scholarly journals Isolated Buildings and the 1997 UBC Near-Source Factors

2000 ◽  
Vol 16 (2) ◽  
pp. 393-411 ◽  
Author(s):  
John F. Hall ◽  
Keri L. Ryan
Keyword(s):  
Computer Simulations ◽  
Ground Motions ◽  
Strong Motion ◽  
The Other ◽  
Structural Behavior ◽  
Northridge Earthquake ◽  
Ground Displacement ◽  
Source Effects ◽  
Supplemental Damping ◽  
Supplemental Dampers

Computer simulations are employed to assess the effects of near-source ground motions on base-isolated buildings that meet the provisions of the 1997 Uniform Building Code. A six-story base-isolated building designed for Nv = 1.6 exhibits essentially elastic structural behavior when subjected to six actual ground motions containing strong near-source effects. However, two simulated records, one intended to represent the most severe motions from the 1994 Northridge earthquake and the other a strong motion from a hypothetical Mw7.0 thrust earthquake produce larger responses well into the nonlinear range. In addition, a 113 cm ground displacement pulse of three-second duration, which is close to the period of the isolated buildings, causes story drifts of nearly 5% for the Nv = 1.6 design and over 2% for a stronger Nv = 2 design. Such drifts are effectively reduced when supplemental dampers are added alongside the isolators. The original Nv = 1.6 design with supplemental damping in the amount of 20% of critical experiences only 1.3% drift for the same three-second ground displacement pulse.

Seismic Response of a Hill in Wenxian, Gansu, Observed from Aftershocks of 2008 Wenchuan Earthquake

2011 ◽  
Vol 243-249 ◽  
pp. 3952-3957 ◽  
Author(s):  
Yu Xia Lu ◽  
Kun Liu ◽  
Yu Cheng Shi ◽  
Qian Li
Keyword(s):  
Site Response ◽  
Ground Motions ◽  
Strong Motion ◽  
Spectral Ratio ◽  
Gansu Province ◽  
Spectra Analysis ◽  
2008 Wenchuan Earthquake ◽  
Motion Data ◽  
Source Effects ◽  
The Hill

To help understand the ground motions of the topographic site, the workers of Seismic Bureau of Gansu province deployed a temporary array of seismometers around the Wenxian hill and recorded ground motions from Wenchuan aftershocks. Only 11 aftershocks were recorded on all stations across the hill, these data were collected to facilitate studies of site response, wave propagation effect, and correlations of mainshock damage with local site conditions. In this paper, we analyze the weak motion data as well as the strong-motion data, and conduct comparisons of peak ground accelerations, seismic spectra analysis, and spectral ratio analysis. A more complete description of the site’s amplification, its relationship to topography, and its relationship to earthquake source effects are provided. The result shows that the ground motion was consistently amplified at station at or near the top of the hill compared with stations at the base of the hill and the amplifications frequency dependent and has its maximum at the resonant frequency of the site.

Seismic response of instrumented structures during the 1994 Northridge, California, earthquake

1995 ◽  
Vol 22 (2) ◽  
pp. 316-337 ◽  
Author(s):  
Carlos E. Ventura ◽  
W. D. Liam Finn ◽  
Norman D. Schuster
Keyword(s):  
Earthquake Engineering ◽  
Structural Damage ◽  
Ground Motions ◽  
Structural Response ◽  
Strong Motion ◽  
Companion Paper ◽  
Northridge Earthquake ◽  
Acceleration Amplification ◽  
Comprehensive Information ◽  
Instrumental Records

This paper presents an overview of strong motion records obtained from instrumented structures during the 1994 Northridge earthquake. It describes the behaviour of buildings, bridges, and dams that have been instrumented by the major strong motion instrumentation networks operating in California and highlights important features of the most significant structural motions recorded during the earthquake. The structural damage observed during a reconnaissance visit to the affected areas by the earthquake is correlated with preliminary analyses of the recorded motions. Detailed discussions of the dynamic behaviour of two instrumented reinforced concrete buildings that suffered damage during the earthquake are presented. The behaviour of these buildings during previous earthquakes is also examined. This paper and the companion paper on ground motions provide comprehensive information about instrumental records obtained in the region affected by the earthquake. Key words: earthquake engineering, structural response, strong motion instrumentation, damage evaluation, buildings, bridges, dams, structural dynamics, acceleration, amplification.

Engineering implications of ground motions from the Northridge earthquake

1996 ◽  
Vol 86 (1B) ◽  
pp. S270-S288 ◽  
Author(s):  
Susan W. Chang ◽  
Jonathan D. Bray ◽  
Raymond B. Seed
Keyword(s):  
Site Response ◽  
Ground Motions ◽  
Free Field ◽  
Strong Motion ◽  
Site Amplification ◽  
Northridge Earthquake ◽  
Horizontal Acceleration ◽  
Predictive Relationships ◽  
Stiff Soil ◽  
Maximum Horizontal Acceleration

Abstract The magnitude, duration, and frequency content of ground motions from the Northridge earthquake are analyzed and compared to predictive relationships typically used in engineering design and to the 1994 Uniform Building Code (UBC). A relationship between maximum horizontal acceleration on soil versus maximum horizontal acceleration on rock is presented based on strong-motion recordings at free-field sites. The effect of geologic conditions on localized damage patterns is shown to be important for this earthquake, although many of the sites within the affected region are stiff soil sites classified as S1 or S2 sites by the UBC. The results of preliminary seismic site response analyses performed at two deep alluvial sites indicate that much of the observed site amplification can be captured by one-dimensional wave propagation analyses.

Ground-motion model for subduction earthquakes in northern South America

2021 ◽  
pp. 875529302110275
Author(s):  
Carlos A Arteta ◽  
Cesar A Pajaro ◽  
Vicente Mercado ◽  
Julián Montejo ◽  
Mónica Arcila ◽  
...  
Keyword(s):  
South America ◽  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Motion Prediction ◽  
Depth Range ◽  
Ground Motion Prediction ◽  
Natural Period ◽  
Nazca Plate ◽  
Northern South America

Subduction ground motions in northern South America are about a factor of 2 smaller than the ground motions for similar events in other regions. Nevertheless, historical and recent large-interface and intermediate-depth slab earthquakes of moment magnitudes Mw = 7.8 (Ecuador, 2016) and 7.2 (Colombia, 2012) evidenced the vast potential damage that vulnerable populations close to earthquake epicenters could experience. This article proposes a new empirical ground-motion prediction model for subduction events in northern South America, a regionalization of the global AG2020 ground-motion prediction equations. An updated ground-motion database curated by the Colombian Geological Survey is employed. It comprises recordings from earthquakes associated with the subduction of the Nazca plate gathered by the National Strong Motion Network in Colombia and by the Institute of Geophysics at Escuela Politécnica Nacional in Ecuador. The regional terms of our model are estimated with 539 records from 60 subduction events in Colombia and Ecuador with epicenters in the range of −0.6° to 7.6°N and 75.5° to 79.6°W, with Mw≥4.5, hypocentral depth range of 4 ≤  Zhypo ≤ 210 km, for distances up to 350 km. The model includes forearc and backarc terms to account for larger attenuation at backarc sites for slab events and site categorization based on natural period. The proposed model corrects the median AG2020 global model to better account for the larger attenuation of local ground motions and includes a partially non-ergodic variance model.

scholarly journals Simulation of non-stationary stochastic ground motions based on recent Italian earthquakes

2021 ◽  
Author(s):  
Fabio Sabetta ◽  
Antonio Pugliese ◽  
Gabriele Fiorentino ◽  
Giovanni Lanzano ◽  
Lucia Luzi
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Strong Motion ◽  
Stochastic Simulations ◽  
Model Parameters ◽  
Motion Model ◽  
Arias Intensity ◽  
Time Frequency ◽  
Ground Motion Model ◽  
Ground Motion Records

AbstractThis work presents an up-to-date model for the simulation of non-stationary ground motions, including several novelties compared to the original study of Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996). The selection of the input motion in the framework of earthquake engineering has become progressively more important with the growing use of nonlinear dynamic analyses. Regardless of the increasing availability of large strong motion databases, ground motion records are not always available for a given earthquake scenario and site condition, requiring the adoption of simulated time series. Among the different techniques for the generation of ground motion records, we focused on the methods based on stochastic simulations, considering the time- frequency decomposition of the seismic ground motion. We updated the non-stationary stochastic model initially developed in Sabetta and Pugliese (Bull Seism Soc Am 86:337–352, 1996) and later modified by Pousse et al. (Bull Seism Soc Am 96:2103–2117, 2006) and Laurendeau et al. (Nonstationary stochastic simulation of strong ground-motion time histories: application to the Japanese database. 15 WCEE Lisbon, 2012). The model is based on the S-transform that implicitly considers both the amplitude and frequency modulation. The four model parameters required for the simulation are: Arias intensity, significant duration, central frequency, and frequency bandwidth. They were obtained from an empirical ground motion model calibrated using the accelerometric records included in the updated Italian strong-motion database ITACA. The simulated accelerograms show a good match with the ground motion model prediction of several amplitude and frequency measures, such as Arias intensity, peak acceleration, peak velocity, Fourier spectra, and response spectra.

A Suite of Alternative Ground-Motion Models (GMMs) for Israel

2021 ◽  
Author(s):  
Soumya Kanti Maiti ◽  
Gony Yagoda-Biran ◽  
Ronnie Kamai
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Empirical Data ◽  
Epistemic Uncertainty ◽  
Ground Motions ◽  
Plate Boundary ◽  
Strong Motion ◽  
Engineering Applications ◽  
Motion Models ◽  
Ground Motion Models

ABSTRACT Models for estimating earthquake ground motions are a key component in seismic hazard analysis. In data-rich regions, these models are mostly empirical, relying on the ever-increasing ground-motion databases. However, in areas in which strong-motion data are scarce, other approaches for ground-motion estimates are sought, including, but not limited to, the use of simulations to replace empirical data. In Israel, despite a clear seismic hazard posed by the active plate boundary on its eastern border, the instrumental record is sparse and poor, leading to the use of global models for hazard estimation in the building code and all other engineering applications. In this study, we develop a suite of alternative ground-motion models for Israel, based on an empirical database from Israel as well as on four data-calibrated synthetic databases. Two host models are used to constrain model behavior, such that the epistemic uncertainty is captured and characterized. Despite the lack of empirical data at large magnitudes and short distances, constraints based on the host models or on the physical grounds provided by simulations ensure these models are appropriate for engineering applications. The models presented herein are cast in terms of the Fourier amplitude spectra, which is a linear, physical representation of ground motions. The models are suitable for shallow crustal earthquakes; they include an estimate of the median and the aleatory variability, and are applicable in the magnitude range of 3–8 and distance range of 1–300 km.

Epicentral intensities and damage in the Hebgen Lake, Montana, earthquake of August 17, 1959

1962 ◽  
Vol 52 (2) ◽  
pp. 181-234
Author(s):  
Karl V. Steinbrugge ◽  
William K. Cloud
Keyword(s):  
Ground Motions ◽  
Strong Motion ◽  
Fault Scarp ◽  
Rock Falls ◽  
Small Unit ◽  
The Earth ◽  
Major Fault ◽  
Seismograph Station ◽  
Fault Scarps ◽  
Earth Fill

ABSTRACT An extensive fault scarp system was formed during the Hebgen Lake earthquake of August 17, 1959 (11:37:15 p.m., M.S.T., Gutenberg-Richter magnitude 7.1). Bedrock beneath Hebgen Lake warped, rotated, and caused a seiche in the lake. A major landslide dammed Madison Canyon, causing a lake to form above the slide. An estimated 19 persons were buried by the slide. Other slides and rock falls took out sections of the main highway north of Hebgen Lake and closed many roads in Yellowstone Park. Small unit masonry structures as well as wooden buildings along the major fault scarps usually survived with little damage when subjected only to vibratory forces. The unit masonry buildings, in particular, had little or no earthquake bracing. Intensity at the major scarp has been given a Modified Mercalli Scale rating of X. However, the maximum intensity ratings based on vibratory motion even a few feet away from the scarps were VII or VIII. Within the limits of observation there was little or no reduction in vibratory intensity 5 to 10 miles away compared to that at the fault. This is not to say that the ground motions were similar. At the closest strong-motion seismograph station (Bozeman, 58 miles from the epicenter) maximum recorded acceleration was about 7 per cent gravity. The earthquake was generally felt in about a 600,000 square mile area, mostly north of the instrumental epicenter. The earth-fill Hebgen Dam was within 1000 feet of a major scarp. The dam was significantly damaged, but it continued to be an effective structure.

scholarly journals A Double Sky-Hook Algorithm for Improving Road-Holding Property in Semi-Active Suspension Systems for Application to In-Wheel Motor

2021 ◽  
Vol 11 (19) ◽  
pp. 8912
Author(s):  
Seunghoon Woo ◽  
Donghoon Shin
Keyword(s):  
Computer Simulations ◽  
Dynamic Models ◽  
Active Suspension ◽  
The Other ◽  
Driving Mode ◽  
The Road ◽  
Suspension Systems ◽  
Active Suspension Systems ◽  
Main Disadvantage ◽  
Advanced Development

This paper presents a double sky-hook algorithm for controlling semi-active suspension systems in order to improve road-holding property for application in an in-wheel motor. The main disadvantage of the in-wheel motor is the increase in unsprung masses, which increases after shaking of the wheel, so it has poor road-holding that the conventional theoretical sky-hook algorithm cannot achieve. The double sky-hook algorithm uses a combination of damper coefficients, one from the chassis motion and the other from the wheel motion. Computer simulations using a quarter and full car dynamic models with the road conditions specified by ISO2631 showed the effectiveness of the algorithm. It was observed that the algorithm was the most effective in the vicinity of the wheel hop frequency. This paper also proposed the parameter set of the double sky-hook algorithm to differentiate the driving mode of vehicles under advanced development.

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