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Research on shear lag effect of box girder with variable width section |
Received:May 02, 2021 Revised:October 05, 2021 |
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DOI:10.7511/jslx20210502001 |
KeyWord:box girder variable width girder shear lag effect energy variation principle difference method |
Author | Institution |
卢敏锋 |
兰州交通大学 土木工程学院, 兰州 |
丁南宏 |
兰州交通大学 土木工程学院, 兰州 |
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Abstract: |
Shear lag warping displacement function of box girders with a variable width section would be defined as the form of cubic parabola.The governing equations for studying shear lag effect of box girders with a variable width section were established via the energy variation principle.The equations were solved by applying the finite difference method.The normal stress of the simply supported box girder subjected to concentrated and uniformly distributed loads respectively was calculated and validated by the finite element method.The calculated results were compared with the normal stress of the box girder with a uniform section.The regularity of distribution of shear lag effect of the box girder was achieved.It is shown that variation of top-flange width of the box girder has a great impact on shear lag effect and the rangeability and peak of normal stress in top flange of the box girder is bigger than that of a usual box girder,under uniformly distributed load.Values of normal stress in middle cross section of the box girder are basically close to a usual box girder and stress distribution curves are in good agreement,which indicates that variation of top-flange width of the box girder hardly affects the shear lag effect under concentrated load.Under a concentrated and uniformly distributed loads respectively,the stress in the middle cross section of the box girder is positive shear lag.When width of top slab,bottom slab and cantilever slabs of box girder are equal to each other,governing differential equations of shear lag effect is also applicable to a box girder with equal cross section. |