Spectral acceleration

About: Spectral acceleration is a research topic. Over the lifetime, 1223 publications have been published within this topic receiving 39329 citations.

A New Attenuation Relation for Strong Ground Motion in Japan Based on Recorded Data

Abstract: Following the 1995 Hyogo-ken Nanbu Kobe. Earthquake, the Japanese government, in an effort to prevent future earthquake disasters, installed networks consisting of a large number of strong-motion observation stations. Further, national seismic hazard maps were made available to the public on an Internet website in March 2005 by the Headquarters for Earthquake Research Promotion. However, these maps indicate only the local seismic intensity for Japan, as empirically con- verted from predicted peak velocity in consolidated soils. For various applications, other strong-motion indexes such as the response spectral acceleration are required. In this study, a database of whole Japanese strong ground motion records between 1963 and 2003 is established in order to identify a new standard attenuation relation for Japan, for response acceleration as well as peak value. It is usually very difficult to determine a suitable model form due to the large variability of strong-motion data and correlation among the model variables, because the strong coupling of variables in an attenuation model, and the statistical power of the data is often not large enough to determine the necessity of these parameters. Therefore, in this study, our model has only three variables: earthquake magnitude, shortest distance to the seismic fault plane, and focal depth. To improve predictions given by the model, site correction terms are adopted and additional terms for correcting regional anomalous seismic intensity with respect to the base model are determined. The good fit between the model and observed strong-motion records suggests that the new model is reasonably robust.

Ground motion prediction equations derived from the Italian strong motion database

Abstract: We present a set of ground motion prediction equations (GMPEs) derived for the geometrical mean of the horizontal components and the vertical, considering the latest release of the strong motion database for Italy. The regressions are performed over the magnitude range 4–6.9 and considering distances up to 200 km. The equations are derived for peak ground acceleration (PGA), peak ground velocity (PGV) and 5%-damped spectral acceleration at periods between 0.04 and 2 s. The total standard deviation (sigma) varies between 0.34 and 0.38 log10 unit, confirming the large variability of ground shaking parameters when regional data sets containing small to moderate magnitude events (M < 6) are used. The between-stations variability provides the largest values for periods shorter than 0.2 s while, for longer periods, the between-events and between-stations distributions of error provide similar contribution to the total variability.

Probabilistic seismic demand analysis using advanced ground motion intensity measures

Abstract: One of the objectives in performance-based earthquake engineering is to quantify the seismic reliability of a structure at a site. For that purpose, probabilistic seismic demand analysis (PSDA) is used as a tool to estimate the mean annual frequency of exceeding a specified value of a structural demand parameter (e.g. interstorey drift). This paper compares and contrasts the use, in PSDA, of certain advanced scalar versus vector and conventional scalar ground motion intensity measures (IMs). One of the benefits of using a well-chosen IM is that more accurate evaluations of seismic performance are achieved without the need to perform detailed ground motion record selection for the nonlinear dynamic structural analyses involved in PSDA (e.g. record selection with respect to seismic parameters such as earthquake magnitude, source-to-site distance, and ground motion epsilon). For structural demands that are dominated by a first mode of vibration, using inelastic spectral displacement (Sdi) can be advantageous relative to the conventionally used elastic spectral acceleration (Sa) and the vector IM consisting of Sa and epsilon (e). This paper demonstrates that this is true for ordinary and for near-source pulse-like earthquake records. The latter ground motions cannot be adequately characterized by either Sa alone or the vector of Sa and e. For structural demands with significant higher-mode contributions (under either of the two types of ground motions), even Sdi (alone) is not sufficient, so an advanced scalar IM that additionally incorporates higher modes is used. Published in 2007 by John Wiley & Sons, Ltd.

Fragility Assessment of Light-Frame Wood Construction Subjected to Wind and Earthquake Hazards

Abstract: A fragility analysis methodology is developed for assessing the response of light-frame wood construction exposed to stipulated extreme windstorms and earthquakes. Performance goals and limit states (structural and nonstructural) are identified from a review of the performance of residential construction during recent hurricanes and earthquakes in the United States. Advanced numerical modeling tools provide a computational platform for risk analysis of light-frame wood building structural systems. The analysis is demonstrated for selected common building configurations and construction (defined, e.g., by roof sheathing, truss spacing, and roof or shear wall nailing patterns). Limit state probabilities of structural systems for the performance levels identified above are developed as a function of 3-s gust wind speed (hurricanes) and spectral acceleration (earthquakes), leading to a relation between limit state probabilities and the hazard stipulated in ASCE Standard 7, “Minimum design loads for buildings ...

Method for Probabilistic Evaluation of Seismic Structural Damage

Abstract: This paper presents a systematic approach for estimating fragility curves and damage probability matrices for different structural systems. Both fragility curves and damage probability matrices express the probabilities that a structure will sustain different degrees of damage at given ground motion levels. In contrast to previous approaches, this paper presents a method that is based on nonlinear dynamic analysis of the structure rather than on heuristics or on empirical data. The ground motion level for fragility curves is characterized by spectral acceleration. For damage probability matrices, modified Mercalli intensity is used as the ground motion parameter. The probabilities associated with the different damage states at a specified ground motion level are evaluated using the Monte Carlo-simulation technique. The nonstationary autoregressive moving average (ARMA) model is used for the generation of earthquake time histories. The approach presented in this paper is used to obtain fragility curves and damage probability matrices for reinforced concrete frames. Three different classes of reinforced concrete frames, based on the number of stories, are considered. Park and Ang’s damage index is used to identify the different degrees of damage.