Flexural Behavior on a Steel-UHPC Composite Deck System of Long-Span Bridges

With rapid economic development in recent decades, long-span bridges have increasingly attracted attention worldwide. The invention of UHPC (ultrahigh performance concrete) materials has brought more alternatives for long-span bridge deck systems. Compared with the traditional orthotropic steel deck, the UHPC-based deck system greatly reduces the risk of deck fatigue cracking. Recently, a steel-UHPC composite bridge deck (SUCD) system using perfobond strip (PBL) shear connectors is proposed, which shows advantages in terms of self-weight and mechanical properties. However, research focusing on this new steel-UHPC composite bridge deck is limited. In this study, based on a field bridge (under construction), eight full-scale slabs for the SUCD are fabricated and tested to investigate the bending behavior of the structure under sagging and hogging moments. The effects of hole spacing in PBL and reinforcement ratio on the flexural behavior of the SUCD are also studied. In addition, the transverse bending behavior of the SUCD is investigated. To accurately predict the cracking moment and bending capacity of the SUCD, a related calculation method considering the hole effect of PBL is developed and validated by the experiment. Compared with other methods, the prediction demonstrates more accurate results. With the proposed prediction method, the effect of a single parameter on the bending performance is analyzed, and the main factors affecting the mechanical behavior of the SUCD are presented. The findings can provide a reference for the design and further study of the SUCD with PBL shear connectors.