey of the deformations is very difficult if traditional tools are used. In the last years advanced survey techniques have been developed, the most powerful of whom resorts to laser scanning. A laser scanner allows the acquisitions of a very large amount of information: building overall dimensions and single elements detailed survey, detection of anomalies, and identification of very limited deformations undetectable with the naked eye. Moreover, contrary to traditional procedures, it allows the survey of the façades without any direct contact with the building, which could be damaged after an earthquake. A laser-scanner surve...
Sensors
Along with the development and improvement of measuring technologies and techniques in recent times, new methods have appeared to model and monitor the behavior of land and constructions over time. The main purpose of this research was to develop a new methodology to model and monitor large buildings in a non-invasive way. The methods proposed in this research are non-destructive and can be used to monitor the behavior of buildings over time. A method of comparing point clouds obtained using terrestrial laser scanning combined with aerial photogrammetric methods was used in this study. The advantages and disadvantages of using non-destructive measurement techniques over the classic methods were also analyzed. With a building located in the University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca campus as a case study and with the help of the proposed methods, the deformations over time of the facades of that building were determined. As one of the main conclusions of...
Automated Damage Detection and Structural Modelling with Laser Scanning
2016
Inspection of aging and deteriorating infrastructure such as bridges, dams, power supply infrastructures are crucial to assure their reliability as well as to estimate their remaining life. This study proposes to use small, low flying autonomous unmanned aerial vehicles, coupled with three-dimensional laser scanning, high-resolution imaging and state-of-art modeling and analysis abilities in order to provide high-precision damage detection, condition assessment and modelling of structures and infrastructure systems. In recent years, laser scanning has been shown to be effective in capturing three-dimensional geometrical information with a high degree of accuracy, which enables automatic visual damage detection and creation of high-precision information and computational models. This paper proposes a set of strategies for processing captured texture-mapped laser point cloud automatically in order to detect surface damage and large element deformation of the infrastructure system as w...