Citation

Albrecht P. Transp. Res. Rec. 1982; 871: 73-80.

Copyright

(Copyright © 1982, Transportation Research Board, National Research Council, National Academy of Sciences USA, Publisher SAGE Publishing)

DOI

unavailable

PMID

unavailable

Abstract

A method of calculating the expected fatigue failure probability of a structural detail, given the distribution of resistance and load, is presented. The resistance data, in terms of cycles to failure, come from previous laboratory tests. The load data come either from stress-range histograms recorded on bridges or from loadmeter surveys. The proposed method replaces each histogram by an equivalent stress range and converts the latter into a distribution in terms of number of cycles. The problem is thus cast into the standard format for reliability analysis and allows one to calculate failure probabilities. Application of the method to designs in accordance with American Association of State Highway and Transportation Officials specifications showed that fatigue failure probabilities for redundant load-path (RLP) structures are inconsistent and vary greatly from P sub F = 9.2 x 10 to the power of -2 for category B to P sub F = 9.2 x 10 to the power of -10 for category E and for nonredundant load-path (NRLP) structures from P sub F = 5.1 x 10 to the power of -2 for category A to P sub F = 2.1 x 10 to the power of -22 for category E. It is proposed that the specifications be revised to include (a) allowable stress ranges for RLP and NRLP structures with uniform failure probabilities; (b) explicit formulation of the specifications in terms of the actual number of single fatigue trucks, each causing an equivalent stress range; and (c) continuous definition of allowable stress range versus truck traffic volume. An example illustrates the design of a bridge not covered by the specifications to a specified failure probability. (Author)

Language: en

Keywords

BRIDGES, HIGHWAY; FATIGUE OF MATERIALS; MATHEMATICAL MODELS