Accelerometer configuration assessment of Milad Tower utilizing operational modal analysis

In operational modal analysis, the observability and quality of the extracted modal parameters, apart from the characteristics of structures, loads, and noise, largely depend on the data acquisition system. Especially in large-scale structures, because of the low frequency- and low amplitude of vibration, the configuration and arrangement of the sensors are of particular interest. Milad Tower, with a height of 435m in Tehran, is the sixth tallest telecommunication tower in the world. The authors have previously identified the tower’s modal parameters by developing an automated data-driven subspace approach and investigated the long-term variations of modal parameters for structural health monitoring purposes. This paper adopts this identification approach to a Milad Tower finite element model subjected to random and seismic loadings. The identified modal parameters are compared with those obtained based on real acceleration records. The MEMS accelerometers’ performance is investigated by stabilizing identified natural frequencies for different setups and scenarios. Also, the performance of various accelerometers temporarily mounted on the tower is compared, and a response signal measured under the most recent earthquake in Tehran is presented. The qualitative and quantitative assessments of the sensors are discussed, and required improvements are recommended.