Optimization Study Of Hybrid-Girder Rigid-Frame Bridge’s Structural Geometrical Parameters

Hybrid girder continuous frame bridge, which makes concrete and steel work together, can benefit from the weight of the concrete. And the length of the main steel-beam span increases greatly and the bending moment of the bridge would be well-distributed. The literature about structural optimization is very limited, so it is important to investigate the influence of the parameters on the structure.Oujiang Bridge is taken as example to analyze the influence of parameters on the structure. And parameters’ optimization objects are found out to optimize parameters. The main work is listed as follows,(1) The state-of-practice of hybrid girder rigid frame bridge and bridge optimization is stated to guide the optimization.(2) Based on the finite element method, the beam-element model of the whole bridge is developed with MIDAS/CIVIL.(3) Structural stress and displacement are parametrically analyzed with the parabolic index of the bottom beam, proportion of the steel-beam out of the main span, height-span ratio at the root and center of the beam and distance of double piers set as parameters. The force whose absolute value of coefficient of variation is biggest and bending strain energy are taken as parameters’ optimization objects to optimize parameters(4) Structural stress is parametrically analyzed with the position of external prestressing as parameters. The force whose absolute value of coefficient of variation is biggest and bending strain energy are taken as optimization objects to carry out the optimization.