Shear Lag Effect And Nonlinear Analysis Of Continuous T Beam

T-beam bridge has the advantages of clear force,simple structure,and material saving.These advantages make T-beam bridge widely used in modern railway bridges,highway bridges,and urban overpasses.The analysis and calculation of T-beam bridges are significantly different from those of ordinary beams,the shear lag effect is an important factor that cannot be ignored.In view of the above problems,this paper mainly makes the following research:(1)After systematically studying and summarizing relevant literature at home and abroad,the main research methods of shear lag effect are obtained,and explain the research status of nonlinear analysis of beams at home and abroad.(2)Explain the theoretical knowledge of nonlinear finite element analysis,such as finite element analysis model,constitutive model,crack model and so on;introduce the calculation model required for the simulation of continuous T-beams with neutral axis at flange plate.Selection of typical examples for analysis confirms that the model selection of the analysis program is effective and lays the foundation for subsequent nonlinear analysis of wide flange continuous T beams.(3)Introduced in detail the comparative test on which this paper relies,mainly analyzed its load-displacement curve and crack distribution,and selected typical cross sections including bending and pure shear,analysis of the strain distribution law and shear lag coefficient distribution law along the width of the flange plate during the elastic phase,and it is confirmed that the continuous T beam has shear lag effect in the whole beam section,and the bending moment is an important factor to produce the shear lag effect,while the shear force has little effect on the shear lag effect.(4)A non-linear analysis program is written in Fortran language,and the full-process numerical analysis is performed on the continuous T-beam.The load-displacement curve and the shear lag coefficient of the typical section in the elastic phase are obtained.Compared with the test,the results fit well.It verifies that the program in this paper is effective;Furthermore,the shear lag analysis of T-beamsin a non-linear state is continued,and the influence of web width and flange plate width-thickness ratio on shear lag coefficient is explored.