Risk-Based Structural Optimization Framework for Connected Structural System Subjected to Extreme Events

Connected structural systems, such as overhead power distribution systems, could fail to function normally under extreme events or environments when the typically anticipated loadings are exceeded. Consequently, in structural designs, the tradeoffs between costs and accepted risks under such extreme loading scenarios need consideration. To this end, structural optimization methods could be applied to minimize costs subject to constraints on the design feasibility. While classical structural optimization techniques are deterministic, risk-based approaches considering the probabilities of structural failure under certain contingencies have been less explored. In the present study, a structural optimization framework is developed and tested on a power distribution system subject to extreme storms. Uncertainties in the material properties, loadings, and construction are integrated for a risk-based assessment with constraints on the acceptable pole failure probability. Various combinations of extreme storm scenarios and acceptable failure probabilities are investigated to explore the risk-cost tradeoff and optimal design criteria. By employing the use of high-class, shorter poles, the optimal configurations are found to reduce the cost for a similar reliability level by about 50%, while, for a similar cost, the system could be designed to a much higher reliability level. Such a framework could be adopted for a variety of structure types and systems under various extreme environments, including future habitats on the Moon or Mars.