Experimental and numerical investigations on the mechanical properties of precast segmental barriers with UHPC connections

Abstract

A novel precast segmental barrier system was proposed to facilitate the connections between barriers and between the barrier and bridge deck by casting ultra-high-performance concrete joints in situ. To assess the performance of the barrier with this connection, a full-scale pseudo-static tests were conducted. At the same time, a comparative assessment was considered the failure mode and load capacity of the precast barrier for two different bridge deck stiffnesses. The results indicated that the ultimate capacity of the precast barrier was comparable to that of a traditional cast-in-place barrier and emphasised the critical role of the deck slab stiffness in the overall load capacity. Based on the damage patterns observed in the barrier and deck slab during the pseudo-static tests, a refined trapezoidal yield-line model considering the deck slab stiffness contribution was derived to more accurately evaluate the load capacity of a precast segmental barrier. Moreover, the calibrated numerical model of the barrier system was employed to investigate the structural dynamic performance under varying scenarios, specifically examining the effects of different impact masses and velocities. Numerical results demonstrated that upon impact by a high-mass, high-velocity object, the barrier experienced a shift in damage mode from flexural–shear to more critical punching shear. This transition concentrated the dynamic load exclusively on the impacted barrier segment, which in turn markedly diminished its dynamic load capacity.