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1
Shin, Changsoo. "Sponge boundary condition for frequency‐domain modeling". GEOPHYSICS 60, nr 6 (listopad 1995): 1870–74. http://dx.doi.org/10.1190/1.1443918.
Pełny tekst źródłaStreszczenie:
Several techniques have been developed to get rid of edge reflections from artificial boundaries. One of them is to use paraxial approximations of the scalar and elastic wave equations. The other is to attenuate the seismic waves inside the artificial boundary by a gradual reduction of amplitudes. These techniques have been successfully applied to minimize unwanted seismic waves for time‐domain seismic modeling. Unlike time‐domain seismic modeling, suppression of edge reflections from artificial boundaries has not been successful in frequency‐domain seismic modeling. Rayleigh waves caused by coupled motions of P‐ and S‐waves near the surface have been a particularly difficult problem to overcome in seismic modeling. In this paper, I design a damping matrix for frequency‐ domain modeling that damps out seismic waves by adding a diffusion term to the wave equation. This technique can suppress unwanted seismic waves, including Rayleigh waves and P‐ and S‐waves from an artificial boundary.
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Kanhaiya, Krishnakant, i Dr Ajay Kumar Jain. "“A Comparative Study of Circular Water Tank in Two Different Loading Conditions (Seismic and Wind Load Condition) using Staad-Pro”". International Journal of Innovative Technology and Exploring Engineering 11, nr 3 (30.01.2022): 75–79. http://dx.doi.org/10.35940/ijitee.l9562.0111322.
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In this paper a comparison of the two loading combinations of a circular water tank i.e. seismic and wind load conditions have been made. The STAADPro software has been used to analyze the circular water tank structure and to compare both the loading combinations. Two similar models of a circular water tank were created, provided with the required attributes (i.e. loading conditions, zones etc.) and were analyzed in both, seismic load condition and wind load condition. The comparison of results from both the analyses revealed that, due to lower seismic zones, the effect of earthquake is slightly less than the effect of wind. It was concluded that, wind load condition should be preferred over seismic load condition while designing, because the wind load condition gives safer design in the severe conditions. This can be used for the design of a circular water tank having similar attributes.
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Bhattarai, Shishir, i Prem Nath Maskey. "Effect of Linear Soil Condition on Seismic Inputs". Technical Journal 2, nr 1 (10.11.2020): 48–55. http://dx.doi.org/10.3126/tj.v2i1.32829.
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Seismic inputs to structures in terms of risk consistent response spectrum and seismic hazard curves are developed at bedrock level considering ten independent seismic source zone in the vicinity of the Kathmandu valley. The seismic hazard curve is derived by assuming temporal occurrence of earthquakes to follow Poisson model. Response spectrum is developed using an empirical relationship of spectral ordinates with magnitude of earthquakes and epicentral distance. The seismic risk factor is introduced in response spectrum using conditional probabilities. Power spectral density function consistent with response spectrum is derived and ground acceleration time histories are derived from power spectral density function using Monte Carlo technique. To obtain free field hazard curves and ground motion parameters, one dimensional wave propagation analysis is used for two different underlying soil conditions.
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Jiang, Huanjun, Yong Wang i Liusheng He. "Study of Seismic Performance of Chinese-Style Single-Layer Suspended Ceiling System by Shaking Table Tests". Advances in Civil Engineering 2021 (13.09.2021): 1–14. http://dx.doi.org/10.1155/2021/9861722.
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During some recent earthquakes, the suspended ceiling system (SCS) in buildings suffered severe damage. The seismic performance of SCS attracted more attention from researchers. In this study, full-scale shaking table tests on two Chinese-style single-layer SCSs with different boundary conditions are conducted. The seismic damage and earthquake responses, including acceleration, displacement, and strain responses, are compared. The effect of the boundary condition on the seismic performance of the SCS is studied. It is found that the seismic performance of the SCS is significantly affected by the boundary condition. Compared with the SCS with the free condition at the boundary, the damage to the SCS installed with seismic clips at the boundary is much slighter. Compared with the SCS with the free condition, the median of acceleration amplification factor (AAF), the peak displacement (PD), and maximum strain of the SCS installed with seismic clips are reduced by up to 63%, 99%, and 84%, respectively. At the end of the tests, the SCS with the free condition at the boundary completely collapsed with 68% of the panels falling, while only 15% of panels fell in the SCS installed with seismic clips. The seismic clips could avoid the falling of the grids from the peripheral support and ensure the integrity of the SCS. With the help of seismic clips installed at the boundary, the responses of the ceiling, such as acceleration, displacement, and strain, decrease significantly, and thereof, the collapse resistance capacity is improved.
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Weibull, Wiktor Waldemar, i Børge Arntsen. "Reverse-time demigration using the extended-imaging condition". GEOPHYSICS 79, nr 3 (1.05.2014): WA97—WA105. http://dx.doi.org/10.1190/geo2013-0232.1.
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The forward and inverse process of seismic migration and demigration or remodeling has many useful applications in seismic data processing. We evaluated a method to reobtain the seismic reflection data after migration, by inverting the common image point gathers produced by reverse-time migration (RTM) with an extended-imaging condition. This provided a transformation of the results of seismic data processing in the image domain back to the data domain. To be able to reconstruct the data with high fidelity, we set up demigration as a least-squares inverse problem and we solved it iteratively using a steepest-descent method. Because we used an extended-imaging condition, the method is not dependent on an accurate estimate of the migration-velocity field, and it is able to accurately reconstruct both primaries and multiples. At the same time, because the method is based on RTM, it can accurately handle seismic reflection data acquired over complex geologic media. Numerical results showed the feasibility of the method and highlighted some of its applications on 2D synthetic and field data sets.
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Duan, Jin Xi, i Z. Shen. "Elastic Seismic Response of Steel-Concrete Composite Frames with Partial Interaction". Applied Mechanics and Materials 268-270 (grudzień 2012): 729–32. http://dx.doi.org/10.4028/www.scientific.net/amm.268-270.729.
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The finite element formulations of steel-concrete composite (SCC) beams considering interlayer slip with end shear restraint is established. Elastic seismic response of SCC frame structures under different shear connection stiffness and slip boundary conditions are examined. The influences of the shear connection stiffness and the slip boundary condition on elastic seismic response are analyzed. With the shear connection stiffness increasing, the free vibration frequencies increase and the seismic responses decrease. The natural vibration properties of SCC frame structures and seismic responses are also significantly affected by the slip boundary condition, and it should be properly imposed on all composite beams in seismic response analysis.
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Zheng, Wen Yi, Jing Zhe Jin, Hai Gong i Peng Pan. "Study on Evaluating the Seismic Performance of Building According to Detail Seismic Condition". Applied Mechanics and Materials 777 (lipiec 2015): 121–29. http://dx.doi.org/10.4028/www.scientific.net/amm.777.121.
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In the performance- based seismic design, seismic performance of building is differently evaluated according to variant seismic conditions. Most of the application programs for structural design (ETABS, SAP, MIDAS, ANSYS etc.) calculate the performance points of building according to Federal Emergency Management Agency（FEMA）, Applied Technology Council -40 (ATC -40)’s seismic building code and parameters. On this paper, we evaluated the seismic performance of building according to our national seismic building code[1] and parameters and maked suggesti- -ons on the design practice.
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Luo, Zhi Qun, Shao Lun Huang i Jian Ru Wan. "Development on Seismic Sensor System with MEMS Technology for Elevator’s Seismic Condition". Applied Mechanics and Materials 713-715 (styczeń 2015): 1009–14. http://dx.doi.org/10.4028/www.scientific.net/amm.713-715.1009.
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A large amount of elevators ruined in seismic events since sudden vibrations are bursting when elevator’s cars or counterweights are running. To solve this practical problem, this paper prospered a seismic sensor system with MEMS technology specializing for elevators. The fatal parts are discussed detailed including hardware design consideration, software improvement of sensor accuracy and seismic evaluation algorithm. Finally, two parts of experiments about P-wave and S-wave were verified successfully. To some extents, it’s reliable, suitable and affordable for domestic elevator’s safety on earthquake abrupt occurrence.
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Sava, Paul, i Sergey Fomel. "Time-shift imaging condition in seismic migration". GEOPHYSICS 71, nr 6 (listopad 2006): S209—S217. http://dx.doi.org/10.1190/1.2338824.
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Seismic imaging based on single-scattering approximation is in the analysis of the match between the source and receiver wavefields at every image location. Wavefields at depth are functions of space and time and are reconstructed from surface data either by integral methods (Kirchhoff migration) or by differential methods (reverse-time or wavefield extrapolation migration). Different methods can be used to analyze wavefield matching, of which crosscorrelation is a popular option. Implementation of a simple imaging condition requires time crosscorrelation of source and receiver wavefields, followed by extraction of the zero time lag. A generalized imaging condition operates by crosscorrelation in both space and time, followed by image extraction at zero time lag. Images at different spatial crosscorrelation lags are indicators of imaging accuracy and are also used for image-angle decomposition. In this paper, we introduce an alternative prestack imaging condition in which we preserve multiple lags of the time crosscorrelation. Prestack images are described as functions of time shifts as opposed to space shifts between source and receiver wavefields. This imaging condition is applicable to migration by Kirchhoff, wavefield extrapolation, or reverse-time techniques. The transformation allows construction of common-image gathers presented as functions of either time shift or reflection angle at every location in space. Inaccurate migration velocity is revealed by angle-domain common-image gathers with nonflat events. Computational experiments using a synthetic data set from a complex salt model demonstrate the main features of the method.
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Sava, Paul. "Stereographic imaging condition for wave-equation migration". GEOPHYSICS 72, nr 6 (listopad 2007): A87—A91. http://dx.doi.org/10.1190/1.2781582.
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Imaging under the single-scattering approximation consists of two steps: wavefield reconstruction of source and receiver wavefields from simulated and recorded data, respectively, and imaging from the extrapolated wavefields of locations where reflectors occur. Conventionally, the imaging condition indicates the presence of reflectors when propagation times of reflections in the source and receiver wavefields match. The main drawback of a conventional crosscorrelation imaging condition is that it ignores the local spatial coherence of reflection events and relies only on their propagation time. This leads to interference between unrelated events that occur at the same time. Sources of crosstalk include seismic events corresponding to different seismic experiments, propagation paths, types of reflections (primary or multiple), or wave modes (P or S). An alternative imaging condition operates on the same extrapolated wavefields, but crosscorrelation takes place in a higher-dimension domain where seismic events are separated based on their local space-time slope. Events are matched based on two parameters (time and local slope), thus justifying the name “stereographic” for this imaging condition. Stereographic imaging attenuates wavefield crosstalk and reduces imaging artifacts compared with conventional imaging. Applications of the stereographic imaging condition include simultaneous imaging of multiple seismic experiments, multiple attenuation in the imaging condition, and attenuation of crosstalk between multiple wavefield branches or multiple wave modes.
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Han, Jianguang, Qingtian Lü, Bingluo Gu i Jiayong Yan. "Q-Compensated Gaussian Beam Migration under the Condition of Irregular Surface". Remote Sensing 15, nr 15 (28.07.2023): 3761. http://dx.doi.org/10.3390/rs15153761.
Pełny tekst źródłaStreszczenie:
The viscosity of actual underground media can cause amplitude attenuation and phase distortion of seismic waves. When seismic images are processed assuming elastic media, the imaging accuracy for the deep reflective layer is often reduced. If this attenuation effect is compensated, the imaging quality of the seismic data can be significantly improved. Q-compensated Gaussian beam migration (Q-GBM) is an effective seismic imaging method for viscous media, and it has the advantages of both wave equation and ray-based Q-compensated imaging methods. This study develops a Q-GBM method in visco-acoustic media with an irregular surface. Initially, the basic principles of Gaussian beam in visco-acoustic media are introduced. Then, by correcting the complex-value time of the Gaussian beam in visco-acoustic media, energy compensation and phase correction are carried out for the forward continuation wavefield at the seismic source of the irregular surface and the reverse continuation wavefield at the beam center, which effectively compensates the absorption and attenuation effects of visco-acoustic media on the seismic wavefield. Further, a Q-GBM method under the irregular surface is proposed using cross-correlation imaging conditions. Through migration tests for three numerical models of visco-acoustic media with irregular surfaces, it is verified that our method is an effective depth domain imaging technique for seismic data in visco-acoustic media under the condition of irregular surfaces.
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Wen, Zeng-ping, Meng-tan Gao, Feng-xin Zhao, Xiao-jun Li, Hong-shan Lu i Shao-lin He. "Seismic vulnerability estimation of the building considering seismic environment and local site condition". Acta Seismologica Sinica 19, nr 3 (maj 2006): 292–98. http://dx.doi.org/10.1007/s11589-003-0292-2.
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Muravieva, Lyudmila V., i Igor G. Ovchinnikov. "Problems of simulating subsea pipeline condition on the arctic shelf under seismic impact". Vestnik MGSU, nr 11 (listopad 2019): 1456–65. http://dx.doi.org/10.22227/1997-0935.2019.11.1456-1465.
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Introduction. The paper represents an approach to studying a model of interaction of a system ‘pipeline – soil’ under conditions of frost penetration and seismic impact. The given problem is connected with the reclamation of the shelf of the Russian sector of the Arctic. There is a feature of induced earthquakes connected with hydrocarbon production. These earthquakes occur in a few years after the beginning of field development and lead to the worst condition of the pipelines. The research aims to the development of a method for subsea pipeline strength assessment allowing for nonlinear properties of an elastic foundation under the seismic impact.
Materials and methods. The research is based on mathematical models of structural strength assessment under seismic conditions in the Arctic. The results are empirically obtained from the safety assessment method for a subsea pipeline under the seismic impact. The work was performed by the procedure of the analysis of existing arctic offshore projects.
Results. The paper develops suggestions on the analysis of subsea pipelines on a nonlinear elastic foundation under conditions of a seismic impact. The suggestions were submitted for consideration to the Russian Maritime Register of Shipping. Buried below the seabed, the subsea pipelines provide an efficient and safe mode of transporting energy resources. Issues of relations of the subsea pipelines with surrounding and frozen ground are considered, pipeline thermal operation modes and seismic risks resulting in damages to the pipelines are taken into account.
Conclusions. Solving the problem of the subsea pipeline condition assessment under arctic conditions is of practical interest in developing energy resource transportation ways. Simulation of a subsea “hot” pipeline is considered allowing for the nonlinearity of elastic foundation properties and seismic impact.
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Rahardiawan, Riza, i Catur Purwanto. "STRUKTUR GEOLOGI LAUT FLORES, NUSA TENGGARA TIMUR". JURNAL GEOLOGI KELAUTAN 12, nr 3 (16.02.2016): 153. http://dx.doi.org/10.32693/jgk.12.3.2014.256.
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Tujuan penelitian seismik saluran banyak di Laut Flores, Nusa Tenggara Timur adalah untuk mengetahui kondisi geologi bawah permukaan dasar laut. Daerah penelitian merupakan daerah yang aktif secara tektonik dan diekspresikan dalam bentuk prisma akresi, vulkanik tidak aktif dan sesar-sesar aktif yang membentuk morfologi dasar laut. Berdasarkan penafsiran stratigrafi seismik lapisan bawah permukaan dasar laut terdiri dari empat satuan batuan: Batuan Dasar, Prisma Akresi, Gunungapi Bawah Laut, dan Sedimen Klastika. Sedimen Klastika ini dibagi menjadi lima unit.
Kata kunci: seismik, morfologi dasar laut, sesar aktif, Laut Flores
The purpose of the study of seismic multi channel in Flores Sea, East Nusa Tenggara is to recognize subsurface geology condition. The study area is an active tectonic that expressed by accretion prisms, inactive vulcanic and active faults form seabed morphology. Based on seismic stratigraphy interpretation, the study area is composed of four rocks units: Basement rocks, Accretionary Wedge, Seamount, and Clastic Sediments. This clactic sediment is divided into five units.
Keywords: seismic, seabed morphology, active fault, Flores Sea
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Lee, Sang Hun, Takao Endo i Ryutaro Kawana. "The Effect of Wave Propagation on Seismic Response at Transmitting Boundary of Discrete System". Applied Mechanics and Materials 878 (luty 2018): 110–14. http://dx.doi.org/10.4028/www.scientific.net/amm.878.110.
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When analyzing the seismic response of a very long elevated structure such as a Shinkansen viaduct, it is common practice to analyze a cutout of the structure under consideration and treat its both ends as free boundaries. This is attributable to the assumption that seismic response analysis assuming free boundary conditions is more conservative than one assuming non-free boundary conditions. In this study, after finding out that response to harmonic ground motion can be greater than under free-boundary conditions if outward energy dissipation occurs from the analysis domain, a series of numerical experiments was performed to determine whether such phenomena occur in seismic response. Then, after confirming that the frequency components of ground motion that satisfy the wave propagation condition greatly affect seismic response, the study showed that the area of the wave propagation condition region of the Fourier spectrum can be used as an indicator by which to judge the likelihood of occurrence of such phenomena.
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Ocak, E. Canan, i Alp Caner. "Condition factor for seismic performance of deteriorated bridges". Bridge Structures 15, nr 4 (31.12.2019): 187–96. http://dx.doi.org/10.3233/brs-190160.
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Yajima, T., i H. Nagahama. "Kawaguchi space, Zermelo's condition and seismic ray path". Nonlinear Analysis: Real World Applications 8, nr 1 (luty 2007): 130–35. http://dx.doi.org/10.1016/j.nonrwa.2005.06.004.
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Dong, Jie. "Time Dependent Rotational Displacement of Retaining Wall under Seismic Condition". Applied Mechanics and Materials 193-194 (sierpień 2012): 1056–60. http://dx.doi.org/10.4028/www.scientific.net/amm.193-194.1056.
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A simple pseudo-dynamic method to predict the seismic rotational displacement of retaining wall is developed. The proposed method, which soil-structure interaction is considered, is a combination of the free-field seismic response of soil and pseudo-dynamic method. It is supposed that soil and structure is connected by a series of springs, the dynamic earth pressure is determined by the deformation of springs. So both active and passive conditions can be taken into account by means of different movement direction of retaining wall, no need to know whether active or passive earth pressure happens before analysis. A significant difference between this analysis and published method is that in the present analysis the time dependent process of earth pressure and displacement is obtained by iterative calculation. Although present analysis is limit to elastic state, comparisons with Mononobe-Okabe method show satisfactory agreement in the value of resultant forces acting on retaining wall. Moreover, it is revealed by numerical examples that the height of the resultant force from the base of the wall is underestimated by the Mononobe- Okabe method, this may cause unsafe factors. Furthermore, the effect of wide range of parameters like time, height of retaining wall, wall friction, horizontal and vertical seismic coefficients are taken into account to evaluate the seismic response of retaining wall. Apart from its intrinsic theoretical interest, the proposed analysis can be used for the assessment of the safety of retaining wall under seismic condition.
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Lazarević, Luka, Dejan Vučković, Milica Vilotijević i Zdenka Popović. "Application of seismic tomography for assessment of the railway substructure condition". Structural Health Monitoring 18, nr 3 (29.05.2018): 792–805. http://dx.doi.org/10.1177/1475921718774778.
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This article presents results obtained in the research conducted on railway infrastructure in Serbia, which aimed at prediction of substructure condition based on the analysis of track quality. It presents the results of seismic tomography application as non-destructive procedure for assessment of railway substructure condition. Track geometry quality was assessed according to analysis of longitudinal level data, which was recorded during regular track geometry inspections. Track section for application of seismic tomography was chosen on the basis of analysed track geometry data recorded during the regular track geometry inspections in 2006, 2008, 2009, 2012, 2013 and 2014. Tomographic imaging of railway platform on Test Section enabled the creation of two-dimensional finite element model, which was used for determination of propagation speed of seismic P-waves. Seismic tomography on Test Section, which is the part of the international railway line Belgrade–Vrbnica, was performed in 2014. Obtained tomographic image was discussed and compared to track geometry data recorded during the regular track geometry inspections.
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Nayak, Chittaranjan B., i Sunil B. Thakare. "Seismic performance of existing water tank after condition ranking using non-destructive testing". International Journal of Advanced Structural Engineering 11, nr 4 (17.09.2019): 395–410. http://dx.doi.org/10.1007/s40091-019-00241-x.
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Abstract There has been a collaborative attempt to address the seismic vulnerability of existing structures in India after an earthquake in Bhuj, Gujarat, in 2001. Seismic diagnosis and seismic retrofit for the existing tanks have become a remarkable issue to be worked since deterioration is a cosmopolitan and natural phenomenon. It is important to know the exact reason for distress and type of distress. To manage such issues, a proper method of repair and rehabilitation with detailed plans and methodology is required. This paper is aimed at evolving systematic investigation metrology for condition ranking procedure based on the analytical hierarchy process (AHP) and strengthening by various retrofitting strategies. For that case study, an existing elevated water tank is considered, which was designed according to state of the art over 40 years ago as per old Indian Standard (IS) code. The ranking assessment of the elevated service reservoir was carried out using different non-destructive tests (NDTs). DER, i.e., degree (D), extent (E) and relevancy (R) rating technique was employed to find out the condition index of the elevated service reservoir (ESR). After finding the condition ranking of the existing structure, an analysis was carried out using SAP 2000 to find the present-day seismic requirements using IS codes. After knowing the seismic demand of the water tank, various retrofitting methods were adopted for improving the drift capacity and flexural capacity of the structure. The results were finally used to address some of the critical issues of the seismic response of the retrofitted structure in terms of a time period, mode shapes, base shear, displacement, acceleration, and velocity. From the case study result of seismic retrofit for the existing elevated water tank, it is confirmed that a relatively simple seismic retrofit method is effective to keep the tank functional after an earthquake.
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Fletcher, Robin P., i Johan O. Robertsson. "Time-varying boundary conditions in simulation of seismic wave propagation". GEOPHYSICS 76, nr 1 (styczeń 2011): A1—A6. http://dx.doi.org/10.1190/1.3511526.
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We propose two new boundary conditions to regulate coherent reflections from the model boundaries in numerical solutions of wave equations. Both boundary conditions have the common feature that the boundary condition is varied with respect to time. The first boundary condition expands or contracts the computational model during a modeling simulation. The effect is to cause a Doppler shift in the reflected wavefield that can be used to shift energy outside a frequency band of interest. In addition, when the computational domain is expanding, the range of possible incidence angles on the boundary is restricted. This can be used to increase the effectiveness of many existing absorbing boundary conditions that are more effective for incidence angles close to normal. The second boundary condition is an extension of random boundaries. By carefully changing the realization of a random boundary over time, a more diffusive wavefield can be simulated. We show results with 2D numerical simulations of the scalar wave equation for both these boundary conditions. The first boundary condition has application to modeling, but both these boundary conditions have potential application within algorithms that rely upon modeling kernels, such as reverse-time migration and full-waveform inversion.
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Pham, Van Vi, Ngoc Anh Do i Daniel Dias. "Sub-Rectangular Tunnel Behavior under Seismic Loading". Applied Sciences 11, nr 21 (23.10.2021): 9909. http://dx.doi.org/10.3390/app11219909.
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Circular and rectangular tunnel shapes are usually chosen when excavating at shallow depths in urban areas. However, special-shaped tunnels such as sub-rectangular tunnels have recently been used to overcome some drawbacks of circular and rectangular tunnels in terms of low space utilization efficiency and stress concentration, respectively. In the literature, experimental studies as well as analytical and numerical models have been developed for the seismic analysis and vulnerability assessment of circular and rectangular tunnels since the early 1990s. However, knowledge gaps regarding the behavior of sub-rectangular tunnels under seismic loading remain and still need to be bridged. The present paper focuses on introducing a numerical analysis of sub-rectangular tunnels under seismic loading. The numerical model of sub-rectangular tunnels is developed based on the numerical analyses of circular tunnels validated by comparing well-known, analytical solutions. This paper aims to highlight the differences between the behavior of sub-rectangular tunnels compared with circular tunnels when subjected to seismic loadings. Special attention is paid to the soil–lining interface conditions. The influence of parameters, such as soil deformations, maximum horizontal acceleration, and lining thickness, on sub-rectangular tunnel behavior under seismic loading is also investigated. The results indicate a significant behavior difference between sub-rectangular and circular tunnels. The absolute extreme incremental bending moments for a circular tunnel (no-slip condition) are smaller than that for the corresponding full-slip condition. The absolute extreme incremental bending moments of sub-rectangular tunnels (no-slip condition) are, however, greater than the corresponding full-slip conditions.
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Zhao, Zhencong, Jingyi Chen, Xiaobo Liu i Baorui Chen. "Frequency-domain elastic wavefield simulation with hybrid absorbing boundary conditions". Journal of Geophysics and Engineering 16, nr 4 (1.08.2019): 690–706. http://dx.doi.org/10.1093/jge/gxz038.
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Abstract The frequency-domain seismic modeling has advantages over the time-domain modeling, including the efficient implementation of multiple sources and straightforward extension for adding attenuation factors. One of the most persistent challenges in the frequency domain as well as in the time domain is how to effectively suppress the unwanted seismic reflections from the truncated boundaries of the model. Here, we propose a 2D frequency-domain finite-difference wavefield simulation in elastic media with hybrid absorbing boundary conditions, which combine the perfectly matched layer (PML) boundary condition with the Clayton absorbing boundary conditions (first and second orders). The PML boundary condition is implemented in the damping zones of the model, while the Clayton absorbing boundary conditions are applied to the outer boundaries of the damping zones. To improve the absorbing performance of the hybrid absorbing boundary conditions in the frequency domain, we apply the complex coordinate stretching method to the spatial partial derivatives in the Clayton absorbing boundary conditions. To testify the validity of our proposed algorithm, we compare the calculated seismograms with an analytical solution. Numerical tests show the hybrid absorbing boundary condition (PML plus the stretched second-order Clayton absorbing condition) has the best absorbing performance over the other absorbing boundary conditions. In the model tests, we also successfully apply the complex coordinate stretching method to the free surface boundary condition when simulating seismic wave propagation in elastic media with a free surface.
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Chen, Baokui, Yujie Du, Yan Shi i Li Fan. "Seismic Analysis of Isolated Continuous Bridge considering Influence of Seawater and Site Condition". Shock and Vibration 2021 (23.08.2021): 1–17. http://dx.doi.org/10.1155/2021/7599715.
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The effects of seawater and site conditions on the seismic response of the isolated continuous girder bridge are evaluated in this study. The seawater-muddy soil-isolated bridge coupling model is built in the dynamic analysis software ADINA, and the external seismic wave input is realized by the seismic wave motion analysis program. The influences of seawater and muddy soil on the seismic response of isolated continuous girder bridges are determined by comparing different offshore site models. The results indicated that the seawater and the muddy soil magnify the displacement of the seabed. The existence of seawater increases the longitudinal relative displacement of piers by 20%–40% but has limited influence on the bending moment and shear force of piers. The muddy soil can increase the longitudinal relative displacement and internal force of the piers remarkably. Moreover, the displacement of bridge bearings increases significantly under the combined influence of muddy soil and seawater. In the seawater-muddy soil-isolated bridge coupling model, the seawater and site condition can influence the seismic performance of sea-crossing bridges obviously.
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Karalar, Memduh, i Murat Çavuşli. "Evaluation of 3D Nonlinear Earthquake Behaviour of the Ilısu CFR Dam under Far-Fault Ground Motions". Advances in Civil Engineering 2019 (8.01.2019): 1–15. http://dx.doi.org/10.1155/2019/7358710.
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In the recent times, many huge concrete face rockfill dams (CFRDs) have been modelled and constructed in the world, and many of these dams are located on the strong earthquake zones. Examination of the seismic behaviour of a CFR dam built on the seismic zone is very important to assess the safety and future of the dam. For this reason, the nonlinear earthquake behaviour of these dams should be constantly observed taking into account the seismicity of the zone. In this study, three-dimensional (3D) seismic behaviour of the Ilısu dam built on the East Anatolian Fault (EAF) line is examined considering the effect of the important various far-fault earthquakes. The 3D finite difference model of the Ilısu dam is created using the FLAC3D software based on the finite difference method. The dam body, foundation, and concrete slab constantly interact during the lifetime of the CFRDs. Therefore, the special interface elements are defined between the dam body, concrete slab, and foundation to represent the interaction condition. The Mohr–Coulomb nonlinear material model is used for the rockfill materials and foundation. Moreover, the concrete slab is modelled considering the Drucker–Prager nonlinear material model to represent the nonlinearity of the concrete. Very special seismic boundary conditions rarely used for CFR dams in the past are used in this work. These boundary conditions are free-field and quiet boundary conditions. The free-field boundary condition that is a very important boundary condition for the nonlinear seismic analyses is considered for the lateral boundaries of the 3D model. In addition, the quiet artificial boundary condition is used for the bottom of the foundation. While defining these boundary conditions, the special fish functions are created and defined to the software. Moreover, the hysteric damping coefficients are separately calculated for all of the materials. These special damping values are defined to the FLAC3D software using the special fish functions to capture the effects of the variation of the modulus and damping ratio with the dynamic shear-strain magnitude. In the numerical analyses, a total of 7 various strong far-fault earthquakes are used for the 3D nonlinear earthquake analyses, and 7 different numerical analyses are performed for the full-reservoir condition of the Ilısu CFR dam. According to the seismic results, the principal stresses for the three critical nodal points on the dam body surface are examined and evaluated in detail. It is clearly understood that the nonlinear seismic behaviour of the Ilısu dam changes depending on the magnitudes and periods of the far-fault earthquakes. Each far-fault earthquake has different seismic effects on the nonlinear principal stress behaviour of the Ilısu CFR dam.
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Kurniawandy, Alex, i Shoji Nakazawa. "Seismic performance evaluation of existing building using Seismic Index method". MATEC Web of Conferences 276 (2019): 01015. http://dx.doi.org/10.1051/matecconf/201927601015.
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Indonesia has frequently suffered major damaging earthquakes over the past 50 years. There are thousands of buildings in earthquakeprone regions that require seismic evaluation and rehabilitation. This paper describes a study about the seismic evaluation of existing buildings using seismic index method based on a Japanese standard. The basic seismic index is calculated based on the criteria of strength and ductility. Two existing buildings have been evaluated in this research. The first building consists of five stories and the second one has four. The seismic index of the structure has a different value for each story. The minimum seismic index occurs on the ground floor, and the index increases as the number of stories increase. The top floor has the maximum seismic index of all stories. The structure’s seismic safety shall be judged if the seismic index (Is) is greater than the seismic demand index (Iso). As a result of the evaluation, buildings A, and B are in an unsatisfactory condition. Especially for the three lower floors of both of buildings. It is also confirmed by drift angle that they exceed the required limit. To sum up, evaluation by using Japanese standards can be applied to building conditions in Indonesia.
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ÇAVUŞLU, Murat. "Assessing Seismic Crack Performance of Diyarbakır Çüngüş Masonry Stone Bridge Considering 2023 Kahramanmaraş, Hatay, Malatya, Gaziantep Earthquakes". Bitlis Eren Üniversitesi Fen Bilimleri Dergisi 12, nr 2 (25.05.2023): 544–56. http://dx.doi.org/10.17798/bitlisfen.1263557.
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Examination of the creep behavior of historical buildings and interpretation of seismic failures in historical buildings are of great importance for the safety and future of these important structures. In this study, time-dependent settlement and three-dimensional (3D) seismic analyzes of a historical stone bridge are investigated using the 3D discrete element modeling technique. For the settlement and seismic analyses, the historical single-span Çüngüş bridge which was built in the 18th century in Diyarbakır-Turkey by Ottoman Empire is used. Since Diyarbakır is in a dangerous zone according to the Turkey seismic map, the examination of this structure is very critical for the history of Turkey. The 3D model of the bridge is created using the FLAC3D program based on the finite difference method and all the stone elements in the historical bridge are modeled separately as blocks. Special interaction elements are defined between the discretely modeled stones. For settlement creep analyses, the Burger-creep material model, which was not used for the creep behavior of historical buildings in the past, is utilized. Firstly, the 500-year long-term creep behavior of the bridge is examined by considering the fix boundary condition and full reservoir condition. According to the creep analyses, it is seen that the most deformation and failure section of the bridge is the arch section. Then, for the seismic analyses of the bridge, free-field and quiet non-reflecting boundary conditions are defined in the model. Furthermore, hysteresis damping coefficients are taken into account in seismic analyzes with the help of special fish functions. 10 various earthquakes are considered for seismic analyses. According to the earthquake analyses, the earthquake behavior of the Çüngüş historical bridge is assessed by considering the full reservoir condition and it is understood that 2023 Kahramanmaraş, Hatay, Malatya, Gaziantep earthquakes significantly changed the seismic safety behavior of Çüngüş single-span historical bridge.
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Li, Yong Bo, Hong Ru Zhang i Chun Feng Li. "Longitudinal Seismic Response Analysis of MSSS Bridge in Qinghai-Tibet Railway". Advanced Materials Research 250-253 (maj 2011): 2667–71. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.2667.
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This paper presents the results of seismic behavior analysis of a multi-span simply supported (MSSS) bridge in Qinghai-Tibet Railway. The main goal is to examine the effects of frozen soil condition and wave passage on seismic behavior of MSSS Bridge. A 2D FE model was established by ANSYS software in order to evaluate the effects of modeling, in which bearings and pounding effects were also considered. Results indicate that frozen soil condition has an important effect on the seismic response in longitudinal direction; wave passage can influence the seismic response of MSSS Bridge within a certain range of seismic wave travelling velocity.
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Kuznetsov, Sergey V., i Aybek E. Nafasov. "Horizontal Acoustic Barriers for Protection from Seismic Waves". Advances in Acoustics and Vibration 2011 (21.09.2011): 1–8. http://dx.doi.org/10.1155/2011/150310.
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The basic idea of a seismic barrier is to protect an area occupied by a building or a group of buildings from seismic waves. Depending on nature of seismic waves that are most probable in a specific region, different kinds of seismic barriers can be suggested. Herein, we consider a kind of a seismic barrier that represents a relatively thin surface layer that prevents surface seismic waves from propagating. The ideas for these barriers are based on one Chadwick's result concerning nonpropagation condition for Rayleigh waves in a clamped half-space, and Love's theorem that describes condition of nonexistence for Love waves. The numerical simulations reveal that to be effective the length of the horizontal barriers should be comparable to the typical wavelength.
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Ji, Hua. "Finite Element Analysis of Wire Mesh Frame Wallboard under Seismic Action". Applied Mechanics and Materials 256-259 (grudzień 2012): 2019–23. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.2019.
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According to the force condition of wire mesh frame wallboard under seismic action, finite element program is used to conduct the deformation simulation analysis of 12 test pieces under different working conditions, obtaining the influencing factors that affect the deformation of wire mesh frame wallboard under vertical seismic action, which offers theoretical foundation for the design of wire mesh frame wallboard.
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Hirosawa, Masaya. "Present Condition of Seismic Retrofit of Buildings in Japan". Concrete Journal 35, nr 10 (1997): 3–8. http://dx.doi.org/10.3151/coj1975.35.10_3.
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Namdar, Abdoullah. "The boundary condition simulation quality for embankment seismic response". Engineering Failure Analysis 126 (sierpień 2021): 105491. http://dx.doi.org/10.1016/j.engfailanal.2021.105491.
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FUKUSHIMA, Sei'ichiro, i Harumi YASHIRO. "AN ANALYSIS FOR CONDITION SETTING IN SECURITIZING SEISMIC RISK". Journal of Architecture and Planning (Transactions of AIJ) 67, nr 555 (2002): 295–302. http://dx.doi.org/10.3130/aija.67.295_2.
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KONO, Kimiaki, Satoshi FUJITA i Asami ISHII. "Influence of Setting Condition of Escalator on Seismic Response". Proceedings of the Transportation and Logistics Conference 2017.26 (2017): 3023. http://dx.doi.org/10.1299/jsmetld.2017.26.3023.
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Chowdhury, Subha Sankar, Kousik Deb i Aniruddha Sengupta. "Behavior of underground strutted retaining structure under seismic condition". Earthquakes and Structures 8, nr 5 (25.05.2015): 1147–70. http://dx.doi.org/10.12989/eas.2015.8.5.1147.
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Yang, Xiao Min. "Design on Engineering Database of Bridge Seismic CAD System". Advanced Materials Research 998-999 (lipiec 2014): 962–65. http://dx.doi.org/10.4028/www.scientific.net/amr.998-999.962.
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Engineering database was the core of Bridge Seismic CAD System. It was a new engineering database for bridge seismic design based on relation database and data characteristic of bridge seismic design. The engineering databasewas suitable for storage and managing data of bridge seismic design, it was also created condition for data storage andmanagement of Bridge Seismic CAD System.
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Cao, Weiping, i Gerard T. Schuster. "Antialiasing condition and filter for the reciprocity equation of correlation type". GEOPHYSICS 75, nr 6 (listopad 2010): WB219—WB224. http://dx.doi.org/10.1190/1.3495542.
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An antialiasing formula has been derived for interferometric redatuming of seismic data. More generally, this formula is valid for numerical implementation of the reciprocity equation of correlation type, which is used for redatuming, extrapolation, interpolation, and migration. The antialiasing condition can be, surprisingly, more tolerant of a coarser trace sampling compared to the standard antialiasing condition. Numerical results with synthetic vertical seismic profile (VSP) data show that interferometry artifacts are effectively reduced when the antialiasing condition is used as a constraint with interferometric redatuming.
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Han, Fang, Dong Wang Zhong i Ji Yun Mo. "Discriminant Condition of Influencing Dynamic Response for Structure-Equipment System". Applied Mechanics and Materials 90-93 (wrzesień 2011): 1477–81. http://dx.doi.org/10.4028/www.scientific.net/amm.90-93.1477.
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In structure-equipment system, there are complex dynamic interactions between structures and equipments. A fast discriminant condition whether the interaction will increase or decrease dynamic response of the structure is achieved in this paper. When the load frequency lies between the basic frequencies of the combined system, it decreases the absolute response of the structure and vice versa. In engineering project, the seismic load can be expanded based on ground characteristic frequency by Fourier transform, so our conclusion can be extended to seismic design for combined systems. Finite element method simulation for a chemical workshop further verifies the discriminant condition.
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Jain, Payal. "Comparative Study of Soil Structure Interaction Analysis of Building on Clayey and Sandy Soil". International Journal for Research in Applied Science and Engineering Technology 9, nr 9 (30.09.2021): 57–65. http://dx.doi.org/10.22214/ijraset.2021.37919.
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Abstract: Present days the analysis of structure with seismic design is more popular. because the first priority of the engineer is effective and durable structure. There are two type of base system first is rigid and second is flexible. In case of flexible base structure, only seismic analysis is not give very effective results. In this condition the SSI effect is more significant and give effective results for flexible base system. The term Soil Structure Interaction (SSI) means interaction between soil to the substructure. This effect give more accurate results after consider in the seismic analysis. If a structure is design according to the seismic analysis with SSI effect than structure could get more durability and safety against earthquake as compare to seismic analysis without SSI effect condition. So the SSI effect can change response of the seismic very significantly. The present study aim is based on seismic analysis of building with Soil Structure Interaction effect on two different soil. A frame rectangular building of G+6 storey has analyzed for flexible base simulating sand and clay soil conditions The software is used SAP2000. Raft foundation has been modeled also. Analysis is made with the response spectrum of IS 1893 2016 code. Seismic response of SSI analysis results are compare in terms of lateral storey displacement, base shear and modal behavior of natural time period on different type of soil ( clay and sand). and conclude that the lateral storey displacement, base shear and natural time period values in SSI analysis with sand soil is maximum as compare to clay soil.
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Astawa, Nyoman, i Wayan Lugra. "GEOLOGI BAWAH PERMUKAAN DASAR LAUT BERDASARKAN PENAFSIRAN REKAMAN SEISMIK PANTUL DANGKAL SALURAN TUNGGAL DI PERAIRAN SELAT SUNDA". JURNAL GEOLOGI KELAUTAN 12, nr 2 (16.02.2016): 103. http://dx.doi.org/10.32693/jgk.12.2.2014.250.
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Penelitian ini bertujuan untuk mengetahui kondisi geologi bawah permukaan dasar laut dengan metode seismik pantul dangkal saluran tunggal, dan pemeruman. Seismik stratigrafi daerah penelitian dapat dibedakan menjadi 3 (tiga) unit, yaitu Unit 1 diinterpretasikan sebagai batuan intrusi, Unit 2 yang dekat dengan Pulau Jawa sebagai batuan volkanik dan yang dekat dengan Pulau Sumatera diduga sebagai Formasi Lampung, dan batuan lava andesit, serta Unit 3 diinterpretasikan sebagai sedimen Kuarter. Kedalaman permukaan dasar yang dapat direkam berkisar antara -5 hingga -125 meter dengan perubahan yang terjadi secara bergradasi dari arah pantai ke laut.
Kata kunci : Morfologi permukaan dasar laut, seismik stratigrafi, geologi bawah permukaan, Selat Sunda
The aims of study is to determine the subsurface geology condition of Sunda Strait by using single channel shallow seismic reflection, and the sounding method. Seismic stratigraphy of the study area can be divided into three (3) units, those are Unit 1, interpreted as intrusive rocks, Unit 2, which is close to Java be expected at volcanic rocks and the adjacent of Sumatera island interpreted Lampung Formation and andesitic lava rock, while Unit 3 as suspected Quaternary sediments. The sea floor depth that can be recorded ranging from -5 to -125 metres with the changes depth gradually from the shore to the sea.
Keywords : Seafloor morphology, seismic stratigraphy, subsurface geology, Sunda Strait
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Hong, Tae-Kyung, Jeongin Lee, Giha Lee, Junhyung Lee i Seongjun Park. "Correlation between Ambient Seismic Noises and Economic Growth". Seismological Research Letters 91, nr 4 (3.06.2020): 2343–54. http://dx.doi.org/10.1785/0220190369.
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Abstract Human activity is a major source of high-frequency seismic noise. Long-term ambient seismic noise levels and their influencing factors are investigated. The diurnal seismic noise level in 5–15 Hz display high correlation with human activities including traffic and industrial operations that are related to economic conditions. The temporal noise-level variations are consistent among three components. Analysis with seismic noises in three consecutive months of each year enables us to estimate the noise levels without seasonal effects. The daytime seismic noise-level changes in major cities of 11 countries are assessed using the 3 month records for decades. The annual seismic noise levels present strong correlations with gross domestic product (GDP), particularly with manufacturing and industrial GDP. The seismic noise levels increase quickly with GDP in low-GDP regions but slowly in high-GDP regions. This is because high-GDP regions already have large volumes of existing noise-inducing sources and because added sources contribute weakly. The seismic noise levels increased by 14%–111% for 5–23 yr depending on the economic conditions. The correlation between ambient seismic noise level and economy growth is a global feature. The high-frequency noise level may be a proxy to present the economic condition. Economic growth affects the Earth environment in a wide range of aspects.
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KOSUGI, Shinji, Hirokuni ISHIGAKI i Takayoshi KAMATA. "Evaluation of Seismic Condition of Equipment Based on Soil-Structure Interaction Analysis Considering Seismic Motion Incoherency". Proceedings of the Dynamics & Design Conference 2019 (2019): 233. http://dx.doi.org/10.1299/jsmedmc.2019.233.
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Konuk, Tugrul, i Jeffrey Shragge. "Modeling full-wavefield time-varying sea-surface effects on seismic data: A mimetic finite-difference approach". GEOPHYSICS 85, nr 2 (9.01.2020): T45—T55. http://dx.doi.org/10.1190/geo2019-0181.1.
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Seismic-data processing flows often ignore spatial and temporal variations in the sea surface during marine seismic acquisition by assuming a flat free surface. However, weather patterns during data acquisition can generate rough sea conditions, which can significantly influence seismic full-wavefield source behavior, including ghost reflections and surface-related multiples, by introducing spatial and temporal distortions of the seismic wavelet. To investigate the effects of rough seas on seismic wave propagation, we have developed and solved a new acoustic wave equation using a mimetic finite-difference time-domain (MFDTD) scheme that uses a dynamic (i.e., moving) generalized coordinate system defined to be conformal to the assumed known time-varying free surface. This “sea-surface” coordinate system allows us to model the full dynamic effects associated with this complex boundary condition. Numerical examples demonstrate that the developed MFDTD method can accurately simulate seismic wavefield propagation on a moving mesh for significant wave heights of 5 m and beyond, and it is thus a reliable tool for applications involving modeling, processing, imaging, and inversion of seismic data acquired in rough seas.
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Nishanth, R., D. Kishok Rai, Hemkar Sharma, Rivington Kingston, Davidson Jebaseelan i Christo Michael. "Numerical Analysis of Fire Water Storage Tank under Seismic Loading". IOP Conference Series: Earth and Environmental Science 850, nr 1 (1.11.2021): 012019. http://dx.doi.org/10.1088/1755-1315/850/1/012019.
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Abstract Maintenance and continuously monitoring the condition of above ground storage tanks are significant when the tanks are placed in service. The American Petroleum Institution (API) 653 and other international codes provides the minimum requirements for inspection & maintaining the integrity of tanks during its service. The tank settlement is one of the major threats for tank’s integrity. In this paper, a storage tank is assessed for uniform settlement under various loading condition such as seismic, dead load, static load, corrosion loss of shell plate etc. In the present study, a finite element model is designed with uniform settlement condition and study of its governing hoop stress at shell plate has been carried out under different loading conditions. A fire water storage tank (constructed with IS 2060 GR. B material) and different seismic zones in India are taken for this study. The finite element analysis simulation shows that increase of hoop stress in the bottom shell course due to uniform settlement, the decrease in plate thickness and with different seismic active regions. Moreover, the maximum stresses have been observed at shell bottom course (close to bottom plate).
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Yu, Jianhua, Lewis J. Katz, Fred Followill, Hongchuan Sun i Gerard T. Schuster. "Autocorrelogram Migration: IVSPWD test". GEOPHYSICS 68, nr 1 (styczeń 2003): 297–307. http://dx.doi.org/10.1190/1.1543215.
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We present the results of applying autocorrelogram migration to inverse vertical seismic‐while‐drilling (IVSPWD) profile data collected in the Austin Chalk formation. The seismic reflections were excited by a drill bit moving along a horizontal well at a depth of 2800 m. The data were recorded by a receiver array on the surface. There were 609 twenty‐second traces recorded at each of 10 three‐component stations. After preprocessing, the traces were autocorrelated and migrated. Two imaging conditions were examined. The ghost‐reflection imaging condition produced a reflectivity section that agreed with a nearby common‐depth‐point section. The migration section obtained with a primary‐reflection imaging condition produced a reflectivity section inferior in quality to that of the ghost image. A possible explanation is that the drill‐bit location was not precisely known, which can be shown to induce weak errors in the ghost‐imaging condition but stronger errors in the primary‐reflection imaging condition. Ghost migration images reflections not only below the drill bit, but also above the drill bit. This investigation is one of the first examples of successfully imaging the earth's reflectivity section from horizontal drill‐bit data, and it offers a potentially useful method for seismic imaging from drill‐bit data.
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Gileva, N. A., i M. A. Khritova. "Condition and prospects of detailed processing of earthquakes of the Baikal region and Transbaikalia". Russian Journal of Seismology 5, nr 2 (26.06.2023): 77–99. http://dx.doi.org/10.35540/2686-7907.2023.2.06.
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Throughout the history of the Baikal seismic network (since 1901), great efforts have been made to preserve the most detailed information about recorded seismic events. The article considers a method for detailed summary processing of earthquakes in the Baikal and Transbaikalia regions used in the BB GS RAS. The level and quality of regional processing are shown on the example of 2019. 7273 earthquakes were registered during the year, most of them are (62%) weak earthquakes (KР=6), for which the error of determining the coordinates of the epicenters was on average less than 5 km. Localization accuracy of epicenters for earthquakes with a KР≥9 is less than 2 km. The results of some studies using data from the Kultuk and Muyakan local temporary networks are presented. A comparison of the results and volumes of earthquake processing with other branches of the GS RAS is shown. Thus, the number of earthquakes in the region of the Baikal and Transbaikalia (N=63081) exceeds any of the other seismically active regions of Russia by at least 2.4 times for the period 2014–2017 (Altai and Sayan – N=26458; Kamchatka and Commander Islands – N=26301). According to the number of seismic stations which are used in the processing of one earthquake (K≥9) and the number of phases of seismic waves, regions of the Baikal, Transbaikalia and of the North Caucasus are leading and close to each other. There are 29 and 33 stations respectively, 87 and 68 phases. In other words, the volume of earthquake processing in the Baikal branch is much larger than in any of the branches of the GS RAS. It was concluded that currently the processing of earthquakes in the BB GS RAS is carried out in an optimal way in view to the size of the region, the number of seismic stations, the quality of communication and the number of recorded earthquakes. Reforming the system of processing seismic events in the BB GS RAS is expedient after a significant increase in the observation points in the region.
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Wu, Zhi Jian, Lan Min Wang, Ping Wang, Hang Shi i Tuo Chen. "The Effect of Site Condition on Ground Motion in Gansu Province during the Wenchun Ms8.0 Earthquake". Advanced Materials Research 594-597 (listopad 2012): 1658–67. http://dx.doi.org/10.4028/www.scientific.net/amr.594-597.1658.
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Based on mobile strong motion array observation, borehole exploration and site seismic response analysis, the site effects of mountainous topography in southeastern Gansu and the topography of loess tableland on ground motion were investigated in details. The analysis on acceleration records of aftershocks showed that the peak ground acceleration at top of the mountain is nearly 2 times of that at the foot of it. The seismic response analysis of sites shows that the loess tableland may amplify PGA by 1.44-2.0 times. Therefore, site effects of mountains and loess topography on ground motion should been taken account into seismic design.
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Piccolo, Assunta Paola, Giovanna Longobardi i Antonio Formisano. "Seismic Vulnerability and Consolidation by FRP/FRCM Systems of a Masonry School Building in the District of Naples". Buildings 12, nr 11 (21.11.2022): 2040. http://dx.doi.org/10.3390/buildings12112040.
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The paper discusses the seismic vulnerability of structures susceptible to overcrowding due to their intended use. Specifically, it addresses the analysis towards earthquake actions of a masonry school located in the Municipality of San Giorgio a Cremano, within the neighbourhood of Naples, providing different reinforcement interventions to ensure its seismic consolidation. After a brief introduction, the description of the analysis representative of the current condition of the structure is performed considering both static and seismic actions. The analysis results determine the seismic risk class of the building, allowing to identify its deficiencies, so to design structural consolidation interventions following the standard code indications. In particular, two retrofit techniques, namely, FRP and FRCM systems, are proposed with the purpose to evaluate their benefits to the school building from a seismic viewpoint. Finally, a comparison between the proposed intervention techniques is made to establish which one guarantees the best upgrading of the seismic condition of the examined building.
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Izadian, Saeed, Kamal Aghazade, Navid Amini i Yanghua Wang. "Semi-exact local absorbing boundary condition for seismic wave simulation". Journal of Geophysics and Engineering 18, nr 1 (1.02.2021): 62–73. http://dx.doi.org/10.1093/jge/gxaa068.
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Abstract An absorbing boundary condition is necessary in seismic wave simulation for eliminating the unwanted artificial reflections from model boundaries. Existing boundary condition methods often have a trade-off between numerical accuracy and computational efficiency. We proposed a local absorbing boundary condition for frequency-domain finite-difference modelling. The proposed method benefits from exact local plane-wave solution of the acoustic wave equation along predefined directions that effectively reduces the dispersion in other directions. This method has three features: simplicity, accuracy and efficiency. Numerical simulation demonstrated that the proposed method has higher efficiency than the conventional methods such as the second-order absorbing boundary condition and the perfectly matched layer (PML) method. Meanwhile, the proposed method shared the same low-cost feature as the first-order absorbing boundary condition method.
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Urlainis, Alon, i Igal M. Shohet. "A Comprehensive Approach to Earthquake-Resilient Infrastructure: Integrating Maintenance with Seismic Fragility Curves". Buildings 13, nr 9 (6.09.2023): 2265. http://dx.doi.org/10.3390/buildings13092265.
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A severe seismic event can cause significant damage to infrastructure systems, resulting in severe direct and indirect consequences. A comprehensive risk-management approach is required for earthquake-resilient infrastructure. This study presents an innovative approach to seismic risk assessment and aims to integrate maintenance considerations with seismic fragility curves. The proposed methodology uniquely quantifies the impact of maintenance conditions on seismic risk, presenting a dynamic perspective of risk changes attributable to maintenance and deterioration. The methodology hinges on the hypothesis that the maintenance condition of the infrastructure and the level of deterioration impacts the seismic resilience of the infrastructure. The methodology synergizes the Building Performance Index (BPI) and the deterioration over time to evaluate their cumulative effect on fragility curves to estimate the infrastructure’s total risk over the lifecycle (TRLC). This proposed methodology is demonstrated through a case study of a low-voltage substation in Bik’at HaYarden, Israel. A Monte Carlo simulation was carried out for the specific conditions of the analyzed substation. A comprehensive sensitivity analysis was performed to understand better the effect of maintenance conditions over time on the TRLC. Key insights reveal a statistically significant correlation between infrastructure performance and maintenance and their consequential impact on the TRLC. Notably, declining maintenance conditions intensify seismic risk uncertainties. The research proposes to researchers, stakeholders, and decision-makers a novel comprehensive perspective on the indispensability of maintenance for seismic risk management and mitigation.