DETERMINATION OF FATIGUE CHARACTERISTICS OF HOT-DIP GALVANIZED A307 AND A449 ANCHOR BARS AND A325 CAP SCREWS
Fatigue lives of hot-dip galvanized anchor bars and cap screws commonly used by Caltrans for highway signs, luminaires, and traffic signals are determined. S-N curves plotted from cyclic test data collected, are presented for various parameters. A total of 190 direct tension fatigue tests were conducted on 1-inch-diameter A449 and 1-1/4-inch-and 1-3/4-inch-diameter A307 anchor bars to determine what effect the amount and type of preload, nut arrangement, length, diameter, and steel type has on fatigue life. In a total 1-inch-diameter, were evaluated to finn the effects of preload, diameter, and typical prying forces on fatigue life. It was found that of the variables evaluated preload was the most important factor affecting fatigue life. Anchor bars with sinnle nuts and preloaded their full length to near yield had the longest fatigue lives, with an endurance limit near the yield stress of the bar. The poorest fatigue performance was exhibited by the unpreloaded double nut anchor bar system currently used by Caltrans. A considerable increase in fatigue life of between two and ten times was obtained for this double nut system by tightening top nuts 1/3 turn past snug tight. Highly preloaded cap screws exhibited long fatigue lives and were affected little by prying loads in specimens tested.
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Corporate Authors:
California Department of Transportation
Transportation Laboratory
5900 Folsom Boulevard
Sacramento, CA United States 95819Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC United States 20590 -
Authors:
- Dusel, J P
- Travis, R
- Stoker, J R
- Publication Date: 1984-2
Media Info
- Features: Appendices; Figures; References; Tables;
- Pagination: 130 p.
Subject/Index Terms
- TRT Terms: Fatigue (Physiological condition); Fatigue tests; Galvanizing; Screws
- Old TRIS Terms: Anchor bars; Cap screws; Hot dip galvanizing
- Subject Areas: Geotechnology; Highways; Materials; I34: Steels and Metals;
Filing Info
- Accession Number: 00393978
- Record Type: Publication
- Report/Paper Numbers: FHWA-CA-TL-84-02 Final Rpt.
- Contract Numbers: F75TL05
- Files: TRIS, USDOT, STATEDOT
- Created Date: Jul 31 1985 12:00AM