Vibrations of metal web joist timber floors with strongbacks.

Zhang, Binsheng; Kermani, Abdy; Fillingham, Tony

Abstract

The aim of this research is to assess the effects of joist spacing, strongbacks and ceiling on the dynamic response of timber floors with metal web joists so as to evaluate the vibrational design criteria, for example, modal frequencies, modal shapes, damping and unit point load deflection, required by Eurocode 5-1-1 and the UK National Annex for timber floors. In general, joist spacing, strongbacks and ceiling do not greatly influence the fundamental frequency and damping ratio, but affect higher modal frequencies. The measured damping ratio for the fundamental mode is 0·86% on average. The use of strongbacks considerably reduces the number of first-order modes below 40 Hz, and provides easier fulfilment of the velocity design criterion. The test results indicate that the decrease in joist spacing, the increase in number, size and stiffness of strongbacks, and the use of a ceiling all greatly reduce the maximum
displacement of the floors. On average, the calculated displacements based on the equations in the UK National Annex are close to those measured.

• Journal Article Type: Article
• Acceptance Date: Aug 27, 2015
• Online Publication Date: Jul 12, 2016
• Publication Date: Aug 8, 2016
• Deposit Date: May 3, 2016
• Journal: Proceedings of the Institution of Civil Engineers. Structures ...
• Electronic ISSN: 1751-7702
• Publisher: ICE Publishing
• Peer Reviewed: Peer Reviewed
• Volume: 169
• Issue: 8
• Pages: 549-562
• DOI: https://doi.org/10.1680/jstbu.14.00130
• Keywords: Codes of practice & standards, dynamics, timber structures,
• Public URL: http://researchrepository.napier.ac.uk/id/eprint/10008
• Publisher URL: http://dx.doi.org/10.1680/jstbu.14.00130
• Contract Date: May 3, 2016