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Title: EFFECT OF CYCLE-COUNTING METHODS ON EFFECTIVE STRESS RANGE AND NUMBER OF STRESS CYCLES FOR FATIGUE-PRONE DETAILS
Accession Number: 00804684
Record Type: Component
Record URL: Availability: Transportation Research Board Business Office 500 Fifth Street, NW Find a library where document is available Abstract: Two important parameters in fatigue life evaluations of existing steel highway bridges are the number of stress cycles experienced and the effective stress range. The inaccuracies in predicting remaining fatigue life can be attributed to either one of these two parameters. However, the AASHTO guide specification has no provisions for the cycle-counting methods to be used to determine these two parameters. A sensitivity analysis that addresses the effects of cycle-counting methods on the effective stress range and the number of cycles for various fatigue-prone details in both main and secondary bridge members is described. A comparison of five cycle-counting methods (level-crossing counting, peak counting, simple-range counting, mean-crossing-peak counting, and rainflow counting) by using a simple variable-amplitude strain-time history showed that both the stress range and the number of cycles are sensitive to cycle-counting methods. Two of the most commonly used cycle-counting techniques for highway bridge variable-amplitude loading are the mean-crossing-peak and the rainflow cycle-counting methods. A comparison of the two methods by using field data taken under normal traffic showed that the rainflow cycle-counting method is more conservative than the mean-crossing-peak method. The relationship between the mean-crossing-peak and the rainflow cycle-counting methods was determined in the form of a correlation coefficient and a linear regression line. There is a nearly perfect positive correlation between the two methods. Therefore, values obtained for the effective stress range and the number of cycles by the mean-crossing-peak method can be converted to values for the rainflow method.
Supplemental Notes: This paper appears in Transportation Research Record No. 1740, Structural Design Issues.
Language: English
Corporate Authors: Transportation Research Board 500 Fifth Street, NW Authors: Clarke, S NGoodpasture, D WBennett, R MDeatherage, J HBURDETTE, E GPagination: p. 49-60
Publication Date: 2000
Serial: ISBN: 0309067448
Features: Figures
(8)
; References
(17)
; Tables
(5)
TRT Terms: Uncontrolled Terms: Subject Areas: Bridges and other structures; Design; Highways; I24: Design of Bridges and Retaining Walls
Files: TRIS, TRB, ATRI
Created Date: Jan 16 2001 12:00AM
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