Experimental and numerical investigation on the flexural behavior of a large-scale prestressed UHPC T-Shaped girder

Abstract

A large scale (10 m long) prestressed ultra-high-performance-concrete (UHPC) T-shaped girder was experimentally investigated in this paper to study its flexural behavior, cracking moment, and ultimate flexural capacity through the bending test. By considering contribution of the tensile strength of UHPC, this paper suggested a modified tensile constitutive model of UHPC to achieve a reliable cracking moment and ultimate flexural design scheme for the prestressed UHPC girders. Effectiveness of this design scheme was demonstrated through the comparative studies on the developed load–deflection curves and ultimate flexural capacity of the girder obtained from the experimental results and that from the suggested design scheme. In addition, this study developed a nonlinear numerical analysis program to investigate the nonlinear flexural performance of the girder, and its flexural capacity calculated by using this program agreed well with the experimental results. Moreover, parametric studies regarding the influences of reinforcement ratios, prestresses of the prestressing tendons, and girder depths on the girder’s flexural resistance were also conducted. Finally, it is concluded that (1) UHPC girder exhibited good ductility and excellent flexural deformation capacity and cracking performance; (2) the tensile strength of UHPC has limited contribution to the ultimate flexural capacity of UHPC girders; and (3) appropriately increasing reinforcement ratio of the prestressing tendons, ultrahigh compressive strength of UHPC could be fully utilized, and thus the cracking moment and ultimate flexural capacity of UHPC girders could be effectively improved.