Study of the Optimum Design for Highway Composite Girder Bridge

摘要

The authors have investigated the composite girder bridge designs by comparing ten designs performed in different countries in the world and found that the designs in each country were quite different. The sizes of web height (depth) and thickness,flange width and thickness and even girder spacing differ widely in the designs. Naturally,the designs follow different standard adopted in each country,therefore it would be difficult to find the best desiga The present paper studies to find the optimum design of highway bridges for a typical type of simply-supported compos ite girder,in particular to find the optimum height of the web by sample desiga The design of girder bridges depends largely on the web height which affects the sizes of upper and lower flanges and resultantly the stiffness of the gird er. The stiffness controls the deflection of the girder, which has to be less than the prescribed limit. Thus, the web height is a key factor of girder design. The stiffness and the sectional area of the girders are investigated when the web height varies. The web thickness is also another important factor and closely related to the use of horizontal and vertical stiffeners which limit the minimum thickness of web in order to prevent from the web buckling. To save the steel material,the stiffeners are effective but increase the fabrication cost.