Efficient numerical simulation of steel-UHPC composite structures based on a fiber beam-column model

To satisfy the demands of different engineering scenarios, ultra-high performance concrete (UHPC) is usually combined with steel to form various steel-UHPC composite structures. This study proposes an efficient numerical method for simulating steel-UHPC composite structures. A finite element analysis program, SU-COMPONA, is developed, which combines the fiber beam-column model and the concept of smeared cracks. Rational material constitutive laws are proposed and integrated into the program to describe the uniaxial behavior of UHPC and steel fibers. The proposed numerical method is validated against sufficient experimental data for various steelUHPC composite structures, including reinforced UHPC beams and slabs, steel-UHPC composite beams and slabs and steel-UHPC-steel sandwich beams. In addition, the simulation performance is evaluated quantitatively. The results show that the proposed method can predict the ultimate capacity, the load-deflection curve and the development of crack widths with satisfactory accuracy and stability. Compared with the elaborate threedimensional finite element method, the proposed method based on the fiber beam-column model is a competitive numerical approach that can achieve higher efficiency with slightly less accuracy.