Analysis Of Box Girders Research Articles

Transverse Analysis of Box-Girder for Continuous Beam Arch Composite Railway Bridge

A comparative study was carried out by establishing an overall bridge spatial finite element model and a transverse frame model on transverse structural characteristics of Kunyang Bridge on Wenzhou-Fuzhou Railway line. The longitudinal variation of transverse stress in box-girder shows peaks distribution. The absolute values of transverse stress decrease gradually at peaks and valleys in overall tendency as it’s close to the mid span. The calculation results of the rigid support frame method can envelop the calculation results of the overall bridge spatial finite element model in side span region without suspenders.It verifies the reasonability of the rigid support frame method to calculate transverse stress of this region. And the width of transverse frame should designate one third of suspender spacing or more in transverse stress calculations of central span region with suspenders.

Dynamic analysis of box girders with tee-stiffening using unconstrained optimization techniques

The paper presents a numerical procedure for dynamic analysis of box girders with tee-stiffeners utilizing unconstrained optimization techniques. Unlike the finite element or finite strip methods, the procedure does not require discretization to the whole structure, thus resulting in great savings in computational time. The potential and kinetic energy of the assembled structure is expressed in terms generalized functions that describe the longitudinal and transverse displacement profiles. The problem is then converted into uunconstrained optimization problem to determine the magnitude of the lowest natural frequency and the associated mode shape. Results are presented showing the sensitivity the natural frequency to the stiffener depth (d) and the flange width (b). It is shown that the number of longitudinal and transverse stiffeners largely influence the magnitude of the natural frequency (λ) of the box girder. Design guidelines are also provided to optimize the dynamic response of the structure. The procedure is very practical and can be utilized in the industry for the analysis of box girders.

Simplified analysis of FRP box-girders

Box-girder analysis and design should take into consideration stresses due to longitudinal bending moment, shear force, torsion, distortion, shear-lag and transverse bending as well as instability of the flange under compression and web under shear as plates and stiffened panels. The orthotropic nature of FRP has to be taken into consideration in all these analyses. Although general purpose finite element software can be used to accurately analyse such a bridge considering all these effects, the time consumed is too high to practically use it in the preliminary and optimum design stages, which involve a large number of trials. A simplified and computationally efficient procedure for the analysis of single cell FRP box-girder bridges made of blade angle or T stiffened panels, for efficient use at these stages, is presented in this paper. This has been validated by comparison with results available in literature or results obtained from finite element analysis.

Extended Trigonometric Series Analysis of Box Girders with Diaphragms

An analytical procedure is presented for the analysis of thin-walled box girders with intermediate diaphragms. The girders are regarded as an assemblage of thin plates, that is, thin-plate theory is applied to the analysis of all members: flanges, webs, and diaphragms. Particular consideration is focused on geometrical and force boundary conditions on the edges of a diaphragm, which cannot be evaluated rigorously by using the ordinary Fourier analysis. The extended trigonometric series analysis presented here makes it possible to seek the analytical solution for the box girders with diaphragms under any end-support conditions and any loading conditions. Numerical examples demonstrate that the extended trigonometric series analysis is essential and quite effective to the analysis of thin-walled box girders with diaphragms.

EBEF Method for Distortional Analysis of Steel Box Girder Bridges

A practical approach to the distortional analysis of steel box girders is presented herein. The EBEF (equivalent beam on elastic foundation) method is an enhancement of the BEF (beam on elastic foundation) method, which has been widely used in design practice. Using the EBEF method on closed (or quasi-closed) box girder analysis provides a simplified procedure to account for the deformation of the cross section for the effect of rigid or flexible interior diaphragms and continuity over the supports. The methodology, numerical examples, and stiffness matrix are also presented in this paper.