Research On Overall Stability Of Monosymmetric I-section Continuous Beams

Unstable failure is the main failure form of steel structure.As the beam is the main component of steel structure,research on stability of steel beam has become the important part of the research steel structure.Continuous beams than simply supported beams have an advantage,whether it is in terms of performance or economic aspects.So the continuous beams have been widely used.After years of foreign and domestic scholars for the research on the stability of steel beams,the research on overall stability of simply supported beam has been relatively mature,but research achievements of the overhanging beams and continuous beams are still very few.Especially domestic stability studies for of continuous steel beam is rarely.At present,there is no overall stability capacity calculation formula of continuous steel beams in our code for design of steel structure.In order to study stability of continuous beam and enrich the existing code for design of steel structure,therefore carried out the research.Based on the residual stress distribution model of monosymmetric I-sections which proposed by the blind hole method test.Programming language FORTRAN used to write the residual stress distribution model into ANSYS initial stress file,and put the file into continuous steel beam finite element calculation to cnsider the effect of residual stress on stability capacity of continuous steel beams.Used the finite element software ANSYS to analysis the 1010 monosymmetric I-section two-span continuous steel beam examples.The examples are in the different sections,different load height,different loading forms and different adjacent span ratio.We do Buckling Analysis and Nonlinear Buckling Analysis with residual stress influence.It's to study the influence of continuous beam overall stability capacity situation,when the section size,beam length and the load changes.The study found that,The overall stability capacity will reduce with increase of the continuous beam span length,the change of main span length is the most significant parameter.Parameters which increase the cross area section can make stable capacity increased,the change of top flange width is the most significant parameter.Useing the finite element software ANSYS to analysis the 124 monosymmetric I-section three-span continuous steel beam examples with the Buckling Analysis and Nonlinear Buckling Analysis with residual stress influence.It's to study the influence of continuous beam overall stability capacity,that changes with length of the beam.The study found that,Non-adjacent span change will also affect the overall stability capacity of continuous beams.The change of main span length is also the most significant parameter.The stability capacity of continuous beam that the main span is the middle span is much larger than that in the side span.Based on the stability capacity calculation formula in the code for design of steel structure GB50017-201X and the calculation formula of steel beam overall stability coefficient ?b,put forward the calculation formula of the overall stability capacity of continuous steel beam.And then,we briefly introduced the regression fitting software SPSS and uesd it to do binary nonlinear fitting.Then,the values of C1 and C2 were obtained,that under the different loading form.And then,value of C1 and C2 are to modified for the actual project.