Numerical simulation of rib distortion in orthotropic steel decks

Abstract

When adopting the trapezoidal section of ribs in orthotropic steel decks, the torsional rigidity of ribs losses radically because of rib distortion especially when the load is eccentric from the axis of the rib. Hence, the rib distortion causes high stress concentrations at the rib-to-crossbeam joint which makes this joint easily prone to fatigue. In this paper, the influence of 4 conventional design parameters on distortional behaviour is investigated by numerical simulation adopting the hot spot stress approach and the sub-model analysis technique. A refined finite element model of an orthotropic steel deck specimen with the dimension of 8.2 m ×4.1 m is built. Research results indicate that the distortional stress rises with the increment of the spacing of crossbeam or the weld length of rib-to-crossbeam joint. The thickness of rib is negatively correlated with the distortional stress. The influence of the spacing of rib on distortional stress depends on the relative size between the width of load area and the spacing of rib. The most unfavourable load position is determined by rib geometries, i.e. the thickness of ribs, whereas rest three parameters do not have obvious influence.