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The sensitivity of vibration characteristics of reinforced concrete beams under incremental static and cyclic loading

Hamad, WI and Owen, JS and Hussein, MFM (2013) The sensitivity of vibration characteristics of reinforced concrete beams under incremental static and cyclic loading. Key Engineering Materials, 569-57. pp. 327-334. ISSN 1013-9826

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Abstract

The use of changes in vibration properties for global damage detection and monitoring of existing concrete structures has received great research attention in the last three decades. To track changes in vibration properties experimentally, structures have been artificially damaged by a variety of scenarios. However, this procedure does not represent realistically the whole design-life degradation of concrete structures. This paper presents experimental work on a set of damaged reinforced concrete beams due to different loading regimes to assess the sensitivity of vibration characteristics. Of the total set, three beams were subject to incremental static loading up to failure to simulate overloading, and two beams subject to 15 million loading cycles with varying amplitudes to produce an accelerated whole-life degradation scenario. To assess the vibration behaviour in both cases, swept sine and harmonic excitations were conducted at every damage level. The results show that resonant frequencies are not sensitive enough to damage due to cyclic loading, whereas cosh spectral and root mean square distances are more sensitive, yet more scattered. In addition, changes in non-linearity follow a softening trend for beams under incremental static loading, whilst they are significantly inconsistent for beams under cyclic loading. Amongst all examined characteristics, changes in modal stiffness are found to be most sensitive to damage and least scattered, but modal stiffness is tedious to compute due mainly to the difficulty of constructing restoring force surfaces from field measurements. © (2013) Trans Tech Publications.

Item Type: Article
Uncontrolled Keywords: Cyclic loading Damage detection Non-linear vibration Reinforced concrete beams
Subjects: UNSPECIFIED
Divisions: UNSPECIFIED
Depositing User: Cron Job
Date Deposited: 07 Mar 2014 12:10
Last Modified: 08 Dec 2014 02:17
DOI: 10.4028/www.scientific.net/KEM.569-570.327