Identifying Seismic Local Collapse Mechanisms in Unreinforced Masonry Buildings through 3D Laser Scanning

2014 ◽  
Vol 628 ◽  
pp. 79-84 ◽  
Author(s):  
Chiara Andreotti ◽  
Domenico Liberatore ◽  
Luigi Sorrentino
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Unreinforced Masonry ◽  
Earthquake Ground Motion ◽  
Collapse Mechanism ◽  
Masonry Buildings ◽  
Survey Techniques ◽  
The Past ◽  
Collapse Mechanisms ◽  
2009 L’Aquila Earthquake

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 survey has been performed in the whole historical centre of Rovere, in the municipality of Rocca di Mezzo, affected by the 2009 L’Aquila earthquake. This survey has been used to study the façades of three different building units, recognising the collapse mechanism triggered by the earthquake ground motion. The mechanisms are fairly different from what suggested by the crack pattern alone and pertain to deformations that cannot be recognised in the photos. Moreover, the faithful geometric models that can be generated from laser scanning allow accounting for deformations and out-of-plumb. Thus, the acceleration activating the mechanism can be estimated much more accurately compared to a perfectly vertical and parallelepiped wall.

scholarly journals THE FLORENCE BAPTISTERY: 3-D SURVEY AS A KNOWLEDGE TOOL FOR HISTORICAL AND STRUCTURAL INVESTIGATIONS

2016 ◽  
Vol XLI-B5 ◽  
pp. 977-984 ◽  
Author(s):  
G. Tucci ◽  
V. Bonora ◽  
L. Fiorini ◽  
A. Conti
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Outer Wall ◽  
Structural Investigations ◽  
Survey Techniques ◽  
Wide Range ◽  
Historical Architecture ◽  
Close Range ◽  
Main Instrument ◽  
New Research

The Baptistery of San Giovanni is one of the most important pieces of architecture in Florence. It is an octagonal building, encrusted with marble both internally and externally (including the pyramidal roof) and covered inside by a magnificent dome with sparkling gold mosaics. During Dante’s time, it appeared much older than the other monuments, so its origins were considered as hailing straight from Florence’s most remote and mythical history. Even though we have much more data now, scholars still disagree over the interpretations on the origin and construction sequence of the monument. <br><br> Survey has always been considered a main instrument for understanding historical architecture, mostly from constructional and structural points of view. During the last century, the Baptistery was surveyed using both traditional techniques and the most up-to-date instruments available at the time, such as topography, close-range photogrammetry and laser scanning. So, a review of those early applications, even if partial or isolated, can significantly attest to the state of the art and evolution of survey techniques. <br><br> During recent years, the Opera di Santa Maria del Fiore promoted new research and a wide range of diagnostic investigations aimed at acquiring greater knowledge of the monument in anticipation of the cleaning and restoration of the outer wall surfaces during 2015. <br><br> Among this research, GeCo Lab carried out a new systematic and complete laser scanner survey of the whole Baptistery, acquiring data for the more inaccessible parts that were given little attention during other survey campaigns. <br><br> First of all, the paper analyses recent contributions given by instrumental surveys in advancing knowledge of the building, with references to the cutting-edge techniques and measurement tools used at the time. Then, it describes the new survey campaign, illustrating the approach followed in the planning, data acquisition and data elaboration phases; finally, it gives examples of some interpretations of the structure stemming from the new acquisitions.

scholarly journals Distinguishing Drones from Birds in a UAV Searching Laser Scanner Based on Echo Depolarization Measurement

Sensors ◽  
2021 ◽  
Vol 21 (16) ◽  
pp. 5597
Author(s):  
Jacek Wojtanowski ◽  
Marek Zygmunt ◽  
Tadeusz Drozd ◽  
Marcin Jakubaszek ◽  
Marek Życzkowski ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Cross Polarization ◽  
Negative Consequences ◽  
Polarization Ratio ◽  
Monitoring Equipment ◽  
The Past ◽  
Novel Approach ◽  
Widespread Availability ◽  
Illegal Activities

Widespread availability of drones is associated with many new fascinating possibilities, which were reserved in the past for few. Unfortunately, this technology also has many negative consequences related to illegal activities (surveillance, smuggling). For this reason, particularly sensitive areas should be equipped with sensors capable of detecting the presence of even miniature drones from as far away as possible. A few techniques currently exist in this field; however, all have significant drawbacks. This study addresses a novel approach for small (<5 kg) drones detection technique based on a laser scanning and a method to discriminate UAVs from birds. The latter challenge is fundamental in minimizing the false alarm rate in each drone monitoring equipment. The paper describes the developed sensor and its performance in terms of drone vs. bird discrimination. The idea is based on simple cross-polarization ratio analysis of the optical echo received as a result of laser backscattering on the detected object. The obtained experimental results show that the proposed method does not always guarantee 100 percent discrimination efficiency, but provides certain confidence level distribution. Nevertheless, due to the hardware simplicity, this approach seems to be a valuable addition to the developed anti-drone laser scanner.

scholarly journals A procedure for point clouds matching from range data and image-based systems

ACTA IMEKO ◽  
2017 ◽  
Vol 6 (3) ◽  
pp. 57 ◽  
Author(s):  
Andrea Angelini ◽  
Damiano Portarena
Keyword(s):  
Laser Scanning ◽  
Numerical Models ◽  
Methodological Approach ◽  
Laser Scanner ◽  
Numerical Data ◽  
Point Clouds ◽  
Range Data ◽  
Survey Techniques ◽  
Meshing Process ◽  
Different Sources

<p class="Abstract"><span lang="EN-US">Most of the survey techniques used in archaeology and architecture are focused on range-data (laser scanning) and image-based systems (digital photogrammetry). The paper aims to highlight a different methodological approach in the acquisition and processing procedures of the numerical data. The proposed methodology suggests an alternative way to match point clouds from laser scanner and image-based systems, exploiting the properties of the ICP algorithms. Some tests were performed at different scale in order to achieve the suitable procedure, evidencing the differences with the classic employed methods. The figures show this comparison and the making of the new procedure. The results are very interesting and concerned the merging of the numerical models from different sources. The correct position of the points in space aids the next step of the surface reconstruction (meshing process) and the final 2D representation.</span></p>

Damage to masonry buildings caused by the 1995 Hyogo-ken Nanbu (Kobe, Japan) earthquake

1996 ◽  
Vol 23 (3) ◽  
pp. 797-807 ◽  
Author(s):  
Michel Bruneau ◽  
Koji Yoshimura
Keyword(s):  
Unreinforced Masonry ◽  
Masonry Buildings ◽  
Masonry Structures ◽  
Design Codes ◽  
Epicentral Area ◽  
The Past ◽  
Masonry Construction ◽  
Kobe Earthquake ◽  
Reinforced Masonry ◽  
A Minor

The seismic performance of the few masonry structures present in the Kobe area and subjected to the severe Hyogo-ken Nanbu earthquake is a minor concern when compared to the overwhelming damage suffered by other types of structures. However, in order to dispel the myth that masonry structures are nonexistent in Japan as well as a few other misconceptions, and for the sake of completeness within the concerted multipaper reporting effort on the Hyogo-ken Nanbu (Kobe) earthquake by the Canadian reconnaissance team which visited the epicentral area of this earthquake, a brief description of the past and present state of masonry construction in Japan is first presented, followed by a short description of the damage to unreinforced masonry buildings, masonry garden-walls, and nonstructural masonry elements, as observed by the authors during their visits to the Kobe area. Key words: earthquake, seismic, masonry, buildings, bearing walls, unreinforced masonry, reinforced masonry, failures, design codes.

scholarly journals La fotogrametría digital: una herramienta para la recuperación de arquitecturas perdidas. Torre del Homenaje del Castillo de Constantina

2015 ◽  
Vol 4 (8) ◽  
pp. 140 ◽  
Author(s):  
Roque Angulo Fornos
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Point Clouds ◽  
Survey Techniques ◽  
Architectural Survey ◽  
Prior State

<p>In recent years, the continuing development of architectural survey techniques based on point clouds captured by laser scanning has revolutionized the field of<br />documentation prior to intervention, management or research in heritage. No clutch, affirming that these techniques have displaced others, such as photogrammetry, that have played an important role in the field of architectural survey, is a precipitated guess. Among other advantages, photogrammetry offers the ability to capture missing realities, lacking the materialness required for the use of laser scanner. In that vein, this paper describes the work of photogrammetric survey, location of parts and graphical anaparástasis of prior state to collapse of the Keep of the Castle of Constantine.</p>

scholarly journals THE FLORENCE BAPTISTERY: 3-D SURVEY AS A KNOWLEDGE TOOL FOR HISTORICAL AND STRUCTURAL INVESTIGATIONS

2016 ◽  
Vol XLI-B5 ◽  
pp. 977-984 ◽  
Author(s):  
G. Tucci ◽  
V. Bonora ◽  
L. Fiorini ◽  
A. Conti
Keyword(s):  
Laser Scanning ◽  
Laser Scanner ◽  
Outer Wall ◽  
Structural Investigations ◽  
Survey Techniques ◽  
Wide Range ◽  
Historical Architecture ◽  
Close Range ◽  
Main Instrument ◽  
New Research

The Baptistery of San Giovanni is one of the most important pieces of architecture in Florence. It is an octagonal building, encrusted with marble both internally and externally (including the pyramidal roof) and covered inside by a magnificent dome with sparkling gold mosaics. During Dante’s time, it appeared much older than the other monuments, so its origins were considered as hailing straight from Florence’s most remote and mythical history. Even though we have much more data now, scholars still disagree over the interpretations on the origin and construction sequence of the monument. &lt;br&gt;&lt;br&gt; Survey has always been considered a main instrument for understanding historical architecture, mostly from constructional and structural points of view. During the last century, the Baptistery was surveyed using both traditional techniques and the most up-to-date instruments available at the time, such as topography, close-range photogrammetry and laser scanning. So, a review of those early applications, even if partial or isolated, can significantly attest to the state of the art and evolution of survey techniques. &lt;br&gt;&lt;br&gt; During recent years, the Opera di Santa Maria del Fiore promoted new research and a wide range of diagnostic investigations aimed at acquiring greater knowledge of the monument in anticipation of the cleaning and restoration of the outer wall surfaces during 2015. &lt;br&gt;&lt;br&gt; Among this research, GeCo Lab carried out a new systematic and complete laser scanner survey of the whole Baptistery, acquiring data for the more inaccessible parts that were given little attention during other survey campaigns. &lt;br&gt;&lt;br&gt; First of all, the paper analyses recent contributions given by instrumental surveys in advancing knowledge of the building, with references to the cutting-edge techniques and measurement tools used at the time. Then, it describes the new survey campaign, illustrating the approach followed in the planning, data acquisition and data elaboration phases; finally, it gives examples of some interpretations of the structure stemming from the new acquisitions.

The consolidation of microscopy technology into a university research support facility: Reflections on the 1980's and projections for the 1990's at the university of iowa

1993 ◽  
Vol 51 ◽  
pp. 476-477
Author(s):  
Kenneth C. Moore
Keyword(s):  
Laser Scanning ◽  
Freeze Fracture ◽  
Freeze Substitution ◽  
Research Support ◽  
University Of Iowa ◽  
Staff Members ◽  
The Past ◽  
Research Grade ◽  
The University ◽  
Support Facility

The University of Iowa Central Electron Microscopy Research Facility(CEMRF) was established in 1981 to support all faculty, staff and students needing this technology. Initially the CEMRF was operated with one TEM, one SEM, three staff members and supported about 30 projects a year. During the past twelve years, the facility has replaced all instrumentation pre-dating 1981, and now includes 2 TEM's, 2 SEM's, 2 EDS systems, cryo-transfer specimen holders for both TEM and SEM, 2 parafin microtomes, 4 ultamicrotomes including cryoultramicrotomy, a Laser Scanning Confocal microscope, a research grade light microscope, an Ion Mill, film and print processing equipment, a rapid cryo-freezer, freeze substitution apparatus, a freeze-fracture/etching system, vacuum evaporators, sputter coaters, a plasma asher, and is currently evaluating scanning probe microscopes for acquisition. The facility presently consists of 10 staff members and supports over 150 projects annually from 44 departments in 5 Colleges and 10 industrial laboratories. One of the unique strengths of the CEMRF is that both Biomedical and Physical scientists use the facility.

Results of studying the dimensional accuracy of the bases of complete removable prostheses made using 3D printing and traditional technologies

2020 ◽  
pp. 34-39
Author(s):  
Vokulova Yu.A. Vokulova ◽  
E.N. Zhulev
Keyword(s):  
3D Printing ◽  
Traditional Method ◽  
Laser Scanning ◽  
Laser Scanner ◽  
Digital Technologies ◽  
Dimensional Accuracy ◽  
3D Printer ◽  
Significance Level ◽  
Average Value ◽  
The Difference

This article presents the results of studying the dimensional accuracy of the bases of complete removable prostheses made using a 3D printer and the traditional method. Bases of complete removable prostheses were made using an intraoral laser scanner iTero Cadent (USA) and a 3D printer Asiga Max UV (Australia). To study the dimensional accuracy of the bases of complete removable prostheses, we used the DentalCAD 2.2 Valletta software. The Nonparametric Wilcoxon W-test was used for statistical analysis of the obtained data. We found that the average value of the difference with the standard for bases made using digital technologies is 0.08744±0.0484 mm. The average value of the difference with the standard for bases made by the traditional method is 0.5654±0.1611 mm. Based on these data, we concluded that the bases of complete removable prostheses made using modern digital technologies (intraoral laser scanning and 3D printer) have a higher dimensional accuracy compared to the bases of complete removable prostheses made using the traditional method with a significance level of p<0.05 (Wilcoxon's W-test=0, p=0.031). Keywords: digital technologies in dentistry, digital impressions, intraoral scanner, 3D printing, ExoCAD, complete removable dentures.

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