Improved Non-probabilistic Global Optimal Solution Method And Its Application In Girder Bridge Reliability Assessment

Due to the complexity of engineering structure,it is difficult to obtain the sample statistical information.This restricts the application of the probability model.Therefore,it is urgent to develop a reliability method which only needs small sample size and low computational cost.The non-probabilistic reliability method is an effective tool to deal with this issues.With several decades development,non-probability theory and algorithm has become more mature and were applied in practice engineering.This dissertation studied on the non-probabilistic reliability algorithm based on the interval model,and proposed the improved global optimal solution method.Girder bridge was widely used in bridge engineering.After several decades use,the bridge career entered a new stage that the bridge construction and the bridge maintenance and reinforcement coexisted.Therefore,the non-probabilistic reliability assessment method proposed in this paper was introduced into the reliability evaluation of existing girder bridges.The study also particularly paid attention to combining the finite element numerical analysis method,which will lay the foundation for the application of the theory of non-probabilistic reliability.The main contents of this thesis are follows:(1)Considering the inadequacies of conventional solution algorithm of non-probabilistic reliability index,this study combined the improved one-dimensional optimization algorithm with the global optimal solution method to present one improved global optimal solution method.(2)According to the structural characteristics of the girder bridge,the improved global optimal solution method was combined with the bridge reliability assessment method,and proposed a reliability evaluation method of the girder bridge based on improved global optimal solution.(3)The improved global optimal evaluation method was introduced into the reliability evaluation of the existing girder bridge,and performed the non-probabilistic reliability assessment of the existing bridge.The reliability analysis results will guide the engineeringpractice of the reinforcement and reconstruction of the girder bridge.