Structural analysis of sign bridge structures and luminaire supports

Abstract

The Wisconsin Department of Transportation has experienced failures of a high-mast luminaire (HML) support structure and a full-span overhead sign support structure. Furthermore, cracking has been found in many sign support structures composed of welded round hollow structural shapes (HSS). The purpose of the research conducted was to provide fatigue life estimates for these structures, which could then shed light onto the causes of the cracking found and the failures experienced. The analytical and experimental effort conducted was also used to establish rational inspection intervals for these structures and recommend changes (as required) to the procedures for design of high-mast luminaire and full-span sign support structures targeted to improve in-service performance.