Authors:Jeno Balogh, Massimo Fragiacomo, Richard Gutkowski, Rebecca Atadero, and Peter Ivanyi
In a wood-concrete composite structural member the wood layer overlapped by the concrete layer are interconnected to prevent the relative slip. In this research notched shear-key interlayer connections were used. A problem with using these novel composite members in bridges is that the fatigue behavior of the composite member is not well known. This paper presents an S-N curve for fatigue verification of notched wood-concrete connections based on static and low-to-high-cycle repeated loading tests on fourteen composite beam specimens. The points on the S-N curve were determined for three levels of the maximum load as a function of the average static failure load.
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.