THE USE OF WIND EXCITATION IN STRUCTURAL IDENTIFICATION

In the identification and control of some structures, such as tall bui ldings and bridges, it is important to be able to resort to special te chniques which may exploit wind and environmental excitation in normal serviceability conditions, since the use of controlled input signals obtained through excitation instrumentation may prove very costly. Hen ce, preliminary signal processing must be designed to extract signific ant data even in the presence of unknown, weak or transient excitation s. The aim of this paper is to compare different structural identifica tion methods suitable in the above-mentioned conditions. Methods that use modal filters are described in detail. To the latter belongs a met hod, based on time-frequency/ambiguity function filtering, recently pr oposed by the authors to identify modal parameters and to detect nonli nearity in serviceability testing conditions. This method is used in t he identification of a switch pylon under nonstationary wind excitatio n The results obtained by such an approach are compared with tradition al frequency domain techniques and time domain ARMA methods. (C) 1998 Elsevier Science Ltd. All rights reserved.