Authors:István Szűcs, Zsuzsa Balogh, and Rose Holtzman
Experimental investigations of laminated timber-concrete and steel-timber-concrete composite floor or bridge beams show that complex failure modes develop in such members. This paper presents acoustic emission investigation results that reveal the development of the failure modes in the steel-timber-concrete composite specimens subjected to short-term static ramp-loading. Accelerometers connected to a four channel dynamic signal analyzer continuously monitored the beam specimens during the load tests. Conventional techniques can be used for time domain data acquisition and evaluation of acoustic emission events generated in the structural member investigated, which contain thousands of independent signals to be processed, even if only in the audible frequency range. While the wavelet series of detected acoustic emission signals in the time domain produce a reliable amount of statistical information about the number and intensity of events, a frequency - time domain visualization may facilitate an advanced interpretation on the basis of spectrogram analysis. With on-site collection of data the methodology could allow for structural monitoring.