Axial compressive property of UHPC plate-CFST laced composite columns

An experimental and analytical investigation of ultrahigh-performance concrete (UHPC) plate-concrete-filled steel tubular (CFST) laced composite columns are presented in this study. A total of 11 stub specimens under axial compression are conducted to quantify the column failure mechanism. Experimental results indicate that the compressive behavior in the UHPC plate dominated the failure mechanism of the UHPC composite columns, and the failure mode is dependent on the peak strain of the UHPC plate and CFST limb. The two main parameters in the tests are the thickness of the steel tube (t) and UHPC plates (tp), which significantly enhance the bearing capacity of UHPC composite columns. Herein, the finite element standard model is established to investigate the influence of various parameters on the compressive behavior of UHPC composite columns. The diameter of the steel tube D is the most sensitive parameter affecting the structural compressive performance, while the ratio of steel reinforcing bars has an ignorable influence on the compressive strength. Based on the ultimate limit states and parametric analysis, a unified formula for predicting the strength of UHPC composite columns is proposed, which is generally in good agreement with the experimental results.