Fatigue Life Assessment of Cracked High-Mast Illumination Poles

摘要

This paper presents the findings of a research program that was conducted to evaluate the probability of failure of high-mast illumination poles (HMIPs) with preexisting cracks at the pole-to-base plate connection detail. A simplified reliability-based analysis framework is presented to evaluate the safe service life of the cracked HMIPs. Vibrations induced by both vortex shedding and natural wind gusts are considered. The influence of different parameters is assessed, including pole geometry, pole location, terrain effects, local wind characteristics, and the assumed level of fatigue degradation attributable to the presence of a preexisting crack. The safe service lives of different standard HMIP designs that are commonly used by the Texas DOT are calculated. The results indicate that the degradation of the poles is predominantly attributable to vortex shedding-induced vibrations in the second and third vibration modes. The findings also demonstrate that the safe service life of a HMIP depends primarily on the effective stress range at the base of the pole attributable to wind-loading effects.