Download or read book Quantification of Ground Motions by Broadband Simulations written by Katrin Kieling and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: In many procedures of seismic risk mitigation, ground motion simulations are needed to test systems or improve their effectiveness. For example they may be used to estimate the level of ground shaking caused by future earthquakes. Good physical models for ground motion simulation are also thought to be important for hazard assessment, as they could close gaps in the existing datasets. Since the observed ground motion in nature shows a certain variability, part of which cannot be explained by macroscopic parameters such as magnitude or position of an earthquake, it would be desirable that a good physical model is not only able to produce one single seismogram, but also to reveal this natural variability. In this thesis, I develop a method to model realistic ground motions in a way that is computationally simple to handle, permitting multiple scenario simulations. I focus on two aspects of ground motion modelling. First, I use deterministic wave propagation for the whole frequency range - from static deformation to approximately 10 Hz - but account for source variability by implementing self-similar slip distributions and rough fault interfaces. Second, I scale the source spectrum so that the modelled waveforms represent the correct radiated seismic energy. With this scaling I verify whether the energy magnitude is suitable as an explanatory variable, which characterises the amount of energy radiated at high frequencies - the advantage of the energy magnitude being that it can be deduced from observations, even in real-time. Applications of the developed method for the 2008 Wenchuan (China) earthquake, the 2003 Tokachi-Oki (Japan) earthquake and the 1994 Northridge (California, USA) earthquake show that the fine source discretisations combined with the small scale source variability ensure that high frequencies are satisfactorily introduced, justifying the deterministic wave propagation approach even at high frequencies. I demonstrate that the energy magnitude can be used to calibrate the high-frequency content in ground motion simulations. Because deterministic wave propagation is applied to the whole frequency range, the simulation method permits the quantification of the variability in ground motion due to parametric uncertainties in the source description. A large number of scenario simulations for an M=6 earthquake show that the roughness of the source as well as the distribution of fault dislocations have a minor effect on the simulated variability by diminishing directivity effects, while hypocenter location and rupture velocity more strongly influence the variability. The uncertainty in energy magnitude, however, leads to the largest differences of ground motion amplitude between different events, resulting in a variability which is larger than the one observed. For the presented approach, this dissertation shows (i) the verification of the computational correctness of the code, (ii) the ability to reproduce observed ground motions and (iii) the validation of the simulated ground motion variability. Those three steps are essential to evaluate the suitability of the method for means of seismic risk mitigation.

Download or read book Ground Motion and Variability from 3 D Deterministic Broadband Simulations written by Kyle Withers and published by . This book was released on 2016 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt: The accuracy of earthquake source descriptions is a major limitation in high-frequency ($>1$ Hz) deterministic ground motion prediction, which is critical for performance-based design by building engineers. With the recent addition of realistic fault topography in 3D simulations of earthquake source models, ground motion can be deterministically calculated more realistically up to higher frequencies. We first introduce a technique to model frequency-dependent attenuation and compare its impact on strong ground motions recorded for the 2008 Chino Hills earthquake. Then, we model dynamic rupture propagation for both a generic strike-slip event and blind thrust scenario earthquakes matching the fault geometry of the 1994 Mw 6.7 Northridge earthquake along rough faults up to 8 Hz. We incorporate frequency-dependent attenuation via a power law above a reference frequency in the form $Q_0f^n$ ,with high accuracy down to Q values of 15, and include nonlinear effects via Drucker-Prager plasticity. We model the region surrounding the fault with and without small-scale medium complexity in both a 1D layered model characteristic of southern California rock and a 3D medium extracted from the SCEC CVMSi.426 including a near-surface geotechnical layer. We find that the spectral acceleration from our models are within 1-2 interevent standard deviations from recent ground motion prediction equations (GMPEs) and compare well with that of recordings from strong ground motion stations at both short and long periods. At periods shorter than 1 second, Q(f) is needed to match the decay of spectral acceleration seen in the GMPEs as a function of distance from the fault. We find that the similarity between the intraevent variability of our simulations and observations increases when small-scale heterogeneity and plasticity are included, extremely important as uncertainty in ground motion estimates dominates the overall uncertainty in seismic risk. In addition to GMPEs, we compare with simple proxy metrics to evaluate the performance of our deterministic models and to determine the importance of different complexities within our model. We find that 3D heterogeneity, at both the long and short scale-lengths, is necessary to agree with data, and should be included in future simulations to best model the ground motion from earthquakes.

Download or read book Best Practices in Physics based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installations written by Luis A. Dalguer and published by Birkhäuser. This book was released on 2017-12-20 with total page 333 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume collects several extended articles from the first workshop on Best Practices in Physics-based Fault Rupture Models for Seismic Hazard Assessment of Nuclear Installations (BestPSHANI). Held in 2015, the workshop was organized by the IAEA to disseminate the use of physics-based fault-rupture models for ground motion prediction in seismic hazard assessments (SHA). The book also presents a number of new contributions on topics ranging from the seismological aspects of earthquake cycle simulations for source scaling evaluation, seismic source characterization, source inversion and physics-based ground motion modeling to engineering applications of simulated ground motion for the analysis of seismic response of structures. Further, it includes papers describing current practices for assessing seismic hazard in terms of nuclear safety in low seismicity areas, and proposals for physics-based hazard assessment for critical structures near large earthquakes. The papers validate and verify the models by comparing synthetic results with observed data and empirical models. The book is a valuable resource for scientists, engineers, students and practitioners involved in all aspects of SHA.

Download or read book Ground Motion Simulations written by Lynne Schleiffarth Burks and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Engineers use earthquake ground motions for a variety of reasons, including seismic hazard assessment, calibration of ground motion prediction equations (GMPEs), and input to nonlinear response history analysis. These analyses require a significant number of ground motions and for some scenarios, such as earthquakes with large magnitudes and short distances, it may be difficult to obtain a sufficient number of ground motion recordings. When sufficient recordings do not exist, engineers modify available recordings using scaling or spectrum matching, or they use ground motion simulations. Ground motion simulations have existed for decades, but recent advances in simulation methods due to improved source characterization and wave propagation, coupled with increased computing power, have increased potential benefits for engineers. But before simulations can be used in engineering applications, simulations must be accessible and consistent with natural observations. This dissertation contributes to the latter issue, and it investigates the application of simulations to specific engineering problems. The Southern California Earthquake Center (SCEC) Broadband Platform (BBP) is an open-source software distribution that enables third-party users to simulate ground motions using research code contributed by model developers. Because the BBP allows users to compute their own simulations with little knowledge of the underlying implementation and it ensures that all calculations are reproducible, it is extremely valuable for simulation validation and engineering applications. In this dissertation, the BBP is evaluated as a simulation generation tool from an engineering perspective. Ground motions are simulated to study parameters of engineering interest, such as high-frequency variability, near-fault ground motions, and local site response. Though some parameters need further development, such as site response (which is currently implemented using simple empirical amplification), the BBP proves to be an effective tool for facilitating these types of engineering studies. This dissertation proposes a simulation validation framework based on simple and robust proxies for the response of more complicated structures. We compile a list of proxies with robust empirical models that are insensitive to changes in earthquake scenario and do not rely on extrapolation for rarely observed events. Because predictions of these proxies are reliable under a variety of earthquake events, we can confidently compare them with simulations. The proposed proxies include correlation of epsilon across periods, ratio of maximum to median response across horizontal orientations, and ratio of inelastic to elastic displacement. The validation framework is applied to example simulations and successfully exposes some parameters that need work, such as variability and correlation of spectral acceleration. Finally, this dissertation investigates the application of simulations to response history analysis and fling-step characterization. A 3D nonlinear structural model is analyzed using recordings and simulations with similar elastic response spectra. The structural performance and resulting design decisions are similar, indicating that simulations are effective for response history analysis subject to certain conditions. To investigate fling-step, we extract fling pulses from a large set of simulations. Extracted fling properties such as amplitude and period are then compared to specially-processed recordings and relevant empirical models for surface displacement and pulse period. Reasonably good agreement is found between simulations, recordings, and empirical models. In general, ground motion simulations are found to be an effective alternative or supplement to recordings in several engineering applications. Because simulation methods are still developing, this work is not intended as an evaluation of existing methods, but rather as a development of procedures that can be used in ongoing work.

Download or read book Enhancement and Validation of Ground Motion Simulations written by Nan Wang and published by . This book was released on 2021 with total page 251 pages. Available in PDF, EPUB and Kindle. Book excerpt: Accurate prediction of strong ground motion is central to seismic hazard analysis in order to estimate losses during major earthquakes. Ground motion simulations are essential to seismic ground motion prediction, especially for locations of infrequent observations, such as large magnitude and short distance events, where simulations can provide a viable alternative to data. Therefore, enhancement and validation of ground motion simulations, the primary goal of this dissertation, are highly desirable. In Chapter 2, we quantify the effects of four important factors on ground motions from large normal-faulting earthquakes on the Wasatch fault in the Salt Lake Basin: rupture direction, location on the hanging wall versus the footwall, deep 3D basin structure, and the distance from the rupture in the near field range. In Chapter 3, we attempt to validate the presence of several proposed waveguides in the Los Angeles area using 3D simulations and observed data from ambient noise. Here, we compare the numerical and empirical surface-to-surface Green tensors for virtual sources located on the San Andreas Fault. The regions of large peak motions caused by waveguide focusing in the simulations show generally good agreement with increases in the Green tensor amplitudes, supporting the presence of two separate waveguides in greater Los Angeles. In Chapters 4 and 5, we develop an empirical frequency-dependent spatial ground motion correlation model and methods to rectify simulation techniques that otherwise produce synthetic time histories deficient in inter-frequency and spatial correlation structure. The methods are tested using a hybrid deterministic-stochastic broadband ground motion generation module, where our method reproduces the empirical correlations well for a large number of realizations without biasing the fit of the median of the spectral accelerations to data. We find that the best fit of the inter-frequency correlation to data is obtained assuming that the horizontal components are correlated with a correlation coefficient of about 0.7.

Download or read book Alternative Ground Motion Model for the Central and Eastern North America Using a New Hybrid Broadband Simulation Technique written by Alireza Shahjouei and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Two main objectives have been studied in this dissertation are proposing a hybrid broadband (HBB) earthquake simulation method and the development of alternative ground-motion prediction equations (GMPEs) for central and eastern North America (CENA). Providing such equations, which represents the expected ground shaking levels from earthquake sources, are important as those are being implemented in the probabilistic seismic hazard and risk analysis, and therefore they are financially contributed in the design and construction of structures and infrastructures. This research has two major part. In the first part, a new platform to generate earthquake time histories is developed based on a hybrid broadband simulation technique. The generation of artificial time histories is a promising solution in the absence of the sufficient and appropriate recorded seismograms. Due to lack of recorded strong ground motions in CENA, generation of synthetic seismograms is inevitable in engineering (e.g., time history analyses of structures) and engineering seismology (e.g., GMPEs development) applications. The proposed method incorporated the kinematic earthquake source model, deterministic wave propagation (using discrete wavenumber/finite element technique), and the stochastic finite-fault method to make a suite of appropriate seismic time histories. A new set of GMPEs is developed for CENA in the second part of this study. The proposed comprehensive framework for HBB simulation technique is implemented to develop the new hybrid empirical GMPEs. Hybrid empirical estimates are derived using the regional adjustment factors between two regions (host and target) along with empirical GMPEs from the host region. In this study, western United States and CENA are considered as the host and target regions, respectively. Modeling parameter variability is considered in ground-motion simulations and GMPEs development. Ground-motion models are developed for the earthquake magnitude range of 5 & ndash;8, in the distance range of 2 & ndash;1000 km, and for the reference rock site condition with Vs30 = 3 km/s for CENA. The products of this research may contribute to update the future national seismic hazard maps developed by U.S. Geological Survey (USGS) and upcoming building codes.

Download or read book Utilization of Physics based Simulated Earthquake Ground Motions for Performance Assessment of Tall Buildings written by Nenad Bijelić and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Databases of recorded motion are limited despite the increasing amount of data collected through strong motion instrumentation programs. Particular lack of data exists for large magnitude events and at close distances as well as on earthquakes in deep sedimentary basins. Additionally, databases of recorded motions are also limited in representation of energy at long periods due to the useable frequencies of recording instruments. This lack of data is currently partially addressed through assumption of ergodicity in development of empirical ground motion prediction equations (GMPEs). Nevertheless, challenges remain for calibration of empirical GMPEs as used in conventional approaches for probabilistic estimation of seismic hazard. At the same time, limited data on strong earthquakes and their effect on structures poses challenges for making reliable risk assessments particularly for tall buildings. For instance, while the collapse safety of tall buildings is likely controlled by large magnitude earthquakes with long du- rations and high long-period content, there are few available recorded ground motions to evaluate these issues. The influence of geologic basins on amplifying ground motion effects raises additional questions. Absent recorded motions from past large magnitude earthquakes, physics-based ground motion simulations provide a viable alternative due to the ability to consider extreme ground motions while being inherently site-specific and explicitly considering instances not well constrained by limited empirical data. This thesis focuses on utilization of physics-based simulated earthquake ground motions for performance assessment of tall buildings with three main goals: (1) developing confidence in the use of simulated ground motions through comparative assessments of recorded and simulated motions; (2) identifying important characteristics of extreme ground motions for col- lapse safety of tall buildings; (3) exploring areas where simulated ground motions provide significant advantages over recorded motions for performance-based engineering. To gain confidence in the use of simulated motions for full performance assessment of tall buildings, a 'similar intensity measure' validation study was performed. Structural responses to ground motions simulated with different methods on the Southern California Earthquake Center (SCEC) Broadband Platform (BBP) are contrasted to recorded motions from PEER NGA database with similar spectral shape and significant durations. Two tall buildings, a 20-story concrete frame and a 42-story concrete core wall building, are analyzed at increasing levels of ground motion intensity, up to structural collapse, to check for statistically significant differences between the responses to simulated and recorded motions. Considered demands include story drift ratios, floor accelerations and collapse response. These comparisons yield similar results in most cases but also reveal instances where certain simulated ground motions can result in biased responses. The source of bias is traced to differences in correlations of spectral values in some of the stochastic ground motion simulations. When the differences in correlations are removed, simulated and recorded motions yield comparable results. Moving beyond validation, the thesis also explored areas where the use of simulated motions provides advantages over approaches based on limited databases of recorded motions for performance-based engineering. One such area is seismic risk in deep sedimentary basins which is studied by examining collapse risk and drift demands of a 20-story archetype tall building utilizing ground motions at four sites in the Los Angeles basin. Seismic demands of the building are calculated form nonlinear structural analyses using large datasets (~500,000 ground motions per site) of unscaled, site-specific simulated seismograms. Seismic hazard and building performance from direct analysis of SCEC CyberShake motions are contrasted with values obtained based on 'conventional' approaches that rely on recorded motions coupled with probabilistic seismic hazard assessments. The analysis shows that, depending on the location of the site within the basin, the two approaches can yield drastically different results. For instance, at a deep basin site the CyberShake-based analysis yields around seven times larger mean annual frequency of collapse ( c) and significantly higher drift demands (e.g. drift demand of 1% is exceeded around three times more frequently) compared to the conventional approach. Both the hazard as well as the spectral shapes of the motions are shown to drive the differences in responses. Deaggregation of collapse risk is performed to identify the relative contributions of earthquake fault ruptures, linking building responses with specific seismograms and contrasting collapse risk with hazard. The effect of earthquake ground motions in deep sedimentary basins on structural collapse risk is further studied through the use of CyberShake earthquake simulations in the Los Angeles basin. Distinctive waveform characteristics of deep basin seismograms are used to classify the ground motions into several archetype groups, and the damaging influence of the basin effects are evaluated by comparing nonlinear structural responses under comparable basin and non-basin ground motions. The deep basin ground motions are observed to have larger durations and spectral intensities than non-basin motions for vibration periods longer than about 1.5 seconds, which can increase the relative structural collapse risk by up to 20 percent between ground motions with otherwise comparable spectral accelerations and significant durations. Two new metrics, termed sustained amplitude response spectra (RSx spectra) and significant duration spectra (Da spectra), are proposed to quantify period-dependent duration effects that are not otherwise captured by conventional ground motion intensity measures. The proposed sustained amplitude response spectra and significant duration spectra show promise for characterizing the damaging effects of long duration features of basin ground motions on buildings and other structures. The large database of CyberShake simulations is utilized to re-examine the relationships between engineering demand parameters and input ground motions on structural response. Focusing on collapse response, machine learning techniques are applied to results of about two million nonlinear time history analyses of an archetype 20-story tall building performed using CyberShake ground motions. The resulting feature selection (based on regularized logistic regression) generally confirms existing understanding of collapse predictors as gained from scaled recorded motions but also reveals the benefit of some novel intensity measures (IMs), in particular the RSx spectral features. In addition, the statistical interrogations of the large collection of hazard-consistent simulations demonstrate the utility of different IMs for collapse predictions in a way that is not possible with recorded motions. A small subset of robust IMs is identified and used in development of an efficient collapse classification algorithm, which is tested on benchmark results from other CyberShake sites. The classification algorithm yields promising results for application to regional risk assessment of building performance.

Download or read book Microearthquake Seismology and Seismotectonics of South Asia written by J.R. Kayal and published by Springer Science & Business Media. This book was released on 2008-08-22 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume is the outcome of about 30 years of research in the field of earthquake seismology in various parts of South Asia. It comprehensively deals with topics raning from plate tectonics to seismic waves in general. State-of-the-art techniques in earthquake location/relocation, fault plane solution, waveform inversion, seismic tomography, fractals etc. are discussed, and the results are interpreted in terms of seismic source processes in the region.

Download or read book Ground Motion Modeling of Hayward Fault Scenario Earthquakes II written by and published by . This book was released on 2009 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: We simulate long-period (T> 1.0-2.0 s) and broadband (T> 0.1 s) ground motions for 39 scenarios earthquakes (Mw 6.7-7.2) involving the Hayward, Calaveras, and Rodgers Creek faults. For rupture on the Hayward fault we consider the effects of creep on coseismic slip using two different approaches, both of which reduce the ground motions compared with neglecting the influence of creep. Nevertheless, the scenario earthquakes generate strong shaking throughout the San Francisco Bay area with about 50% of the urban area experiencing MMI VII or greater for the magnitude 7.0 scenario events. Long-period simulations of the 2007 Mw 4.18 Oakland and 2007 Mw 4.5 Alum Rock earthquakes show that the USGS Bay Area Velocity Model version 08.3.0 permits simulation of the amplitude and duration of shaking throughout the San Francisco Bay area, with the greatest accuracy in the Santa Clara Valley (San Jose area). The ground motions exhibit a strong sensitivity to the rupture length (or magnitude), hypocenter (or rupture directivity), and slip distribution. The ground motions display a much weaker sensitivity to the rise time and rupture speed. Peak velocities, peak accelerations, and spectral accelerations from the synthetic broadband ground motions are, on average, slightly higher than the Next Generation Attenuation (NGA) ground-motion prediction equations. We attribute at least some of this difference to the relatively narrow width of the Hayward fault ruptures. The simulations suggest that the Spudich and Chiou (2008) directivity corrections to the NGA relations could be improved by including a dependence on the rupture speed and increasing the areal extent of rupture directivity with period. The simulations also indicate that the NGA relations may under-predict amplification in shallow sedimentary basins.

Download or read book Spatial Modelling and Failure Analysis of Natural and Engineering Disasters through Data based Methods written by Faming Huang and published by Frontiers Media SA. This book was released on 2022-10-07 with total page 541 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Semi empirical Characterization of Ground Motions Including Source Path and Nonlinear Site Effects written by Emel Seyhan and published by . This book was released on 2013 with total page 282 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this thesis is to improve the physical understanding of earthquake ground motion characteristics related to source, path and nonlinear site effects and our ability to model those effects with engineering models. This was achieved through four research studies consisting of: (1) calibrating broadband simulation procedures to remove previously recognized sources of bias in distance attenuation and standard deviation; (2) enhancing a site database used for assigning site parameters to ground motion recordings, particularly with regard to the level of rigor and transparency with which the database is populated; (3) leveraging a state-of-the-art ground motion database and recent simulation-based studies to develop a nonlinear site amplification model suitable for use in g̲round m̲otion p̲redictions e̲quations (GMPEs) and relatively simplified building code applications; and (4) developing GMPEs that provides mean and standard deviation of ground motion intensity measures in active crustal regions. The high-frequency component of the simulation procedure considered in this study combines deterministic Fourier amplitude spectra (dependent on source, path, and site models) with random phase. Significantly too-fast distance attenuation bias identified in prior work has been removed by increasing the quality factor (Q). We introduced random site-to-site variations to Fourier amplitudes using a log-normal standard deviation ranging from 0.45 for M 7 to zero for M8 to achieve dispersion terms that are more compatible with those from empirical models but remain lower at large distances (e.g., 100 km). Site database work was performed within the context of the NGA-West 2 project. Starting with the site database from original (2008) NGA project (last edited in 2006), we provided site classifications for 2538 new sites and re-classifications of previous sites. The principal site parameter is the time-averaged shear wave velocity in the upper 30 m Vs30, which is characterized using measurements where available, and proxy-based relationships otherwise. We improved the documentation and consistency of site descriptors used as proxies for the estimation of Vs30, developed evidence-based protocols for Vs30 estimation from available proxies, and augmented estimates of various basin depth parameters. Site factors typically have a small-strain site amplification that captures impedance and resonance effects coupled with nonlinear components. Site factors in current NEHRP Provisions are empirically-derived at relatively small ground motion levels and feature simulation-based nonlinearity. We show that current NEHRP site factors have discrepancies with respect to the site terms in the original NGA GMPEs both in the linear site amplification (especially for Classes B, C, D, and E) and the degree of nonlinearity (Classes C and D). We analyzed the NGA-West 2 dataset and simulation-based models for site amplification to develop a new model. The model has linear and nonlinear additive components. The linear component is fully empirical, being derived from worldwide ground motion data (regional effects were examined but found to not be sufficiently important to be included in the model). The model features linear Vs30-scaling in a log-log sense below a corner velocity (Vc), and no Vs30-scaling for velocities faster than Vc. The nonlinear component is developed from consideration of empirical data analysis and simulation results within a consistent context. The resulting nonlinearity operates principally at short periods and soft soils. This model is suitable for use as a site term in GMPEs and was applied to develop a proposal for updating the NEHRP site factors. The recommended factors remove a discrepancy between the reference condition used in the site factors and the national seismic hazard maps published by USGS. We have developed empirical equations for predicting the average horizontal component of earthquake ground motions from active crustal region earthquakes worldwide. The equations build upon a previous ground-motion model by Boore and Atkinson in 2008. Significant new features of the proposed GMPEs include: modified site terms; a modified magnitude scaling function that produces a higher degree of saturation at large magnitude for high-frequency ground motions; region-specific apparent anelastic attenuation term; basin depth correction factors that are centered on the average level of basin amplification conditional on Vs30; standard deviation terms that depend on M for between-event standard deviations and M-1, Rjb and Vs30-dependent within-event standard deviations. The resulting equations are applicable for events over a magnitude range of 3 to 8.5 for strike-slip or reverse-slip events (M3 to 8 for normal slip events), distance range up to 400 km, and site conditions ranging from Vs30 = 150 to 1500 m/s. The equations are useful for prediction of the ground motion i̲ntensity m̲easures (IMs) PGA, PGV, and PSA at periods T = 0 to 10 sec.

Download or read book Physic based Classification Quantification and Simulation of Ground Motion for Earthquake Engineering Applications written by Banu Mena Cabrera and published by . This book was released on 2010 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advances in the Protection of Museum Collections from Earthquake Damage written by Jerry Podany and published by Getty Publications. This book was released on 2008 with total page 220 pages. Available in PDF, EPUB and Kindle. Book excerpt: For nearly three decades, the J. Paul Getty Museum has played a leading role in the development of seismic mitigation for museum collections. Contributors to this volume--ranging from museum conservators, mount makers, and historical archaeologists to seismologists and structural engineers--discuss and illustrate a wide variety of earthquake-mitigation efforts for collections, from the simple and inexpensive to the complex and costly. The book's essays examine the techniques applied to large collections and to small house museums, to exhibition cases containing objects as well as to monumental works of art and historical structures. Approaches range from securing and restraining objects to decoupling them from the ground through a variety of base-isolation mechanisms. These pioneering efforts have been developed in the face of significant challenges since, as any engineer, conservator, or mount maker who has undertaken this work can attest, a small sculpture can often be a far greater challenge to protect than a multistory building.

Download or read book Nonlinear Effects in Ground Motion Simulations written by Wei Li and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: While site effects are accounted for in most modern U.S. seismic design codes for building structures, there exist no standardized procedures for the computationally efficient integration of nonlinear ground response analyses in broadband ground motion simulations. In turn, the lack of a unified methodology affects the prediction accuracy of site-specific ground motion intensity measures, the evaluation of site amplification factors when broadband simulations are used for the development of hybrid attenuation relations and the estimation of inelastic structural performance when strong motion records are used as input in aseismic structural design procedures. In this study, a set of criteria is established, which quantifies how strong nonlinear effects are anticipated to manifest at a site by investigating the empirical relation between nonlinear soil response, soil properties, and ground motion characteristics. More specifically, the modeling variability and parametric uncertainty of nonlinear soil response predictions are studied, along with the uncertainty propagation of site response analyses to the estimation of inelastic structural performance. Due to the scarcity of design level ground motion recording, the geotechnical information at 24 downhole arrays is used and the profiles are subjected to broadband ground motion synthetics.

Download or read book Reliability Evaluation of Dynamic Systems Excited in Time Domain Redset written by Achintya Haldar and published by John Wiley & Sons. This book was released on 2023-02-17 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: RELIABILITY EVALUATION OF DYNAMIC SYSTEMS EXCITED IN TIME DOMAIN – REDSET Multi-disciplinary approach to structural reliability analysis for dynamic loadings offering a practical alternative to the random vibration theory and simulation Reliability Evaluation of Dynamic Systems Excited in Time Domain – REDSET is a multidisciplinary concept that enables readers to estimate the underlying risk that could not be solved in the past. The major hurdle was that the required limit state functions (LSFs) are implicit in nature and the lack of progress in the reliability evaluation methods for this class of problems. The most sophisticated deterministic analysis requires that the dynamic loadings must be applied in the time domain. To satisfy these requirements, REDSET is developed. Different types and forms of dynamic loadings including seismic, wind-induced wave, and thermomechanical loading in the form of heating and cooling of solder balls used in computer chips are considered to validate REDSET. Time domain representations and the uncertainty quantification procedures including the use of multiple time histories are proposed and demonstrated for all these dynamic loadings. Both onshore and offshore structures are used for validation. The potential of REDSET is demonstrated for implementing the Performance Based Seismic Design (PBSD) concept now under development in the United States. For wider multidisciplinary applications, structures are represented by finite elements to capture different types of nonlinearity more appropriately. Any computer program capable of conducting nonlinear time domain dynamic analysis can be used, and the underlying risk can be estimated with the help of several dozens or hundreds of deterministic finite element analyses, providing an alternative to the simulation approach. To aid comprehension of REDSET, numerous illustrative examples and solution strategies are presented in each chapter. Written by award-winning thought leaders from academia and professional practice, the following sample topics are included: Fundamentals of reliability assessment including set theory, modeling of uncertainty, the risk-based engineering design concept, and the evolution of reliability assessment methods Implicit performance or limit state functions are expressed explicitly by the extensively modified response surface method with several new experimental designs Uncertainty quantification procedures with multiple time histories for different dynamic loadings, illustrated with examples The underlying risk can be estimated using any computer program representing structures by finite elements with only few deterministic analyses REDSET is demonstrated to be an alternative to the classical random vibration concept and the basic simulation procedure for risk estimation purposes REDSET changes the current engineering design paradigm. Instead of conducting one deterministic analysis, a design can be made more dynamic load tolerant, resilient, and sustainable with the help of a few additional deterministic analyses This book describing REDSET is expected to complement two other books published by Wiley and authored by Haldar and Mahadevan: Probability, Reliability and Statistical Methods in Engineering Design and Reliability Assessment Using Stochastic Finite Element Analysis. The book is perfect to use as a supplementary resource for upper-level undergraduate and graduate level courses on reliability and risk-based design.

Download or read book Computational Methods in Earthquake Engineering written by Manolis Papadrakakis and published by Springer Science & Business Media. This book was released on 2010-12-06 with total page 585 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides an insight in advanced methods and concepts for structural analysis and design against seismic loading. The book consists of 25 chapters dealing with a wide range of timely issues in contemporary Earthquake Engineering. In brief, the topics covered are: collapse assessment, record selection, effect of soil conditions, problems in seismic design, protection of monuments, earth dam structures and liquid containers, numerical methods, lifetime assessment, post-earthquake measures. A common ground of understanding is provided between the communities of Earth Sciences and Computational Mechanics towards mitigating seismic risk. The topic is of great social and scientific interest, due to the large number of scientists and practicing engineers currently working in the field and due to the great social and economic consequences of earthquakes.

Download or read book Proceedings written by Structural Engineers Association of California. Convention and published by . This book was released on 1996 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: