City Of Prestressed Concrete Continuous Wide Box Girder Bridge Design Parameter Optimization Study

With the rapid development of modernization, the growing demand for the highway capacity, multicellular boxes of large cantilever arm of the statically indeterminate box beam with its advantage of in tension and compression and bending and twisting more and more applied in the design. With the continuous increase of the width of the bridge, the space effect of box girder is significant, the lateral deflection increasing trend. But in the past in the bridge design light heavy vertical and horizontal. Therefore, study of multicellular wide box girder stress characteristics, optimize the structure arrangement of the cross section of provide the basis for such cross section forms of bridge design, not only have great theoretical significance and important application value.Based on the single box five chamber section of shenzhen airport project three span continuous box girder bridge as the engineering background, the specific study of the following several aspects:1) To explore suitable for prestressed concrete continuous wide box girder structure analysis method.Briefly in this paper, the method of single beam, beam elements and characteristics of plate and shell finite element modeling method. Then based on the finite element software Midas/civil is the same bridge structure modeling analysis, compare three methods of calculation results and analyzes their respective advantages and disadvantages. Through analysis, the choice as wide box girder of plate and shell finite element model analysis method is more reasonable. Basic mature plate unit model theory, model analysis of data obtained from the comprehensive, higher credibility.2) In order to control the width of shear lag coefficient of box girder bridge engineeringIn view of the present specification and scholars study the phenomenon of wide box girder unclear definition, with wide span ratio and aspect ratio as the research object, the uniformity of shear lag coefficient as comparative index, definition of wide box girder of generalized engineering. The results show that with wide span ratio greater than 0.5 is used to define the width box girder bridge with certain reliability. And compare the wide span simply supported box girder with wide than the same continuous wide box girder of the difference of shear lag coefficient distribution to get the most value and continuous beam shear lag coefficient value changes beam are larger, and the shear lag effect more apparent, increasingly prominent inhomogeneity of conclusion. And analysis of the applicability of the index of shenzhen airport project.3) Geometric parameters on the stress and shear lag effect of box girder wide impact analysisIn this project, for example under the action of dead load is put forward the main factors influencing the wide box girder stress distribution. Model, using the control variable method to study the variable coefficient of shear lag of box girder and the stress distribution law; Explore by adjusting the cross section size optimization section stress distribution of the feasibility and practical value, finally got this project cross section the location factors have influence on the result of the stress distribution and shear lag coefficient.4) Wide box girder of artificial neural network parameter optimizationData based on the above study, the article USES the method of numerical simulation, the MATLAB neural network toolbox to optimize parameters selection, determine to stress uniformity index, shear lag coefficient and cost as the standard for evaluation of girder optimization analysis conclusion.