Site-dependent spectra for earthquake-resistant design

1976 ◽  
Vol 66 (1) ◽  
pp. 221-243 ◽  
Author(s):  
H. Bolton Seed ◽  
Celso Ugas ◽  
John Lysmer
Keyword(s):  
United States ◽  
Statistical Analysis ◽  
Ground Motion ◽  
The United States ◽  
Design Criteria ◽  
Earthquake Resistant Design ◽  
Geological Conditions ◽  
Earthquake Resistant ◽  
Ground Motion Records ◽  
Spectral Shapes

abstract The paper presents the results of a statistical analysis of the spectral shapes of 104 ground-motion records obtained from 23 earthquakes, mostly in the western part of the United States. The analysis shows clear differences in spectral shapes for different soil and geological conditions, indicating the need for consideration of these effects in selecting earthquake-resistant design criteria.

Proposal of orientation-independent measure of intensity for earthquake-resistant design

2021 ◽  
pp. 875529302110382
Author(s):  
Alan Poulos ◽  
Eduardo Miranda
Keyword(s):  
United States ◽  
Ground Motion ◽  
The United States ◽  
Design Codes ◽  
Intensity Measure ◽  
Independent Measure ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant ◽  
Ground Motion Records ◽  
Structural Engineers

A new measure of ground motion intensity in the horizontal direction is proposed. Similarly to other recently proposed measures of intensity, the proposed intensity measure is also independent of the as-installed orientation of horizontal sensors at recording stations. This new measure of horizontal intensity, referred to as MaxRotD50, is defined using the maximum 5%-damped response spectral ordinate of two orthogonal horizontal directions and then computing the 50th percentile for all non-redundant rotation angles, that is, the median of the set of spectral ordinates in a range of 90°. This proposed measure of intensity is always between the median and maximum spectral ordinate for all non-redundant orientations, commonly referred to as RotD50 and RotD100, respectively. A set of 5065 ground motion records is used to show that MaxRotD50 is, on average, approximately 13%–16% higher than Rot50 and 6% lower than RotD100. The new measure of intensity is particularly well suited for earthquake-resistant design where a major concern for structural engineers is the probability that the design ground motion intensity is exceeded in at least one of the two principal horizontal components of the structure, which for most structures are orthogonal to each other. Currently, design codes in the United States are based on RotD100, and hence using MaxRotD50 for structures with two orthogonal principal horizontal components would result in a reduction of the ground motion intensities used for design purposes.

Site-Dependent Spectra Derived from Ground Motion Records in Turkey

2004 ◽  
Vol 20 (4) ◽  
pp. 1111-1138 ◽  
Author(s):  
Erol Kalkan ◽  
Polat Gülkan
Keyword(s):  
Ground Motion ◽  
Seismic Region ◽  
Data Set ◽  
Design Spectra ◽  
Attenuation Relationships ◽  
Scenario Earthquakes ◽  
Geological Conditions ◽  
Ground Motion Records ◽  
Strong Ground ◽  
Spectral Shapes

The current spectral shapes in the Turkish Seismic Code ( TSC) are based on broadly described geological conditions, ignoring fault distance or magnitude dependencies on spectral ordinates. To address this deficiency, a data set created from a suite of 112 strong ground motion records from 57 earthquakes that occurred between 1976 and 2003 has been used to develop horizontal attenuation relationships for Turkey. This way it is possible to construct hazard-consistent design spectra for any national seismic region. The results are compared with the site-dependent spectral shapes of the Uniform Building Code ( UBC) and the current TSC. It is shown that corner periods are consistent with those of UBC. TSC yields wider constant spectral acceleration plateau. Design spectra in both of these documents are conservative if the ground motion library that we used in deriving the spectral shapes is taken as representative. The results of this study enable site-distance–magnitude-specific design spectra suitable as a tool both for deterministic (scenario earthquakes) and probabilistic seismic hazard assessments.

scholarly journals The measurement of ground motion of destructive earthquakes

1963 ◽  
Vol 53 (2) ◽  
pp. 419-437
Author(s):  
D. E. Hudson
Keyword(s):  
United States ◽  
Transient Response ◽  
Strong Motion ◽  
The United States ◽  
Geodetic Survey ◽  
Natural Period ◽  
Earthquake Resistant Design ◽  
Earthquake Resistant ◽  
The World ◽  
Structural Engineers

abstract The need for a greatly expanded network of strong-motion accelerographs throughout the seismic regions of the world is stressed. A summary of the characteristics of currently available strong-motion accelerographs is presented, and the design details are given for an instrument suitable for acquiring the basic data needed by structural engineers for earthquake resistant design. It is shown that for such an instrument, the natural period must be less than 0.1 seconds, and that the recording speed must be at least 1 cm/sec. The critical nature of the inertia starting device is discussed, and some information is given on the transient response of the standard pendulum starter used in the United States Coast and Geodetic Survey Strong-Motion Accelerograph. The use of simpler, non-time-recording instruments such as the U.S.C.G.S. Seismoscope to supplement the accelerograph network is described.

Who Wins and Who Loses in the Provincial Courts of Appeal? A Statistical Analysis, 1920–1990

1994 ◽  
Vol 9 (2) ◽  
pp. 21-40 ◽  
Author(s):  
Peter McCormick
Keyword(s):  
United States ◽  
Statistical Analysis ◽  
Great Britain ◽  
Data Base ◽  
The United States ◽  
Different Types ◽  
Party Capability ◽  
Time Periods ◽  
Appeal Courts ◽  
Different Levels

AbstractGiven the visibility and obvious importance of judicial power in the age of the Charter, it is important to develop the conceptual vocabulary for desribing and assessing this power. One such concept that has been applied to the study of appeal courts in the United States and Great Britain is “party capability”, a theory which suggests that different types of litigant will enjoy different levels of success as both appellant and respondent. Using a data base derived from the reported decisions of the provincial courts of appeal for the second and seventh year of each decade since the 1920s, this article applies party capability theory to the performance of the highest courts of the ten provinces; comparisons are attempted across regions and across time periods, as well as with the findings of similar studies of American and British courts.

scholarly journals COVID-19 In United States: Statistical Analysis and Inferences From the Empirical Data

2021 ◽  
Author(s):  
Nivedita Rethnakar
Keyword(s):  
United States ◽  
Statistical Analysis ◽  
Statistical Inference ◽  
Empirical Data ◽  
Respiratory Diseases ◽  
Temporal Dynamics ◽  
The United States ◽  
Mortality Statistics ◽  
Race Ethnicity ◽  
The Impact

Abstract This paper investigates the mortality statistics of the COVID-19 pandemic from the United States perspective. Using empirical data analysis and statistical inference tools, we bring out several exciting and important aspects of the pandemic, otherwise hidden. Specific patterns seen in demo- graphics such as race/ethnicity and age are discussed both qualitatively and quantitatively. We also study the role played by factors such as population density. Connections between COVID-19 and other respiratory diseases are also covered in detail. The temporal dynamics of the COVID-19 outbreak and the impact of vaccines in controlling the pandemic are also looked at with suf- ficient rigor. It is hoped that statistical inference such as the ones gathered in this paper would be helpful for better scientific understanding, policy prepa- ration and thus adequately preparing, should a similar situation arise in the future.

A comparison of earthquake damage areas as a function of magnitude across the United States

1993 ◽  
Vol 83 (4) ◽  
pp. 1064-1080 ◽  
Author(s):  
G. A. Bollinger ◽  
M. C. Chapman ◽  
M. S. Sibol
Keyword(s):  
United States ◽  
North America ◽  
Ground Motion ◽  
Epicentral Distance ◽  
The United States ◽  
Western United States ◽  
Eastern North America ◽  
Similar Response ◽  
Eastern United States ◽  
The West

Abstract This study investigates the relationship between earthquake magnitude and the size of damage areas in the eastern and western United States. To quantify damage area as a function of moment magnitude (M), 149 MMI VI and VII areas for 109 earthquakes (88 in the western United States, 21 in the eastern United States and Canada) were measured. Regression of isoseismal areas versus M indicated that areas in the East were larger than those in the West, at both intensity levels, by an average 5 × in the M 4.5 to 7.5 range. In terms of radii for circles of equivalent area, these results indicate that damaging ground motion from shocks of the same magnitude extend 2 × the epicentral distance in eastern North America compared to the West. To determine source and site parameters consistent with the above results, response spectral levels for eastern North America were stochastically simulated and compared with response spectral ordinates derived from recorded strong ground motion data in the western United States. Stress-drop values of 200 bars, combined with a surficial 2-km-thick low velocity “sedimentary” layer over rock basement, produced results that are compatible with the intensity observations, i.e., similar response spectral levels in the east at approximately twice their epicentral distance in the western U.S. distance. These results suggest that ground motion modeling in eastern North America may need to incorporate source and site parameters different from those presently in general use. The results are also of importance to eastern U.S. hazard assessments as they require allowance for the larger damage areas in preparedness and mitigation programs.

An Analysis of Unmanned Aircraft Registration Effectiveness

2017 ◽  
Vol 4 (1) ◽  
pp. 54-66
Author(s):  
Ronald Pentz ◽  
He (Herman) Tang
Keyword(s):  
United States ◽  
Statistical Analysis ◽  
The United States ◽  
Unmanned Aircraft ◽  
Unmanned Aircraft Systems ◽  
Courts Of Appeals ◽  
Chi Square ◽  
Difficult Time ◽  
Significant Difference ◽  
Rapid Pace

This article describes how small unmanned aircraft systems (sUAS) are growing at a rapid pace. They are inexpensive and widely available for both hobbyist and commercial use. However, with this rapid growth, regulations are having a difficult time keeping pace to safely incorporate them into the United States National Airspace. Recent regulations requiring the registration of all sUAS have been overturned by the United States Courts of Appeals. This research provides a statistical analysis of the effectiveness of the registration regulation in the reduction of unauthorized and careless sUAS operation prior to being overturned by the courts. Statistical analysis including descriptive statistics and chi square hypothesis tests were used to analyze more than 3,000 reported unauthorized and careless events. The findings show a significant difference in events pre-registration and post registration.

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