DAMAGE DETECTION OF ACTUAL BUILDING STRUCTURES THROUGH SINGULAR VALUE DECOMPOSITION OF POWER SPECTRAL DENSITY MATRICES OF MICROTREMOR RESPONSES

Abstract

Damage detection through microtremor measurements was applied to two actual building structures in which walls and a beam were damaged artificially. The responses recorded in the time domain are transformed into the power spectral density matrix at each discrete frequency. The matrix is decomposed into a set of auto spectral density functions by the singular value decomposition. The changes of the resonant frequencies and the corresponding modal shapes are searched by comparing the state after damage with the state before damage. Structural damage locations are found through the largest change of the modal shape.