ABSTRACT
With the development of traffic construction in China, curved box girder bridges have been widely applied to the construction of highways and bridges, especially to construction of the overhead viaducts and flyovers in urban areas. Curved box girder has such advantages as great bending rigidity and torsional stiffness, good mechanical performance, large span capacity as well as broad bridge view, so it is widely used at present [1]. In curved box cross-section girder because of the nonuniform distribution [2] of shear deformation along the width of flange plate of the box girder the longitudinal displacement of the frange plate distancing rib plate is slower than that of the frange plate nearing rib plate while bending transverse distribution of bending normal stress takes on curve shape. The phenomenon is called “ Shear Lag Effect” [3]. If influences brought by shear lag is neglected in curved box girder, the actual stress and deflection at the junction of structural web plate and frange plate will be underrated, leading to insecurity in
the effects that the velocity of moving load had on shear lag effect of curved box girder. Sang-Youl Lee [7] carried out the three dimension dynamic analysis of large-span box shaped girder bridge under the action of moving load, and made relevant calculation by using 4-nodes Lagrangian and Hermitian finite element. ZHAO Yun-an [8] analyzed shear lag effect of concrete continuous box girder by using FEM, and carried key research mainly studied the influence that vehicle load types and action position had on shear lag effect of box girder. But the research about simulated vehicle load still remains insufficient, the paper will discuss the distribution regular pattern of mid-span crosssection shear lag effect, and uses the finite element software ANSYS to simulate moving vehicle load with four focused loads at different velocity on value and at different positions moving toward the mid-span cross-section.
