Ambient Data Modeling and Analysis

Abstract

This chapter presents some basic tools for analyzing a sample history of ambient data. Procedures for plotting the power spectral density and singular value spectra are presented. Their theoretical statistical properties near the resonance band of a structural vibration mode are discussed, allowing one to interpret and detect potential modes in applications. A detailed example with field data is presented to illustrate in a step-by-step manner the procedures and considerations in the production and analysis of these spectra. Ambient data of other nature are also discussed, including asynchronous data that exhibits artificial vibration modes in their spectra, and microtremor data that can be used to infer site characteristics. Procedures for generating synthetic ambient data are presented, which are useful for verifying algorithms or parametric studies.