Transactions on Engineering and Computer Science

Based on the mathematical definition of Doppler shift equation, the commutative relation between Doppler shift and path difference can be obtained by using the difference of distance. By using the basic trigonometric function, a passive ranging solution based only on two consecutive Doppler frequency shift measurement can be obtained. Compared with the existing ranging solution obtained by frequency shift difference based on mathematical definition of Doppler rate of change, the new ranging solution still keeps the simple mathematical expression and has better calculation accuracy. However, by comparison, it can be found that: under the same measurement method, although the mathematical expression of the ranging solution is different, the ranging error still remains the same magnitude. At the same time, it is found that the moving single-station Doppler frequency shift ranging has three characteristics: frequency shift exchange, mean effect, and result lag.

People have noticed that earthquake is the most destructive natural phenomenon to bridges. So, doing dynamic reliability assessment under seismic load of the bridge during in service has great significance. The most difficult thing is how to assess the safety influence of seismic load to bridges. Therefore, we take a large-span continuous rigid frame bridge as the background bridge, based on the monitored strain data collected from the structural health monitoring system (SHMS) of the bridge during in service and 3-D FEM technology, we suggest a dynamic reliability evaluation methodology in this article to evaluate the safety influence of seismic load to the background bridge during in service stage. Firstly, with using the large amount of the monitored strain data, the quasi dynamic reliability near the sensor is acquired; furthermore, by using 3-D FEM method, the simulation model of the background bridge is built and the dynamic reliability under 6 seismic intensity with different middle-span web plates were analyzed and calculated. Through comparative analysis and discussing, we get the influence degree of seismic load on the reliability of the bridge. This method can provide reference for seismic design of the bridge.