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Modal identification of bridges under varying environmental conditions: Temperature and wind effects
Author(s) -
Li Hui,
Li Shunlong,
Ou Jinping,
Li Hongwei
Publication year - 2010
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.319
Subject(s) - modal , wind speed , modal analysis , engineering , modal testing , damping ratio , principal component analysis , structural engineering , computer science , acoustics , meteorology , vibration , materials science , artificial intelligence , physics , finite element method , polymer chemistry
Numerous investigations have indicated that structural modal parameters are significantly impacted by varying environmental and operational conditions. This phenomenon will cause confusion when conducting modal‐based damage detection and model updating. This paper investigates the dependency of modal frequencies, modal shapes and the associated damping ratios on temperature and wind velocity. The nonlinear principal component analysis (NLPCA) is first employed as a signal pre‐processing tool to distinguish temperature and wind effects on structural modal parameters from other environmental factors. The pre‐processed dataset by NLPCA implies the relationship between modal parameters and temperature as well as wind velocity. Consequently, the artificial neural network (ANN) technique is employed to model the relationship between the pre‐processed modal parameters and environmental factors. Numerical results indicate that pre‐processed modal parameters by NLPCA can retain the most features of original signals. Furthermore, the pre‐processed modal frequency and damping ratios are dramatically affected by temperature and wind velocity. The ANN regression models have good capacities for mapping relationship of environmental factors and modal frequency, damping ratios. However, environmental effects on the entire modal shapes are insignificant. Copyright © 2009 John Wiley & Sons, Ltd.