Study on Shear-Lag Effect of Steel-UHPC Ribbed Slab Composite Structures Using Bar Simulation Method

Recently, Ultra-High Performance Concrete (UHPC) has attracted increasing attention in civil engineering. Numerous steel-UHPC composite structures have been constructed around the world. The proper consideration of the shear-lag effect has a significant influence on the safety of structures. In view of the shear-lag effect of steel-UHPC ribbed slab composite structure (SURSCS) in the elastic stage, a theoretical calculation model based on the bar simulation method is first developed. Then, the feasibility and accuracy of that are verified using both experimental data and numerical simulation. Moreover, many factors (including width-to-span ratio, the ratio of rib height to UHPC layer thickness, the ratio of rib width to rib spacing, and the number of transverse ribs) are parametrically investigated to further investigate the structural shear-lag effect using the proposed method. In addition, the orthogonal analysis is applied to determine the sensitivity of each parameter to the shear-lag effect. The parametric interactions are also considered. At last, the comparison between calculation results of the proposed method and specifications are discussed. The results show that the proposed approach can accurately predict the shear-lag effect on SU-RSCSs in the elastic stage. It is also found that the width-to-span ratio has a great influence on the structural shear-lag effect, while the number of transverse ribs has no significant influence on that.