Damage Mapping Research Articles

Geração de Mapas de Danos de Formação de Manchas em Fachadas a Partir dos Métodos de DSM e PDI, e Utilização de VANT

O objetivo deste trabalho foi aplicar uma metodologia para geração automática de mapas de danos em ortoimagens de fachadas de edifícios, utilizando-se VANT para a captura das fotografias. A geração de mapas de danos visa auxiliar na inspeção visual, método empregado nas atividades de recuperação manutenção ou intervenção em edifícios. Utilizando a técnica de dense stereo matching (DSM), modelos geométricos de edifícios foram gerados por nuvem de pontos no programa PhotoScan para a obtenção de ortoimagens. Após esta etapa, as ortoimagens foram submetidas à etapa de geração de mapas de danos de manchas escuras no Programa Tyche, que mapeou e quantificou percentualmente estas manifestações patológicas. Os resultados dos mapas de danos foram classificados também qualitativamente. A aplicação de VANT demonstrou ser uma ferramenta eficiente para a atividade de inspeção de fachadas e para a captura de imagens a serem utilizadas por meio da DSM. A geração de mapas de danos pelo Tyche demonstrou ser também eficaz, no entanto a interação do usuário mostrou-se importante para alcançar os resultados esperados.

Methodology for the damage assessment of vehicles exposed to flooding in urban areas

Within urban areas, humans carry out a great diversity of activities, and some of them require the use of vehicles. Floods, especially in urban areas, can generate significant tangible direct damages to vehicles themselves and to the urban elements in case of loss of stability and collision, which cannot be dismissed. In this paper, after a state‐of‐the‐art review on damage curves for vehicles, a methodology to assess the direct economic impact for vehicles exposed to flooding has been described, and applied within a study carried out in the framework of the BINGO H2020 EU Project. Only three different studies focused on damages to vehicles in contact with floodwater have been found. Contrasting damage curves for vehicles are found when comparing the three approaches, however, the ones proposed by the U.S. Army Corps of Engineers (USACE) offer a high level of completeness and accuracy. Moreover, USACE's development is the most current research and all the steps for the development of the damage curves are comprehensively described. Finally, after the description of a detailed methodology for flood damage mapping for vehicles, a procedure to evaluate the Expected Annual Damage for vehicles is offered.

Effective Properties of Micro-cracked Viscoelastic Materials

The aim of this paper is to model the effective properties of micro-cracked viscoelastic materials based on a dilute and Mori-Tanka estimates under the condition that the Poisson’s ratio of matrix is time-independent. Firstly, the key points of viscoelastic homogenization theory were presented based on the introduction of a viscoelastic Eshelby tensor. Secondly, the stress-based estimate approaches of effective mechanical properties for crack-damaged elastic materials were extended to viscoelastic circumstances. It is shown that a damage mapping tensor which maps the undamaged creep compliance into a damaged one is time-independent, and this verify the assumption adopted in Abdel-Tawab’s viscoelastic constitutive model that damage affects the long-term and transient compliance in a common manner.

Nucleotide-Resolution Genome-Wide Mapping of Oxidative DNA Damage by Click-Code-Seq.

Single-nucleotide-resolution sequencing of DNA damage is required to decipher the complex causal link between the identity and location of DNA adducts and their biological impact. However, the low abundance and inability to specifically amplify DNA damage hinders single-nucleotide mapping of adducts within whole genomes. Despite the high biological relevance of guanine oxidation and seminal recent advances in sequencing bulky adducts, single-nucleotide-resolution whole genome mapping of oxidative damage is not yet realized. We coupled the specificity of repair enzymes with the efficiency of a click DNA ligation reaction to insert a biocompatible locator code, enabling high-throughput, nucleotide-resolution sequencing of oxidative DNA damage in a genome. We uncovered thousands of oxidation sites with distinct patterns related to transcription, chromatin architecture, and chemical oxidation potential. Click-code-seq overcomes barriers to DNA damage sequencing and provides a new approach for generating comprehensive, sequence-specific information about chemical modification patterns in whole genomes.

Combining TerraSAR-X and Landsat Images for Emergency Response in Urban Environments

Rapid damage mapping following a disaster event, especially in an urban environment, is critical to ensure that the emergency response in the affected area is rapid and efficient. This work presents a new method for mapping damage assessment in urban environments. Based on combining SAR and optical data, the method is applicable as support during initial emergency planning and rescue operations. The study focuses on the urban areas affected by the Tohoku earthquake and subsequent tsunami event in Japan that occurred on 11 March 2011. High-resolution TerraSAR-X (TSX) images of before and after the event, and a Landsat 5 image before the event were acquired. The affected areas were analyzed with the SAR data using only one interferometric SAR (InSAR) coherence map. To increase the damage mapping accuracy, the normalized difference vegetation index (NDVI) was applied. The generated map, with a grid size of 50 m, provides a quantitative assessment of the nature and distribution of the damage. The damage mapping shows detailed information about the affected area, with high overall accuracy (89%), and high Kappa coefficient (82%) and, as expected, it shows total destruction along the coastline compared to the inland region.

CT-Scan study of crack patterns of fiber-reinforced concrete loaded monotonically and under low-cycle fatigue

Most fatigue models for concrete under compression assume, as an axiom, that compressive tests are a limit case for a cyclic test where failure is achieved in the first cycle. This is supported by the fact that the crack patterns obtained in both cases are similar to the naked eye. This paper focuses on verifying whether this observation is correct or not. For that, we used a Computed Tomography Scan together with digital image processing to obtain 3D damage maps of tested 40 mm edge-length cubes made of steel fiber-reinforced concrete. The cubes were classified in series according to the type of loading: intact, monotonic and cyclic. They were scanned to acquire their 3D damage maps. Additionally, a specific post-processing algorithm was developed by the authors to compare the different crack patterns. The results show that average damage maps for monotonically and cyclically-tested cubes are statistically similar, thereby confirming the initial hypothesis for steel fiber-reinforced concrete. Furthermore, damage distribution near the platens apparently depends on whether it is a fixed platen or it is adjustable to the specimen surface due to a spherical seat.

In vivo imaging of neuronal calcium during electrode implantation: Spatial and temporal mapping of damage and recovery

Implantable electrode devices enable long-term electrophysiological recordings for brain-machine interfaces and basic neuroscience research. Implantation of these devices, however, leads to neuronal damage and progressive neural degeneration that can lead to device failure. The present study uses in vivo two-photon microscopy to study the calcium activity and morphology of neurons before, during, and one month after electrode implantation to determine how implantation trauma injures neurons. We show that implantation leads to prolonged, elevated calcium levels in neurons within 150 μm of the electrode interface. These neurons show signs of mechanical distortion and mechanoporation after implantation, suggesting that calcium influx is related to mechanical trauma. Further, calcium-laden neurites develop signs of axonal injury at 1–3 h post-insert. Over the first month after implantation, physiological neuronal calcium activity increases, suggesting that neurons may be recovering. By defining the mechanisms of neuron damage after electrode implantation, our results suggest new directions for therapies to improve electrode longevity.

Use of active learning for earthquake damage mapping from UAV photogrammetric point clouds

ABSTRACTThis article presents an effective classification method for earthquake damage mapping from unmanned aerial vehicles (UAV) photogrammetric point clouds. The classification method consists of three main components: (a) construction of a point feature descriptor regarding to spectral, textural, and geometrical features, (b) optimization of collecting informative training samples through an active learning (AL) method, and (c) fine-tuning the point-based classification results with contextual information. Besides using existing spectral and geometrical features, we design a textural feature based on fractal theory to construct a point feature descriptor through linear combination. A batch-model AL method called Margin Sampling and Multiclass Level Uncertainty (MS-MCLU) is proposed based on classification uncertainty using a Support Vector Machine classifier. We use a multi-label Markov random fields to fine-tune the point-based classification results with a pairwise model. The proposed method was tested using three sets of point clouds generated from UAV images over Mirabello, Lushan, and Wenchuan earthquake scenarios in 2012, Italy, and in 2013 and 2008, China, respectively. The proposed classification method was compared with that of two other feature descriptors, i.e. spectral combined with textural features (Spe_Tex) and geometrical features (Geo). The results show that classification accuracies were improved by using the proposed point feature descriptor. Results also show that the proposed MS-MCLU AL method evidently saved the cost of collecting informative training samples and produced higher classification accuracies than a random sampling strategy. Moreover, contextual information contributed to the improvement on the point-based classification results and was suggested to be considered in earthquake damage mapping applications.

Correlation between earthquake damage and seismic site effects: The study case of Lentini and Carlentini, Italy

On December 13th 1990 a magnitude 5.6 seismic event, felt throughout Sicily, and having maximum seismic intensity VII-VIII, occurred. Although, it is classified as moderate magnitude, it caused causalities and the collapse of a few buildings. Two of the most struck cities were Carlentini and Lentini, located in south-eastern Sicily at about 20 km from the instrumental epicenter. In order to evaluate the influence of ground features on the damage distribution, both vulnerability and damage maps were drawn using information collected in about 6000 forms coming from official ascertainments. Significant damage observed in some portions of the investigated areas, appears related to the modest quality of the buildings that were classified as medium to high vulnerability. To evaluate the role played by the geologic setting, two sites were instrumented to measure shear-wave velocity of the main lithotypes. Sixty-three ambient vibrations measurements were also performed both in free field and inside some buildings. Moreover, using information coming from geological and geophysical surveys, 1D numerical modelling were done to achieve information about the main ground motion parameters. The results highlight the occurrence of significant site effects and the potential presence of resonance phenomena between site and structure during the occurrence of a seismic event. Seismic site amplifications together with the buildings' vulnerability, observed through damage surveys, contributed to enhance the inherent seismic risk of the investigated area.

Genome-wide excision repair in Arabidopsis is coupled to transcription and reflects circadian gene expression patterns

Plants are exposed to numerous DNA-damaging stresses including the exposure to ultraviolet (UV) component of solar radiation. They employ nucleotide excision repair to remove DNA-bulky adducts and to help eliminate UV-induced DNA lesions, so as to maintain their genome integrity and their fitness. Here, we generated genome-wide single-nucleotide resolution excision repair maps of UV-induced DNA damage in Arabidopsis at different circadian time points. Our data show that the repair of UV lesions for a large fraction of the genome is controlled by the joint actions of the circadian clock and transcription by RNA polymerase II. Our findings reveal very strong repair preference for the transcribed strands of active genes in Arabidopsis, and 10–30% of the transcription-coupled repair is circadian time-dependent. This dynamic range in nucleotide excision repair levels throughout the day enables Arabidopsis to cope with the bulky DNA lesion-inducing environmental factors including UV.

A Prognosis Methodology for Underground Infrastructure Damage in Sublevel Cave Mining

In sublevel caving (SLC), the caving of the hangingwall due to ore extraction emphasises placement of the mining infrastructure in the footwall. While the footwall in general is less affected by ground settlement compared to the hangingwall, the changes in stress field from mining are significant. The footwall infrastructure must thus be positioned sufficiently far into the footwall to avoid damage from the mining-induced stress; however, placing the infrastructure farther into the footwall increases costs associated with additional drifting and operational distances. This paper presents a case study in which a robust prognosis tool for predicting infrastructure damage associated with SLC mining is developed. The concept of the proposed methodology was developed for the Luossavaara-Kiirunavaara Aktiebolag Kiirunavaara SLC mine. Initial steps are data collection through systematic damage mapping followed by conceptual modelling of the general rock mass response to mining. The results of the conceptual models are used as the basis for refined calibrated models detailing the damage development and failure mechanisms. The main system behaviour, failure mechanism and associated damage evolution are incorporated into a bilinear equation using the studied depth and local ore width as input to estimate the final horizontal damage extent from the footwall contact after mining of any specific level. The proposed relationship accurately replicates the current damage pattern within 40 m for more than 70% of the recorded observations up until current mining. The anticipated future damage extent is also shown to be well correlated with current micro-seismic event locations. The connection between seismic rock mass damage and subsequent infrastructure damage during de-confinement suggests that current seismic records from operations, which currently experience no stability issues, might become important at later mining stages.

A geographic information system-based approach of flood hazards modelling, Paschim Medinipur district, West Bengal, India.

From the beginning of civilisation, human beings have preferred living on the river banks which have been the most vulnerable areas of flood hazards and consequent disasters. During the monsoon period, in many developing countries of south-east Asia, flood hazards and disasters have been a serious challenge for their development. Most of the rivers exceed their normal channel capacity attaining the flood stage and frequently overflow their banks, causing great havoc to the life and property of the people. Flooding is a very serious problem in many districts of West Bengal. The prime concern of delineation of flood-prone areas is to regulate the land use in the flood-prone areas to restrict damage potential and also mitigate the negative effects of floods on people and the economy. In a regulated way, flood-prone areas are required to be developed. Because, on one hand, it is to be ensured that existing hazard and flood damage potential do not increase and new developmental works become a step towards mitigation of disaster risk. In a perspective view, the demarcation and identification of flood-prone areas of different magnitudes, frequencies and return periods on a large-scale map seem to have great importance. Satellite-derived flood maps from 2007 to 2016 have been applied to form a flood frequency map and the same as a group of flood depth maps has been employed to produce the Flood Damage Map for depth data of flood. Finally, the modelling of flood hazards has been directed by envisaging amalgamation of Flood Depth and Flood Affected Frequency. Then the final flood hazard map amalgamated with population and housing data has been used to ascertain the flood disclosure for these two components. Flood hazard analysis in the study area revealed that 24% of the population has been located in high flood hazard zones, where 39% of human settlements are located in different flood hazard zones.

Earthquake damage mapping: An overall assessment of ground surveys and VHR image change detection after L'Aquila 2009 earthquake

Earth Observation (EO) data are used to map mostly affected urban areas after an earthquake generally exploiting change detection techniques applied at pixel scale. However, Civil Protection Services require damage assessment of each building according to a well-established scale to manage rescue operations and to estimate the economic losses.Considering the earthquake that hit L'Aquila city (Italy) on April 6, 2009, this work assess the feasibility of producing damage maps at the scale of single building from Very High Resolution (VHR) optical images collected before and after the seismic event. We considered the European Macroseismic Scale 1998 (EMS-98) and assessed the possibility to discriminate between collapsed or heavy damaged buildings (damage grade DG equal to 5 in the EMS-98 scale) and less damaged or undamaged buildings (DG < 5 in the EMS-98).The proposed approach relies on a pre-existing urban map to identify image objects corresponding to building footprints. The image analysis is carried out according to many different parameters with the objective of assessing their effectiveness in singling out changes associated to the building collapse. Features describing texture and colour changes, as well statistical similarity and correlation descriptors, such as the Kullbach Leibler Distance and the Mutual Information, were included in our analysis. Two supervised classification approaches, respectively, based on the use of the Bayesian Maximum A Posteriori (MAP) criterion and on Support Vector Machines (SVM), were compared. In our experiment, we considered the whole L'Aquila historical centre comparing classification results with the ground survey performed by the Istituto Nazionale di Geofisica e Vulcanologia (INGV).The work represents one of the first attempt to detect damage at the scale of single building, validated against an extensive ground survey. It addresses methodological aspects, highlighting the potential of textural features computed at object scale and SVMs, and discuss potential and limitations of EO in this field compared to ground surveys.

Assessment and quantification of ballistic impact damage of a single-layer woven fabric composite

A methodology is developed to visually analyze and quantify macroscale and mesoscale impact damage on a single layer of S-2 glass/SC15 toughened epoxy plain weave composite. Specimens were clamped in a 203 mm diameter circular frame and impacted by a 5.5 mm (0.22 caliber) right circular cylindrical steel projectile at impact velocities ranging from 104 to 472 m/s. High-resolution images were obtained at the point of impact and up to the edge of the circular frame using an 80 MP camera. Three types of mesoscale damage were identified: (i) transverse tow cracks, (ii) tow–tow delamination, and (iii) 45° matrix cracks. A MATLAB program was developed to translate the image data into a digital damage map whereby the output of color intensity correlated with the quantity and type of material damage. Digital maps generated for select specimens revealed that characteristic damage patterns arise for woven fabric composites including a diamond pattern in matrix cracking and a cross pattern in tow–tow delamination. The greatest extent of matrix cracks and tow–tow delamination over any specimen was observed for the projectile impact with initial velocity of 174 m/s, which is very close to the calculated ballistic limit velocity of 175 m/s.

Soil erosion by water in Northern Germany: long-term monitoring results from Lower Saxony

Soil erosion caused by water has been monitored for 17 years on 465 ha cropland in Lower Saxony (Northern Germany). The 86 monitored fields are representative for three different typical agricultural landscapes with an intermediate to high water erosion risk in Northern Germany. The monitoring scheme included regularly conducted erosion damage mapping and cultivation surveys. The collected data encompasses 1275 field years and 1355 mapped erosion systems, giving evidence on the extent, frequency and rate of soil erosion by water. Mean mapped soil loss for all fields was relatively small at 0.85 t ha−1 a−1. The highest rate for a single field amounted to 7.02 t ha−1 a−1. Variability of soil loss in time and space was high: annual losses (mean of all fields) ranged between 0.04 and 2.81 t ha−1 a−1. The highest annual loss on a single field was 53.07 t ha−1. Every year, at least 24% of the monitored fields were not affected by erosion, only 1.3% of the monitored area eroded at least once a year. Spatial analysis of mapped erosion features shows that the highest soil loss is located in topographically-defined flow paths and in wheel tracks oriented in line of the steepest slope. Cultivated crops and tillage management have a high influence on loss rates ranging from 0.07 for catch crop to 2.78 t ha−1 a−1 for potato. Additionally, the results prove that farmers in the investigation areas were able to significantly reduce soil loss rates of the five most important crops from 0.6 to 0.37 t ha−1 a−1 by using conservation tillage measures. The annual variability in the collected data emphasises the importance of appropriate long-term monitoring programmes to create sound data on the extent, frequency and rate of soil erosion by water at a field to landscape scale.

Structural Health Monitoring system based on a concept of Lamb wave focusing by the piezoelectric array

Abstract Piezoelectric transducer arrays are utilized in Structural Health Monitoring systems as a means for excitation and sensing of elastic waves. Anomalies of propagating waves have enabled to develop damage detection algorithms. Depending on actuation-sensing strategies these algorithms can be classified as pitch-catch and pulse-echo. Despite many signal processing methods such as delay-sum, time-reversal, probability-based diagnostic imaging, etc. the spatial damage information provided by the actuator-sensor paths to reconstruct the damage image is limited. A novel strategy based on Lamb wave focusing is proposed in order to increase damage imaging resolution. In the proposed method all actuators are used at the same time exciting specially designed waveforms so that inspect one specific point of the structure. Damage map is created by applying appropriate signal processing. It uses dispersion curve of selected Lamb wave mode for dispersion compensation. The dispersion curve is acquired by using laser scanning Doppler vibrometer. The damage indicator is calculated based on the energy of compensated signals registered by sensors. It is shown that apart from high energy level at excitation point, energy is concentrated exactly in the damaged region. An example of crack detection and visualization in an aluminum plate is shown confirming the accuracy of the proposed method. Also the proposed method is compared to well-established delay-and-sum algorithm.

Earthquake scenario in a national drill, the case of “Turning Point 6”, 2012, Israel

National exercises are an excellent opportunity to practice earthquake preparedness. Such exercises can greatly benefit from productive communication between the civil protection agencies (CPs) and the earth sciences community (SC). The challenge of the scientists in this interaction is to properly formulate their message and convey their perspective in a manner understandable to the responsible emergency agencies. On October 2012, Israel held its first national earthquake emergency exercise (TP6) that examined the response of the country’s systems at large to an Mw ~ 7 earthquake. The exercise greatly benefited from brain storming meetings between the CPs and researchers from the Geological Survey of Israel (GSI) that were held prior to the drill. These helped in choosing the earthquake scenario and establish the concept of the exercise. Geological hazards and damage maps, including numerous discrete events, were prepared in advance with the HAZUS Multi-Hazard Loss Estimation software and were conveyed to the drilled authorities during the exercise. The exercise also benefitted from close collaboration between researchers of FEMA and the GSI. During the drill, the GSI and its relevant scientists practiced the preparation and transfer of the relevant material to the decision makers in “real time.” The drill provided the following lessons: (1) In real time, the damage maps should be delivered by earthquake researchers, thereby helping the CP agencies to grasp the information. (2) Damage maps should be prepared in advance and accessibly stored by the CP agencies for a range of probable scenarios. (3) Damage maps based on dot density that represent number of buildings damaged, number of casualties and weight of debris were found to be the most comprehensible when presenting the scope of the damage. The lessons learned from the collaboration between the CP and SC in TP6 provide an excellent example for optimal planning of national earthquake exercises, thereby helping in minimizing the anticipated impact of destructive earthquakes.

Structural assessment and seismic vulnerability of earthen historic structures. Application of sophisticated numerical and simple analytical models

Adobe constructions account for a significant portion of the built heritage, associated with early building techniques, material accessibility and low-cost. Nonetheless, adobe buildings, due to their low mechanical properties and overturning resistance, are subject to early structural damage, such as cracking, separation of structural elements and, possibly, collapse in areas of high seismic hazard. The lack of maintenance and absence of adequate retrofitting techniques usually intensifies the loss of historic fabric. The current paper, aims at the structural assessment and seismic safety, in current conditions, of the Church of Kuño Tambo, a religious adobe structure of the 17th century, in Cusco region, in Peru. The inspection and diagnosis involved sonic testing and damage mapping, while ambient vibration tests revealed the modal response of the structure. The assessment of seismic vulnerability, together with the necessity of retrofitting measures were verified through nonlinear static and pushover parametric analyses, complemented with a macro-block limit analysis and a performance based assessment, under local seismic criteria. A more realistic response from dynamically induced ground motions was performed, by a nonlinear time history analysis, according to the Eurocode 8 framework. Through an integrated approach, in situ inspection, testing, numerical and analytical modelling are associated under the scope of reproducing the existing structural damage, the sequence of inelastic behavior and verification of the necessity of retrofitting measures.

The theory of the S-N fatigue damage envelope: Generalization of linear, double-linear, and non-linear fatigue damage models

A new theory for macroscopic fatigue damage estimation based on the S-N curve is presented. The proposed concept assumes that the area bounded by the S and N axes, and the S-N curve, can provide a characteristic damage map for each material. Finite element analysis is used to derive colored damage zones and non-linear isodamage lines within the S-N fatigue damage envelope. Implementation of this theory on two arbitrarily selected alloys under stepwise variable stresses is provided, and the successful prediction of the remaining life is discussed. The proposed S-N fatigue damage envelope theory is a generalization of most of the existing fatigue damage models.

Time marks: an assessment of the conservation status of Tafona Farm main house from damage maps

The concern of preserving architectonic assets includes also the care to watch over the urban and rural landscape of different localities. This study aims to evaluate the state of conservation of the facades of São José Farm’s main house, located in the municipality of Cachoeira do Sul / RS, in the southern region of Brazil, by mapping its damages. It is part of a research project carried out by researchers from the Universidade Federal de Santa Maria, Cachoeira do Sul Campus, titled "Tafona Farm: a trip to the memory world of Rio Grande do Sul". The Damages Map uses the registry data of Tafona Farm main house and aims to contribute to the project through the evaluation of the external facades of the same. For the development of this study, the methodology of Damage Map was used, which consisted in mapping the pathologies of the building facades through its graphic representation complemented by photos, identification of the materials that compose the facade, mapping and dimensioning of the different pathologies and indications of possible interventions. It’s worth noting that the Damage Map is an important instrument for the budget forecast of restoration and intervention projects. In this sense, the material elaborated in this work contributes to the recognition of Tafona’s main house state of conservation and can serve as a support for future preservation and recovery postures of this important architectonic asset.