Fragility analysis of wind-excited traffic signal structures

• Probabilistic framework proposed to predict structure component fatigue life.
• Characteristics of local wind environment are related to fatigue damage accumulation.
• Models inter-relate wind hazard to structural response and hence fatigue damage.
• Test structure response described from monitoring, capacity from past fatigue tests.
• Demonstrated application describes parameter derivation and inter-relationships.

Traffic signal structures are prone to fatigue failure due to wind-induced excitation that is often difficult to characterize due to the variable response arising from a combinations of along- and across-wind effects and the uncertainties associated with the fatigue and fracture phenomena. A probabilistic framework is proposed to predict structure component fatigue life. To solve the problem of wind-induced fatigue, the model is introduced to inter-relate wind hazard to structural response and hence fatigue damage. Stress range demand variabilities are considered separately from the randomness associated with the fatigue capacity. To characterize the natural wind response of a representative structure, full-scale structural monitoring is conducted, and the data were incorporated into an example application of the framework. To successfully demonstrate the efficacy of the proposed framework, resulting wind-induced fatigue life distributions are compared against compiled inspection records for a large traffic signal structure population in Wyoming.