The Research On Optimum Designing Of Steel Box Girder

Steel box girder is composed of high-intensity material. It is strong and light. Steel box girder is ideal structure of big stride-across bridge. In the present age, steel box girder has been used extensively in China. So optimum of the steel box girder becomes the problem which badly needs to be solved in civil engineering.In traditional engineering design, designer usually considers conservative safety much more than structure economy. The designer usually designs steel box girder according to regulation of the strengthen, stiffens, stability of steel box girder. Traditional design method is only to check up the structure. Its process is: hypothesis-analysis-checking up-re-design. The goal of re-design is to select a reasonable design, and it is only a kind of simple analysis which is accomplished according to the experience of the designer. Structure optimum design is a kind of structure synthesis design. Its process is: hypothesis-analysis-searching- optimum design. The searching process is the process in which designer amends his design. The amended is to get the optimum designing goal according to the certain optimum method. It is an initiative regulated search process which ends up with the scheduled optimum goal.New mechanics model is set up to analysis the strength and stability of flange and web of steel box girder according to structure optimum method. The thesis shows the way to use full-stress standard method constrained by the critical stress to solve the optimum of steel box girder structure. The program for designing steel box girder pressed web optimum is compiled. In addition, proposal which is fit for steel box girder optimum design got by comparing the program calculating result is brought forward.The bucking coefficient, optimum parameter and overall bucking parameter are mentioned in the thesis to bring forward an initiative method for steel box girder optimum method, and compile the program to realize it.In this thesis, the detailed method of stiffened plate's design is given. The design specifications of other countries are reference. This method can be supplement of design specification.