ABSTRACT
An improved ASCE/SEI 7–10 ground-motion scaling procedure for three-dimensional (3D) response history analysis (RHA) of buildings is presented. In this procedure, different scale factors for two horizontal components of the ground motion are used, and their spectral shapes are considered in ground-motion selection stage. The accuracy of the improved procedure is evaluated by utilizing 3D models of nine asymmetric-plan buildings. It is demonstrated that the improved procedure provides on average 15% conservative estimates of engineering demand parameters while the original version underestimates them on average 29%. Thus, the improved ground-motion selection and scaling procedure is found to be appropriate for nonlinear RHAs of multi-story plan-asymmetric buildings.
Nomenclature
The following symbols and abbreviations are used in this paper:
median value of
median value of
target pseudo-acceleration spectrum in x-direction
vector of spectral values
5%-damped response spectrum for x-component
vector of spectral values
target pseudo-acceleration spectra for y-direction
vector of spectral values
5%-damped response spectrum for y-component
vector of spectral values
number of ground-motion records in a set
L plan asymmetric about x- and y-axes
number of sets of records
total number of vibration modes considered
R quasi-rectangular plan
RJB Joyner–Boore distance
final scale factor for horizontal component of record
final scale factor for horizontal component of record
first scale factor for horizontal component of record
first scale factor for horizontal component of record
second scale factor for horizontal component of record
second scale factor for horizontal component of record
T plan symmetric about y-axis
vibration period
median of a log-normal distribution
torsional irregularity factor
maximum story drift
average story drift
maximum normalized difference for horizontal component of record
maximum normalized difference for horizontal component of record
plastic rotation
yield rotation
mean of a log-normal distribution
geometric mean of a log-normal distribution
Acknowledgments
The authors would like to thank Charlie Kircher, Kishor Jaiswal, Brad Aagaard, Jamie Steidl, and three anonymous reviewers for their critical reviews, constructive comments, and editorial suggestions, which improved technical content and presentation of this paper.
Data and resources
Ground-motion records used in this study are available from the University of California, Berkeley Pacific Earthquake Engineering Research Center Ground-Motion Database at https://ngawest2.berkeley.edu/(last accessed on May 2018). The ground-motion selection and scaling procedure proposed herein are available as a MatLAB® function. This function and finite element models developed for this study are available from the authors upon request.