As an example, the procedure for constructing a standardized DBE response spectrum based

DOE-STD-1023-95

(3)

Numerical modeling

The median response spectrum shape is calculated from numerical models such as

band-width-limited-white-noise/random vibration theory models benchmarked

against response spectra from actual ground motion records associated with

magnitudes, distances, and soil profiles as similar to those of the site under study.

For this method, the input parameters, the numerical model used, and the validation

of the appropriateness of the model shall be documented.

A3.1.3.2-a. As an example, the procedure for constructing a standardized DBE response spectrum based

on Newmark and Hall (1978), using the authors' original units, is summarized below:

(1) Determine the horizontal ground motion parameters: PGA, PGV, and PGD.

a. Obtain the design basis mean peak ground acceleration (PGA) in units of "g"

based on a site specific probabilistic seismic hazard assessment.

b. For a competent alluvium site with Vs (shear wave velocity) < 3500 ft/sec,

determine the peak ground velocity (PGV) in "in/sec" and peak ground

displacement (PGD) in "in" by the following formulas:

PGV = 48 PGA

PGD = 36 PGA

c. For a rock site with Vs > 3500 ft/sec, determine PGV and PGD by the following

formulas:

PGV = 36 PGA

PGD = 20 PGA

(2) Determine the maximum amplified response acceleration (amax), velocity (vmax), and

displacement (dmax) for median spectra (50th percentile):

amax = PGA (3.21 - 0.68 ln )

vmax = PGV (2.31 - 0.41 ln )

dmax = PGD (1.82 - 0.27 ln )

where "" is the critical damping ratio in "percent" and "ln" is the natural logarithm.

A-7