Study On Shear Lag Effect Of Of Small Box Girder With Corrugated Steel Webs

The composite box girder structure with corrugated steel webs does not suffer from the cracking of traditional concrete box girder webs,and has various advantages of composite beam structures.Therefore,this bridge structure is being adopted and promoted by more and more bridge designers.The corrugated steel web steel bottom plate composite small box girder,like the conventional box girder structure,has a shear lag effect.In order to study its shear lag effect,the following work was carried out:(1)Based on the energy variational method,a cubic parabola is selected as the shear lag warping displacement function,and relevant factors such as different materials,different load conditions,shear deformation of corrugated steel webs,and full section axial force self balance are considered for derivation.The theoretical calculation formulas for the deflection,stress,and shear lag coefficient of the corrugated steel web steel bottom plate composite small box beam are obtained.(2)Based on practical engineering,a combination of finite element analysis and theoretical derivation was used to study and analyze the shear lag effect of practical engineering under different working conditions.The results and distribution patterns of stress,deflection,shear lag coefficient at key nodes of the actual bridge were obtained.(3)By using parameter sensitivity analysis,different load conditions including load form,loading position,and bridge design parameters were selected as analysis variables to obtain the influence laws and results of shear lag effect and shear lag effect additional deflection of the corrugated steel web steel bottom plate composite small box beam under the above variables.(4)Based on the bridge design parameters in the universal atlas used in practical engineering,combined with three current industry standards,the calculation methods and results of the effective distribution width of the flange plate of the actual bridge were solved and compared,and a calculation formula for the effective distribution width of the flange plate on the bridge under different spans in the universal atlas was proposed.In response to the unique shear deformation additional deflection of the corrugated steel web steel bottom plate composite small box girder,combined with the theoretical derivation results of this article and relevant industry standards,the calculation differences and influencing factors were analyzed.