Micro-Vibration Prediction and Evaluation Analysis of the Structural Foundation of a Precision Instrument Plant Across the Reservoir

The precision instrument plant is usually subjected to micro-vibration excitation by the passing of a high-speed railway, which affects the normal operation and working accuracy of precision instruments in the plant. This paper focuses on the natural vibration characteristics and micro-vibration of a large-scale precision scientific device plant across a reservoir. The whole finite element model of the final designed scheme of heavy bridge and culvert was established. The numerical analysis results show that the first 10 natural frequencies of the concrete structure of the main structure completely avoid the inherent frequency of the site of 5 ~ 10 Hz. The root means square of the comprehensive displacement of the foundation slab of the plant within the frequency of 1 ~ 100 Hz according to the time-history analysis does not exceed 150 nm, which meets the demands of micro-vibration control. Comparing the calculation results of two different damping ratio schemes, it is found that the damping ratio is an important factor in micro-vibration. The chosen designed scheme of heavy bridge and culvert across the reservoir is feasible to control the micro-vibration.