Analysis of terrestrial laser scanning technology for structural

Monitoring displacements and deformations of anthropogenic spatial structures and objects represents\ud one of the most intricate areas in geodetic surveying. Besides the measurement technologies\ud that have been traditionally used for such tasks, terrestrial laser scanning represents another possibility\ud employing the surface-wise deformation inspection of the objects’ surfaces. The main aim of\ud the thesis is to try to provide answers whether terrestrial laser scanning can be used for monitoring\ud displacements and deformations in a long-term perspective and how this could be achieved for any\ud arbitrary surface. Furthermore, the hypothesis will be challenged with the statement that the deformation\ud inspection can be performed in the millimeter domain with this remote sensing measurement\ud technology. In order to solve the problem of a stable reference system and to assure the high quality\ud of possible position changes of point clouds, scanning is integrated with two complementary\ud surveying techniques, i.e., high quality static GNSS positioning and precise classical terrestrial surveying.\ud The methodology of such high precision monitoring approach is proposed in the thesis and\ud was tested in two case study outdoor experiments. Besides these two outdoor experiments, also indoor\ud tests were designed to evaluate the quality of the surveying equipment (laser scanning targets)\ud as well as the response of the scanner to the surface material

Prediction of the peak shear strength of the rock joints with artificial neural networks

With the development of computer technology, artificial neural networks are becoming increasingly useful in the field of engineering geology and geotechnics. With artificial neural networks, the geomechanical properties of rocks or their behaviour could be predicted under different stress conditions. Slope failures or underground excavations in rocks mostly occurred through joints, which are essential for the stability of geotechnical structures. This is why the peak shear strength of a rock joint is the most important parameter for a rock mass stability. Testing of the shear characteristics of joints is often time consuming and suitable specimens for testing are difficult to obtain during the research phase. The roughness of the joint surface, tensile strength and vertical load have a great influence on the peak shear strength of the rock joint. In the presented paper, the surface roughness of joints was measured with a photogrammetric scanner, and the peak shear strength was determined by the Robertson direct shear test. Based on six input characteristics of the rock joints, the artificial neural network, using a backpropagation learning algorithm, successfully learned to predict the peak shear strength of the rock joint. The trained artificial neural network predicted the peak shear strength for similar lithological and geological conditions with average estimation error of 6 %. The results of the calculation with artificial neural networks were compared with the Grasselli experimental model, which showed a higher error in comparison with the artificial neural network model

Use of Terrestrial Laser Scanning Technology for Long Term High Precision Deformation Monitoring

The paper presents a new methodology for high precision monitoring of deformations with a long term perspective using terrestrial laser scanning technology. In order to solve the problem of a stable reference system and to assure the high quality of possible position changes of point clouds, scanning is integrated with two complementary surveying techniques, i.e., high quality static GNSS positioning and precise tacheometry. The case study object where the proposed methodology was tested is a high pressure underground pipeline situated in an area which is geologically unstable

Analysis of terrestrial laser scanning technology for structural deformation monitoring

Spremljanje premikov in deformacij antropogenih prostorskih struktur in objektov predstavlja eno izmed najbolj zahtevnih področij v geodeziji. Poleg merskih tehnologij, ki se tradicionalno uporabljajo za izvedbo takšnih nalog, predstavlja terestrično lasersko skeniranje dodatno možnost ploskovnega načina analiziranja objektnih površin. Glavni cilj doktorske naloge je v zagotovitvi odgovorov o možnostih uporabe terestričnega laserskega skeniranja za dolgoročno spremljanje premikov in deformacij ter o načinu izvedbe takšne oblike spremljave na poljubnih objektih. Poleg tega bo v okviru naloge ovrednotena hipoteza, da lahko s pomočjo te tehnologije daljinskega zaznavanja k analizi deformacij pristopimo v območju milimetrov. Za rešitev problema stabilnega referenčnega sistema, ki pogojuje visoko kakovostno analiziranje morebitnih sprememb položajev oblakov točk, je skeniranje treba povezati z ostalimi geodetskimi tehnikami, tj. zelo natančno statično izmero GNSS in precizno klasično terestrično izmero. Naloga predlaga metodologijo takšnega zelo natančnega načina spremljanja, ki je bila preizkušena v okviru dveh testov v naravi. Poleg teh dveh testov so bili za potrebe naloge zasnovani tudi testi za preverjanje kakovosti uporabljene merske opreme (tarč laserskega skeniranja) in odzivnosti skenerja na lastnosti površinskega materiala..Monitoring displacements and deformations of anthropogenic spatial structures and objects represents one of the most intricate areas in geodetic surveying. Besides the measurement technologies that have been traditionally used for such tasks, terrestrial laser scanning represents another possibility employing the surface-wise deformation inspection of the objects’ surfaces. The main aim of the thesis is to try to provide answers whether terrestrial laser scanning can be used for monitoring displacements and deformations in a long-term perspective and how this could be achieved for any arbitrary surface. Furthermore, the hypothesis will be challenged with the statement that the deformation inspection can be performed in the millimeter domain with this remote sensing measurement technology. In order to solve the problem of a stable reference system and to assure the high quality of possible position changes of point clouds, scanning is integrated with two complementary surveying techniques, i.e., high quality static GNSS positioning and precise classical terrestrial surveying. The methodology of such high precision monitoring approach is proposed in the thesis and was tested in two case study outdoor experiments. Besides these two outdoor experiments, also indoor tests were designed to evaluate the quality of the surveying equipment (laser scanning targets) as well as the response of the scanner to the surface material

Automatic relative orientation procedure

Diplomsko delo obravnava avtomatizacijo celotnega postopka relativne orientacije stereopara. V ta namen je bil v okviru praktičnega dela naloge v razvojnem okolju Visual C++ 6.0 izdelan testni program za avtomatizacijo tega fotogrametričnega procesa. Opisana so teoretična izhodišča, ki nudijo oporo pri razumevanju delovanja programa: relativna orientacija, digitalna obdelava slik za pridobitev vhodnih podatkov in robustna ocena pogreškov, ki je nujna, če hočemo nadzor nad pogreški relativne orientacije avtomatizirati in hkrati zmanjšati njihov vpliv na iskane orientacijske parametre. Predstavljene so tudi faze nastajanja testnega programa in shematični opisi njegovega delovanja. Poseben poudarek je bil posvečen različnim metodam zajema homolognih točk, ki so bile najprej določene ročno, nato polavtomatsko in nazadnje še povsem avtomatsko. Na ta način smo lahko ugotavljali prednosti in slabosti avtomatiziranega pristopa. Relativno orientacijo smo izvedli na različnih stereoparih, tako za aero- kot tudi za bližnjeslikovne posnetke.The present work describes an automatic approach to relative orientation procedure performed on an individual stereopair. For this purpose a test program has been built using Visual C++ 6.0 to enable this photogrammetric process to be fully automatic. The backgrounds are presented to describe the working of the program: relative orientation, image processing for determination of input data and robust estimation techniques, which are necessary for automatic control over the blunders, found in the relative orientation procedure and for minimizing their effect on orientation parameters. The work also describes the steps of building the test program and schematic diagrams of its functionality. A special emphasis is placed on different methods for determining conjugate points. Initially the points were identified and measured manually furthermore a semi-automatic approach was implemented and finally a fully automatic one. Determining the conjugate points according to these steps it was possible to compare the results and to point out the advantages and disadvantages of the automatic relative orientation. The program was tested on aerial and close range images

Real-time monitoring and analyses of sensory data integrated into the bim platform

Bridges and tunnels, crucial elements of the railway infrastructure, are exposed to various types of deterioration processes. Their condition is a subject of monitoring, as it is important to collect as much as possible information in every life cycle phase to reliably predict their future performance. An enormous quantity of monitoring data is generated during the whole life cycle of these assets. EU funded Shift2Rail research project Assets4Rail which is focusing on measuring, monitoring, and data handling for railway assets, as data management is as important as their generation. This paper presents the major outcomes of the Assets4Rail project and its application to infrastructure projects

Vehicle–bridge interaction modelling using precise 3D road surface analysis

Uneven road surfaces are the primary source of excitation in the dynamic interaction between a bridge and a vehicle and can lead to errors in bridge weigh-in-motion (B-WIM) systems. In order to correctly reproduce this interaction in a numerical model of a bridge, it is essential to know the magnitude and location of the various roadway irregularities. This paper presents a methodology for measuring the 3D road surface using static terrestrial laser scanning and a numerical model for simulating vehicle passage over a bridge with a measured road surface. This model allows the evaluation of strain responses in the time domain at any bridge location considering different parameters such as vehicle type, lateral position and speed, road surface unevenness, bridge type, etc. Since the time domain strains are crucial for B-WIM algorithms, the proposed approach facilitates the analysis of the different factors affecting the B-WIM results. The first validation of the proposed methodology was carried out on a real bridge, where extensive measurements were performed using different sensors, including measurements of the road surface, the response of the bridge when crossed by a test vehicle and the dynamic properties of the bridge and vehicle. The comparison between the simulated and measured bridge response marks a promising step towards investigating the influence of unevenness on the results of B-WIM

Complete Automation of the relative Orientation of a Stereopair : Avtomatizacija celotnega postopka relativne orientacije stereopara

In the paper the results of the research on the complete automation of the relative orientation of a stereo pair is presented. The theoretical background needed for understanding this topic is described and the results of testing the algorithms with real data are presented. In general, the relative orientation procedure consists of three phases: input data acquisition, computation ofrelative orientation parameters and estimation of observation errors. In the process of the complete relative orientation automation, the key step is the automation of homologous points acquisition in the stereo area. In the tests presented, the homologous points were acquired with different methods: manually, semiautomatically and fully automatically. The results ofthe computed relative orientation parameters have been compared. It has been concluded that the automation of the relative orientation procedure is successful and reliable if the control of the observation errors estimation is built into the procedure, and,especially, we get the results faster than with the manual or semi-automated method

Digital Twins and Road Construction Using Secondary Raw Materials

Secondary raw materials (SRMs) tend to be a valuable replacement for finite virgin materials especially since construction works (i.e., building and civil engineering work such as road construction) require vast quantities of raw materials. Using SRM originating from recycling a broad range of inorganic waste materials (e.g., mining waste, different industrial wastes, construction, and demolition waste) has been recognized as a promising, generally more cost-efficient, and environmentally friendly alternative to the exploitation of natural resources. Despite the benefits of using SRM, several challenges need to be addressed before using SRM even more. One of them is the long-term durability and little-known response of construction works built using such alternative materials. In this paper, we present the activities to establish a fully functioning digital twin (DT) of a road constructed using SRM. The first part of the paper is devoted to the theoretical justification of efforts and ways of establishing the monitoring systems, followed by a DT case study where an integrated data environment synthesizing a Building Information Model and monitored data is presented. Although the paper builds upon a small scale, the case study is methodologically designed to allow parallels to be drawn with much larger construction projects

Load testing of the first stress ribbon bridge in Slovenia

Paper presents selected results of the diagnostic load testing of a newly-built footbridge in Novo Mesto, Slovenia. The bridge is significant as the first bridge in Slovenia being built with the stress ribbon technology. The diagnostic load testing took place in March 2023 and comprised of three-stage static load testing, dynamic testing with a light truck driving over artificial obstacles, and measurement of ambient vibrations. The consistency between the actual response of the bridge and the response of the finite element (FE) model, used in the design, was evaluated by comparing vertical displacements from the static load testing, natural frequencies and mode shapes. The comparison of the results indicates a satisfactory agreement between the measurements and the response of the FE model, confirming the appropriateness of the employed FE model