Preference-based Multi-objective Optimization Model for Life-cycle Seismic Design of Bridge

Considering the economy, structural performance and other factors under the earthquake, the preference-based multi-objective optimization and decision-making method was applied to the life-cycle seismic design of beam bridge. A single-column pier was regarded as an application example, and the seismic design was to minimize the life-cycle cost and maximize the seismic capacity and the deformation index. Based on theoretical analysis and engineering judgment, the cost preference and safety preference information under the reasonable displacement ductility was used to construct corresponding value functions, progressively directing at the multi-objective optimization algorithm to the corresponding preferred solutions. The results indicate that the preference-based multi-objective optimization decision model can, in the life-cycle seismic design of bridge, meet the multiple performance requirements at various seismic hazard levels. Compared with the traditional multi-objective optimization algorithm which faces difficulties in obtaining a full approximation of the entire Pareto optimal front for large-dimensional problems and cognitive difficulty in selecting one preferred solution from all these solutions, the proposed model is available to find the global Pareto front to satisfy the corresponding preference. Furthermore, to overcome the shortcomings of repeated trial and passive verification in the classical code-compliant algorithm, the proposed model is used to actively strive the search for the more preferred solution space along the gradient of the current value function, and ultimately converge to the expected Pareto front which meets not only the needs of the lowest cost or the highest safety preference but also the rational displacement ductility. © 2017, Editorial Department of China Journal of Highway and Transport. All right reserved.