Abstract

Historic buildings are public symbols, standing as sacred reminders. Many of them have been recognized as World Heritage Sites. In this study, real time vibration measurement of an important axisymmetric masonry pagoda was performed. With the measured vibration data, inverse analysis was proposed to backward determine its damping and natural period. The proposed algorithm utilizes Duhamel’s time integration method for solving the equation of motion and the Gauss-Newton algorithm to minimize the sum-of-squares error between the calculated and real-time measured accelerations of the structure. Four distant earthquake-induced vibrations were recorded and used for the analysis. The results show that the dynamic parameters determined by the proposed method agree with those obtained from the previous study adopting finite element analysis. The obtained dynamic properties of the two perpendicular directions are slightly different, indicating the non-homogenous body of the axisymmetric structure or there would be a particular damage zone. From the results, an onsite damage investigation can be specifically identified. In summary, continuous structural health monitoring and time-dependent deterioration of historic buildings are possible with real time measurement and the proposed analytical algorithm.