The Health Evaluation For The Serviced PC Bridge Based On Dynamic Characteristics

Bridge is the hub and lifeblood of transportation, plays an important role in social and economic development. Because of various factors, the damage and deterioration of the Bridge are unavoidable during use. At present, the damnification udentification method based on Bridge dynamic characteristics is the best characterization of macro variation of the overall structure. The studies showed that the combination of the dynamic load test and numerical analysis, can well evaluate the health for the steel Bridge. At present, the health evaluation for PC Bridge is still relatively small.The dynamic loading test was conducted to investigate the natural vibration characteristics of an existing PC Bridge. In this study, to measure the vibration acceleration of the bridge, 42 high-sensitive servo-type vibration meters were used and a wireless LAN system was applied. The bridge vibration response was monitored under the ambient vibration after unregulated traffic passing. And also, actual natural vibration frequencies and modes of the bridge were compared with the numerical results obtained from 3D-FE analysis,based on Bridge dynamic characteristics identified the deterioration degree and the damage level of this bridge, and then evaluated the health of the serviced PC Bridge. The results can be references for the dynamic characteristics study of the same type bridge.The main research contexts are as follows:1) The conducting ambient vibration tests have been done on the continuous PC Bridge.The study show that natural vibration frequencies and modes are specified by conducting ambient vibration tests;2) The modal of PC Bridge between the dynamic loading test and finite element analysis were compared. The study show that excitation by oversize vehicles running on the PC Bridge, only in small range can accurately reflect the vibration characteristic of the PC Bridge.3) The frequencies of conducting ambient vibration tests and finite element analysis.Although some differences between both results are observed, it may be due to the modeling of rebar and PC wires and supporting conditions;4) The natural frequencies of PC Bridge between construction stage and 50 years-passed were compared. The frequency of PC Bridge was decreased. To a great extent, is due to the impact of sidewalk added during ues; the material deterioration affecting followed; and, the vibration test measurement accuracy of construction stage is also influence.