Fire Performance of Steel-Reinforced Ultrahigh-Toughness Cementitious Composite Columns: Experimental Investigation and Numerical Analyses

Abstract

The fire performances of steel-reinforced ultrahigh-toughness cementitious composite (SRU) columns are investigated and compared with that of steel-reinforced concrete (SRC) columns by experimental and numerical methods in this study while a critical parameter, load ratio, is considered. A three-dimensional finite element (FE) model is developed to simulate the fire behavior of the columns. In the FE modeling, a nonlinear constitutive model for ultrahigh-toughness cementitious composite (UHTCC) under uniaxial compression at elevated temperatures is proposed and adopted. The constitutive model of UHTCC is validated by test results and can be used in FE analyses in further study. A concrete explosive spalling (CES) coefficient is proposed to consider the effect of CES in the fire-resistance prediction for the SRC column in numerical analyses. The results indicate that the fire performance of SRU columns is better than that of SRC columns. The internal temperatures of SRU columns are much lower than those of SRC columns under the same test conditions. Moreover, the temperature difference can reach up to 165°C after 60 min duration in fire. The fire resistance of the SRU column is higher than that of the SRC column under the same axial load ratio of 0.5.