Experimental and analytical studies on a streamlined steel box girder

A new type of streamlined girder (lenticular cross-section) bridge with a thin-walled steel box girder is proposed. In order to deal with the problem of increasing traffic congestion, this bridge is designed with a large width-to-span ratio, which results in significant shear lag effects and causes non-uniform stress distribution in the three-cell thin-walled box girder, especially along the flanges of the girder. The aim of this study is to investigate the effect of shear lag in thin-walled box girder bridges with large width-to-span ratios through both experimental and numerical studies. A large-scale Plexiglas model is tested under different loading cases. The material parameters are obtained from physical characteristics tests and tensile tests. In addition, a computational model is presented for a comprehensive simulation of a girder bridge including the orthotropic top/bottom/web plates and their ribs, which leads to accurate modeling of structural properties of the girder. The simulation of the computation results compared well with the experimental results. It is illustrated that the finite element analysis is an effective method to predict properties of this class of bridges.