Study On Box Girder Based On Fine Analysis

With the rapid development of economy in 12 th Five-Year,the vehicle load level and the number of vehicles is increasing,"13th Five-Year" during the period of,requirements of social security and the scale of traffic facilities is more and more high,the new bridge width is gradually increasing,at the same time,the number of diseases of bridge is raising.Box girder has been widely used in bridge construction because of its good mechanical properties,such as bending resistance and torsion resistance.Therefore,it is necessary to study and analyze the precision of box girder.In the past,the design of the bridge is limited by the development of computer calculation,and the structural calculation is carried out by it,which is rough working out used the flat beam.In practical engineering,the structure is calculated by the specification of the bar system,but the disease is inevitable in the later operation.The calculation results to compensate for the inherent defects of plane frame,the fine analysis,through continuous girder fine modeling method,a detailed analysis of the structure of the state,and coMPared with plane frame model,where the difference between the two studies,for the future of the box girder,further research will provide some guidance,and from the perspective of meticulous analysis in view of the disease,giving a possible and reasonable reinforcement scheme.The main research results and conclusions are as follows:This paper summarizes the current situation and development trend of domestic and foreign development of box girder bridge in the bridge construction,sort out the common case of typical bridge diseases,the research results at home and abroad,as well as the current status of the shortcomings are summarized.Moreover,the common symptoms and causes of box girder bridges are introduced.The calculation principle and applicable conditions,detailed calculation model of plane rod system advantages and disadvantages are discussed,a simple calculation method for the beam grid,grid model,finally emphatically summarized the calculation method of the finite element model of the superiority,principle and matters needing attention.First,introduced LISP language grammar,development source,focus on the use of Visual LISP to three span continuous beam as an example MCT language programfile,program aided automatic modeling,overcomes the steel beam information input,node unit and other complex problems,provide quick solutions for strengthening modeling.In section three span continuous beam as an example,a planar model and FEA refined model,were selected in the pier top roof location,across the floor and side span 0~1/4L regional analysis the stress condition,through two kinds of model analysis norms mainly focus on the top and bottom "out of plane stress" "the web,in-plane principal stress and principal stress difference index.From the point of view of FEA analysis,it is proposed that the main stress in the face of the roof and floor should also be controlled by the theory.If the check is not checked,it will lead to the cracks in the top floor.Again,for the plane frame calculation results with the current"flat beam" structure of the actual stress error and proposed design process requires not only the structure of bar system check calculation and the best spatial block unit,and review more secure.In the end,the paper gives the common reinforcement technology for various diseases.