Modeling Error Uncertainty Characterization for Reliability-Based Fatigue Assessment in Sign Support Structures

Abstract

Sign and luminaire support structures are prevalent throughout the transportation infrastructure network. Collapse and inspection of these signs pose hazards to the motoring public and the inspection personnel charged with their maintenance. There is a need to develop inspection protocols and understand variability in their performance to ensure public safety and to rationally disperse limited fiscal and personnel resources. This paper outlines a methodology that enables simulated and easured time histories of wind speed and resulting bending stress to be used in establishing parameters defining lognormal statistical models for modeling error that can be included in reliability-based assessment of structures subject to the tendency toward fatigue-induced crack initiation. Rainflow cycle counting is used to generate expected stress ranges from simulated and measured bending stress signals. The ratio of simulated expected stress range to measured expected stress range is defined as the modeling error bias factor. Statistical analysis of this factor at various magnitudes of wind speed is then used to formulate lognormal modeling error parameters suitable for implementation into a reliability-based assessment of fatigue-induced crack initiation risk for sign support structures.