Premium
Application of stochastic subspace identification for stay cables with an alternative stabilization diagram and hierarchical sifting process
Author(s) -
Wu WenHwa,
Wang ShengWei,
Chen ChienChou,
Lai Gwolong
Publication year - 2016
Publication title -
structural control and health monitoring
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.587
H-Index - 62
eISSN - 1545-2263
pISSN - 1545-2255
DOI - 10.1002/stc.1836
Subject(s) - subspace topology , modal , identification (biology) , operational modal analysis , process (computing) , vibration , modal analysis , diagram , range (aeronautics) , deck , engineering , computer science , control theory (sociology) , algorithm , structural engineering , mathematics , acoustics , statistics , artificial intelligence , finite element method , chemistry , botany , physics , control (management) , polymer chemistry , biology , aerospace engineering , operating system
Summary The modal parameters of numerous modes for a stay cable are usually required in engineering practice. The application of conventional stochastic subspace identification techniques without delicate cautions, however, has been found to be unsuccessful in this case. Aiming to attack such a difficulty, this study establishes a new methodology based on the covariance type of stochastic subspace identification for extensively identifying the modal parameters of a stay cable. Several details of choosing the parameters in performing stochastic subspace identification are first discussed. An important discovery is that the lower limit for setting the time lag parameter can be decided by the ratio of the fundamental period of cable to the sampling time increment for a valid identification with the conventional stabilization diagram. Inspired by the aforementioned criterion, an alternative stabilization diagram is further proposed to more conveniently distinguish stable modal parameters of cable. A hierarchical sifting process including three stages is then developed to systematically and automatically extract reliable modal parameters from the alternative stabilization diagram. Demonstrated by analyzing the ambient vibration measurements for three stay cables of Chi‐Lu Bridge, the feasibility of this new approach is verified with successfully obtaining the modal frequencies, damping ratios, and mode shape ratios for almost all the cable modes in the examined frequency range. Another interesting finding is that the modal frequencies and damping ratios of bridge deck can also be effectively identified from the ambient vibration signals of cable. Copyright © 2016 John Wiley & Sons, Ltd.