Study On The Basic Mechanical Of Prestressed Concrete Composite Continuous Beam Bridge With Steel Truss Belly

As a relatively new structural form,the composite continuous beam bridge with steel girders is similar to the composite continuous beam bridge with corrugated steel webs in structural features.On the other hand,the change of web material can reduce the self-weight of the structure and achieve the lightness of the structure,thus shortening the construction period and reducing the project cost.The internal prestressing beam arranged at the web is replaced by the external prestressing beam.The research and application of steel-truss prestressed concrete composite continuous beam bridge in China is far inferior to that of traditional PC continuous beam bridge and corrugated steel web composite continuous beam bridge,and most of the relevant theoretical analysis is based on the analysis of simply supported beams with equal section,which lacks the research on long-span continuous beam bridge with variable section.Based on this,the finite element method is used to analyze the basic mechanical properties of prestressed concrete composite continuous beam bridge with steel truss belly,so as to understand the mechanical characteristics of the structure more comprehensively.In this paper,MIDAS FEA software is used to establish three solid unit models of prestressed concrete composite continuous beam bridge with steel truss belly,composite continuous beam bridge with corrugated steel webs and traditional PC continuous beam bridge with the same span of(60+100+60)m.The basic mechanical properties of prestressed concrete composite continuous beams with steel girders under three typical loads: dead weight,concentrated load and uniformly distributed load are analyzed.Study of prestressed concrete composite steel girder abdomen the shear lag effect of continuous girder bridge under rating load,transverse in the midspan cross,1/4 midspan,side span across three typical position in cross section,longitudinal with steel bar retainer position in cross section,namely the structure of vertical and horizontal width length on the two dimensions analysis of three kinds of roof and floor of the configuration of the longitudinal distribution of normal stress,shear lag coeffi-cient,and with the same span traditional PC continuous beam bridge with corrugated steel web composite simple comparison between the shear lag effect of continuous girder bridge,explore the steel girder abdomen characteristics of the shear lag effect of combination of prestressed concrete continuous girder bridge.Analysis compares the creep and shrinkage of concrete prestressed loss of steel girder abdomen combination of prestressed concrete continuous girder bridge in the initial stages to twenty years into a bridge into a bridge,within the scope of the two factors influence on long-term downwarping across,which respectively on the shrinkage and creep coefficient,the initial load of concrete annual average relative humidity independent age and the environment analysis,explore the coefficient of shrinkage and creep effects on the structure midspan deflection.