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原文传递 Investigation of Anchor Nut Loosening on Highway Ancillary Structures

题名：	Investigation of Anchor Nut Loosening on Highway Ancillary Structures
正文语种：	eng
作者：	Singh, Japsimran;Hebdon, Matthew H.
作者单位：	Walter P Moore & Associates Inc Diagnost 300 S Orange Ave 1200 Orlando FL 32801 USA;Virginia Tech Charles E Via Jr Dept Civil & Environm Engn Blacksburg VA 24060 USA
关键词：	Vibrations;Nut loosening;Resonance;Traffic signals;Wind-induced vibrations;Anchor rod;Pretension;Nut rotation;Ancillary structures;Tightening procedures;Turn-of-the-nut
摘要：	Documented evidence shows that anchor nut loosening on highway ancillary structures has been a problem in the transportation industry since at least the 1990s. There have been reported cases in the past, where loose anchor nuts were found to be partially responsible for the failure of ancillary structures. Resonant vibrations in ancillary structures as a result of variable frequency winds are believed to be one of the potential causes of loose anchor nuts. The current research primarily focused on investigating the effect of wind-induced vibrations on the loosening of anchor nuts in double-nut moment connections in ancillary structures. The research involved large-scale vibration testing of a traffic signal on the basis of vibration stress results from a 4-month field monitoring program. The purpose of the large-scale testing was to establish the relationship between the number of vibratory cycles, rod pretension, and nut loosening. A small-scale vibration test was also performed to validate the large-scale testing results. The testing results showed that anchor rods tightened in a double-nut moment connection above a pretension of 38 MPa (5.5 Ksi) do not experience nut loosening under vibrations. (C) 2021 American Society of Civil Engineers.
出版年：	2021
期刊名称：	Journal of structural engineering
卷：	147
期：	4