Lightweight design method of orthotropic steel bridge deck with U-ribs based on multi-objective optimization

This paper proposed a lightweight design method for orthotropic steel bridge deck U-ribs. Firstly, the U-rib is analyzed in static structural properties. An analytic hierarchy model was constructed to maximize the stiffness for multi-objective topology optimization. Secondly, a parametric reconfiguration model of the topologically optimized U-rib was established. Finally, static tests are carried out and the performance of the 3D printing scale model was tested. The test results show that the method is effective. Weight of the original model with U-rib is 99.8 kg, and the weight of its optimized model is 76.8 kg. The method achieved a weight reduction of 23% for the U-ribs, and the stiffness still met the permitted conditions. The orthotropic steel bridge deck composed of the optimized U-ribs effectively reduced the weight by 150 kg on the basis of basically unchanged stiffness. The method provides an important reference for the lightweight transformation of assembled bridge structures.