Download or read book Impact of Ground Motion Characterization on Conservatism and Variability in Seismic Risk Estimates written by and published by . This book was released on 1996 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study evaluates the impact, on estimates of seismic risk and its uncertainty, of alternative methods in treatment and characterization of earthquake ground motions. The objective of this study is to delineate specific procedures and characterizations that may lead to less biased and more precise seismic risk results. This report focuses on sources of conservatism and variability in risk that may be introduced through the analytical processes and ground-motion descriptions which are commonly implemented at the interface of seismic hazard and fragility assessments. In particular, implication of the common practice of using a single, composite spectral shape to characterize motions of different magnitudes is investigated. Also, the impact of parameterization of ground motion on fragility and hazard assessments is shown. Examination of these results demonstrates the following. (1) There exists significant conservatism in the review spectra (usually, spectra characteristic of western U.S. earthquakes) that have been used in conducting past seismic risk assessments and seismic margin assessments for eastern U.S. nuclear power plants. (2) There is a strong dependence of seismic fragility on earthquake magnitude when PGA is used as the ground-motion characterization. When, however, magnitude-dependent spectra are anchored to a common measure of elastic spectral acceleration averaged over the appropriate frequency range, seismic fragility shows no important nor consistent dependence on either magnitude or strong-motion duration. Use of inelastic spectral acceleration (at the proper frequency) as the ground spectrum anchor demonstrates a very similar result. This study concludes that a single, composite-magnitude spectrum can generally be used to characterize ground motion for fragility assessment without introducing significant bias or uncertainty in seismic risk estimates.

Download or read book Impact of Ground Motion Characterization on Conservatism and Variability in Seismic Risk Estimates written by Robert Thomas Sewell and published by . This book was released on 1996 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ground Motion Input in Seismic Evaluation Studies written by and published by . This book was released on 1996 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Conservatism and variability in seismic risk estimates are studied: effects of uniform hazard spectrum (UHS) are examined for deriving probabilistic estimates of risk and in-structure demand levels, as compared to the more-exact use of realistic time history inputs (of given probability) that depend explicitly on magnitude and distance. This approach differs from the conventional in its exhaustive treatment of the ground-motion threat and in its more detailed assessment of component responses to that threat. The approximate UH-ISS (in-structure spectrum) obtained based on UHS appear to be very close to the more-exact results directed computed from scenario earthquakes. This conclusion does not depend on site configurations and structural characteristics. Also, UH-ISS has composite shapes and may not correspond to the characteristics possessed a single earthquake. The shape is largely affected by the structural property in most cases and can be derived approximately from the corresponding UHS. Motions with smooth spectra, however, will not have the same damage potential as those of more realistic motions with jagged spectral shapes. As a result, UHS-based analysis may underestimate the real demands in nonlinear structural analyses.

Download or read book Ground Motion Variability and Its Effect on the Probabilistic Seismic Hazard Analysis written by Vasily Pavlenko and published by . This book was released on 2016 with total page 83 pages. Available in PDF, EPUB and Kindle. Book excerpt: The majority of injuries and casualties during earthquakes occur as a result of partial or complete collapse of buildings. The assessment of possible seismic ground motions for the purposes of earthquake-resistant design can be performed by following the deterministic or probabilistic methodology. Chapter 1 presents an overview of the current practice in seismic hazard analysis with emphasis on PSHA. At present, the Cornell-McGuire method prevails in PSHA studies. Despite significant development and modifications, this method has several controversial aspects. Absence of an upper bound of the seismic hazard curve is one of the most disputable aspects of the method, as it leads to unrealistic ground motion estimates for very low probabilities of exceedance. This problem stems from using the unbounded log-normal distribution in the modelling of the ground motion variability. The main objective of the study was to investigate this variability and suggest a more realistic probability distribution which would allow accounting for the finiteness of the ground motion induced by earthquake. Chapter 2 introduces the procedure that is suitable for studying the ground motion variability. Given the data sample, this procedure allows selecting the most plausible probability distribution from a set of candidate models. Chapter 3 demonstrates the application of this procedure to PGA data recorded in Japan. This analysis demonstrated the superiority of the GEVD in the vast majority of considered examples. Estimates of the shape parameter of the GEVD were negative in every considered example, indicating the presence of a finite upper bound of PGA. Therefore, the GEVD provides a model that is more realistic for the scatter of the logarithm of PGA, and the application of this model leads to a bounded seismic hazard curve. In connection with a revival of interest in seismic intensity as an analogue for physical ground motion parameters, the problem of accounting for anisotropy in the attenuation of MMI is considered in Chapter 4. A set of four equations that could account for this anisotropy was proposed and the applicability of these equations was demonstrated by modelling the isoseismal maps of two well-recorded seismic events that have occurred in South Africa. The results demonstrated that, in general, the new equations were superior to the isotropic attenuation equation, especially as regards to the pronounced anisotropy. As several different PSHA methods exist, it is important to know how the results of application of these methods corresponded to each other. Chapter 5 presents the comparative study of three major PSHA methods, namely, the Cornell-McGuire method, the Parametric-Historic method, and the method based on Monte Carlo simulations. Two regions in Russia were selected for comparison, and the PGA estimates were compared for return periods of 475 and 2475 years. The results indicated that the choice of a particular method for conducting PSHA has relatively little effect on the hazard estimates when the same seismic source model was used in the calculations. The considered PSHA methods would provide closely related results for areas of moderate seismic activity; however, the difference among the results would apparently increase with increasing seismic activity.

Download or read book Impact of Input Ground Motions and Site Variability on Seismic Site Response written by Albert Richard Kottke and published by . This book was released on 2006 with total page 382 pages. Available in PDF, EPUB and Kindle. Book excerpt: Seismic site response analysis allows an engineer to assess the effect of local soil conditions on the ground motions expected during an earthquake. In seismic site response analysis, an input ground motion on rock is propagated through a site specific soil column. The computed response at the surface is dependent on both the input ground motion and the soil properties that characterize the site. However, there is uncertainty in both the input ground motion and the soil properties, as well as natural variability in the soil properties across a site. To account for the uncertainty in the input ground motions, engineers use a suite of motions that are selected and scaled to fit a scenario input motion. This study introduces a semi-automated method to select and scale the input motions to fit a target input motion and its variability. The proposed method is intended to replace tedious trials of combinations by hand with combinations performed by a computer. However, as in the traditional selection methods, the final selection of the combination is done by the engineer.The effect of the selected ground motion combination on the computed surface response spectrum from the site response analysis, and its variability, was investigated in this study. The results show by using a combination with as few as five motions, the median surface response spectrum can be predicted with an error of 10%. Additionally, the manner used to scale the input motions does not impact the accuracy of the median surface response spectrum, as long as the median response spectrum of the input combination agrees with the target input response spectrum. However, if the standard deviation of the surface response spectrum is to be considered (e.g., to develop median plus one standard deviation spectra), a input combination of at least 20 motions is recommended and the combination must be scaled such that the standard deviation of the input combination matches the standard deviation of the input target spectrum. Monte Carlo simulations were used to assess the impact of soil property variability on surface spectra computed by seismic site response. The results from this study indicate that by accounting for the variability of the shear-wave velocity profile of a site can cause a significant decrease in the median surface response spectrum, as well as a slight increase in the standard deviation of the surface response spectrum at periods less than the site period. By considering the variability of the nonlinear properties (shear modulus reduction and damping ratio) the median response spectrum decreased only slightly, but the standard deviation increased in a manner similar to the increase observed when considering the variability of the shear-wave velocity profile. Simultaneously considering the variability of the shear-wave velocity profile and nonlinear properties resulted in a median surface response spectrumsimilar to the median surface response spectrumcomputed with considering the variability of the shear-wave velocity alone. However, the standard deviation of the surface response spectrum was larger than the standard deviation computed by independent consideration of the variability of the shear-wave velocity or nonlinear properties.

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 Spatial Variation of Seismic Ground Motions written by Aspasia Zerva and published by CRC Press. This book was released on 2016-04-19 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: The spatial variation of seismic ground motions denotes the differences in the seismic time histories at various locations on the ground surface. This text focuses on the spatial variability of the motions that is caused by the propagation of the waveforms from the earthquake source through the earth strata to the ground surface, and it brings toge

Download or read book Uncertainty and Conservatism in the Seismic Analysis and Design of Nuclear Facilities written by and published by . This book was released on 1986 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ground Motion Input in Seismic Evaluation Studies written by and published by . This book was released on 1996 with total page 313 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report documents research pertaining to conservatism and variability in seismic risk estimates. Specifically, it examines whether or not artificial motions produce unrealistic evaluation demands, i.e., demands significantly inconsistent with those expected from real earthquake motions. To study these issues, two types of artificial motions are considered: (a) motions with smooth response spectra, and (b) motions with realistic variations in spectral amplitude across vibration frequency. For both types of artificial motion, time histories are generated to match target spectral shapes. For comparison, empirical motions representative of those that might result from strong earthquakes in the Eastern U.S. are also considered. The study findings suggest that artificial motions resulting from typical simulation approaches (aimed at matching a given target spectrum) are generally adequate and appropriate in representing the peak-response demands that may be induced in linear structures and equipment responding to real earthquake motions. Also, given similar input Fourier energies at high-frequencies, levels of input Fourier energy at low frequencies observed for artificial motions are substantially similar to those levels noted in real earthquake motions. In addition, the study reveals specific problems resulting from the application of Western U.S. type motions for seismic evaluation of Eastern U.S. nuclear power plants.

Download or read book Non ergodic Probabilistic Seismic Hazard Analysis and Spatial Simulation of Variation in Ground Motion written by Melanie Anne Walling and published by . This book was released on 2009 with total page 526 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spatial Variability of Shear Wave Velocity and Its Effects on Seismic Ground Response written by Laura Luna and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since it is unfeasible to sample every point at a site, there will always be a level of uncertainty in the mechanical properties that are used in geotechnical design. As the geotechnical community transitions towards reliability and risk-based designs, the formal treatment of these uncertainties throughout the analysis process becomes increasingly important. This study has two objectives. The first is to quantify the spatial variability of shear wave velocity based on 206 seismic cone penetration tests available for sites in British Columbia, Canada. The second is to assess how this spatial variability affects the response of a soil mass subject to earthquake ground motions. The statistical properties of shear wave velocity were estimated using a multiplica- tive form, where the random shear wave velocity (V (d)) was expressed as the product of a deterministic trend (v̂(d)) and a lognormal random variable (Y ). The distribu- tion of Y was estimated using the method of moments, and the correlation length was estimated using two approaches, a commonly used direct-fitting method, as well as a bias-matched method. Additionally, a comparison is presented to the first-order, auto-regressive method to randomize shear wave velocity proposed by Toro (1995). Finally, a discrete-time, two-state Markov chain is used to generate realizations of soil layering, modeling the transitions between clay-like and sand-like materials. Several probabilistic, equivalent-linear ground response analyses (GRA) were com- pleted to assess how the spatial variability of shear wave velocity affects the peak ground acceleration, cyclic stress ratio, and spectral acceleration response spectra. In general, randomizing shear wave velocity was found to result in lower mean stresses and accelerations when compared against the results obtained from a deterministic approach using the mean shear wave velocity. The sensitivity of the results to the random field parameters was also explored. The distribution of peak ground accel- eration (PGA) and cyclic stress ratio (CSR) were found to be most sensitive to the coefficient of variation of shear wave velocity, with correlation length and correlation anisotropy having a smaller influence on the results.

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 Ground Motion Intensity Measures for Seismic Probabilistic Risk Analysis written by Marco De Biasio and published by . This book was released on 2014 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fundamental issue that arises in the framework of Probabilistic Seismic Risk Analysis is the choice of groundmotion Intensity Measures (IMs). In addition to reducing record-to-record variability, an improved IM (i.e. one able tobetter capture the damaging features of a record, as well as the site hazard) provides criteria for selecting input groundmotions to loosen restrictions.Two new structure-specific IMs are proposed in this study: the first, namely ASAR (i.e. Relative Average SpectralAcceleration), is conceived for Structural demand prediction, the second namely, E-ASAR (i.e. Equipment-RelativeAverage Spectral Acceleration), aims to predict Non-Structural components acceleration demand. The performance ofthe proposed IMs are compared with the ones of current IMs, based on: a) a large dataset of thousands recordedearthquake ground motions; b) numerical analyses conducted with state-of-the-art FE models, representing actualload-bearing walls and frame structures, and validated against experimental tests; and c) systematic statistical analysesof the results. According to the comparative study, the introduced IMs prove to be considerably more “efficient” withrespect to the IMs currently used. Likewise, both ASAR and E-ASAR have shown to own the characteristic of“sufficiency” with respect to magnitude, source-to-site distance and soil-type (Vs30). Furthermore, both the introducedIMs possess the valuable characteristics to need (in order to be computed) merely the knowledge of the building'sfundamental frequency, exactly as it is for the wide-spread spectral acceleration Spa(f1). This key characteristic makesboth ASAR and E-ASAR easily exploitable in Probabilistic Seismic Hazard Analysis.Therefore, due to their proven efficiency, sufficiency, robustness and applicable formulation, both ASAR and EASARcan be considered as worthy candidates for defining seismic hazard within the frameworks of both Probabilisticand Deterministic Seismic Risk Analysis.

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 Ground Motion Selection and Seismic Demand Modeling written by Amin Ahmadi and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The effectiveness of Ground Motion Selection and Modification (GMSM) methodologies is generally assessed by their ability to minimize the effect of ground motion variability during structural demand estimation. This study is concerned with issues and challenges in ground motion selection and modification as well as the consequences of the adopted modification schemes in developing reliable seismic demand models. The estimation of the nonlinear dynamic structural response to a specified level of seismic demand requires hazard consistent ground motion records. The most common way of imposing the hazard consistency is through the scaling of the acceleration intensity value of the ground motion record at the fundamental period of the structure to a target value; this target value (i.e., intensity measure) is estimated by the attenuation models for a specified earthquake scenario. Previous studies have not made a distinction between the dominant modes that result in a specific maximum inter-story drift ratio (MIDR). In this study, by considering the conditional MIDR (dominant mode dependent), it is shown that the aforementioned scaling procedure results in a biased estimation of the median MIDR if the selected records do not contain an equal number of records in each dominant mode set. An alternative scaling scheme is proposed which reduces the dependency of the MIDR estimation on the dominant response mode. A seismic demand model attempts to describe the behavior of a structure in terms of a set of predictor variables that represents the loading. Such predictive demand models are expected to establish a stable and reliable relationship between the dependent variable (structural response) and the independent variables (spectral accelerations). This expectation, however, is problematic in the presence of multicollinearity of the predictor variables because it undermines the performance of the demand model. It is demonstrated that biased estimation of the regression coefficients remedies both the overfitting problem and the instability of the regression coefficients. Finally, the dominant dynamic modes imposed by the ground motion suite are found to have a significant effect on the model predictions. In this study, this influence is quantified in terms of the coefficient of partial determination. It is shown that the marginal contribution of the included variables in the demand model is dependent on the response mode that yields the MIDR. An alternative method of estimating the regression coefficients, i.e., the Ridge estimation, is discussed as an approach that minimizes the influence of the dominant mode on the demand model. The performance of the Ridge estimation is compared with the least squares (unbiased) counterpart using the cross-validation method. Findings from this study have a major impact on the selection and modification of ground motions for seismic assessment of structures.

Download or read book Nuclear Regulatory Commission Issuances written by U.S. Nuclear Regulatory Commission and published by . This book was released on 1979 with total page 950 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Seismic Hazard and Risk Analysis written by Robin K. McGuire and published by . This book was released on 2004 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the twenty-sixth volume in the Earthquake Engineering Research Institute's series, Connections: The EERI Oral History Series. EERI began this series to preserve the recollections of some of those who have had pioneering careers in the field of earthquake engineering.Mete Sozen (1932-2018) is the Karl H. Kettelhut Distinguished Professor Emeritus of Civil Engineering at Purdue University, Indiana, United States.Besides his academic interest in the development of design codes for concrete structures, Sozen is notable for his contributions to the official post 9/11-government studies of terrorist attacks, including the Oklahoma City bombing, and The Pentagon. Sozen also led a team that created an engineering simulation of American Airlines Flight 11 crashing into the North Tower of the World Trade Center. The computer-animated visualizations were made entirely from the simulation data. He was elected to the National Academy of Engineering in 1977 for contributions to understanding the structural design and behavior of buildings and bridges subjected to earthquake motions.Sozen received his undergraduate education at Robert College (Turkey, 1951) and his master's (1952) and doctoral degrees (1957) from the University of Illinois at Urbana-Champaign.