Significance of Rotating Ground Motions on Behavior of Symmetric- and Asymmetric-Plan Structures: Part I. Single-Story Structures

2015 ◽  
Vol 31 (3) ◽  
pp. 1591-1612 ◽  
Author(s):  
Juan C. Reyes ◽  
Erol Kalkan
Keyword(s):  
Statistical Evaluation ◽  
Rotation Angle ◽  
Ground Motions ◽  
Three Dimensional ◽  
Normal Fault ◽  
Near Fault ◽  
Earthquake Ground Motions ◽  
History Analysis ◽  
Response History Analysis ◽  
Design Values

The California Building Code requires at least two ground motion components for the three-dimensional (3-D) response history analysis (RHA) of structures. For near-fault sites, these records should be rotated to fault-normal/fault-parallel (FN/FP) directions, and two RHA analyses should be performed separately. This approach is assumed to lead to two sets of responses that envelope the range of possible responses over all non-redundant rotation angles. This assumption is examined here using 3-D computer models of single-story structures having symmetric and asymmetric plans subjected to a suite of bidirectional earthquake ground motions. The influence that the rotation angle has on several engineering demand parameters is investigated in linear and nonlinear domains to evaluate the use of the FN/FP directions, and the maximum direction (MD). The statistical evaluation suggests that RHAs should be conducted by rotating a set of records to the MD and FN/FP directions, and taking the maximum response values from these analyses as design values.

scholarly journals Significance of Rotating Ground Motions on Behavior of Symmetric- and Asymmetric-Plan Structures: Part II. Multi-Story Structures

2015 ◽  
Vol 31 (3) ◽  
pp. 1613-1628 ◽  
Author(s):  
Erol Kalkan ◽  
Juan C. Reyes
Keyword(s):  
Ground Motion ◽  
Nonlinear Response ◽  
Rotation Angle ◽  
Ground Motions ◽  
Three Dimensional ◽  
Companion Paper ◽  
Apparent Velocity ◽  
Near Fault ◽  
Design Values ◽  
Linear And Nonlinear

The influence of the ground motion rotation angle on engineering demand parameters (EDPs) is examined in the companion paper based on three-dimensional (3-D) computer models of single-story structures. Further validations are performed here using 3-D models of nine-story buildings that have symmetric and asymmetric layouts subjected to a suite of bi-directional near-fault records with and without apparent velocity-pulses. The linear and nonlinear response-history analyses (RHAs) are used for evaluating the use of fault-normal and fault-parallel (FN/FP) directions and maximum-direction (MD) to rotate ground motions. This study suggests that individual ground motions rotated to MD or FN/FP directions not always provide conservative EDPs in nonlinear range, but often produce larger EDPs than as-recorded motions. In practice, when a suite of ground motions is used, nonlinear RHAs should be performed by rotating them to the MD and FN/FP directions, and maximum response values should be taken from these analyses as design values.

Correlation of Near-Fault Ground Motions for Western United States

2012 ◽  
Author(s):  
Yin-Nan Huang
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Correlation Coefficients ◽  
Nuclear Facilities ◽  
Design Standards ◽  
Near Fault ◽  
History Analysis ◽  
Orthogonal Components ◽  
Response History Analysis ◽  
Ground Motion Records

Design standards for safety-related nuclear facilities such as ASCE Standard 4-98 and ASCE Standard 43-05 require the correlation coefficient for two orthogonal components of ground motion for response-history analysis to be less than 0.3. The technical basis of this requirement was developed by Hadjian three decades ago using 50 pairs of recorded ground motions that were available at that time. Since then a significant number of ground-motion records have been acquired. The limiting value of 0.3 presented in ASCE Standards 4-98 and 43-05 is re-evaluated in this study using records from large ground-motion databases compiled recently for the near-fault WUS sites. In the past several years, research has addressed the correlation of spectral demand at different periods as well as its impact on the performance of structures. In this paper, the correlation coefficients of maximum spectral demands at different periods were computed and compared with those for geomean spectral demand developed by Baker and Jayaram.

A subset of CyberShake ground-motion time series for response-history analysis

2021 ◽  
pp. 875529302098197
Author(s):  
Jack W Baker ◽  
Sanaz Rezaeian ◽  
Christine A Goulet ◽  
Nicolas Luco ◽  
Ganyu Teng
Keyword(s):  
Time Series ◽  
Los Angeles ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Motions ◽  
Response Spectra ◽  
Motion Time ◽  
History Analysis ◽  
Response History Analysis ◽  
Simulated Ground Motions

This manuscript describes a subset of CyberShake numerically simulated ground motions that were selected and vetted for use in engineering response-history analyses. Ground motions were selected that have seismological properties and response spectra representative of conditions in the Los Angeles area, based on disaggregation of seismic hazard. Ground motions were selected from millions of available time series and were reviewed to confirm their suitability for response-history analysis. The processes used to select the time series, the characteristics of the resulting data, and the provided documentation are described in this article. The resulting data and documentation are available electronically.

Performance of bi-directional elliptical rolling rods for base isolation of buildings under near-fault earthquakes

2017 ◽  
Vol 21 (5) ◽  
pp. 675-693 ◽  
Author(s):  
Aruna Rawat ◽  
Naseef Ummer ◽  
Vasant Matsagar
Keyword(s):  
Base Isolation ◽  
Ground Motions ◽  
Frictional Resistance ◽  
Curved Surface ◽  
Isolation System ◽  
Near Fault ◽  
Earthquake Ground Motions ◽  
Base Isolation System ◽  
Near Fault Earthquakes ◽  
Storey Building

Rolling base isolation system provides effective isolation to the structures from seismic base excitations by virtue of its low frictional resistance. Herein, dynamic analysis of flexible-shear type multi-storey building mounted on orthogonally placed elliptical rolling rod base isolation systems subjected to bi-directional components of near-fault earthquake ground motions is presented. The orthogonally placed rods would make it possible to resist the earthquake forces induced in the structure in both the horizontal directions. The curved surface of these elliptical rods has a self-restoring capability due to which the magnitude of peak isolator displacement and residual displacement is reduced. The roughness of the tempered curved surface of the rollers dissipates energy in motion due to frictional damping. The seismic performance of the multi-storey building mounted on the elliptical rolling rod base isolation system is compared with that mounted on the sliding pure-friction and cylindrical rolling rod systems. Parametric studies are conducted to examine the behavior of the building for different superstructure flexibilities, eccentricities of the elliptical rod, and coefficients of friction. It is concluded that the elliptical rolling rod base isolation system is effective in mitigation of damaging effects of the near-fault earthquake ground motions in the multi-storey buildings. Even under the near-fault earthquake ground motions, the base-isolated building mounted on the elliptical rolling rods shows considerable reduction in seismic response. The isolator displacement with the elliptical rolling rod base isolation system is less in comparison to the pure-friction and cylindrical rolling rod systems.

Evaluation of Hybrid Broadband Ground Motion Simulations for Response History Analysis and Design

2015 ◽  
Vol 31 (3) ◽  
pp. 1691-1710 ◽  
Author(s):  
Lynne S. Burks ◽  
Reid B. Zimmerman ◽  
Jack W. Baker
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Spectral Response ◽  
Analysis And Design ◽  
History Analysis ◽  
Response History Analysis ◽  
Simulated Ground Motions ◽  
Broadband Ground Motion ◽  
New Buildings ◽  
Selection Of

Chapter 16 of ASCE 7 governs the selection of ground motions for analysis of new buildings and requires recordings that meet specified criteria. If a sufficient number of recordings cannot be found, it allows the use of “appropriate simulated ground motions,” but does not provide further guidance. This paper outlines a procedure for generating and selecting a set of “appropriate” hybrid broadband simulations and a comparable set of recordings. Both ground motion sets are used to analyze a building in Berkeley, California, and the predicted structural performance is compared. The structural behavior resulting from recordings and simulations is similar, and most discrepancies are explained by differences in directional properties such as orientation of the maximum spectral response. These results suggest that when simulations meet the criteria outlined for recordings in ASCE 7 and properties such as directionality are realistically represented, simulations provide useful results for structural analysis and design.

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