Industrial Masonry Chimney Geometry Analysis: A Total Station Based Evaluation of the Unmanned Aerial System Photogrammetry Approach

Abstract

High industrial chimney inclination monitoring and analysis is crucial from a stability point of view because, if not maintained, it can pose a great potential hazard for its surroundings. Various modern approaches of chimneys’ geometrical parameters determination have been proposed and are actively in use. However, little research regarding the applicability of the unmanned aerial system (UAS)-based photogrammetric approach of chimney structural monitoring has been conducted and a comprehensive analysis with validated methods is lacking. Therefore, this research is focused on the determination of geometrical structural parameters of a masonry chimney whereby two independent methods have been applied. Reference values of the chimney geometrical parameters have been determined by precise total station (TS) measurements and, in relation to them, the applicability of the UAS-based photogrammetric approach is evaluated. Methodologically, the reference and validation values of the chimney geometrical parameters have been determined based on double modeling of the chimney structure. Firstly, cross-sectional elliptical regression has been applied to determine the geometrical values of the chimney at predefined above-ground levels (AGLs). Secondly, the spatial chimney axis has been derived by polynomial regression to determine the inclination of the full chimney structure. Lastly, the structural stability of the chimney is validated based on its axis inclination whereby permitted deviations are determined according to the European Standard EN 1996-1-1:2005. Experimental results of our research show that consistently better results are gained by TS-based surveys and, although the determination of the chimney’s geometrical values by the UAS-based approach is certainly possible, great attention must be given to the accuracy of the UAS-generated point cloud (PC) if high accuracy results are needed.

Selection of an Algorithm for Assessing the Verticality of Complex Slender Objects Using Semi-Automatic Point Cloud Analysis

“…The analyses and theoretical modeling performed above demonstrate the importance of a problem that is often overlooked in studies of the geometric state of slender and elongated objects. In the previously cited articles, e.g., [6,7], researchers analyze deflections of structures with a circular cross-section. Determining the center of such a construction is unambiguous.…”

“…Marjetič and Štebe [6] assess the shape of an industrial chimney based on laser scanning, taking into account the impact of solar radiation on daily fluctuations in deviations from the vertical. A similar assessment of the shape of a chimney based on UAV (Unmanned Airborne Vehicle) measurements is presented in Zrinjski et al [7], who use a standard geometric evaluation procedure, first building a spatial model and then breaking it down into cross-sectional profiles, for which they determine the centers of fitted circles and ellipses (for ovality evaluation). On this basis, they identify the current spatial course of the axis of the building in relation to the theoretical plumb line.…”

A BIM-Based Model for Structural Health Monitoring of the Central Body of the Monserrate Palace: A First Approach

“…According to the characteristics of the building (e.g., the irregularity or dimension of objects), there are many alternatives for the acquisition of geometry using more conventional methods, such as the classical methods of topography [3], photogrammetry [4] or terrestrial laser scanning (TLS) [5], which produce a three-dimensional point cloud. TLS allows for the rapid collection of data from geometry with a high level of detail [6].…”