Vibration Analysis for Dynamic Machine Foundation Using the Rapid Load Test of Pile

摘要

In LNG plants and refineries, foundations for heavy rotating machines are required to be designed to limit the vibration induced by the unbalanced force and the moment of the machines to be within allowable amplitude for designated performance. When designing a pile-supported foundation for those dynamic machines, soil-pile spring constant to be used for dynamic analysis is calculated by conventional methods. However, there have been few studies of examining the accuracy of these methods and comparing them with the actual vibration data. The authors had an opportunity to carry out the vibration-proof design of reciprocating-type compressor foundation of which supporting PC piles were tested by rapid load test with a single mass model analysis. Moreover, vibration measurement was conducted at the Commissioning and multiple-point vibration data were obtained and studied by FFT analysis. Consequently, soil-pile spring constant was estimated from the rapid load test and the vibration analysis was conducted by 3D FEM software (STAAD. Pro)1. In particular, the vibration amplitude and the mode of various wave components calculated based on the rapid load test and conventional methods, and those measured by actual vibration, were compared. From this result, we confirmed the validity of the analysis method based on the rapid load test result, which can be proposed for dynamic machine foundation design.