Deflection calculation of concrete composite box girder with steel truss webs

Abstract

Abstract: In order to study the calculation method of deflection for concrete composite box girder with steel truss webs and factors influencing the composite box girder′s deflection, steel truss webs are converted into steel webs with equivalent thickness, the longitudinal displacement function of cantilever plate is modified, and a formula considering steel truss webs′ shearing deformation and shear lag effect is deduced for predicting deflection by variational method. Then, a finite element model of the composite box girder is established by using the finite element software ANSYS. The numerically predicted values and theoretically calculated values are compared and analyzed respectively. On this basis, the influence of height-span ratio and the horizontal inclination angle of abdominal rod on the additional deflection produced by steel truss webs' shearing deformation and shear lag effect are both studied in details. The results show that: the accuracy of deflection calculation can be improved by modifying the longitudinal displacement function of cantilever plate of composite box girder; for composite box girder with reasonable height span ratio, the additional deflection produced by steel truss webs′ shearing deformation and shear lag effect may not be ignored; the horizontal inclination angle of abdominal rod only affects the additional deflection caused by steel truss webs′ shearing deformation.

Key words: bridge engineering, concrete composite box girder with steel truss webs, variational method, deflection, shearing deformation, revised longitudinal displacement function of projecting slab

CLC Number:

TU31
U448.21

YANG Xia-lin, ZHANG Yan, JI Wei. Deflection calculation of concrete composite box girder with steel truss webs[J]. Journal of Lanzhou University of Technology, 2020, 46(5): 130-136.

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