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As the technology of high-precision 3D laser scanning becomes increasingly prevalent in the fields of hydraulic building modeling and deformation monitoring, the quality of point clouds plays an increasingly crucial role in data processing. This paper investigates an automatic extraction method of anchor rod points based on geometric features, which focuses on the influence of anchor rod points and mixed pixels in the data of an underground powerhouse of a pumped storage power station on modeling and deformation monitoring during the construction period. This workflow consists of two steps that can automatically extract anchor rod points from high-density point cloud data. Triangular mesh features in the local neighborhood and the parameters of the anchor rods are used to locate the anchor rod in downsampled data, and curvature features are used to extract anchor rod points precisely. The experiment of extracting anchor rods shows that the accuracy of this method of initial identification is 97.2%. Furthermore, precise extraction based on curvature curve fitting is applicable. This method can accurately separate the three types of anchor rods from the dense point cloud on the rough surface of a cavern roof; the false-extraction rate of anchor rod points is about 0.11% to 5.09%. This method can provide high-quality and dependable data sources for the precise registration, modeling and deformation analysis of point clouds in a construction cavern. [ABSTRACT FROM AUTHOR]

A tunnel is a symmetric structure working under uncertain load. In the traditional method of monitoring and measurement of tunnel deformation, only a small number of symmetric measuring point displacements are engaged to represent the overall deformation of the tunnel, and it is difficult to fully reflect the displacement changes of the tunnel during the construction process. In this paper, a deformation monitoring method is proposed for the tunnel construction process based on 3D laser scanning technology. Initially, 3D laser scanning was used to obtain scattered clouds of irregular structures considering the New Austrian Tunneling Method (NATM). Afterward, the modified B-spline interpolation and greedy triangulation were used to fit the surfaces. Moreover, the normal vector matrix was innovatively applied to express the deformation of the tunnel fitting surface, which solved the problem of scattered point clouds in 3D laser scanning. A normal vector was obtained by the intersection of the normal of one fitted surface with the other. Subsequently, the maximum entropy method was introduced to form the probability density function of the normal vector, and the 1% and 5% probability eigenvalues were used to analyze the overall deformation trend of the tunnel. Finally, the eigenvalue of 5% probability, which was less affected by construction uncertainties, was selected for analysis. This way, the analysis and prediction method for overall tunnel deformation was established. [ABSTRACT FROM AUTHOR]

Construction is a powerful industry that is not indifferent to the environment. Neither the maintenance of buildings in a proper technical condition nor their eventual demolition is indifferent to the environment. The main threats to the environment are still the inefficient use of construction materials and energy needed for their production and installation, as well as the emission of harmful substances to the environment at the stage of operation of buildings and their demolition. This article discusses the importance of wood as a renewable material in terms of its physical and mechanical properties. The restoration of forest areas is of great importance to the global ecosystem and the sustainable development system, reducing the threat of global warming and the greenhouse effect by reducing CO2 levels. In addition, demolition wood can be reused in construction, can be safely recycled as it quickly decomposes, or can be used as a source of renewable energy. The preservation of existing timber-framed buildings in good condition contributes to a lower consumption of this raw material for repair, which already significantly reduces the energy required for their manufacture, transport, and assembly. This also reduces the amount of waste that would have to be disposed of in various ways. Both at the stage of design, execution, and then exploitation, one forgets about the physical processes taking place inside the partitions and about the external climatic influences of the environment (precipitation, water vapor, and temperature) on which the type, intensity, and extent of chemical and biological corrosion depend to a very high degree. This paper presents examples of the influence of such impacts on the operational safety of three selected objects: a feed storehouse and an officer casino building from the second half of the nineteenth century and an 18th century rural homestead building. The research carried out on wooden structures of the above-mentioned objects "in situ" was verified by means of simulation models, which presented their initial and current technical conditions in relation to the type and amount of impact they should safely absorb. Moreover, within the framework of this paper, artificial intelligence methods have been implemented to predict the biological corrosion of the structures studied. The aim of the paper was to draw attention to the timber already built into buildings, which may constitute waste even after several years of operation, requiring disposal and at the same time the production of a substitute. The purpose of the research carried out by the authors of the article was to examine the older and newer buildings in use, the structures of which, in whole or in part, were made of wood. On a global scale, there will be considerable demand for the energy required to thermally dispose of this waste or to deposit it in landfills with very limited capacity until its complete biological decomposition. These energy demands and greenhouse gas emissions can be prevented by effective diagnostics of such structures and the predictability of their behaviour over time, with respect to the conditions under which they are operated. The authors of the article, during each assessment of the technical condition of a building containing wooden elements, analysed the condition of their protection each time and predicted the period of their safe life without the need for additional reinforcements or replacement by others. As the later reality shows, it is a very effective method of saving money and energy. [ABSTRACT FROM AUTHOR]

Nowadays designing of selected areas of mines underground workings can be effectively improved by the application of computer techniques: 3D scanning, computer simulations and Virtual Reality. This, in fact, would result in the more reliable design process, significantly reduced designing costs and efforts, and improvement of the mines staff's safety. This scientific paper presents a method developed for redesigning of selected areas of mines underground workings in which auxiliary transport is carried out. The method combines 3D laser scanning technique with computer simulations carried out in a CAD/MBS system, in order to determine the location of potential collisions of the transported loads with the arch yielding support and the equipment. The obtained results, visualized using Virtual Reality, will form input data in the process of designing the selected area of the mines underground workings. Finally, an example of the application of the described method during transportation of big-size load is given. [ABSTRACT FROM AUTHOR]

Damage mechanisms of Reactive Powder Concrete (RPC) under fatigue loading are investigated using the 3D laser scanning technology. An independently configured 3D laser scanning system is used to monitor the damaging procedure. Texture analysis technique is also applied to enhance the understanding of the damage mechanisms of RPC under fatigue loading. In order to obtain the characteristic parameters of point cloud data, a point clouds projection algorithm is proposed. Damage evolution is described by the change of point cloud data of the damage in the 2D plane and 3D space during fatigue loading. The Gray Level Co-occurrence Matrix (GLCM) method is used to extract the characteristic parameters to evaluate the statue of the structural. Angular Second Moment and Cluster Shadow of typical sensitive characteristic indexes is screened by using the Digital Feature Screening. The reliability of the damage index was verified by image texture analysis and data expansion. Indexes extracted in this paper can be used as a new structural health monitoring indicator to assess health condition. [ABSTRACT FROM AUTHOR]

High-precision 3D laser scanning pavement data contains rich pavement scene information and certain components associations. Moreover, for pavement maintenance and management, there is an urgent need to develop automatic methods that can extract comprehensive information about different pavement indicators simultaneously. By analyzing the frequency and sparse characteristics of pavement distresses and performance indicators—including the cracks, road markings, rutting, potholes, textures—this paper proposes 3D pavement components decomposition model (3D-PCDM) which decomposes the 3D pavement profiles into sparse components x, low-frequency components f, and vibration components t. Designed high-pass filter was first employed to separate f, then, x and t are separated by total variation de-noising which based on sparse characteristics. Decomposed x can be used to characterize the location and depth information of sparse and sparse derived signals such as cracks, road marks, grooves, and potholes in profiles. Decomposed f can be used to determine the slow deformation of pavement. While decomposed t reflects the fluctuation of the pavement material particles. Experiments were conducted using actual pavement 3D data, the decomposed components can obtain by 3D-PCDM. The effectiveness and accuracy of the x are verified by actual cracks and road markings, the accuracy of extracted sparse components is over 92.75%. [ABSTRACT FROM AUTHOR]