The Damping Analysis of Experimental Concrete Beams under Free-Vibration

Abstract

This paper presents an overview of the free-vibration damping analysis technique commonly employed by laboratories to determine the amount of material damping contained by a concrete specimen. From laboratory investigations the difficulties associated with a technique often employed for the extraction of damping from the free-vibration decay curve are identified. Extensive free-vibration tests undertaken on a wide variety of concrete beams indicate that for the traditional logdec technique, damping is to be extracted from the optimal peak ratio (^An/_A1) region of the free-vibration decay curve. An analysis of the effect of experimental test variables; hammer weight and hammer excitation position, on the calculation of damping is undertaken. The results show that neither test variable produces measurable impact on the calculation of damping.

Keywords

damping free-vibration logarithmic decrement reinforced concrete

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