Seismic performance of precast interior joints with UHPC composite beams and HSC columns

Abstract

To investigate the seismic performance and shear capacity of precast interior joints with ultra-high performance concrete (UHPC) composite beams and high-strength concrete (HSC) columns, five full-size precast interior joints and one full-size cast-in-place interior joint were fabricated for quasi-static testing. The research examines the impact of the column axial load ratio and post-cast UHPC in the joint core area on seismic performance. The findings reveal that the seismic performance of precast joints is comparable to that of cast-in-place joints. Precast joints exhibit superior resistance to cyclic loading and enhanced stiffness. Post-cast UHPC in the core area of precast joints significantly improves ultimate shear capacity and reduces shear deformation. Similar stiffness and energy dissipation capacities can be attained despite a 40 % reduction in the stirrup ratio within the core area. Increasing the column axial load ratio from 0.3 to 0.5 results in heightened shear capacity for the precast joints and a decrease in shear deformation. The modified simplified softened strut-and-tie model proves to be computationally accurate and is suitable for calculating the shear capacity of the precast joint.