Evaluation of wind directionality on wind load effects and assessment of system reliability of wind-excited structures

This study re-evaluate wind directionality effect on various structural responses having distinct directionality characteristics using a relatively simple but sufficiently accurate approach with closed-form estimation of response with a given mean recurrence interval. The approach is established on the basis that the directional yearly maximum responses observed at different hours can be assumed to be mutually independent at the distribution upper tail region, even when the directional yearly maximum wind speeds can be correlated to some extent. This study also evaluates the performance of AIJ procedure and traditional sector-by-sector approach through comprehensive case studies. Furthermore, this study presents an analysis framework for assessing overall reliability/risk of a wind-exited structure associated with multiple limit state responses. The limit state responses can be considered to be mutually independent especially in the distribution upper tail region and when the wind directionality is further considered. Therefore, the failure probability associated with multiple limit state responses can be estimated as the sum of those associated with each response at each wind direction. The characteristics of failure probability influenced by wind directionality and structural orientation are investigated. This study also highlights the sensitivity of failure probability estimation to assumed probability distribution model of extreme response.