Inertial Measurement Method for Railway Bridge Dynamic Deflection
Xie Yi Yan Puqiang Mao Leshan (State Key Lab. of Precision Measurement Technology and Instruments Dep. Tsinghua Univ. Beijing 100084)
Railway Bridge Dynamic Deflection (BDD)is an important parameter for bridge quality evaluation. BDD influences the security and stability of a train in motion. However, measurement of BDD remains an unresolved problem up to now. On one hand, it is difficult to find a stationary reference plane in testing site for a re lative measurement system. On the other hand, the BDD signal will be distorted when measured with a seismic transducer due to the limited low frequency response effect of seismic transducer. In this paper, the authors put forward a new method for measurement of BDD with seismic low frequency vibration transducer (called DP). Signal recovery technique is adopted to compensate DP's output which is distorted by DP's frequency response characteristics. And part known of knowledge of BDD is furtherly incorporated in reconstruction of some low frequency spectral lines which are contaminated seriously by low frequency noise. Then the real measured signal is acquired. The work in this paper provides a convenient and effective method for measurement of BDD, which lays the foundation for measurement and research of bridge spatial vibration excited by a train passing by.