Experimental and Numerical Study on Shear Performance of a Full-Scale Thin-Walled Retard-Bonded Prestressed Concrete Box Girder

In order to produce long-span precast bridge members and reduce the transport pressure of precast members, the lightweight design of bridge components has become a key area of research. In this study, utilizing retard-bonded prestressing technology and high-strength concrete, a full-scale thin-walled box girder measuring 30,000 mm in length and 1600 mm in height was designed and fabricated. A shear test with a shear-span ratio of 2.5 was conducted to investigate the failure mode and shear carrying capacity. Subsequently, an Abaqus finite element (FE) model was established and validated with experimental data. Based on the FE model, numerical investigations were conducted to examine the influence of bonding between prestressed steel strands and concrete, stirrup ratio, web thickness and bottom flange thickness at the end of the box girder, concrete strength and length of UHPC end zone on the shear performance of thin-walled box girder. The results indicate that the retard-bonded prestressed box girder exhibits acceptable mechanical performance. Additionally, intensifying the ends of the box girder with ultra-high-performance concrete (UHPC) can further reduce the wall (i.e., web and bottom flange) thickness of the girder, enhance its shear carrying capacity, and achieve lightweighting. This discovery provides new insights into the lightweight design of bridge components.