Recording duration of ambient vibration monitoring for system identification of tall telecommunication towers

It is necessary to have reliable field measurement records for estimation of dynamic characteristics. Increasing duration of the record is one of the common methods for reduction of such errors in the results. Dynamic characteristics of telecommunication towers in higher modes are important for designers, but these parameters could be obtained from ambient vibration monitoring during typhoons in which duration of vibration is not long enough for reducing measurement errors. This paper suggests a procedure for obtaining the duration of recording time for more reliable determination of structural characteristics of telecommunication towers. It is suggested to record the vibration of towers in the form of a set of long‐term and short‐term duration recordings for lower and higher modes, respectively. This procedure was verified with field measurement of Milad telecommunication tower. The results show that natural frequencies determined by this procedure are in good agreement with finite element model analysis. Copyright © 2013 John Wiley & Sons, Ltd.