Detail Categories for Reliability-Based Fatigue Evaluation of Mast-Arm Sign Support Structures

Abstract

Sign and luminaire support structures are prevalent throughout the transportation infrastructure network. Collapse and inspection of these pose hazards to the motoring public and the inspection personnel charged with their maintenance. There is a need to understand variability in their performance and to develop inspection protocols consistent with this expected performance to ensure public safety and to rationally disperse limited fiscal and personnel resources. Because mast-arm sign support structures are most often decommissioned when cracks are found, these protocols will focus on detecting crack initiation. Inspection protocols for assessing service life and the limit state of fatigue-induced crack initiation are most effectively developed using reliability-based procedures. The objective of this manuscript is to present two methods for synthesizing archival fatigue test data into a form suitable for implementation in reliability-based procedures for fatigue-induced crack initiation assessment of mast-arm sign support structures. The methods culminate in statistical parameters suitable for lognormal models of fatigue life for connection details. The two methods presented suggest that it is likely more appropriate to classify connection details according to stress concentration factors rather than visual appearance.