NEHRP Clearinghouse

Title
Accelerogram Processing Using Reliability Bounds and Optimal Correction Methods.
File
PB91170209.pdf
Author(s)
Levine, M. B. P.
Source
National Science Foundation, Washington, DC., cJanuary 1990, 303 p.
Identifying Number(s)
EERL-90-02
Abstract
The study addresses the problem of obtaining reliable velocities and displacements from accelerograms, a concern which often arises in earthquake engineering. A closed-form acceleration expression with random parameters is developed to test any strong-motion accelerogram processing method. Integration of the analytical time history yields the exact velocities, displacements and Fourier spectra. Noise and truncation can also be added. A two-step testing procedure is proposed and the original Volume II routine is used as an illustration. The main sources of error are identified and discussed. Although these errors may be reduced, it is impossible to extract the true time histories from an analog or digital accelerogram because of the uncertain noise level and missing data. Based on these uncertainties, a probabilistic approach is proposed as a new accelerogram processing method. A most probable record is presented as well as a reliability interval which reflects the level of error-uncertainty introduced by the recording and digitization process. The data is processed in the frequency domain, the discussed correction method has been applied to existing strong-motion far-field, near-field, and structural data with promising results.
Keywords
Ground motion; Velocity measurement; Error analysis; Earthquake engineering; Theses; Displacement measurement; Time domain; Accelerograms; Frequency domain; California; Imperial Valley Earthquake