Regardless to the service lifetime of a structure, unwanted vibration can occur due to unknown sources. Excessive vibration may lead to uncomfortable feeling of the occupant, or deterioration of sensitive instruments in an industrial building. To determine the nature of the mentioned vibration problems, an evaluation of dynamic properties of the structure is required. Recently, researchers and engineers have spent a lot of effort to control the vibration behavior of structures. Several methods have been developed in the field of system identification. Alternative methods to estimate the structural modal parameters are SSI and ARMA. This paper discusses the evaluation of dynamic properties of existing platform structures. Unwanted vibration appears when the material is pumped into the pipe which tends to cause fatigue unwillingly. Dynamic evaluation is performed to obtain the natural frequency of structures by using the SSI and ARMA model. The response measurement is taken while the structure is under operational condition. In this contribution, the mentioned models give satisfactory result compared to FEM model. (C) 2017 The Authors. Published by Elsevier Ltd.