Structural Optimizations of Extradosed Cable‐Stayed Bridge by Using Genetic Algorithm

An extradosed cable‐stayed bridge employs a structure that combines the main elements of both a prestressed box girder bridge and a cable‐stayed bridge. In extradosed cable‐stayed bridge to apply optimization, because this type of bridge has hybrid nature; bridges have significant additional complexity and oversizing of structure [7]. This research paper evaluated the optimum depth of the box girder with pylon height, angle of stay cable, and effect of concrete grade on those three main parameters of an extradosed cable‐stay bridge for fixed span length (100+180+100) m. The formulated optimization problem was code into Mat lab R2019a software to run the optimization using genetic algorithm and analysis results retrieved from SAP2000v23 bridge software to carry out the optimization process. The results of optimization indicate that box girder depth was less than recommended value of extradosed bridge depth, the optimum pylon height found to be more reduce than previous research work and the optimum first stay cable angle is 32.13o for using optimum concrete grade C‐45.