Experiment And Analysis Of Shear-lag Effect Of The Steel-concrete Composite Box Girder

The steel-concrete composite beam has some merits, such as light weight, better economical efficiency and constructs convenience. Shear lag effect of steel-concrete box girder is important problem in bridge structure designing and construction. Its value influences the bearing capacity and vertical deflection of the beam directly. As the shear lag effect, the stress distribution across section of concrete flange is not the same as obtained in mechanics of materials which is even everywhere. The study about shear lags effect of steel-concrete box girder in and abroad are mostly based on theory of elasticity butIn the paper two 1/12 models of steel-concrete composite beam according to actual project was fabricated. The main conclusion drawn from the elastic and plastic test on steel-concrete box girder as follows: 1. The influence of transverse diaphragm design on shear lag of the composite beam is not great. 2. The influence of lateral loading position on the shear lags effect of steel-concrete composite beam is great. 3. The further from the loading position, the effect of the shear lag is less.4.Compared with steel box beam, the shear lag effect on the composite box beam is less. 5. The effect of shear lags on top flange decrease with load increasing. However,The effect of shear lag on bottom flange keep instant.In this paper, finite element model for steel-concrete composite beam are established by solid65 and shell43 based on laboratory experiment. The calculated results are compared with experimental ones, which agree very well. In general, the simulated load-deformation curves, stress distribution rules are corresponding well with experimental results. This will be helpful for parameter analysis study on shear lag effects of steel-concrete composite beam.