Specialized parameter estimation algorithms for multiple reference testing

In the past several years there has been renewed interest in Multiple Reference Impact Testing. Increasing the number of references, to as many as thirty, has significantly improved the quality of the modal data gathered, particular for those cases in which good impact measurements are difficult to make. In this paper an improved spatial/frequency domain parameter estimation algorithm is developed for processing multiple reference data. The algorithm integrates the Complex Mode Indicator Function and Enhanced Frequency Response Function method with a low-order frequency domain eigenvalue estimation algorithm. The methods are evaluated on a carefully conducted laboratory experiment and data gathered on a bridge tested as part of an infrastructure investigation.