Statistical analysis of stress spectra for fatigue life assessment of steel bridges with structural health monitoring data

This paper aims at developing a monitoring-based method for fatigue life assessment of steel bridges with use of long-term monitoring data of dynamic strain. A standard daily stress spectrum is derived by statistically analyzing the stress spectra accounting for highway traffic, railway traffic, and typhoon effects. The optimal number of daily strain data for derivation of the standard daily stress spectrum is determined by examining the predominant factors which affect the prediction of fatigue life. With the continuously measured dynamic strain responses from the instrumented Tsing Ma Bridge carrying both highway and railway traffic, the proposed method is exemplified to evaluate the fatigue life of fatigue-critical welded details on the bridge.