Acoustic Testing for the Preliminary Assessment of Timber Beams — A Pilot Study. Issue 7 (3rd October 2019)

• Record Type: Journal Article
• Authors: Riccadonna, Daniele; Giongo, Ivan; Casagrande, Daniele; Piazza, Maurizio
• Is Part Of: International journal of architectural heritage. Volume 13:Issue 7(2019)
• Page Start: 979
• Page End: 991
• Publication Date: 2019-10-03
• Subjects: Impact hammer test -- microphone -- non-destructive testing -- spectral analysis -- stress wave -- wood decay; Architecture -- Conservation and restoration -- Periodicals; Historic buildings -- Periodicals; Historic preservation -- Planning -- Periodicals; 721.0288
• DOI: 10.1080/15583058.2019.1598516
• Languages: English
• ISSNs: 1558-3058

Abstract

ABSTRACT: This article studies the use of sound spectral analysis as a possible diagnostic technique for the assessment of existing timber structures. The idea is to analyze the spectrum of the sound that is generated by hitting a wood surface with a hammer (or an equivalent tool) and is recorded by a microphone. The sound spectrum and its relevant indicators are compared to reference data obtained for sound wood, in order to detect the presence of damage/decay. A first insight on the method applicability was obtained by testing the technique on 10 timber specimens in different conditions, from sound to completely decayed. The study was then expanded on 20 more beams (10 with a 2 m span and 10 with a 4 m span) that were tested in sound conditions and after an induced damage. Recording of the signals was obtained by using different mid-market smartphone microphones and a professional microphone. Moment analysis was used to evaluate and compare the experimental data. The parameters that were expected to have the most significant impact on the sound signal (e.g., impact location, boundary conditions, etc.) and that can negatively influence the assessment were then identified and investigated.