Investigation of ambient noise seismological methods on a bridge model

2021 ◽  
Author(s):  
Chun-Man Liao ◽  
Franziska Mehrkens ◽  
Celine Hadziioannou ◽  
Ernst Niederleithinger
Keyword(s):  
Wave Propagation ◽  
Large Scale ◽  
Seismic Velocity ◽  
Measurement Data ◽  
Correlation Coefficients ◽  
Coda Wave ◽  
Velocity Change ◽  
Promising Tool ◽  
Bridge Model ◽  
Noise Measurements

<p>The aim of this work is to investigate the application of seismological noise-based monitoring for bridge structures. A large-scale two-span concrete bridge model with a build-in post-tensioning system, which is exposed to environmental conditions, is chosen as our experimental test structure. Ambient seismic noise measurements were carried out under different pre-stressed conditions. Using the seismic interferometry technique, which is applied to the measurement data in the frequency domain, we reconstruct waveforms that relate to wave propagation in the structure. The coda wave interferometry technique is then implemented by comparing two waveforms recorded in two pre-stress states. Any relative seismic velocity changes are identified by determining the correlation coefficients and reveal the influence of the pre-stressing force. The decrease of the wave propagation velocity indicates the loss of the pre-stress and weakening stiffness due to opening or event extension of cracks. We conclude that the seismological methods used to estimate velocity change can be a promising tool for structural health monitoring of civil structures.</p>

scholarly journals Hanging glacier monitoring with icequake repeaters and seismic coda wave interferometry: a case study of the Eiger hanging glacier

2021 ◽  
Author(s):  
Małgorzata Chmiel ◽  
Fabian Walter ◽  
Lukas Preiswerk ◽  
Martin Funk ◽  
Lorenz Meier ◽  
...  
Keyword(s):  
Large Scale ◽  
Wave Attenuation ◽  
Seismic Velocity ◽  
Swiss Alps ◽  
Coda Wave ◽  
Diurnal Cycles ◽  
Ice Surface ◽  
Novel Approach ◽  
Seismic Coda ◽  
Coda Wave Interferometry

Abstract. Driven by the force of gravity, hanging glacier instabilities can lead to catastrophic rupture events. Reliable forecasting remains a challenge as englacial damage leading to large-scale failure is masked from modern sensing technology focusing on the ice surface. The Eiger hanging glacier, located in the Swiss Alps, was intensely monitored between April and August 2016 before a moderate 15,000 m3 break-off event from the ice cliff. Among different instruments, such as an automatic camera and interferometric radar, four 3-component seismometers were installed on the glacier. A single seismometer operated throughout the whole monitoring period. It recorded over 200,000 repeating icequakes showing strong englacial seismic coda waves. We propose a novel approach for hanging glacier monitoring by combining repeating icequake analysis, coda wave interferometry, and attenuation measurements. Our results show a seasonal 0.1 % decrease in relative englacial seismic velocity dv/v and an increase in coda wave attenuation Qc−1 (Qc decreases from ~50 to ~30). Comparison of dv/v and Qc with air temperature suggests that these changes are driven by a seasonal increase in the glacier’s ice and firn pack temperature that might affect the top 20 m of the glacier. Diurnal cycles of Qc−1, repeating icequake activity, and the velocity of the glacier front shift from cosinusoidal to sinusoidal variations under the presence of meltwater. The proposed approach extends the monitoring of the hanging glacier beyond the ice surface and allows for a better understanding of the glacier’s response to time-dependent external forcing, which is an important step towards improved break-off forecasting systems.

scholarly journals PECULIARITIES OF MONITORING FOR INFRASOUND POLLUTION OF RESIDENTIAL AREAS LOCATED IN PROXIMITY TO HIGHWAYS

2018 ◽  
Vol 97 (12) ◽  
pp. 1141-1145 ◽  
Author(s):  
Elena B. Kuznetsova ◽  
I. D. Bulavina
Keyword(s):  
Large Scale ◽  
Free Field ◽  
Experimental Studies ◽  
Measurement Data ◽  
Sound Field ◽  
Wind Load ◽  
Residential Areas ◽  
Noise Measurements ◽  
Research Findings ◽  
Determination Of Parameters

Introduction. Procedural provision of studies on monitoring for infrasound pollution of residential areas located in proximity to highways is the issue of the consideration in this article. The fact of the absence of a standardized procedure for carrying out large-scale studies of the infrasound range of the sound pressure in residential areas is reported. A brief review of regulatory documents currently used by experts of accredited laboratories, hygiene and epidemiology centers to solve sanitary problems of infrasound range acoustics, is given. Material and Methods. As a rule, experts use techniques for a hearing range of noise measurements and procedures specified by device service instructions which result in significant inconsistencies of research findings. Determination of parameters affecting the accuracy of research findings carried out with the help of routine devices available in hygiene and epidemiology centers was the objective of infrasound measurements presented here. Results. Effect of wind flows, study duration and monitoring location point were found to be the major parameters affecting the accuracy of research findings. Data on wind load on Saint-Petersburg territory is reported. Territories in the immediate proximity to the “West Speed Diameter” (WSD) highway, Ring motorway and Sinopskaya embankment being potential infrasound sources, were chosen for experimental studies. Such choice was caused by the heavy freight and passenger car traffic characterized by relatively permanent intensity. Discussion. Measurement series at various wind loads and of different durations were done. Measurement points were chosen in free field and in the vicinity of echoing areas. Measurement data were assessed taking into account expanded uncertainty, at 95% confidence level. It was found that reliable measurement results in infrasound frequency range can be obtained on the territory at wind velocity not exceeding 1 m/sec, during measurements in the free sound field with duration over 20 minutes. Given wind load conditions can be realized in St.-Petersburg for several days a month.

Soil/Tire Interaction Analysis Using FEM and FVM

2005 ◽  
Vol 33 (1) ◽  
pp. 38-62 ◽  
Author(s):  
S. Oida ◽  
E. Seta ◽  
H. Heguri ◽  
K. Kato
Keyword(s):  
Large Scale ◽  
Interaction Analysis ◽  
Yield Criterion ◽  
Surrounding Medium ◽  
Flow Analysis ◽  
Measurement Data ◽  
Traction Force ◽  
Elastoplastic Material ◽  
The Road ◽  
Soil Flow

Abstract Vehicles, such as an agricultural tractor, construction vehicle, mobile machinery, and 4-wheel drive vehicle, are often operated on unpaved ground. In many cases, the ground is deformable; therefore, the deformation should be taken into consideration in order to assess the off-the-road performance of a tire. Recent progress in computational mechanics enabled us to simulate the large scale coupling problem, in which the deformation of tire structure and of surrounding medium can be interactively considered. Using this technology, hydroplaning phenomena and tire traction on snow have been predicted. In this paper, the simulation methodology of tire/soil coupling problems is developed for pneumatic tires of arbitrary tread patterns. The Finite Element Method (FEM) and the Finite Volume Method (FVM) are used for structural and for soil-flow analysis, respectively. The soil is modeled as an elastoplastic material with a specified yield criterion and a nonlinear elasticity. The material constants are referred to measurement data, so that the cone penetration resistance and the shear resistance are represented. Finally, the traction force of the tire in a cultivated field is predicted, and a good correlation with experiments is obtained.

scholarly journals Inverse Infiltration Modeling of Dike Covers Made of Dredged Material Using PEST and AMALGAM

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 41
Author(s):  
Tim Jurisch ◽  
Stefan Cantré ◽  
Fokke Saathoff
Keyword(s):  
Large Scale ◽  
Measurement Data ◽  
Fine Grained ◽  
Dredged Materials ◽  
Measurement Results ◽  
Large Scale Field ◽  
Eigenvalue Ratio ◽  
Ill Posed ◽  
Materials Used ◽  
Installation Technology

A variety of studies recently proved the applicability of different dried, fine-grained dredged materials as replacement material for erosion-resistant sea dike covers. In Rostock, Germany, a large-scale field experiment was conducted, in which different dredged materials were tested with regard to installation technology, stability, turf development, infiltration, and erosion resistance. The infiltration experiments to study the development of a seepage line in the dike body showed unexpected measurement results. Due to the high complexity of the problem, standard geo-hydraulic models proved to be unable to analyze these results. Therefore, different methods of inverse infiltration modeling were applied, such as the parameter estimation tool (PEST) and the AMALGAM algorithm. In the paper, the two approaches are compared and discussed. A sensitivity analysis proved the presumption of a non-linear model behavior for the infiltration problem and the Eigenvalue ratio indicates that the dike infiltration is an ill-posed problem. Although this complicates the inverse modeling (e.g., termination in local minima), parameter sets close to an optimum were found with both the PEST and the AMALGAM algorithms. Together with the field measurement data, this information supports the rating of the effective material properties of the applied dredged materials used as dike cover material.

Imaging the Chicxulub Central Crater Zone from Large-Scale Seismic Acoustic Wave Propagation and Gravity Modeling

2021 ◽  
Author(s):  
Carlos Ortiz-Aleman ◽  
Ronald Martin ◽  
Jaime Urrutia-Fucugauchi ◽  
Mauricio Orozco del Castillo ◽  
Mauricio Nava-Flores
Keyword(s):  
Wave Propagation ◽  
Acoustic Wave ◽  
Large Scale ◽  
Gravity Modeling ◽  
Acoustic Wave Propagation ◽  
Central Crater

Fast Large-Scale Algorithm for Electromagnetic Wave Propagation in 3D Media

2019 ◽  
Author(s):  
Mitchell Tong Harris ◽  
M. Harper Langston ◽  
Pierre-David Letourneau ◽  
George Papanicolaou ◽  
James Ezick ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Electromagnetic Wave ◽  
Large Scale ◽  
Electromagnetic Wave Propagation

scholarly journals Sensitivity of Ultrasonic Coda Wave Interferometry to Material Damage—Observations from a Virtual Concrete Lab

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4033
Author(s):  
Claudia Finger ◽  
Leslie Saydak ◽  
Giao Vu ◽  
Jithender J. Timothy ◽  
Günther Meschke ◽  
...  
Keyword(s):  
Elastic Moduli ◽  
Concrete Specimen ◽  
Coda Wave ◽  
Velocity Change ◽  
Damage Scenarios ◽  
Different Types ◽  
Source Signal ◽  
The Impact ◽  
Structural Scale ◽  
Coda Wave Interferometry

Ultrasonic measurements are used in civil engineering for structural health monitoring of concrete infrastructures. The late portion of the ultrasonic wavefield, the coda, is sensitive to small changes in the elastic moduli of the material. Coda Wave Interferometry (CWI) correlates these small changes in the coda with the wavefield recorded in intact, or unperturbed, concrete specimen to reveal the amount of velocity change that occurred. CWI has the potential to detect localized damages and global velocity reductions alike. In this study, the sensitivity of CWI to different types of concrete mesostructures and their damage levels is investigated numerically. Realistic numerical concrete models of concrete specimen are generated, and damage evolution is simulated using the discrete element method. In the virtual concrete lab, the simulated ultrasonic wavefield is propagated from one transducer using a realistic source signal and recorded at a second transducer. Different damage scenarios reveal a different slope in the decorrelation of waveforms with the observed reduction in velocities in the material. Finally, the impact and possible generalizations of the findings are discussed, and recommendations are given for a potential application of CWI in concrete at structural scale.

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