A review of the fatigue limit for steel bridges under Ontario highway traffic loading

Abstract

In many design codes for roadway bridges, it is required that a design truck be passed over influence lines for stress at various locations on the bridge to obtain nominal stress ranges for design. For the fatigue design of Canadian bridges in the infinite or very long-life domain, the nominal stress range is compared with a fatigue limit, after modification by an appropriate correction factor to account for the difference between the nominal stress range and some measure of the extreme stress range in the expected real traffic histogram, which governs infinite life design. The extent to which the influence of simultaneous truck crossings was considered in the establishment of the correction factors is believed to be limited. With this in mind, a simulation-based study, conducted to investigate the effects of simultaneous vehicle crossings on the fatigue limits for steel bridges under Ontario highway traffic loading, is presented in this paper.