Genetic Algorithm in Identifying Pre-stress Loss of the Long Span Bridge Sheng Chengwu Wen Jijun Huang Zhigang Zhang Kaiyin Xiang Musheng School of Transportation, WUT, Wuhan 430063,China.A genetic algorithm is applied in identifying the pre stress loss of the long span bridge. A model with some parameters is made to assess the pre stress loss. Based on the differences between the design value and the survey of the bridge deck elevation in constructing the pre stressed long span bridge, the model parameters are identified by the genetic algorithm, and the pre stress loss values of different sections are given. It is demonstrated that the genetic algorithm is efficient and the theoretical results fit well with the stress survey.long span bridge; pre stress loss; genetic algorithm; parameter identification