A Study on the Optimal Design of Prestressed Concrete Box Girder Bridges

프리스트레스트 콘크리트 박스 거더 교량의 최적 설계에 관한 연구

In the preliminary design stage of Prestressed Concrete (PSC) Box Girder Bridges, the design factors(including depth, thickness of web, and jacking force) decided by inexperience designer could heavily affect the final design factors. So there is a possibility that the design ends up with an excessively wasteful design. To aim at an economical design with preventing an excessive design, the optimal design program has been developed by using ADS optimal program and SPCFRAME(PSC Bridge analysis program) in these studies. The optimal design program automatically calculates economically optimized design studies. The optimal design program automatically calculates economically optimized design factors by introducing the optimal design techniques of PSC box girder bridge design. The objective function for optimal design is material cost of box girder and constrained functions are constituted with design specifications and workability. The optimal design techniques used the Sequential Unconstraint Minimization Technique (SUMT) with performing the optimal design program. In this study, We designed unprismatic section bridge and prismatic section bridge in the same design condition by optimal design program developed in this study. By analyzing the results we suggested the practical form of tendon's layout comparing the optimal desingns on the basis of each tendon's layout.