Analysis Of The Impact On Main Girder Force In Diaphragm And Cross-sectional Layout Of Three Span Continuous T-beam

After the reform and opening up,with the rapid economic development of china,transportation industry has entered a new period.According to the statistics,the proportion of medium and small span bridges in our country is relatively larger at the present stage.The prestressed concrete simply supported-continuous T-beam bridge,with the advantages of its mature design and construction experiences,reasonable loading system and driving comfort,has been widely used in engineering.In bridge design process,setting a reasonable diaphragm number,beam depth and the main beam spacing,affects the safety and durability of the structures directly.This paper is relying on the Baby River Bridge in Inner Mongolia.Based on the mechanical characteristics of the prestressed concrete simple supported-continuous T-beam bridge,conduct onsite tests for the upper part of the bridge structure.The cross-section stress variation at its midspan and girder end is measured under the action of the automobile loading.Using Midas Civil and Midas Fea finite element software,establish 40 m three-span simply supported-continuous T-beam bridge models.Comparing the model calculation results with the measured data,the models are proved to be correct.Using the model calculation results,analyze the effects of the diaphragm number(3,5,7)on the structure internal force,deflection,the local stress and the load transverse distribution.The results show that,as the number of diaphragm increases,the lateral flexural rigidity of the structure will increase,the torsional deformation of the girder and the flange will reduce,the ability of the structures to resist the overloaded vehicles will also increase,and draw a more reasonable beam layout programme for this bridge type by the comparison at last.Set different depth and spacing of beams for three different widths(12.25 m,16.5m,21.5m)of the bridges,comparing the stress and strain calculation effects,to obtain the reasonable depth and spacing for this bridge type.