System Identification of An Isolated Bridge Considering Nonlinearity of Soil

• Main Authors: Huan-Yi Wu, 吳桓毅
• Other Authors: R.Y. Tan
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/13121096130548619561

碩士 === 國立臺灣大學 === 土木工程學研究所 === 101 === The objective of the research is to establish a system identitfication procedure with isolated bridge, expecting to identify the physical meaning of the parameters. The bridge can be simplified by ten degrees of freedom with lumped mass. In the procedure of identification, assuming the bridge deck is rigid, and the mechanical behavior of the pier is linear. The horizontal stiffness of the rubber bearing between superstructure and abutment is simulated by linear-elastic spring, and the damping effect of the rubber is also considered. Moreover, the mechanical property of lead rubber bearings used for isolation system between superstructure and pier is simulated by bilinear hysteresis loop model. The structure parameters of the pier and isolation devices can be identified by output-error method. Besides, in pile foundation, the author describe the soil-structure interaction system with the soil-spring method, then the effect of soil and structure can be simplified into an equivalent spring and damper, and assume that the reaction is non-linear behavior, following the Bouc-Wen model. The parameters of the Bouc-Wen model can be identified by least square method. In the case study, the research use the Bai-He Bridge, and measurement data is obtained by Chiayi earthquake, which occurred on October 22,1999. Structure parameters are generated directly by identitfication procedure, then time history response of the bridge can be easily calculated. Finally, the reliability of the identification procedure is verified by comparison of the measurement data for actual bridge with the corresponding data obtained from identification procedure.