Existing spectral matching techniques in the
frequency domain distort the displacement time history of the ground
motions. This study shows that the velocity value at the end of the
record is not affected by Fourier amplitude spectrum scaling but the
displacement may linearly increase (or decrease) boundlessly. Two
numerical solutions are proposed to solve the displacement drift
problem in the frequency domain. Following the proposed frequency
domain baseline correction procedure, one does not need to perform
a baseline correction in the time domain after completing the
spectral matching. As a result, acceleration, velocity, and
displacement time histories will remain fully compatible and the
boundary conditions of the velocity and displacement time histories
will be preserved. The proposed procedure is not limited to spectrum
matching methods and can be used with any general filtering process
to retain the final displacement of the record.
The possibility of applying a zeropadding technique
to the spectral matching filter is also discussed. It is shown that
applying an appropriate window along with the zeropadding technique
can lead to a reasonable displacement time history. The proposed
procedures can be easily added to existing or new frequency domain
spectral matching algorithms without significantly disrupting the
spectral matching process.
 Ground Motion Prediction Models
In the field of earthquake engineering,
groundmotion prediction models are frequently used to estimate the
peak ground motion (PGA) and the pseudo spectral acceleration (PSA).
In regions of the world where groundmotion recordings are plentiful
(such as WNA), the groundmotion prediction equations are obtained
using empirical methods. In other regions such as eastern North
America (ENA), with insufficient groundmotion data, other methods
must be used to develop groundmotion prediction equations. The
hybrid empirical method is one such method used to develop
groundmotion prediction equations in areas with sparse ground
motion. This method uses the stochastic method to adjust empirical
groundmotion prediction relations developed for a region with
abundant strong motion recordings. It estimates strongmotion
parameters in a region with a sparse database. The adjustments take
into account differences in the earthquake source, wave propagation,
and siteresponse characteristics between the two regions. The
purpose of this study is to use a hybrid empirical method and to
develop a new hybrid empirical groundmotion prediction equation for
ENA, using five new groundmotion prediction models developed by the
Pacific Earthquake Engineering Research Center (PEER) for WNA. A new
functional form is defined for the groundmotion prediction relation
for a magnitude range of 5 to 8 and closest distances to the fault
rupture up to 1000 km. Groundmotion prediction equations are
developed for the response spectra (pseudoacceleration, 5% damped)
and the peak ground acceleration (PGA) for hardrock sites in ENA.
The resulting groundmotion prediction model developed in this study
is compared with recent groundmotion prediction relations developed
for ENA, as well as with available observed data for ENA.
 Riskbased seismic design for optimal
structural and nonstructural system performance
An automated performancebased design
methodology to optimize structural and nonstructural system
performance is outlined and it is shown that it can be used to
enhance understanding of structural steel system design for minimum
lifecycle costs. Performance is assessed using loss probability
with direct economic loss expressed as a percentage of the building
replacement cost. Timebased performance assessment is used to
compute the expected annual loss of a given steel framing system
assuming exposure to three seismic hazard levels. Damage to the
structural system, nonstructural displacementsensitive components,
and nonstructural accelerationsensitive components is
characterized using fragility functions. A steel building with
threestory, fourbay topology taken from the literature is used to
demonstrate application of the algorithm with subsequent comparison
of designs obtained using the proposed methodology and others found
in the literature.
