WIT Press


Coherency Between Ground Motions Synthesized For Analysis Input Of A Large Span Structure

Price

Free (open access)

Paper DOI

10.2495/ERES110101

Volume

120

Pages

10

Page Range

113 - 122

Published

2011

Size

530 kb

Author(s)

X. Tao, H. Liu, J. Lu, X. Sun & H. Wang

Abstract

In order to fit the requirement of non-consistent input for seismic analysis of a large span structure with multi-supports, coherency of a synthesized ground motion field is validated in this paper. The result shows that the correlation between motions close to each other on rock site is strong, the mean values of coherencies are from 0.7 to 0.8, and the maximum is up to 1.0. The coherency decreases with the distance between the motion points. Correlation between low frequency motions close to each other on soil site is very strong, the mean of coherencies is larger than 0.8. The correlation of low frequency motions decreases also with the distance. The correlation between high frequency motions (>5Hz) is weak, the coherencies corresponding to various distances are all less than 0.5, and the mean is mostly less than 0.25. The result is consistent with the conclusion from the statistics of the observed data on some dense arrays like SMART-1 during the past earthquakes. Keywords: non-consistent input, ground motion, synthesis, coherency, multi-support. 1 Introduction Seismic risk of a large span structure is generally evaluated from response analysis, since there are very few experiences of this kind of structure during past earthquakes. Non-consistent input for seismic analysis of a large span structure with multi-supports is emphasized in the last decades, from the spatial variation

Keywords

non-consistent input, ground motion, synthesis, coherency,multi-support